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# 05 – Object-Oriented Programming (OOP) in Python
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This document explains the basics of **Object-Oriented Programming (OOP)** in Python using simple examples.
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We cover:
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* Classes and objects
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* Attributes and methods
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* Class attributes vs instance attributes
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* Inheritance
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* Special (magic) methods
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---
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## 1. Basic Class, Attribute, and Method
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### Code
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```python
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class test_class():
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def __init__(self, input):
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self.parm = input
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print("Class Created")
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def result(self):
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print(f"param is : {self.parm}")
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var = test_class('abbas')
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var.result()
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```
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### Explanation
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#### Class
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* `test_class` is a **class**, which acts as a blueprint for creating objects.
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#### `__init__` method (Constructor)
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* `__init__` is a **special method** that runs automatically when a new object is created.
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* `input` is a **parameter** passed when creating the object.
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* `self.parm = input` creates an **instance attribute** called `parm`.
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#### Attribute
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* `parm` is an **attribute** (a variable that belongs to the object).
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* It stores data specific to each object.
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#### Method
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* `result()` is a **method** (a function that belongs to the class).
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* It uses `self.parm` to access the object’s data.
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#### Object Creation
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```python
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var = test_class('abbas')
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```
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* Creates an object named `var`.
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* Calls `__init__` automatically.
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#### Method Call
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```python
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var.result()
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```
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* Calls the `result` method on the object.
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---
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## 2. Class Attributes vs Instance Attributes
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### Code
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```python
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class test_class():
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test_value = 'abbas'
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def __init__(self, input):
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self.parm = input
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print("Class Created")
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def result(self):
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print(f"param is : {self.parm}")
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var = test_class('abbas')
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var2 = test_class('mmd')
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var.result()
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var.test_value
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var2.test_value = 'mmd'
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var2.test_value
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var.test_value
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```
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### Explanation
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#### Class Attribute
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```python
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test_value = 'abbas'
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```
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* This is a **class attribute**.
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* It belongs to the class itself.
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* Shared by all objects unless overridden.
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#### Instance Attribute
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```python
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self.parm = input
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```
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* This is an **instance attribute**.
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* Each object has its own value.
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#### Behavior Analysis
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```python
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var.test_value
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```
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* Accesses the class attribute → `'abbas'`
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```python
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var2.test_value = 'mmd'
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```
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* Creates a **new instance attribute** for `var2`.
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* Does not change the class attribute.
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```python
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var2.test_value
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```
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* Returns `'mmd'` (instance attribute)
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```python
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var.test_value
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```
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* Still returns `'abbas'` (class attribute)
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#### Key Rule
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* Instance attributes override class attributes **only for that object**.
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---
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## 3. Inheritance
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### Code
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```python
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class class_1():
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def __init__(self):
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print("Class 1 Created")
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def hi(self):
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print("Hi")
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class class_2(class_1):
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def __init__(self):
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print("Class 2 Created")
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self.hi()
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b = class_2()
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```
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### Explanation
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#### Parent Class
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```python
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class class_1():
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```
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* `class_1` is the **parent (base) class**.
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#### Child Class
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```python
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class class_2(class_1):
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```
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* `class_2` **inherits** from `class_1`.
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* It automatically has access to all public methods of `class_1`.
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#### Method Usage
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```python
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self.hi()
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```
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* `hi()` is defined in `class_1`.
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* Because of inheritance, `class_2` can call it.
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#### Output Order
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```text
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Class 2 Created
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Hi
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```
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#### Important Note
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* `class_1.__init__()` is **not called automatically** here.
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* To call it, you would need:
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```python
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super().__init__()
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```
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---
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## 4. Special (Magic) Methods
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### Code
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```python
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class class_1():
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def __init__(self):
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print("Class 1 Created")
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def __len__(self):
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return 1
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def __str__(self):
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return 'print command on class'
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def __del__(self):
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return 'on del value'
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```
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### Explanation
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Special methods start and end with **double underscores (`__`)** and control built-in behavior.
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#### `__init__`
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* Runs when an object is created.
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#### `__len__`
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```python
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len(object)
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```
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* Defines the behavior of `len()` on the object.
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* Returns `1` in this example.
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#### `__str__`
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```python
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print(object)
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```
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* Defines the string representation of the object.
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* Used by `print()` and `str()`.
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#### `__del__`
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* Runs when the object is deleted or garbage-collected.
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* Used rarely in modern Python.
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* Return value is ignored.
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---
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## Summary
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* **Class**: Blueprint for objects
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* **Object**: Instance of a class
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* **Attribute**: Data stored in an object
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* **Method**: Function inside a class
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* **Class Attribute**: Shared across all objects
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* **Instance Attribute**: Unique per object
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* **Inheritance**: Child class reuses parent class logic
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* **Magic Methods**: Customize built-in Python behavior
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@@ -1,218 +0,0 @@
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# 06 – Packages and Modules in Python
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This document explains how **modules**, **packages**, and the `__name__` concept work in Python.
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These features help organize code, reuse functionality, and build scalable projects.
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---
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## 1. Importing External Modules
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Python allows you to import **external libraries** installed in your environment.
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### Example: Using the `emoji` Module
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### Code
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```python
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import emoji
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print(emoji.emojize("abbas is :red_heart:"))
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```
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### Explanation
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* `import emoji` imports the entire `emoji` module.
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* `emoji.emojize()` converts emoji aliases into actual emoji characters.
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* You must use the module name (`emoji`) to access its functions.
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---
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### Importing a Specific Function
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### Code
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|
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```python
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from emoji import emojize
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print(emojize("abbas is :red_heart:"))
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```
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### Explanation
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* `from emoji import emojize` imports only the `emojize` function.
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* You can call the function directly without prefixing the module name.
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* This approach is cleaner when you only need a specific function.
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---
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## 2. Creating a Module
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A **module** is a single Python file containing functions, classes, or variables.
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### File Structure
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```
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hi.py
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main.py
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```
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### `hi.py`
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```python
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def hi():
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print("Hi :)")
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```
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### `main.py`
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```python
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import hi
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hi.hi()
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```
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### Explanation
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* `hi.py` is a module.
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* `hi()` is a function defined inside the module.
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* `import hi` loads the module.
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* `hi.hi()` calls the function from the module.
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---
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## 3. Creating a Package
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A **package** is a directory that contains multiple modules.
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### Package Structure
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|
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```
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honor/
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│── __init__.py
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│── hi.py
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main.py
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```
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|
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### `honor/hi.py`
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|
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```python
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def hello():
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print("Hi :)")
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```
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|
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### `honor/__init__.py`
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|
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```python
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```
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|
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### Explanation
|
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|
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* The `honor` directory is a package.
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* `__init__.py` tells Python that this directory is a package.
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* The file can be empty, but it **must exist** (especially for older Python versions and clarity).
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|
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---
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|
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### Importing from a Package (Method 1)
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|
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### `main.py`
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|
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```python
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from honor import hi
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hi.hello()
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```
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|
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#### Explanation
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|
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* Imports the `hi` module from the `honor` package.
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* Accesses the function using `hi.hello()`.
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|
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---
|
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|
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### Importing from a Package (Method 2)
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|
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### `main.py`
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|
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```python
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from honor.hi import hello
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hello()
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```
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||||
|
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#### Explanation
|
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|
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* Imports the `hello` function directly.
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* Allows calling the function without the module name.
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* Cleaner when only one function is needed.
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|
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---
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## 4. The `__name__` Concept
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|
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Every Python file has a built-in variable called `__name__`.
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|
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### Code
|
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|
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```python
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print(__name__)
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```
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|
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### Behavior
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|
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#### When a File Is Run Directly
|
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|
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```bash
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python3 abbas.py
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```
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|
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Output:
|
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|
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```text
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__main__
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```
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|
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* This means the file is the **entry point** of the program.
|
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|
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#### When a File Is Imported
|
||||
|
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```python
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import abbas
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```
|
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|
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Output:
|
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|
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```text
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abbas
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```
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|
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* `__name__` is set to the **module name**, not `__main__`.
|
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|
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---
|
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|
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## 5. Why `__name__ == "__main__"` Is Important
|
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|
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This pattern allows code to run **only when the file is executed directly**, not when imported.
|
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|
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### Example
|
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|
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```python
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def main():
|
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print("Running directly")
|
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|
||||
if __name__ == "__main__":
|
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main()
|
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```
|
||||
|
||||
### Explanation
|
||||
|
||||
* The code inside the `if` block runs only when the file is executed directly.
|
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* Prevents unwanted execution when the file is imported as a module.
|
||||
* This is a standard Python best practice.
|
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|
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---
|
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|
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## Summary
|
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|
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* **Module**: A single `.py` file
|
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* **Package**: A directory containing modules
|
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* `__init__.py`: Marks a directory as a package
|
||||
* `import module`: Imports the whole module
|
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* `from module import item`: Imports specific items
|
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* `__name__`: Identifies how a file is executed
|
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|
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@@ -1,219 +0,0 @@
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# 06 – Error Handling, Linting, Formatting, and Testing in Python
|
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|
||||
This document explains how Python handles runtime errors, how to write safer code using `try / except`, and how to improve code quality using **linting**, **formatting**, and **unit testing** tools.
|
||||
|
||||
---
|
||||
|
||||
## 1. Error Handling with `try / except`
|
||||
|
||||
Python uses `try / except` blocks to handle runtime errors gracefully without crashing the program.
|
||||
|
||||
### Example
|
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|
||||
```python
|
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def abbas(a, b):
|
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try:
|
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res = a / b
|
||||
print(res)
|
||||
except ZeroDivisionError:
|
||||
print("Zero Number Detected")
|
||||
except Exception as e:
|
||||
print(f"Error Detected {e}")
|
||||
|
||||
abbas(1, 0)
|
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```
|
||||
|
||||
### Explanation
|
||||
|
||||
* The code inside `try` is executed first.
|
||||
* If no error occurs, the result is printed.
|
||||
* If `b` is `0`, a `ZeroDivisionError` is raised.
|
||||
* The specific `ZeroDivisionError` block runs first.
|
||||
* Any other error is caught by the generic `Exception` block.
|
||||
|
||||
### Key Rule
|
||||
|
||||
* Always catch **specific exceptions first**.
|
||||
* Use `Exception` only as a fallback.
|
||||
|
||||
---
|
||||
|
||||
## 2. Full `try / except` Structure
|
||||
|
||||
Python supports additional blocks for more control.
|
||||
|
||||
### Syntax
|
||||
|
||||
```python
|
||||
try:
|
||||
# code that may raise an error
|
||||
except:
|
||||
# runs if an error occurs
|
||||
else:
|
||||
# runs if no error occurs
|
||||
finally:
|
||||
# always runs
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
* `try`: code that may fail
|
||||
* `except`: handles errors
|
||||
* `else`: runs only if no exception occurred
|
||||
* `finally`: runs no matter what (used for cleanup)
|
||||
|
||||
---
|
||||
|
||||
## 3. Linting with `pylint`
|
||||
|
||||
Linting analyzes code for:
|
||||
|
||||
* Syntax errors
|
||||
* Style problems
|
||||
* Bad practices
|
||||
|
||||
### Basic Command
|
||||
|
||||
```bash
|
||||
pylint main.py
|
||||
```
|
||||
|
||||
### Detailed Report
|
||||
|
||||
```bash
|
||||
pylint --report y main.py
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
* `pylint` gives a score and suggestions.
|
||||
* Helps maintain readable and maintainable code.
|
||||
* Commonly used in professional Python projects.
|
||||
|
||||
---
|
||||
|
||||
## 4. Code Formatting with `black`
|
||||
|
||||
`black` is an automatic code formatter that enforces a consistent style.
|
||||
|
||||
### Command
|
||||
|
||||
```bash
|
||||
black main.py
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
* Reformats code automatically.
|
||||
* Removes style debates.
|
||||
* Safe and widely used.
|
||||
|
||||
---
|
||||
|
||||
## 5. Unit Testing with `unittest`
|
||||
|
||||
Unit tests verify that individual parts of code behave as expected.
|
||||
|
||||
---
|
||||
|
||||
### Application Code
|
||||
|
||||
#### `abbas.py`
|
||||
|
||||
```python
|
||||
def bemola(a, b):
|
||||
try:
|
||||
res = a / b
|
||||
print(res)
|
||||
except ZeroDivisionError:
|
||||
print("Zero Number Detected")
|
||||
except Exception as e:
|
||||
print(f"Error Detected {e}")
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
### Test Code
|
||||
|
||||
#### `abbas_test.py`
|
||||
|
||||
```python
|
||||
import unittest
|
||||
from abbas import bemola
|
||||
|
||||
class TestAbbas(unittest.TestCase):
|
||||
|
||||
def test_bemola(self):
|
||||
a = 10
|
||||
b = 2
|
||||
self.assertEqual(bemola(a, b), 5)
|
||||
|
||||
if __name__ == "__main__":
|
||||
unittest.main()
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
### Explanation
|
||||
|
||||
#### `unittest.TestCase`
|
||||
|
||||
* Base class for writing test cases.
|
||||
|
||||
#### Test Method
|
||||
|
||||
```python
|
||||
def test_bemola(self):
|
||||
```
|
||||
|
||||
* Test methods must start with `test_`.
|
||||
|
||||
#### Assertion
|
||||
|
||||
```python
|
||||
self.assertEqual(bemola(a, b), 5)
|
||||
```
|
||||
|
||||
* Checks if the function returns the expected result.
|
||||
|
||||
---
|
||||
|
||||
### Important Note (Design Issue)
|
||||
|
||||
The function `bemola` **prints** the result but does not return it.
|
||||
|
||||
```python
|
||||
print(res)
|
||||
```
|
||||
|
||||
This causes the test to fail because the function returns `None`.
|
||||
|
||||
#### Correct Implementation
|
||||
|
||||
```python
|
||||
def bemola(a, b):
|
||||
try:
|
||||
return a / b
|
||||
except ZeroDivisionError:
|
||||
return "Zero Number Detected"
|
||||
except Exception as e:
|
||||
return f"Error Detected {e}"
|
||||
```
|
||||
|
||||
This version:
|
||||
|
||||
* Returns values instead of printing
|
||||
* Is testable
|
||||
* Follows best practices
|
||||
|
||||
---
|
||||
|
||||
## Summary
|
||||
|
||||
* `try / except` prevents program crashes
|
||||
* `else` runs only when no error occurs
|
||||
* `finally` always runs
|
||||
* `pylint` improves code quality
|
||||
* `black` enforces formatting
|
||||
* `unittest` verifies correctness
|
||||
* Functions should **return values**, not print them, when tested
|
||||
@@ -1,182 +0,0 @@
|
||||
# 08 – Decorators in Python
|
||||
|
||||
This document explains **decorators**, how they work, and how they are used to extend function behavior without modifying the original function code.
|
||||
|
||||
---
|
||||
|
||||
## 1. What Is a Decorator?
|
||||
|
||||
A **decorator** is a function that:
|
||||
|
||||
* Takes another function as input
|
||||
* Adds extra behavior
|
||||
* Returns a new function
|
||||
|
||||
Decorators are commonly used for:
|
||||
|
||||
* Input validation
|
||||
* Logging
|
||||
* Authentication
|
||||
* Performance measurement
|
||||
* Access control
|
||||
|
||||
---
|
||||
|
||||
## 2. Basic Decorator Structure
|
||||
|
||||
A decorator has three layers:
|
||||
|
||||
1. The decorator function
|
||||
2. The wrapper function
|
||||
3. The original function
|
||||
|
||||
### General Pattern
|
||||
|
||||
```python
|
||||
def decorator(func):
|
||||
def wrapper(*args, **kwargs):
|
||||
# extra behavior
|
||||
return func(*args, **kwargs)
|
||||
return wrapper
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 3. Example: Input Validation Decorator
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
def check_number(func):
|
||||
def wrapper(a, b):
|
||||
if not (isinstance(a, (int, float)) and isinstance(b, (int, float))):
|
||||
print("Input must be numbers")
|
||||
return
|
||||
return func(a, b)
|
||||
return wrapper
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
* `check_number` is the decorator.
|
||||
* `func` is the function being decorated.
|
||||
* `wrapper` replaces the original function.
|
||||
* `a` and `b` are the arguments passed to the original function.
|
||||
* `isinstance(a, (int, float))` ensures inputs are numeric.
|
||||
* If validation fails, execution stops.
|
||||
* If validation passes, the original function is called.
|
||||
|
||||
---
|
||||
|
||||
## 4. Using the Decorator with `@` Syntax
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
@check_number
|
||||
def bemola(a, b):
|
||||
try:
|
||||
res = a / b
|
||||
print(res)
|
||||
except ZeroDivisionError:
|
||||
print("Zero Number Detected")
|
||||
except Exception as e:
|
||||
print(f"Error Detected {e}")
|
||||
```
|
||||
|
||||
### What Happens Internally
|
||||
|
||||
This line:
|
||||
|
||||
```python
|
||||
@check_number
|
||||
```
|
||||
|
||||
Is equivalent to:
|
||||
|
||||
```python
|
||||
bemola = check_number(bemola)
|
||||
```
|
||||
|
||||
The function `bemola` is replaced by `wrapper`.
|
||||
|
||||
---
|
||||
|
||||
## 5. Execution Flow
|
||||
|
||||
When calling:
|
||||
|
||||
```python
|
||||
bemola(10, 2)
|
||||
```
|
||||
|
||||
The flow is:
|
||||
|
||||
1. `wrapper(10, 2)` is called
|
||||
2. Inputs are validated
|
||||
3. `func(10, 2)` is executed
|
||||
4. Result is printed
|
||||
|
||||
If calling:
|
||||
|
||||
```python
|
||||
bemola(10, "a")
|
||||
```
|
||||
|
||||
The output will be:
|
||||
|
||||
```text
|
||||
Input must be numbers
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 6. Why Use Decorators?
|
||||
|
||||
Without decorators, input validation would need to be repeated in every function.
|
||||
|
||||
Decorators allow:
|
||||
|
||||
* Reusable logic
|
||||
* Cleaner code
|
||||
* Separation of concerns
|
||||
|
||||
---
|
||||
|
||||
## 7. Limitations in This Example
|
||||
|
||||
* The decorator only works with exactly two arguments.
|
||||
* It does not preserve the original function’s metadata (`__name__`, `__doc__`).
|
||||
|
||||
---
|
||||
|
||||
## 8. Improved Version (Best Practice)
|
||||
|
||||
```python
|
||||
from functools import wraps
|
||||
|
||||
def check_number(func):
|
||||
@wraps(func)
|
||||
def wrapper(*args, **kwargs):
|
||||
if not all(isinstance(x, (int, float)) for x in args):
|
||||
print("Input must be numbers")
|
||||
return
|
||||
return func(*args, **kwargs)
|
||||
return wrapper
|
||||
```
|
||||
|
||||
### Improvements
|
||||
|
||||
* Supports any number of arguments
|
||||
* Preserves function name and documentation
|
||||
* More reusable and professional
|
||||
|
||||
---
|
||||
|
||||
## Summary
|
||||
|
||||
* Decorators modify function behavior without changing its code
|
||||
* They wrap functions inside another function
|
||||
* `@decorator` is syntactic sugar
|
||||
* Commonly used for validation, logging, and access control
|
||||
* Best practice is to use `*args`, `**kwargs`, and `functools.wraps`
|
||||
@@ -1,266 +0,0 @@
|
||||
# 09 – Python Standard Library
|
||||
|
||||
This document introduces some of the most commonly used **Python standard library** modules:
|
||||
|
||||
* `datetime`
|
||||
* `math`
|
||||
* `random`
|
||||
* `decimal`
|
||||
|
||||
These modules come bundled with Python and require no external installation.
|
||||
|
||||
---
|
||||
|
||||
## 1. Date and Time with `datetime`
|
||||
|
||||
The `datetime` module provides classes for working with dates and times.
|
||||
|
||||
---
|
||||
|
||||
### Working with Dates
|
||||
|
||||
#### Code
|
||||
|
||||
```python
|
||||
import datetime
|
||||
|
||||
date_1 = datetime.date(2026, 1, 1)
|
||||
|
||||
print(date_1.year)
|
||||
print(date_1.month)
|
||||
print(date_1.day)
|
||||
|
||||
print(date_1.weekday)
|
||||
print(date_1.ctime)
|
||||
```
|
||||
|
||||
#### Explanation
|
||||
|
||||
* `datetime.date(year, month, day)` creates a date object.
|
||||
* `.year`, `.month`, `.day` access individual components.
|
||||
|
||||
#### Important Note
|
||||
|
||||
```python
|
||||
date_1.weekday()
|
||||
```
|
||||
|
||||
* Returns the day of the week as an integer:
|
||||
|
||||
* Monday = 0
|
||||
* Sunday = 6
|
||||
|
||||
```python
|
||||
date_1.ctime()
|
||||
```
|
||||
|
||||
* Returns a human-readable string representation of the date.
|
||||
|
||||
---
|
||||
|
||||
### Working with Time
|
||||
|
||||
#### Code
|
||||
|
||||
```python
|
||||
time_1 = datetime.time(12, 12)
|
||||
|
||||
print(time_1.hour)
|
||||
print(time_1.min)
|
||||
```
|
||||
|
||||
#### Explanation
|
||||
|
||||
* `datetime.time(hour, minute)` creates a time object.
|
||||
* `.hour` returns the hour.
|
||||
* `.minute` returns the minute.
|
||||
|
||||
---
|
||||
|
||||
### Working with Date and Time Together
|
||||
|
||||
#### Code
|
||||
|
||||
```python
|
||||
abbas_birth = datetime.datetime(2026, 1, 1, 12, 12)
|
||||
today = datetime.date.today()
|
||||
now = datetime.datetime.now()
|
||||
|
||||
diff_time = now - abbas_birth
|
||||
```
|
||||
|
||||
#### Explanation
|
||||
|
||||
* `datetime.datetime` includes both date and time.
|
||||
* `date.today()` returns today’s date.
|
||||
* `datetime.now()` returns the current date and time.
|
||||
* Subtracting two `datetime` objects returns a `timedelta`.
|
||||
|
||||
---
|
||||
|
||||
## 2. Mathematical Operations with `math`
|
||||
|
||||
The `math` module provides advanced mathematical functions and constants.
|
||||
|
||||
---
|
||||
|
||||
### Mathematical Constants
|
||||
|
||||
```python
|
||||
import math
|
||||
|
||||
print(math.pi)
|
||||
print(math.e)
|
||||
print(math.inf)
|
||||
```
|
||||
|
||||
* `math.pi`: π constant
|
||||
* `math.e`: Euler’s number
|
||||
* `math.inf`: infinity
|
||||
|
||||
---
|
||||
|
||||
### Power and Rounding
|
||||
|
||||
```python
|
||||
print(math.pow(2, 3))
|
||||
|
||||
print(round(4.2))
|
||||
print(round(4.8))
|
||||
```
|
||||
|
||||
* `math.pow(a, b)` returns `a` raised to the power of `b`.
|
||||
* `round()` rounds to the nearest integer.
|
||||
|
||||
---
|
||||
|
||||
### Floor and Ceil
|
||||
|
||||
```python
|
||||
print(math.floor(4.2))
|
||||
print(math.floor(4.9))
|
||||
|
||||
print(math.ceil(4.2))
|
||||
print(math.ceil(4.9))
|
||||
```
|
||||
|
||||
* `floor`: rounds down
|
||||
* `ceil`: rounds up
|
||||
|
||||
---
|
||||
|
||||
### Logarithms
|
||||
|
||||
```python
|
||||
print(math.log(100, 10))
|
||||
```
|
||||
|
||||
* Returns the logarithm of 100 with base 10.
|
||||
|
||||
---
|
||||
|
||||
## 3. Random Values with `random`
|
||||
|
||||
The `random` module is used to generate pseudo-random values.
|
||||
|
||||
---
|
||||
|
||||
### Random Numbers
|
||||
|
||||
```python
|
||||
import random
|
||||
|
||||
print(random.randint(1, 6))
|
||||
print(random.random())
|
||||
```
|
||||
|
||||
* `randint(a, b)`: random integer between `a` and `b` (inclusive)
|
||||
* `random()`: random float between `0` and `1`
|
||||
|
||||
---
|
||||
|
||||
### Random Selection
|
||||
|
||||
```python
|
||||
number_list = list(range(15))
|
||||
print(random.choice(number_list))
|
||||
|
||||
char_list = ['a', 'm', 's']
|
||||
print(random.choice(char_list))
|
||||
```
|
||||
|
||||
* `choice()` selects a random element from a sequence.
|
||||
|
||||
---
|
||||
|
||||
### Shuffling
|
||||
|
||||
```python
|
||||
random.shuffle(number_list)
|
||||
print(number_list)
|
||||
```
|
||||
|
||||
* `shuffle()` randomly rearranges the list in place.
|
||||
|
||||
---
|
||||
|
||||
## 4. Decimal Precision with `decimal`
|
||||
|
||||
The `decimal` module provides precise decimal arithmetic, avoiding floating-point errors.
|
||||
|
||||
---
|
||||
|
||||
### Decimal Context
|
||||
|
||||
```python
|
||||
import decimal
|
||||
|
||||
print(decimal.getcontext())
|
||||
```
|
||||
|
||||
* Shows current precision and rounding settings.
|
||||
|
||||
---
|
||||
|
||||
### Float vs Decimal
|
||||
|
||||
```python
|
||||
print(decimal.Decimal(0.1))
|
||||
print(decimal.Decimal('0.1'))
|
||||
```
|
||||
|
||||
* Passing a float carries floating-point error.
|
||||
* Passing a string preserves exact value.
|
||||
|
||||
---
|
||||
|
||||
### Precision Comparison
|
||||
|
||||
```python
|
||||
print(0.1 + 0.2 == 0.3)
|
||||
```
|
||||
|
||||
Returns `False` due to floating-point precision issues.
|
||||
|
||||
```python
|
||||
print(decimal.Decimal(0.1) + decimal.Decimal(0.2) == decimal.Decimal(0.3))
|
||||
```
|
||||
|
||||
Still `False` because the floats are imprecise.
|
||||
|
||||
```python
|
||||
print(decimal.Decimal('0.1') + decimal.Decimal('0.2') == decimal.Decimal('0.3'))
|
||||
```
|
||||
|
||||
Returns `True` because strings preserve precision.
|
||||
|
||||
---
|
||||
|
||||
## Summary
|
||||
|
||||
* `datetime` handles dates and times
|
||||
* `math` provides mathematical constants and functions
|
||||
* `random` generates pseudo-random values
|
||||
* `decimal` solves floating-point precision problems
|
||||
* Always use strings when creating `Decimal` values
|
||||
|
||||
@@ -0,0 +1,68 @@
|
||||
```python
|
||||
import docker
|
||||
import time
|
||||
|
||||
docker_client = docker.DockerClient(base_url="unix://var/run/docker.sock")
|
||||
docker_client.ping()
|
||||
|
||||
print("All Networks:\n")
|
||||
|
||||
all_networks = docker_client.networks.list()
|
||||
|
||||
for network in all_networks:
|
||||
print(network.name, network.id)
|
||||
|
||||
print("\nNetworks Named host and bridge:\n")
|
||||
|
||||
system_networks = docker_client.networks.list(names=["host", "bridge"])
|
||||
|
||||
for network in system_networks:
|
||||
print(network.name, network.id)
|
||||
|
||||
print("\nNetwork With Custom ID:\n")
|
||||
|
||||
custom_id_networks = docker_client.networks.list(
|
||||
ids=["29c9e588bb8e0db6445f2a2278a1c2f42e39dc163c0a404f744dc4139fe47d21"]
|
||||
)
|
||||
|
||||
for network in custom_id_networks:
|
||||
print(network.name, network.id)
|
||||
|
||||
print("\nNetwork With Custom ID (Including Attributes):\n")
|
||||
|
||||
custom_id_networks = docker_client.networks.list(
|
||||
ids=["29c9e588bb8e0db6445f2a2278a1c2f42e39dc163c0a404f744dc4139fe47d21"]
|
||||
)
|
||||
|
||||
for network in custom_id_networks:
|
||||
print(network.name, network.id, network.attrs)
|
||||
|
||||
print("\nNetwork With Custom Filter:\n")
|
||||
|
||||
filtered_networks = docker_client.networks.list(
|
||||
names=["gitea_default"],
|
||||
filters={"driver": "bridge"}
|
||||
)
|
||||
|
||||
for network in filtered_networks:
|
||||
if network.attrs["Driver"]:
|
||||
print(network.name, network.id)
|
||||
|
||||
print("\nNetwork With Custom Filter (Greedy):\n")
|
||||
|
||||
filtered_networks = docker_client.networks.list(
|
||||
names=["gitea_default"],
|
||||
filters={"driver": "bridge"},
|
||||
greedy=True
|
||||
)
|
||||
|
||||
for network in filtered_networks:
|
||||
if network.attrs["Driver"]:
|
||||
print(network.name, network.id, network.attrs)
|
||||
|
||||
```
|
||||
|
||||
|
||||
```python
|
||||
|
||||
```
|
||||
@@ -1,22 +1,12 @@
|
||||
# FastAPI – Simple Route Example
|
||||
|
||||
## Overview
|
||||
|
||||
This document explains how to create a basic FastAPI application with a single HTTP route and how to run it using `uvicorn`.
|
||||
|
||||
FastAPI is an ASGI web framework, and `uvicorn` is commonly used as the ASGI server to run FastAPI applications.
|
||||
This document demonstrates how to create a basic FastAPI application with a single HTTP route and how to run it using `uvicorn`, which is the default and recommended ASGI server for FastAPI.
|
||||
|
||||
---
|
||||
|
||||
# 1. Create a Simple FastAPI Application
|
||||
## Create a Simple FastAPI Application
|
||||
|
||||
Create a Python file named:
|
||||
|
||||
```text
|
||||
main.py
|
||||
```
|
||||
|
||||
Add the following code:
|
||||
Create a Python file named `main.py` and add the following content:
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI
|
||||
@@ -29,243 +19,72 @@ def home_dir():
|
||||
return {"message": "Home Page"}
|
||||
```
|
||||
|
||||
---
|
||||
### Explanation
|
||||
|
||||
# 2. Code Explanation
|
||||
|
||||
## Import FastAPI
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI
|
||||
```
|
||||
|
||||
This imports the `FastAPI` class from the FastAPI package.
|
||||
* `FastAPI()` initializes the application instance.
|
||||
* `@app.get("/")` registers an HTTP GET endpoint at the root path (`/`).
|
||||
* The `home_dir` function is the request handler and returns a JSON response.
|
||||
* FastAPI automatically handles JSON serialization and response headers.
|
||||
|
||||
---
|
||||
|
||||
## Create the Application Instance
|
||||
## Running the Application
|
||||
|
||||
```python
|
||||
app = FastAPI()
|
||||
```
|
||||
FastAPI applications are typically run using **uvicorn**, an ASGI server designed for high performance.
|
||||
|
||||
This creates the main FastAPI application instance.
|
||||
### Option 1: Run Using FastAPI CLI (Development Mode)
|
||||
|
||||
The variable name `app` is important because it is later used by `uvicorn` when starting the server.
|
||||
|
||||
---
|
||||
|
||||
## Define a GET Route
|
||||
|
||||
```python
|
||||
@app.get("/")
|
||||
def home_dir():
|
||||
return {"message": "Home Page"}
|
||||
```
|
||||
|
||||
This creates an HTTP `GET` endpoint at the root path:
|
||||
|
||||
```http
|
||||
GET /
|
||||
```
|
||||
|
||||
When a user sends a request to `/`, the `home_dir` function is executed.
|
||||
|
||||
The function returns a Python dictionary:
|
||||
|
||||
```python
|
||||
{"message": "Home Page"}
|
||||
```
|
||||
|
||||
FastAPI automatically converts this dictionary into a JSON response.
|
||||
|
||||
---
|
||||
|
||||
# 3. Running the Application
|
||||
|
||||
FastAPI applications are usually run using `uvicorn`.
|
||||
|
||||
---
|
||||
|
||||
## Option 1: Run Using FastAPI CLI
|
||||
|
||||
You can run the application in development mode using:
|
||||
FastAPI provides a development-friendly CLI wrapper that uses `uvicorn` internally:
|
||||
|
||||
```bash
|
||||
fastapi dev main.py
|
||||
```
|
||||
|
||||
This command starts the FastAPI application in development mode.
|
||||
This command:
|
||||
|
||||
It is useful during local development because it supports automatic reload when the source code changes.
|
||||
* Starts the application in development mode
|
||||
* Enables auto-reload on code changes
|
||||
* Automatically binds to a local development interface
|
||||
|
||||
---
|
||||
|
||||
## Option 2: Run Directly with Uvicorn
|
||||
### Option 2: Run Directly with Uvicorn (Recommended)
|
||||
|
||||
You can also run the application directly using `uvicorn`:
|
||||
For explicit control over runtime configuration, run the application directly with `uvicorn`:
|
||||
|
||||
```bash
|
||||
uvicorn main:app --reload --host 0.0.0.0 --port 1234
|
||||
```
|
||||
|
||||
This is the more explicit and commonly used method.
|
||||
#### Command Breakdown
|
||||
|
||||
* `main` → Python file name (without `.py`)
|
||||
* `app` → FastAPI application instance
|
||||
* `--reload` → Automatically reloads the server on code changes (development only)
|
||||
* `--host 0.0.0.0` → Exposes the service on all network interfaces
|
||||
* `--port 1234` → Custom application port
|
||||
|
||||
---
|
||||
|
||||
# 4. Uvicorn Command Breakdown
|
||||
## Accessing the Application
|
||||
|
||||
```bash
|
||||
uvicorn main:app --reload --host 0.0.0.0 --port 1234
|
||||
```
|
||||
Once running, the application will be available at:
|
||||
|
||||
## `uvicorn`
|
||||
* API Endpoint:
|
||||
`http://localhost:1234/`
|
||||
|
||||
Starts the ASGI server.
|
||||
* Interactive API Docs (Swagger UI):
|
||||
`http://localhost:1234/docs`
|
||||
|
||||
## `main`
|
||||
|
||||
Refers to the Python file name:
|
||||
|
||||
```text
|
||||
main.py
|
||||
```
|
||||
|
||||
You write `main`, not `main.py`.
|
||||
|
||||
## `app`
|
||||
|
||||
Refers to the FastAPI application instance:
|
||||
|
||||
```python
|
||||
app = FastAPI()
|
||||
```
|
||||
|
||||
## `--reload`
|
||||
|
||||
Automatically restarts the server when code changes.
|
||||
|
||||
This should only be used in development.
|
||||
|
||||
## `--host 0.0.0.0`
|
||||
|
||||
Makes the application listen on all available network interfaces.
|
||||
|
||||
This is useful when running inside Docker, virtual machines, or remote servers.
|
||||
|
||||
## `--port 1234`
|
||||
|
||||
Runs the application on port `1234`.
|
||||
* Alternative API Docs (ReDoc):
|
||||
`http://localhost:1234/redoc`
|
||||
|
||||
---
|
||||
|
||||
# 5. Accessing the Application
|
||||
## Best Practices
|
||||
|
||||
After starting the server, the application will be available at:
|
||||
* Use `--reload` only in development environments
|
||||
* In production, run `uvicorn` behind a process manager (e.g., systemd, Docker, Kubernetes)
|
||||
* Explicitly define host and port for containerized and cloud deployments
|
||||
* Keep the application entry point (`main:app`) consistent across environments
|
||||
|
||||
```text
|
||||
http://localhost:1234/
|
||||
```
|
||||
|
||||
The response will be:
|
||||
|
||||
```json
|
||||
{
|
||||
"message": "Home Page"
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 6. Interactive API Documentation
|
||||
|
||||
FastAPI automatically generates API documentation.
|
||||
|
||||
## Swagger UI
|
||||
|
||||
```text
|
||||
http://localhost:1234/docs
|
||||
```
|
||||
|
||||
Swagger UI allows you to test API endpoints directly from the browser.
|
||||
|
||||
## ReDoc
|
||||
|
||||
```text
|
||||
http://localhost:1234/redoc
|
||||
```
|
||||
|
||||
ReDoc provides a clean documentation view for the API.
|
||||
|
||||
---
|
||||
|
||||
# 7. Complete Example
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
|
||||
@app.get("/")
|
||||
def home_dir():
|
||||
return {"message": "Home Page"}
|
||||
```
|
||||
|
||||
Run it with:
|
||||
|
||||
```bash
|
||||
uvicorn main:app --reload --host 0.0.0.0 --port 1234
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 8. Best Practices
|
||||
|
||||
Use `--reload` only during development.
|
||||
|
||||
Use a consistent application entry point such as:
|
||||
|
||||
```text
|
||||
main:app
|
||||
```
|
||||
|
||||
Explicitly define the host and port in Docker, cloud, or server environments.
|
||||
|
||||
Use `0.0.0.0` when the application needs to be reachable from outside the local machine.
|
||||
|
||||
Use `127.0.0.1` or `localhost` when the application should only be accessible locally.
|
||||
|
||||
Do not expose development servers directly to the internet.
|
||||
|
||||
In production, run FastAPI behind a proper process manager, reverse proxy, or container orchestration platform.
|
||||
|
||||
---
|
||||
|
||||
# 9. DevOps Production Note
|
||||
|
||||
The following command is suitable for local development:
|
||||
|
||||
```bash
|
||||
uvicorn main:app --reload --host 0.0.0.0 --port 1234
|
||||
```
|
||||
|
||||
For production, avoid using `--reload`.
|
||||
|
||||
A typical production setup may include:
|
||||
|
||||
```text
|
||||
FastAPI
|
||||
Uvicorn or Gunicorn with Uvicorn workers
|
||||
Nginx or Traefik
|
||||
Docker or Kubernetes
|
||||
Logging and monitoring
|
||||
Health checks
|
||||
Environment-based configuration
|
||||
```
|
||||
|
||||
Example production-style command:
|
||||
|
||||
```bash
|
||||
uvicorn main:app --host 0.0.0.0 --port 1234
|
||||
```
|
||||
|
||||
@@ -1,14 +1,10 @@
|
||||
# FastAPI – GET Endpoints and JSON Responses
|
||||
|
||||
## Overview
|
||||
|
||||
This document explains how to create multiple `GET` endpoints in FastAPI, return JSON responses, and use path parameters to retrieve specific data from an in-memory dataset.
|
||||
|
||||
The example uses a simple list of users to simulate a database.
|
||||
This document demonstrates how to define multiple **GET endpoints** in FastAPI, return JSON responses, and use **path parameters** to retrieve specific data from an in-memory dataset.
|
||||
|
||||
---
|
||||
|
||||
# 1. Example Application
|
||||
## Example Application
|
||||
|
||||
Create or update `main.py` with the following content:
|
||||
|
||||
@@ -39,38 +35,24 @@ def get_user_by_name(name_input: str):
|
||||
for item in users:
|
||||
if item["name"] == name_input:
|
||||
return {"information": item}
|
||||
|
||||
return {"message": "User not found"}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 2. Application Initialization
|
||||
## Code Overview
|
||||
|
||||
### Application Initialization
|
||||
|
||||
```python
|
||||
app = FastAPI()
|
||||
```
|
||||
|
||||
This creates the main FastAPI application instance.
|
||||
|
||||
The variable `app` is used by `uvicorn` when starting the service.
|
||||
|
||||
Example:
|
||||
|
||||
```bash
|
||||
uvicorn main:app --reload
|
||||
```
|
||||
|
||||
In `main:app`:
|
||||
|
||||
```text
|
||||
main = Python file name
|
||||
app = FastAPI application instance
|
||||
```
|
||||
Initializes the FastAPI application instance.
|
||||
|
||||
---
|
||||
|
||||
# 3. In-Memory Data Store
|
||||
### In-Memory Data Store
|
||||
|
||||
```python
|
||||
users = [
|
||||
@@ -80,64 +62,21 @@ users = [
|
||||
]
|
||||
```
|
||||
|
||||
This list is used as temporary storage.
|
||||
|
||||
Each user is represented as a Python dictionary.
|
||||
|
||||
FastAPI can automatically convert these dictionaries into JSON responses.
|
||||
|
||||
Example Python object:
|
||||
|
||||
```python
|
||||
{"name": "abbas", "age": 20}
|
||||
```
|
||||
|
||||
Example JSON response:
|
||||
|
||||
```json
|
||||
{
|
||||
"name": "abbas",
|
||||
"age": 20
|
||||
}
|
||||
```
|
||||
|
||||
## Important Note
|
||||
|
||||
This in-memory list is only suitable for learning, development, and testing.
|
||||
|
||||
If the application restarts, the data will be reset.
|
||||
|
||||
For production, use a persistent database such as PostgreSQL, MySQL, MongoDB, or another database system.
|
||||
* Simulates a database using a Python list
|
||||
* Each user is represented as a JSON-compatible dictionary
|
||||
* Suitable for development and testing purposes
|
||||
|
||||
---
|
||||
|
||||
# 4. Defined Endpoints
|
||||
## Defined Endpoints
|
||||
|
||||
The application defines three `GET` endpoints:
|
||||
|
||||
```http
|
||||
GET /
|
||||
GET /users
|
||||
GET /user/{name_input}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 5. Root Endpoint
|
||||
|
||||
```python
|
||||
@app.get("/")
|
||||
def root_dir():
|
||||
return {"message": "API is working"}
|
||||
```
|
||||
|
||||
This endpoint is available at:
|
||||
### Root Endpoint
|
||||
|
||||
```http
|
||||
GET /
|
||||
```
|
||||
|
||||
It returns a simple JSON response:
|
||||
**Response:**
|
||||
|
||||
```json
|
||||
{
|
||||
@@ -145,96 +84,43 @@ It returns a simple JSON response:
|
||||
}
|
||||
```
|
||||
|
||||
This type of endpoint is commonly used as a simple health check.
|
||||
|
||||
For example, load balancers, monitoring systems, or Kubernetes probes can use it to check whether the API is reachable.
|
||||
Used as a health check or readiness probe.
|
||||
|
||||
---
|
||||
|
||||
# 6. Get All Users Endpoint
|
||||
|
||||
```python
|
||||
@app.get("/users")
|
||||
def get_users():
|
||||
return users
|
||||
```
|
||||
|
||||
This endpoint is available at:
|
||||
### Get All Users
|
||||
|
||||
```http
|
||||
GET /users
|
||||
```
|
||||
|
||||
It returns the full list of users.
|
||||
|
||||
Example response:
|
||||
**Response:**
|
||||
|
||||
```json
|
||||
[
|
||||
{
|
||||
"name": "abbas",
|
||||
"age": 20
|
||||
},
|
||||
{
|
||||
"name": "mmd",
|
||||
"age": 37
|
||||
},
|
||||
{
|
||||
"name": "asghar",
|
||||
"age": 19
|
||||
}
|
||||
{"name": "abbas", "age": 20},
|
||||
{"name": "mmd", "age": 37},
|
||||
{"name": "asghar", "age": 19}
|
||||
]
|
||||
```
|
||||
|
||||
FastAPI automatically serializes the Python list into a JSON array.
|
||||
Returns the full list of users as JSON.
|
||||
|
||||
---
|
||||
|
||||
# 7. Get User by Name Endpoint
|
||||
|
||||
```python
|
||||
@app.get("/user/{name_input}")
|
||||
def get_user_by_name(name_input: str):
|
||||
for item in users:
|
||||
if item["name"] == name_input:
|
||||
return {"information": item}
|
||||
|
||||
return {"message": "User not found"}
|
||||
```
|
||||
|
||||
This endpoint is available at:
|
||||
### Get User by Name (Path Parameter)
|
||||
|
||||
```http
|
||||
GET /user/{name_input}
|
||||
```
|
||||
|
||||
The `{name_input}` part is a path parameter.
|
||||
|
||||
Example request:
|
||||
**Example Request:**
|
||||
|
||||
```http
|
||||
GET /user/abbas
|
||||
```
|
||||
|
||||
In this request, FastAPI assigns:
|
||||
|
||||
```python
|
||||
name_input = "abbas"
|
||||
```
|
||||
|
||||
The function then searches the `users` list for a user whose name matches the input.
|
||||
|
||||
---
|
||||
|
||||
# 8. Successful Response Example
|
||||
|
||||
Request:
|
||||
|
||||
```http
|
||||
GET /user/abbas
|
||||
```
|
||||
|
||||
Response:
|
||||
**Successful Response:**
|
||||
|
||||
```json
|
||||
{
|
||||
@@ -245,17 +131,7 @@ Response:
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 9. Failure Response Example
|
||||
|
||||
Request:
|
||||
|
||||
```http
|
||||
GET /user/ali
|
||||
```
|
||||
|
||||
Response:
|
||||
**Failure Response:**
|
||||
|
||||
```json
|
||||
{
|
||||
@@ -263,304 +139,31 @@ Response:
|
||||
}
|
||||
```
|
||||
|
||||
In the current simple version, the API returns a normal JSON message even when the user does not exist.
|
||||
---
|
||||
|
||||
However, in a real API, it is better to return a proper `404 Not Found` response.
|
||||
## Path Parameters
|
||||
|
||||
* `name_input` is a dynamic path parameter
|
||||
* Automatically validated and converted to `str` by FastAPI
|
||||
* Used to filter data at runtime
|
||||
|
||||
---
|
||||
|
||||
# 10. Path Parameters
|
||||
## Running the Application
|
||||
|
||||
A path parameter is a dynamic part of the URL.
|
||||
|
||||
In this route:
|
||||
|
||||
```python
|
||||
@app.get("/user/{name_input}")
|
||||
```
|
||||
|
||||
`name_input` is a path parameter.
|
||||
|
||||
Example:
|
||||
|
||||
```http
|
||||
GET /user/mmd
|
||||
```
|
||||
|
||||
FastAPI extracts the value from the URL and passes it to the function:
|
||||
|
||||
```python
|
||||
def get_user_by_name(name_input: str):
|
||||
```
|
||||
|
||||
Because `name_input` is defined as a string:
|
||||
|
||||
```python
|
||||
name_input: str
|
||||
```
|
||||
|
||||
FastAPI validates it as a string.
|
||||
|
||||
---
|
||||
|
||||
# 11. Better Version with HTTPException
|
||||
|
||||
The previous version works, but it does not return the correct HTTP status code when a user is not found.
|
||||
|
||||
A better version uses `HTTPException`.
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI, HTTPException, status
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
users = [
|
||||
{"name": "abbas", "age": 20},
|
||||
{"name": "mmd", "age": 37},
|
||||
{"name": "asghar", "age": 19},
|
||||
]
|
||||
|
||||
|
||||
@app.get("/")
|
||||
def root_dir():
|
||||
return {"message": "API is working"}
|
||||
|
||||
|
||||
@app.get("/users")
|
||||
def get_users():
|
||||
return users
|
||||
|
||||
|
||||
@app.get("/user/{name_input}")
|
||||
def get_user_by_name(name_input: str):
|
||||
for item in users:
|
||||
if item["name"] == name_input:
|
||||
return {"information": item}
|
||||
|
||||
raise HTTPException(
|
||||
status_code=status.HTTP_404_NOT_FOUND,
|
||||
detail="User not found"
|
||||
)
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 12. Improved Failure Response
|
||||
|
||||
Request:
|
||||
|
||||
```http
|
||||
GET /user/ali
|
||||
```
|
||||
|
||||
Response:
|
||||
|
||||
```json
|
||||
{
|
||||
"detail": "User not found"
|
||||
}
|
||||
```
|
||||
|
||||
HTTP status code:
|
||||
|
||||
```http
|
||||
404 Not Found
|
||||
```
|
||||
|
||||
This is better because the API response now correctly tells the client that the requested resource does not exist.
|
||||
|
||||
---
|
||||
|
||||
# 13. Running the Application
|
||||
|
||||
Start the FastAPI application using `uvicorn`:
|
||||
Use `uvicorn` to start the service:
|
||||
|
||||
```bash
|
||||
uvicorn main:app --reload
|
||||
```
|
||||
|
||||
The application will be available at:
|
||||
|
||||
```text
|
||||
http://localhost:8000
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 14. Accessing the Endpoints
|
||||
## Best Practices
|
||||
|
||||
Root endpoint:
|
||||
* Use structured JSON responses (`key: value`) instead of tuples
|
||||
* Validate user input when moving beyond in-memory data
|
||||
* Replace in-memory storage with a database for production
|
||||
* Use proper HTTP status codes (`404`, `200`) in real-world APIs
|
||||
* Separate routing, models, and business logic as the project grows
|
||||
|
||||
```text
|
||||
http://localhost:8000/
|
||||
```
|
||||
|
||||
Get all users:
|
||||
|
||||
```text
|
||||
http://localhost:8000/users
|
||||
```
|
||||
|
||||
Get user by name:
|
||||
|
||||
```text
|
||||
http://localhost:8000/user/abbas
|
||||
```
|
||||
|
||||
Interactive API documentation:
|
||||
|
||||
```text
|
||||
http://localhost:8000/docs
|
||||
```
|
||||
|
||||
Alternative API documentation:
|
||||
|
||||
```text
|
||||
http://localhost:8000/redoc
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 15. Testing with curl
|
||||
|
||||
## Test Root Endpoint
|
||||
|
||||
```bash
|
||||
curl http://localhost:8000/
|
||||
```
|
||||
|
||||
Response:
|
||||
|
||||
```json
|
||||
{
|
||||
"message": "API is working"
|
||||
}
|
||||
```
|
||||
|
||||
## Test Get All Users
|
||||
|
||||
```bash
|
||||
curl http://localhost:8000/users
|
||||
```
|
||||
|
||||
Response:
|
||||
|
||||
```json
|
||||
[
|
||||
{
|
||||
"name": "abbas",
|
||||
"age": 20
|
||||
},
|
||||
{
|
||||
"name": "mmd",
|
||||
"age": 37
|
||||
},
|
||||
{
|
||||
"name": "asghar",
|
||||
"age": 19
|
||||
}
|
||||
]
|
||||
```
|
||||
|
||||
## Test Get User by Name
|
||||
|
||||
```bash
|
||||
curl http://localhost:8000/user/abbas
|
||||
```
|
||||
|
||||
Response:
|
||||
|
||||
```json
|
||||
{
|
||||
"information": {
|
||||
"name": "abbas",
|
||||
"age": 20
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
## Test User Not Found
|
||||
|
||||
```bash
|
||||
curl http://localhost:8000/user/ali
|
||||
```
|
||||
|
||||
Response:
|
||||
|
||||
```json
|
||||
{
|
||||
"detail": "User not found"
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 16. Complete Recommended Version
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI, HTTPException, status
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
users = [
|
||||
{"name": "abbas", "age": 20},
|
||||
{"name": "mmd", "age": 37},
|
||||
{"name": "asghar", "age": 19},
|
||||
]
|
||||
|
||||
|
||||
@app.get("/")
|
||||
def root_dir():
|
||||
return {"message": "API is working"}
|
||||
|
||||
|
||||
@app.get("/users")
|
||||
def get_users():
|
||||
return users
|
||||
|
||||
|
||||
@app.get("/user/{name_input}")
|
||||
def get_user_by_name(name_input: str):
|
||||
for item in users:
|
||||
if item["name"] == name_input:
|
||||
return {"information": item}
|
||||
|
||||
raise HTTPException(
|
||||
status_code=status.HTTP_404_NOT_FOUND,
|
||||
detail="User not found"
|
||||
)
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 17. Best Practices
|
||||
|
||||
Use `GET` endpoints only for retrieving data.
|
||||
|
||||
Do not use `GET` requests to create, update, or delete resources.
|
||||
|
||||
Return structured JSON responses.
|
||||
|
||||
Use proper HTTP status codes.
|
||||
|
||||
Use `404 Not Found` when a requested resource does not exist.
|
||||
|
||||
Use `200 OK` when the request is successful.
|
||||
|
||||
Replace in-memory lists with a real database in production.
|
||||
|
||||
Keep route names clear and consistent.
|
||||
|
||||
Use plural naming for collection endpoints, such as:
|
||||
|
||||
```http
|
||||
GET /users
|
||||
```
|
||||
|
||||
Use specific resource endpoints for single items, such as:
|
||||
|
||||
```http
|
||||
GET /users/{username}
|
||||
```
|
||||
|
||||
As the project grows, separate code into different files for routes, models, services, and database logic.
|
||||
|
||||
@@ -1,19 +1,12 @@
|
||||
# FastAPI – POST Endpoint and JSON Input
|
||||
|
||||
## Overview
|
||||
|
||||
This document explains how to create a `POST` endpoint in FastAPI for adding new users. It covers two approaches:
|
||||
|
||||
1. Sending input as query parameters
|
||||
2. Sending input as a JSON request body using a Pydantic model
|
||||
|
||||
For real API development, the Pydantic model approach is recommended because it provides a cleaner structure, better validation, and more realistic request handling.
|
||||
This section demonstrates how to handle **POST requests** in FastAPI to create new resources using request data and return JSON responses.
|
||||
|
||||
---
|
||||
|
||||
# 1. Example Application Using Query Parameters
|
||||
## Example Application (POST Request)
|
||||
|
||||
Create or update `main.py` with the following code:
|
||||
Extend `main.py` with the following code:
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI
|
||||
@@ -39,154 +32,59 @@ def create_user(name: str, age: int):
|
||||
return {"msg": "User created successfully"}
|
||||
```
|
||||
|
||||
## Explanation
|
||||
---
|
||||
|
||||
## Code Overview
|
||||
|
||||
### POST Endpoint Definition
|
||||
|
||||
```python
|
||||
@app.post("/new_user")
|
||||
def create_user(name: str, age: int):
|
||||
```
|
||||
|
||||
This registers a `POST` endpoint at:
|
||||
* Registers an HTTP **POST** endpoint at `/new_user`
|
||||
* Accepts input parameters:
|
||||
|
||||
```http
|
||||
POST /new_user
|
||||
```
|
||||
* `name` → string
|
||||
* `age` → integer
|
||||
* FastAPI automatically validates input types
|
||||
|
||||
The endpoint receives two parameters:
|
||||
---
|
||||
|
||||
### Creating a New Resource
|
||||
|
||||
```python
|
||||
name: str
|
||||
age: int
|
||||
new_user = {"name": name, "age": age}
|
||||
users.append(new_user)
|
||||
```
|
||||
|
||||
FastAPI automatically validates the input types. If `age` is not an integer, FastAPI returns a validation error.
|
||||
* Constructs a new user object
|
||||
* Appends it to the in-memory `users` list
|
||||
* Simulates creating a record in a database
|
||||
|
||||
---
|
||||
|
||||
### JSON Response
|
||||
|
||||
```python
|
||||
return {"msg": "User created successfully"}
|
||||
```
|
||||
|
||||
* Returns a structured JSON response
|
||||
* Automatically serialized by FastAPI
|
||||
|
||||
---
|
||||
|
||||
## Example Request
|
||||
|
||||
### Using `curl`
|
||||
|
||||
```bash
|
||||
curl -X POST "http://localhost:8000/new_user?name=ali&age=25"
|
||||
```
|
||||
|
||||
## Example Response
|
||||
|
||||
```json
|
||||
{
|
||||
"msg": "User created successfully"
|
||||
}
|
||||
```
|
||||
|
||||
## Important Note
|
||||
|
||||
In this version, the data is sent through query parameters, not as a JSON body.
|
||||
|
||||
This is acceptable for simple testing, but it is not the best practice for real APIs that create resources.
|
||||
|
||||
---
|
||||
|
||||
# 2. Recommended Application Using JSON Body
|
||||
|
||||
A better approach is to define a Pydantic model and receive the user data as JSON.
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI
|
||||
from pydantic import BaseModel
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
|
||||
class User(BaseModel):
|
||||
name: str
|
||||
age: int
|
||||
|
||||
|
||||
users = [
|
||||
{"name": "abbas", "age": 20},
|
||||
{"name": "mmd", "age": 37},
|
||||
{"name": "asghar", "age": 19},
|
||||
]
|
||||
|
||||
|
||||
@app.get("/")
|
||||
def home_page():
|
||||
return {"msg": "API is working"}
|
||||
|
||||
|
||||
@app.post("/new_user")
|
||||
def create_user(user: User):
|
||||
new_user = {"name": user.name, "age": user.age}
|
||||
users.append(new_user)
|
||||
return {"msg": "User created successfully"}
|
||||
```
|
||||
|
||||
## Explanation
|
||||
|
||||
```python
|
||||
class User(BaseModel):
|
||||
name: str
|
||||
age: int
|
||||
```
|
||||
|
||||
This creates a request model named `User`.
|
||||
|
||||
The model defines the expected structure of the JSON input:
|
||||
|
||||
```json
|
||||
{
|
||||
"name": "ali",
|
||||
"age": 25
|
||||
}
|
||||
```
|
||||
|
||||
FastAPI uses this model to:
|
||||
|
||||
Validate incoming data
|
||||
Convert JSON into a Python object
|
||||
Generate automatic API documentation
|
||||
Return useful validation errors when input is invalid
|
||||
|
||||
---
|
||||
|
||||
# 3. POST Endpoint Definition
|
||||
|
||||
```python
|
||||
@app.post("/new_user")
|
||||
def create_user(user: User):
|
||||
```
|
||||
|
||||
This creates a `POST` endpoint at:
|
||||
|
||||
```http
|
||||
POST /new_user
|
||||
```
|
||||
|
||||
The endpoint expects a JSON request body matching the `User` model.
|
||||
|
||||
---
|
||||
|
||||
# 4. Creating a New Resource
|
||||
|
||||
```python
|
||||
new_user = {"name": user.name, "age": user.age}
|
||||
users.append(new_user)
|
||||
```
|
||||
|
||||
This code creates a new dictionary using the received request data and appends it to the `users` list.
|
||||
|
||||
The `users` list acts as temporary in-memory storage.
|
||||
|
||||
This simulates inserting a new record into a database.
|
||||
|
||||
---
|
||||
|
||||
# 5. Returning a JSON Response
|
||||
|
||||
```python
|
||||
return {"msg": "User created successfully"}
|
||||
```
|
||||
|
||||
FastAPI automatically converts the returned dictionary into a JSON response.
|
||||
|
||||
Example response:
|
||||
### Response
|
||||
|
||||
```json
|
||||
{
|
||||
@@ -196,174 +94,34 @@ Example response:
|
||||
|
||||
---
|
||||
|
||||
# 6. Example Request Using curl
|
||||
## Verifying the Result
|
||||
|
||||
```bash
|
||||
curl -X POST "http://localhost:8000/new_user" \
|
||||
-H "Content-Type: application/json" \
|
||||
-d '{"name": "ali", "age": 25}'
|
||||
```
|
||||
|
||||
## Response
|
||||
|
||||
```json
|
||||
{
|
||||
"msg": "User created successfully"
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 7. Verifying the Result
|
||||
|
||||
To verify that the user was added, you should also define a `GET /users` endpoint.
|
||||
|
||||
```python
|
||||
@app.get("/users")
|
||||
def get_users():
|
||||
return users
|
||||
```
|
||||
|
||||
Then send this request:
|
||||
After creating a user, retrieve the updated list:
|
||||
|
||||
```http
|
||||
GET /users
|
||||
```
|
||||
|
||||
Example response:
|
||||
|
||||
```json
|
||||
[
|
||||
{
|
||||
"name": "abbas",
|
||||
"age": 20
|
||||
},
|
||||
{
|
||||
"name": "mmd",
|
||||
"age": 37
|
||||
},
|
||||
{
|
||||
"name": "asghar",
|
||||
"age": 19
|
||||
},
|
||||
{
|
||||
"name": "ali",
|
||||
"age": 25
|
||||
}
|
||||
]
|
||||
```
|
||||
Response will now include the newly added user.
|
||||
|
||||
---
|
||||
|
||||
# 8. Complete Recommended Version
|
||||
## Running the Application
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI, status
|
||||
from pydantic import BaseModel
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
|
||||
class User(BaseModel):
|
||||
name: str
|
||||
age: int
|
||||
|
||||
|
||||
users = [
|
||||
{"name": "abbas", "age": 20},
|
||||
{"name": "mmd", "age": 37},
|
||||
{"name": "asghar", "age": 19},
|
||||
]
|
||||
|
||||
|
||||
@app.get("/")
|
||||
def home_page():
|
||||
return {"msg": "API is working"}
|
||||
|
||||
|
||||
@app.get("/users")
|
||||
def get_users():
|
||||
return users
|
||||
|
||||
|
||||
@app.post("/new_user", status_code=status.HTTP_201_CREATED)
|
||||
def create_user(user: User):
|
||||
new_user = {"name": user.name, "age": user.age}
|
||||
users.append(new_user)
|
||||
|
||||
return {
|
||||
"msg": "User created successfully",
|
||||
"user": new_user
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 9. Running the Application
|
||||
|
||||
Start the FastAPI application using `uvicorn`:
|
||||
Start the FastAPI service using `uvicorn`:
|
||||
|
||||
```bash
|
||||
uvicorn main:app --reload
|
||||
```
|
||||
|
||||
The API will run at:
|
||||
|
||||
```text
|
||||
http://localhost:8000
|
||||
```
|
||||
|
||||
Interactive API documentation will be available at:
|
||||
|
||||
```text
|
||||
http://localhost:8000/docs
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 10. Best Practices
|
||||
## Best Practices
|
||||
|
||||
Use `POST` requests when creating new resources.
|
||||
* POST requests should be used to create resources
|
||||
* Avoid modifying in-memory data in production environments
|
||||
* Use request bodies with Pydantic models instead of query parameters for real APIs
|
||||
* Return appropriate HTTP status codes (`201 Created`)
|
||||
* Validate and sanitize all client-provided input
|
||||
* Replace in-memory storage with persistent databases
|
||||
|
||||
Use Pydantic models for request bodies instead of query parameters.
|
||||
|
||||
Return proper HTTP status codes, such as:
|
||||
|
||||
```http
|
||||
201 Created
|
||||
```
|
||||
|
||||
Do not use in-memory lists for production data storage.
|
||||
|
||||
Use a real database such as PostgreSQL, MySQL, or MongoDB in production.
|
||||
|
||||
Validate and sanitize all client-provided input.
|
||||
|
||||
Keep model names clear and professional. For example, use `User` instead of `user_class`.
|
||||
|
||||
Return meaningful responses that include the created resource when useful.
|
||||
|
||||
Use `/docs` to test and verify API behavior during development.
|
||||
|
||||
---
|
||||
|
||||
# 11. Production Note for DevOps
|
||||
|
||||
The in-memory `users` list is reset every time the application restarts. In production environments, application data must be stored in a persistent database.
|
||||
|
||||
For production deployment, the FastAPI application should usually run behind a process manager and reverse proxy, such as:
|
||||
|
||||
```text
|
||||
Gunicorn / Uvicorn workers
|
||||
Nginx or Traefik
|
||||
Docker or Kubernetes
|
||||
PostgreSQL or another persistent database
|
||||
```
|
||||
|
||||
The development command:
|
||||
|
||||
```bash
|
||||
uvicorn main:app --reload
|
||||
```
|
||||
|
||||
should not be used in production because `--reload` is intended only for local development.
|
||||
|
||||
122
Docs/Libs/FastAPI/09-Json-Responce.md
Normal file
122
Docs/Libs/FastAPI/09-Json-Responce.md
Normal file
@@ -0,0 +1,122 @@
|
||||
# FastAPI – JSONResponse (Explicit JSON Responses)
|
||||
|
||||
This document demonstrates how to return **explicit JSON responses** in FastAPI using `JSONResponse`.
|
||||
While FastAPI automatically serializes dictionaries to JSON, `JSONResponse` is useful when you need **full control** over the response.
|
||||
|
||||
---
|
||||
|
||||
## Example Application
|
||||
|
||||
Create or update `main.py` with the following content:
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI, status
|
||||
from fastapi.responses import JSONResponse
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
|
||||
@app.get("/")
|
||||
def home():
|
||||
return JSONResponse(
|
||||
content={"msg": "API is working"},
|
||||
status_code=status.HTTP_200_OK
|
||||
)
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## Why Use `JSONResponse`
|
||||
|
||||
FastAPI automatically converts Python dictionaries into JSON responses.
|
||||
However, `JSONResponse` is useful when you need to:
|
||||
|
||||
* Explicitly control the response type
|
||||
* Set custom status codes dynamically
|
||||
* Customize headers
|
||||
* Return non-standard JSON structures
|
||||
* Override default response behavior
|
||||
|
||||
---
|
||||
|
||||
## Response Behavior
|
||||
|
||||
### Endpoint
|
||||
|
||||
```http
|
||||
GET /
|
||||
```
|
||||
|
||||
### Response Body
|
||||
|
||||
```json
|
||||
{
|
||||
"msg": "API is working"
|
||||
}
|
||||
```
|
||||
|
||||
### HTTP Status Code
|
||||
|
||||
```
|
||||
200 OK
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## Comparison: Default Response vs JSONResponse
|
||||
|
||||
### Default FastAPI Response
|
||||
|
||||
```python
|
||||
@app.get("/")
|
||||
def home():
|
||||
return {"msg": "API is working"}
|
||||
```
|
||||
|
||||
* Automatically serialized to JSON
|
||||
* Simpler and recommended for most cases
|
||||
|
||||
---
|
||||
|
||||
### Explicit JSONResponse
|
||||
|
||||
```python
|
||||
return JSONResponse(
|
||||
content={"msg": "API is working"},
|
||||
status_code=status.HTTP_200_OK
|
||||
)
|
||||
```
|
||||
|
||||
* Explicit control over response
|
||||
* Useful for advanced use cases
|
||||
|
||||
---
|
||||
|
||||
## When to Use `JSONResponse`
|
||||
|
||||
* Returning conditional status codes
|
||||
* Adding custom headers
|
||||
* Returning responses outside standard request flow
|
||||
* Building middleware or exception handlers
|
||||
* Integrating with legacy systems
|
||||
|
||||
---
|
||||
|
||||
## Running the Application
|
||||
|
||||
Start the application using `uvicorn`:
|
||||
|
||||
```bash
|
||||
uvicorn main:app --reload
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## Best Practices
|
||||
|
||||
* Prefer returning dictionaries for simple APIs
|
||||
* Use `JSONResponse` only when additional control is required
|
||||
* Keep response formats consistent across endpoints
|
||||
* Avoid mixing response styles unnecessarily
|
||||
* Use response models for structured APIs
|
||||
|
||||
@@ -1,514 +0,0 @@
|
||||
# FastAPI – Response Model and JSONResponse
|
||||
|
||||
## Overview
|
||||
|
||||
This document explains two important FastAPI response concepts:
|
||||
|
||||
1. Using `response_model` to control what data is returned to the client
|
||||
2. Using `JSONResponse` when you need explicit control over the response body, status code, or headers
|
||||
|
||||
Response models are especially useful when you want to hide sensitive fields such as passwords from API responses.
|
||||
|
||||
---
|
||||
|
||||
# 1. Response Model
|
||||
|
||||
## Incorrect Example
|
||||
|
||||
The following code has several issues:
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI, status , HTTPExption
|
||||
from pydantic import BaseModel
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
|
||||
class usersin(BaseModel):
|
||||
username: str
|
||||
pass: str
|
||||
|
||||
class usersout(BaseModel):
|
||||
username: str
|
||||
|
||||
|
||||
@app.post("/user")
|
||||
def home(user: usersin, responce_model=usersout):
|
||||
return user
|
||||
```
|
||||
|
||||
## Problems in the Code
|
||||
|
||||
### 1. `HTTPExption` is misspelled
|
||||
|
||||
Correct import:
|
||||
|
||||
```python
|
||||
HTTPException
|
||||
```
|
||||
|
||||
### 2. `pass` cannot be used as a field name
|
||||
|
||||
`pass` is a reserved keyword in Python.
|
||||
|
||||
Instead of:
|
||||
|
||||
```python
|
||||
pass: str
|
||||
```
|
||||
|
||||
Use:
|
||||
|
||||
```python
|
||||
password: str
|
||||
```
|
||||
|
||||
### 3. `response_model` is written in the wrong place
|
||||
|
||||
This is incorrect:
|
||||
|
||||
```python
|
||||
def home(user: usersin, responce_model=usersout):
|
||||
```
|
||||
|
||||
`response_model` must be passed inside the route decorator.
|
||||
|
||||
Correct:
|
||||
|
||||
```python
|
||||
@app.post("/user", response_model=UserOut)
|
||||
```
|
||||
|
||||
### 4. `responce_model` is misspelled
|
||||
|
||||
Correct spelling:
|
||||
|
||||
```python
|
||||
response_model
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 2. Correct Response Model Example
|
||||
|
||||
Create or update `main.py` with the following content:
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI
|
||||
from pydantic import BaseModel
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
|
||||
class UserIn(BaseModel):
|
||||
username: str
|
||||
password: str
|
||||
|
||||
|
||||
class UserOut(BaseModel):
|
||||
username: str
|
||||
|
||||
|
||||
@app.post("/user", response_model=UserOut)
|
||||
def create_user(user: UserIn):
|
||||
return user
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 3. How Response Model Works
|
||||
|
||||
## Input Model
|
||||
|
||||
```python
|
||||
class UserIn(BaseModel):
|
||||
username: str
|
||||
password: str
|
||||
```
|
||||
|
||||
This model defines the data that the API receives from the client.
|
||||
|
||||
Example request body:
|
||||
|
||||
```json
|
||||
{
|
||||
"username": "abbas",
|
||||
"password": "123456"
|
||||
}
|
||||
```
|
||||
|
||||
The API accepts both fields:
|
||||
|
||||
```text
|
||||
username
|
||||
password
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## Output Model
|
||||
|
||||
```python
|
||||
class UserOut(BaseModel):
|
||||
username: str
|
||||
```
|
||||
|
||||
This model defines the data that the API returns to the client.
|
||||
|
||||
Even though the endpoint receives the password, the response only returns the username.
|
||||
|
||||
Example response:
|
||||
|
||||
```json
|
||||
{
|
||||
"username": "abbas"
|
||||
}
|
||||
```
|
||||
|
||||
The password is removed from the response automatically.
|
||||
|
||||
---
|
||||
|
||||
# 4. Endpoint Definition
|
||||
|
||||
```python
|
||||
@app.post("/user", response_model=UserOut)
|
||||
def create_user(user: UserIn):
|
||||
return user
|
||||
```
|
||||
|
||||
This creates a `POST` endpoint at:
|
||||
|
||||
```http
|
||||
POST /user
|
||||
```
|
||||
|
||||
The endpoint receives data based on `UserIn` and returns data based on `UserOut`.
|
||||
|
||||
FastAPI uses `response_model` to filter the response before sending it to the client.
|
||||
|
||||
---
|
||||
|
||||
# 5. Example Request
|
||||
|
||||
## Using curl
|
||||
|
||||
```bash
|
||||
curl -X POST "http://localhost:8000/user" \
|
||||
-H "Content-Type: application/json" \
|
||||
-d '{"username": "abbas", "password": "123456"}'
|
||||
```
|
||||
|
||||
## Response
|
||||
|
||||
```json
|
||||
{
|
||||
"username": "abbas"
|
||||
}
|
||||
```
|
||||
|
||||
The password is not included in the response.
|
||||
|
||||
---
|
||||
|
||||
# 6. Why Use Response Models
|
||||
|
||||
Response models are useful because they help you:
|
||||
|
||||
Protect sensitive data
|
||||
Keep API responses consistent
|
||||
Control exactly what the client receives
|
||||
Improve automatic documentation
|
||||
Validate response data before sending it
|
||||
Separate input schemas from output schemas
|
||||
|
||||
---
|
||||
|
||||
# 7. Better Version with Status Code
|
||||
|
||||
For user creation endpoints, it is better to return `201 Created`.
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI, status
|
||||
from pydantic import BaseModel
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
|
||||
class UserIn(BaseModel):
|
||||
username: str
|
||||
password: str
|
||||
|
||||
|
||||
class UserOut(BaseModel):
|
||||
username: str
|
||||
|
||||
|
||||
@app.post(
|
||||
"/user",
|
||||
response_model=UserOut,
|
||||
status_code=status.HTTP_201_CREATED
|
||||
)
|
||||
def create_user(user: UserIn):
|
||||
return user
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 8. JSONResponse
|
||||
|
||||
FastAPI automatically converts Python dictionaries into JSON responses.
|
||||
|
||||
For most endpoints, this is enough:
|
||||
|
||||
```python
|
||||
@app.get("/")
|
||||
def home():
|
||||
return {"msg": "API is working"}
|
||||
```
|
||||
|
||||
However, FastAPI also allows you to use `JSONResponse` when you need more control.
|
||||
|
||||
---
|
||||
|
||||
# 9. Example Application Using JSONResponse
|
||||
|
||||
Create or update `main.py` with the following content:
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI, status
|
||||
from fastapi.responses import JSONResponse
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
|
||||
@app.get("/")
|
||||
def home():
|
||||
return JSONResponse(
|
||||
content={"msg": "API is working"},
|
||||
status_code=status.HTTP_200_OK
|
||||
)
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 10. Response Behavior
|
||||
|
||||
## Endpoint
|
||||
|
||||
```http
|
||||
GET /
|
||||
```
|
||||
|
||||
## Response Body
|
||||
|
||||
```json
|
||||
{
|
||||
"msg": "API is working"
|
||||
}
|
||||
```
|
||||
|
||||
## HTTP Status Code
|
||||
|
||||
```http
|
||||
200 OK
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 11. Default Response vs JSONResponse
|
||||
|
||||
## Default FastAPI Response
|
||||
|
||||
```python
|
||||
@app.get("/")
|
||||
def home():
|
||||
return {"msg": "API is working"}
|
||||
```
|
||||
|
||||
This is the recommended style for most simple APIs.
|
||||
|
||||
FastAPI automatically serializes the dictionary into JSON.
|
||||
|
||||
---
|
||||
|
||||
## Explicit JSONResponse
|
||||
|
||||
```python
|
||||
return JSONResponse(
|
||||
content={"msg": "API is working"},
|
||||
status_code=status.HTTP_200_OK
|
||||
)
|
||||
```
|
||||
|
||||
This gives more direct control over the response.
|
||||
|
||||
---
|
||||
|
||||
# 12. When to Use JSONResponse
|
||||
|
||||
Use `JSONResponse` when you need to:
|
||||
|
||||
Return dynamic status codes
|
||||
Add custom headers
|
||||
Customize the response structure manually
|
||||
Return responses from exception handlers
|
||||
Return responses from middleware
|
||||
Override FastAPI’s default response behavior
|
||||
|
||||
---
|
||||
|
||||
# 13. Example: JSONResponse with Custom Status Code
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI, status
|
||||
from fastapi.responses import JSONResponse
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
|
||||
@app.post("/login")
|
||||
def login():
|
||||
return JSONResponse(
|
||||
content={"msg": "Login successful"},
|
||||
status_code=status.HTTP_200_OK
|
||||
)
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 14. Example: JSONResponse with Headers
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI
|
||||
from fastapi.responses import JSONResponse
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
|
||||
@app.get("/custom")
|
||||
def custom_response():
|
||||
return JSONResponse(
|
||||
content={"msg": "Custom response"},
|
||||
headers={"X-App-Version": "1.0.0"}
|
||||
)
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 15. Complete Example with Response Model and JSONResponse
|
||||
|
||||
```python
|
||||
from fastapi import FastAPI, status
|
||||
from fastapi.responses import JSONResponse
|
||||
from pydantic import BaseModel
|
||||
|
||||
app = FastAPI()
|
||||
|
||||
|
||||
class UserIn(BaseModel):
|
||||
username: str
|
||||
password: str
|
||||
|
||||
|
||||
class UserOut(BaseModel):
|
||||
username: str
|
||||
|
||||
|
||||
@app.get("/")
|
||||
def home():
|
||||
return JSONResponse(
|
||||
content={"msg": "API is working"},
|
||||
status_code=status.HTTP_200_OK
|
||||
)
|
||||
|
||||
|
||||
@app.post(
|
||||
"/user",
|
||||
response_model=UserOut,
|
||||
status_code=status.HTTP_201_CREATED
|
||||
)
|
||||
def create_user(user: UserIn):
|
||||
return user
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 16. Running the Application
|
||||
|
||||
Start the FastAPI application using `uvicorn`:
|
||||
|
||||
```bash
|
||||
uvicorn main:app --reload
|
||||
```
|
||||
|
||||
The API will run at:
|
||||
|
||||
```text
|
||||
http://localhost:8000
|
||||
```
|
||||
|
||||
Interactive API documentation will be available at:
|
||||
|
||||
```text
|
||||
http://localhost:8000/docs
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
# 17. Best Practices
|
||||
|
||||
Use `response_model` to control API output.
|
||||
|
||||
Never return sensitive data such as passwords, tokens, or secrets.
|
||||
|
||||
Use separate models for input and output.
|
||||
|
||||
Use clear class names such as `UserIn` and `UserOut`.
|
||||
|
||||
Use `password` instead of `pass` because `pass` is a reserved Python keyword.
|
||||
|
||||
Place `response_model` inside the route decorator, not inside the function parameters.
|
||||
|
||||
Prefer returning normal dictionaries for simple responses.
|
||||
|
||||
Use `JSONResponse` only when extra control is required.
|
||||
|
||||
Use proper HTTP status codes, such as:
|
||||
|
||||
```http
|
||||
200 OK
|
||||
201 Created
|
||||
400 Bad Request
|
||||
401 Unauthorized
|
||||
404 Not Found
|
||||
500 Internal Server Error
|
||||
```
|
||||
|
||||
Do not use `uvicorn --reload` in production.
|
||||
|
||||
---
|
||||
|
||||
# 18. DevOps Production Note
|
||||
|
||||
In production, the FastAPI application should usually run behind a production-grade ASGI server setup and a reverse proxy.
|
||||
|
||||
A common production stack is:
|
||||
|
||||
```text
|
||||
FastAPI
|
||||
Gunicorn with Uvicorn workers
|
||||
Nginx or Traefik
|
||||
Docker or Kubernetes
|
||||
PostgreSQL or another persistent database
|
||||
```
|
||||
|
||||
The development command:
|
||||
|
||||
```bash
|
||||
uvicorn main:app --reload
|
||||
```
|
||||
|
||||
is only for local development.
|
||||
|
||||
For production, use a more stable process configuration, such as Gunicorn with Uvicorn workers, container health checks, logging, monitoring, and proper secret management.
|
||||
@@ -1,312 +0,0 @@
|
||||
# HTTP Requests in Python with `requests`
|
||||
|
||||
This document explains how to use the **`requests`** library to send HTTP requests, handle responses, work with APIs, upload/download files, manage headers, authentication, errors, and more.
|
||||
|
||||
> `requests` is not part of the standard library and must be installed:
|
||||
```bash
|
||||
pip install requests
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 1. Sending a Basic GET Request
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
import requests
|
||||
|
||||
r = requests.get("http://myip.abbascloud.ir")
|
||||
|
||||
print(r.url)
|
||||
print(r.status_code, r.ok)
|
||||
print(r.text)
|
||||
print(r.content)
|
||||
print(r.json())
|
||||
print(r.headers)
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- `requests.get(url)` sends an HTTP GET request.
|
||||
- `r.url`: final URL after redirects.
|
||||
- `r.status_code`: HTTP status code (e.g. 200, 404).
|
||||
- `r.ok`: `True` if status code is < 400.
|
||||
- `r.text`: response body as string.
|
||||
- `r.content`: response body as raw bytes.
|
||||
- `r.json()`: parses JSON response into Python objects.
|
||||
- `r.headers`: response headers as a dictionary.
|
||||
|
||||
---
|
||||
|
||||
## 2. Passing Query Parameters
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
params = {
|
||||
"q": "python",
|
||||
"page": 1
|
||||
}
|
||||
|
||||
response = requests.get("https://api.example.com/search", params=params)
|
||||
print(response.url)
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- `params` are appended to the URL as query strings.
|
||||
- Automatically encoded by `requests`.
|
||||
- Resulting URL:
|
||||
```
|
||||
https://api.example.com/search?q=python&page=1
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 3. Sending POST Requests (Form Data)
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
data = {
|
||||
"username": "alex",
|
||||
"password": "secret"
|
||||
}
|
||||
|
||||
requests.post(url, data=data)
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- Sends data as `application/x-www-form-urlencoded`.
|
||||
- Common for HTML form submissions.
|
||||
|
||||
---
|
||||
|
||||
## 4. Sending POST Requests (JSON)
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
json_data = {
|
||||
"name": "Alex",
|
||||
"age": 25
|
||||
}
|
||||
|
||||
requests.post(url, json=json_data)
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- Automatically serializes data to JSON.
|
||||
- Sets `Content-Type: application/json`.
|
||||
- Preferred for REST APIs.
|
||||
|
||||
---
|
||||
|
||||
## 5. Custom Request Headers
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
headers = {
|
||||
"Authorization": "Bearer YOUR_TOKEN",
|
||||
"User-Agent": "MyApp/1.0",
|
||||
"Accept": "application/json"
|
||||
}
|
||||
|
||||
response = requests.get(url, headers=headers)
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- Used for authentication, API versioning, and content negotiation.
|
||||
- Common headers:
|
||||
- `Authorization`
|
||||
- `User-Agent`
|
||||
- `Accept`
|
||||
|
||||
---
|
||||
|
||||
## 6. Authentication (Basic Auth)
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
from requests.auth import HTTPBasicAuth
|
||||
|
||||
requests.get(
|
||||
"https://api.example.com",
|
||||
auth=HTTPBasicAuth("username", "password")
|
||||
)
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- Sends credentials using HTTP Basic Authentication.
|
||||
- Automatically encodes credentials in headers.
|
||||
|
||||
---
|
||||
|
||||
## 7. Working with Cookies
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
response = requests.get(url)
|
||||
print(response.cookies)
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- Cookies are stored in a `RequestsCookieJar`.
|
||||
- Useful for sessions and login persistence.
|
||||
|
||||
---
|
||||
|
||||
## 8. Uploading Files
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
files = {
|
||||
"file": open("example.txt", "rb")
|
||||
}
|
||||
|
||||
response = requests.post(url, files=files)
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- Sends files as `multipart/form-data`.
|
||||
- Common for file uploads to APIs.
|
||||
|
||||
---
|
||||
|
||||
## 9. Downloading Files
|
||||
|
||||
### Simple Download
|
||||
|
||||
```python
|
||||
response = requests.get("https://example.com/image.png")
|
||||
|
||||
with open("image.png", "wb") as f:
|
||||
f.write(response.content)
|
||||
```
|
||||
|
||||
- Downloads entire file into memory.
|
||||
- Suitable for small files.
|
||||
|
||||
---
|
||||
|
||||
### Streaming Large Files
|
||||
|
||||
```python
|
||||
response = requests.get(url, stream=True)
|
||||
|
||||
with open("big.zip", "wb") as f:
|
||||
for chunk in response.iter_content(chunk_size=8192):
|
||||
f.write(chunk)
|
||||
```
|
||||
|
||||
- Downloads file in chunks.
|
||||
- Prevents high memory usage.
|
||||
- Recommended for large files.
|
||||
|
||||
---
|
||||
|
||||
## 10. Timeout and Error Handling
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
try:
|
||||
response = requests.get(url, timeout=5)
|
||||
response.raise_for_status()
|
||||
except requests.exceptions.Timeout:
|
||||
print("Request timed out")
|
||||
except requests.exceptions.HTTPError as e:
|
||||
print("HTTP error:", e)
|
||||
except requests.exceptions.RequestException as e:
|
||||
print("Request failed:", e)
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- `timeout`: maximum wait time (seconds).
|
||||
- `raise_for_status()`: raises exception for 4xx / 5xx errors.
|
||||
- `RequestException`: base class for all request errors.
|
||||
|
||||
---
|
||||
|
||||
## 11. Using Proxies
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
proxies = {
|
||||
"http": "http://127.0.0.1:8080",
|
||||
"https": "http://127.0.0.1:8080"
|
||||
}
|
||||
|
||||
requests.get(url, proxies=proxies)
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- Routes requests through a proxy server.
|
||||
- Useful for debugging, privacy, or corporate networks.
|
||||
|
||||
---
|
||||
|
||||
## 12. SSL Verification
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
requests.get(url, verify=True) # default
|
||||
requests.get(url, verify=False) # NOT recommended
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- `verify=True` checks SSL certificates.
|
||||
- Disabling SSL verification is insecure and should only be used for testing.
|
||||
|
||||
---
|
||||
|
||||
## 13. Real API Example (GitHub)
|
||||
|
||||
### Code
|
||||
|
||||
```python
|
||||
import requests
|
||||
|
||||
API_URL = "https://api.github.com/users/octocat"
|
||||
|
||||
response = requests.get(API_URL)
|
||||
|
||||
if response.ok:
|
||||
user = response.json()
|
||||
print(user["login"], user["public_repos"])
|
||||
else:
|
||||
print("Error:", response.status_code)
|
||||
```
|
||||
|
||||
### Explanation
|
||||
|
||||
- Sends a GET request to GitHub’s public API.
|
||||
- Parses JSON response.
|
||||
- Accesses specific fields safely.
|
||||
- Checks request success using `response.ok`.
|
||||
|
||||
---
|
||||
|
||||
## Summary
|
||||
|
||||
- `requests` simplifies HTTP communication
|
||||
- Supports GET, POST, headers, params, JSON, files
|
||||
- Handles authentication, cookies, proxies, and SSL
|
||||
- Built-in error handling improves reliability
|
||||
- Widely used for REST APIs and web services
|
||||
Reference in New Issue
Block a user