update services doc to libs

2026-01-23 23:21:00 +03:30
parent 6be588aa58
commit 6fbd717868
16 changed files with 1 additions and 1 deletions
--- a/Docs/Libs/FastAPI/01-Setup.md
+++ b/Docs/Libs/FastAPI/01-Setup.md
@@ -0,0 +1,100 @@
+# FastAPI – Environment Setup
+
+This document describes the initial setup required to prepare a Python environment for developing a FastAPI application.
+The steps below ensure isolation, dependency management, and reproducibility across environments.
+
+---
+
+## Prerequisites
+
+Before starting, ensure the following are installed on your system:
+
+* Python 3.8 or higher
+* `pip` (Python package manager)
+* `venv` module (included by default with most Python installations)
+
+You can verify your Python version with:
+
+```bash
+python3 --version
+```
+
+---
+
+## Step 1: Create a Virtual Environment
+
+A virtual environment isolates project dependencies and prevents conflicts with system-wide Python packages.
+
+From the project root directory, run:
+
+```bash
+python3 -m venv .venv
+```
+
+This command creates a `.venv` directory containing the isolated Python environment.
+
+---
+
+## Step 2: Activate the Virtual Environment
+
+Activate the virtual environment before installing any dependencies.
+
+### Linux / macOS
+
+```bash
+source .venv/bin/activate
+```
+
+### Windows (PowerShell)
+
+```powershell
+.venv\Scripts\Activate.ps1
+```
+
+After activation, your shell prompt should indicate that the virtual environment is active.
+
+---
+
+## Step 3: Install FastAPI
+
+With the virtual environment activated, install FastAPI using `pip`:
+
+```bash
+pip install fastapi
+```
+
+This installs the FastAPI framework and its required dependencies.
+
+> Note: In a real application, FastAPI is commonly used with an ASGI server such as `uvicorn`, which can be installed later if needed.
+
+---
+
+## Step 4: Freeze Dependencies
+
+To ensure reproducibility across environments (local, CI/CD, staging, production), export the installed dependencies to a requirements file:
+
+```bash
+pip freeze > requirement.txt
+```
+
+This file should be committed to version control and used by deployment pipelines to install exact dependency versions.
+
+---
+
+## Resulting Files
+
+After completing the steps above, your project directory should include:
+
+* `.venv/` – Python virtual environment (should not be committed to VCS)
+* `requirement.txt` – Dependency lock file
+
+---
+
+## Best Practices
+
+* Always activate the virtual environment before working on the project
+* Do not commit `.venv/` to source control
+* Keep `requirement.txt` updated when adding or upgrading dependencies
+* Use the same `requirement.txt` in CI/CD pipelines for consistent builds
+
+---
--- a/Docs/Libs/FastAPI/02-Simple-Route.md
+++ b/Docs/Libs/FastAPI/02-Simple-Route.md
@@ -0,0 +1,90 @@
+# FastAPI – Simple Route Example
+
+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.
+
+---
+
+## Create a Simple FastAPI Application
+
+Create a Python file named `main.py` and add the following content:
+
+```python
+from fastapi import FastAPI
+
+app = FastAPI()
+
+
+@app.get("/")
+def home_dir():
+    return {"message": "Home Page"}
+```
+
+### Explanation
+
+* `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.
+
+---
+
+## Running the Application
+
+FastAPI applications are typically run using **uvicorn**, an ASGI server designed for high performance.
+
+### Option 1: Run Using FastAPI CLI (Development Mode)
+
+FastAPI provides a development-friendly CLI wrapper that uses `uvicorn` internally:
+
+```bash
+fastapi dev main.py
+```
+
+This command:
+
+* 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 (Recommended)
+
+For explicit control over runtime configuration, run the application directly with `uvicorn`:
+
+```bash
+uvicorn main:app --reload --host 0.0.0.0 --port 1234
+```
+
+#### 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
+
+---
+
+## Accessing the Application
+
+Once running, the application will be available at:
+
+* API Endpoint:
+  `http://localhost:1234/`
+
+* Interactive API Docs (Swagger UI):
+  `http://localhost:1234/docs`
+
+* Alternative API Docs (ReDoc):
+  `http://localhost:1234/redoc`
+
+---
+
+## Best Practices
+
+* 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
+
--- a/Docs/Libs/FastAPI/03-Get-Method.md
+++ b/Docs/Libs/FastAPI/03-Get-Method.md
@@ -0,0 +1,169 @@
+# FastAPI – GET Endpoints and JSON Responses
+
+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.
+
+---
+
+## Example Application
+
+Create or update `main.py` with the following content:
+
+```python
+from fastapi import FastAPI
+
+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}
+    return {"message": "User not found"}
+```
+
+---
+
+## Code Overview
+
+### Application Initialization
+
+```python
+app = FastAPI()
+```
+
+Initializes the FastAPI application instance.
+
+---
+
+### In-Memory Data Store
+
+```python
+users = [
+    {"name": "abbas", "age": 20},
+    {"name": "mmd", "age": 37},
+    {"name": "asghar", "age": 19},
+]
+```
+
+* Simulates a database using a Python list
+* Each user is represented as a JSON-compatible dictionary
+* Suitable for development and testing purposes
+
+---
+
+## Defined Endpoints
+
+### Root Endpoint
+
+```http
+GET /
+```
+
+**Response:**
+
+```json
+{
+  "message": "API is working"
+}
+```
+
+Used as a health check or readiness probe.
+
+---
+
+### Get All Users
+
+```http
+GET /users
+```
+
+**Response:**
+
+```json
+[
+  {"name": "abbas", "age": 20},
+  {"name": "mmd", "age": 37},
+  {"name": "asghar", "age": 19}
+]
+```
+
+Returns the full list of users as JSON.
+
+---
+
+### Get User by Name (Path Parameter)
+
+```http
+GET /user/{name_input}
+```
+
+**Example Request:**
+
+```http
+GET /user/abbas
+```
+
+**Successful Response:**
+
+```json
+{
+  "information": {
+    "name": "abbas",
+    "age": 20
+  }
+}
+```
+
+**Failure Response:**
+
+```json
+{
+  "message": "User not found"
+}
+```
+
+---
+
+## Path Parameters
+
+* `name_input` is a dynamic path parameter
+* Automatically validated and converted to `str` by FastAPI
+* Used to filter data at runtime
+
+---
+
+## Running the Application
+
+Use `uvicorn` to start the service:
+
+```bash
+uvicorn main:app --reload
+```
+
+---
+
+## Best Practices
+
+* 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
+
--- a/Docs/Libs/FastAPI/04-Post-Method.md
+++ b/Docs/Libs/FastAPI/04-Post-Method.md
@@ -0,0 +1,127 @@
+# FastAPI – POST Endpoint and JSON Input
+
+This section demonstrates how to handle **POST requests** in FastAPI to create new resources using request data and return JSON responses.
+
+---
+
+## Example Application (POST Request)
+
+Extend `main.py` with the following code:
+
+```python
+from fastapi import FastAPI
+
+app = FastAPI()
+
+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(name: str, age: int):
+    new_user = {"name": name, "age": age}
+    users.append(new_user)
+    return {"msg": "User created successfully"}
+```
+
+---
+
+## Code Overview
+
+### POST Endpoint Definition
+
+```python
+@app.post("/new_user")
+def create_user(name: str, age: int):
+```
+
+* Registers an HTTP **POST** endpoint at `/new_user`
+* Accepts input parameters:
+
+  * `name` → string
+  * `age` → integer
+* FastAPI automatically validates input types
+
+---
+
+### Creating a New Resource
+
+```python
+new_user = {"name": name, "age": age}
+users.append(new_user)
+```
+
+* 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"
+```
+
+### Response
+
+```json
+{
+  "msg": "User created successfully"
+}
+```
+
+---
+
+## Verifying the Result
+
+After creating a user, retrieve the updated list:
+
+```http
+GET /users
+```
+
+Response will now include the newly added user.
+
+---
+
+## Running the Application
+
+Start the FastAPI service using `uvicorn`:
+
+```bash
+uvicorn main:app --reload
+```
+
+---
+
+## Best Practices
+
+* 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
+
--- a/Docs/Libs/FastAPI/05-Put-Method.md
+++ b/Docs/Libs/FastAPI/05-Put-Method.md
@@ -0,0 +1,162 @@
+# FastAPI – PUT Method 
+
+This document demonstrates how to use the **HTTP PUT method** in FastAPI to update an existing resource.
+It builds on previous GET and POST examples and completes a basic CRUD-style workflow.
+
+---
+
+## Example Application
+
+Create or update `main.py` with the following content:
+
+```python
+from fastapi import FastAPI
+
+app = FastAPI()
+
+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 show_users():
+    return users
+
+
+@app.post("/create_user")
+def create_user(name: str, age: int):
+    new_user = {"name": name, "age": age}
+    users.append(new_user)
+    return {"msg": f"user {name} with age {age} created"}
+
+
+@app.put("/update_user/{target_name}")
+def update_user(target_name: str, age: int):
+    for user in users:
+        if user["name"] == target_name:
+            user["age"] = age
+            return {"msg": f"user {target_name} updated"}
+    return {"msg": "user not found"}
+```
+
+---
+
+## Code Overview
+
+### PUT Endpoint Definition
+
+```python
+@app.put("/update_user/{target_name}")
+def update_user(target_name: str, age: int):
+```
+
+* Registers an HTTP **PUT** endpoint
+* `target_name` is a **path parameter**
+* `age` is a **query parameter**
+* Used to update an existing user’s data
+
+---
+
+### Update Logic
+
+```python
+for user in users:
+    if user["name"] == target_name:
+        user["age"] = age
+```
+
+* Iterates over the in-memory users list
+* Matches user by name
+* Updates the `age` field in place
+
+---
+
+### Success Response
+
+```json
+{
+  "msg": "user abbas updated"
+}
+```
+
+Returned when the target user exists and is updated successfully.
+
+---
+
+### Failure Response
+
+```json
+{
+  "msg": "user not found"
+}
+```
+
+Returned when no matching user exists.
+
+---
+
+## Example Requests
+
+### Update User Age (PUT)
+
+```bash
+curl -X PUT "http://localhost:8000/update_user/abbas?age=25"
+```
+
+### Verify Update
+
+```http
+GET /users
+```
+
+Updated response:
+
+```json
+[
+  {"name": "abbas", "age": 25},
+  {"name": "mmd", "age": 37},
+  {"name": "asghar", "age": 19}
+]
+```
+
+---
+
+## Running the Application
+
+Start the service using `uvicorn`:
+
+```bash
+uvicorn main:app --reload
+```
+
+---
+
+## HTTP Method Summary
+
+| Method | Endpoint              | Purpose                 |
+| ------ | --------------------- | ----------------------- |
+| GET    | `/`                   | Health check            |
+| GET    | `/users`              | Retrieve all users      |
+| POST   | `/create_user`        | Create a new user       |
+| PUT    | `/update_user/{name}` | Update an existing user |
+
+---
+
+## Best Practices
+
+* Use **PUT** for full updates and **PATCH** for partial updates
+* Return proper HTTP status codes (`404`, `200`, `201`)
+* Avoid using in-memory data stores in production
+* Use Pydantic models for request bodies instead of query parameters
+* Add input validation and error handling
+* Separate routes, services, and models as the project grows
+* Make PUT operations idempotent
+
--- a/Docs/Libs/FastAPI/06-Delete-Method.md
+++ b/Docs/Libs/FastAPI/06-Delete-Method.md
@@ -0,0 +1,172 @@
+# FastAPI – DELETE Method (Remove Resource)
+
+This document demonstrates how to use the **HTTP DELETE method** in FastAPI to remove an existing resource.
+It completes the CRUD workflow using **GET, POST, PUT, and DELETE** operations.
+
+---
+
+## Example Application
+
+Create or update `main.py` with the following content:
+
+```python
+from fastapi import FastAPI
+
+app = FastAPI()
+
+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 show_users():
+    return users
+
+
+@app.post("/create_user")
+def create_user(name: str, age: int):
+    new_user = {"name": name, "age": age}
+    users.append(new_user)
+    return {"msg": f"user {name} with age {age} created"}
+
+
+@app.put("/update_user/{target_name}")
+def update_user(target_name: str, age: int):
+    for user in users:
+        if user["name"] == target_name:
+            user["age"] = age
+            return {"msg": f"user {target_name} updated"}
+    return {"msg": "user not found"}
+
+
+@app.delete("/delete_user/{target_name}")
+def delete_user(target_name: str):
+    for user in users:
+        if user["name"] == target_name:
+            users.remove(user)
+            return {"msg": f"user {target_name} deleted"}
+    return {"msg": "user not found"}
+```
+
+---
+
+## Code Overview
+
+### DELETE Endpoint Definition
+
+```python
+@app.delete("/delete_user/{target_name}")
+def delete_user(target_name: str):
+```
+
+* Registers an HTTP **DELETE** endpoint
+* `target_name` is a **path parameter**
+* Used to remove a user from the data store
+
+---
+
+### Delete Logic
+
+```python
+for user in users:
+    if user["name"] == target_name:
+        users.remove(user)
+```
+
+* Iterates through the users list
+* Finds a matching user by name
+* Removes the user from the list
+
+---
+
+### Success Response
+
+```json
+{
+  "msg": "user abbas deleted"
+}
+```
+
+Returned when the user is successfully removed.
+
+---
+
+### Failure Response
+
+```json
+{
+  "msg": "user not found"
+}
+```
+
+Returned when the specified user does not exist.
+
+---
+
+## Example Requests
+
+### Delete a User
+
+```bash
+curl -X DELETE "http://localhost:8000/delete_user/abbas"
+```
+
+---
+
+### Verify Deletion
+
+```http
+GET /users
+```
+
+Response:
+
+```json
+[
+  {"name": "mmd", "age": 37},
+  {"name": "asghar", "age": 19}
+]
+```
+
+---
+
+## Running the Application
+
+Start the service with `uvicorn`:
+
+```bash
+uvicorn main:app --reload
+```
+
+---
+
+## CRUD Endpoint Summary
+
+| Method | Endpoint              | Description        |
+| ------ | --------------------- | ------------------ |
+| GET    | `/`                   | Health check       |
+| GET    | `/users`              | Retrieve all users |
+| POST   | `/create_user`        | Create a user      |
+| PUT    | `/update_user/{name}` | Update a user      |
+| DELETE | `/delete_user/{name}` | Delete a user      |
+
+---
+
+## Best Practices
+
+* Use **DELETE** only for resource removal
+* Return appropriate HTTP status codes (`204`, `404`)
+* Ensure delete operations are idempotent
+* Avoid modifying in-memory data in production
+* Add authentication and authorization for destructive operations
+* Log delete actions for auditability
+* Use database transactions when deleting persistent data
+
--- a/Docs/Libs/FastAPI/07-Query-Parameter.md
+++ b/Docs/Libs/FastAPI/07-Query-Parameter.md
@@ -0,0 +1,199 @@
+# FastAPI – Query Parameters
+
+This document demonstrates how to use **query parameters** in FastAPI using multiple typing styles, including:
+
+* Native Python union types (`str | None`)
+* `Optional` from `typing`
+* `Annotated` with `Query` validation
+
+---
+
+## Example Application
+
+Create or update `main.py` with the following content:
+
+```python
+from fastapi import FastAPI, Query
+from typing import Optional, Annotated
+
+app = FastAPI()
+
+users = [
+    {"name": "abbas", "age": 20},
+    {"name": "abbas", "age": 32},
+    {"name": "abbas", "age": 54},
+    {"name": "abbas", "age": 15},
+    {"name": "mmd", "age": 37},
+    {"name": "asghar", "age": 19},
+]
+
+
+@app.get("/")
+def home_page():
+    return {"msg": "API is working"}
+
+
+@app.get("/user")
+def get_users(target_name: str | None = None):
+    if target_name:
+        return [item for item in users if item["name"] == target_name]
+    return users
+
+
+@app.get("/user2")
+def get_users_optional(target_name: Optional[str] = None):
+    if target_name:
+        return [item for item in users if item["name"] == target_name]
+    return users
+
+
+@app.get("/user3")
+def get_users_annotated(
+    target_name: Annotated[str | None, Query(max_length=50)] = None
+):
+    if target_name:
+        return [item for item in users if item["name"] == target_name]
+    return users
+```
+
+---
+
+## Query Parameter Overview
+
+Query parameters are key-value pairs appended to the URL after `?`.
+
+**Example:**
+
+```
+/user?target_name=abbas
+```
+
+---
+
+## Defined Endpoints
+
+### 1. Basic Query Parameter (Python Union Type)
+
+```python
+@app.get("/user")
+def get_users(target_name: str | None = None):
+```
+
+* Uses Python 3.10+ union syntax
+* `target_name` is optional
+* If not provided, all users are returned
+
+**Example Request:**
+
+```
+GET /user?target_name=abbas
+```
+
+---
+
+### 2. Optional Query Parameter (`typing.Optional`)
+
+```python
+@app.get("/user2")
+def get_users_optional(target_name: Optional[str] = None):
+```
+
+* Uses `Optional[str]` for compatibility with older Python versions
+* Behavior is identical to the first endpoint
+
+**Example Request:**
+
+```
+GET /user2?target_name=abbas
+```
+
+---
+
+### 3. Validated Query Parameter (`Annotated + Query`)
+
+```python
+@app.get("/user3")
+def get_users_annotated(
+    target_name: Annotated[str | None, Query(max_length=50)] = None
+):
+```
+
+* Uses `Annotated` for metadata binding
+* Adds validation rules:
+
+  * `max_length=50`
+* Automatically returns validation errors if constraints are violated
+
+**Example Invalid Request:**
+
+```
+GET /user3?target_name=verylongnamethatexceedslimit...
+```
+
+**Response:**
+
+```json
+{
+  "detail": [
+    {
+      "type": "string_too_long",
+      "loc": ["query", "target_name"],
+      "msg": "String should have at most 50 characters",
+      "input": "..."
+    }
+  ]
+}
+```
+
+---
+
+## Example Responses
+
+### Filtered Response
+
+```json
+[
+  {"name": "abbas", "age": 20},
+  {"name": "abbas", "age": 32},
+  {"name": "abbas", "age": 54},
+  {"name": "abbas", "age": 15}
+]
+```
+
+---
+
+### Default Response (No Query Parameter)
+
+```json
+[
+  {"name": "abbas", "age": 20},
+  {"name": "abbas", "age": 32},
+  {"name": "abbas", "age": 54},
+  {"name": "abbas", "age": 15},
+  {"name": "mmd", "age": 37},
+  {"name": "asghar", "age": 19}
+]
+```
+
+---
+
+## Running the Application
+
+Start the service using `uvicorn`:
+
+```bash
+uvicorn main:app --reload
+```
+
+---
+
+## Best Practices
+
+* Use query parameters for filtering and searching
+* Always provide defaults for optional parameters
+* Use `Query()` for validation and constraints
+* Return full datasets when no filters are applied
+* Avoid large in-memory datasets in production
+* Use pagination for large result sets
+* Combine query parameters with database queries in real systems
+
--- a/Docs/Libs/FastAPI/08.Status-Codes.md
+++ b/Docs/Libs/FastAPI/08.Status-Codes.md
@@ -0,0 +1,192 @@
+# FastAPI – HTTP Status Codes and Error Handling
+
+This document demonstrates how to use **HTTP status codes** in FastAPI to accurately represent the result of an API operation.
+Correct status codes improve API reliability, observability, and client-side behavior.
+
+---
+
+## Example Application
+
+Create or update `main.py` with the following content:
+
+```python
+from fastapi import FastAPI, status, HTTPException
+
+app = FastAPI()
+
+users = [
+    {"name": "abbas", "age": 20},
+    {"name": "mmd", "age": 37},
+    {"name": "asghar", "age": 19},
+]
+
+
+@app.get("/", status_code=status.HTTP_200_OK)
+def home_page():
+    return {"msg": "API is working"}
+
+
+@app.get("/users", status_code=status.HTTP_200_OK)
+def show_users():
+    return users
+
+
+@app.post("/create_user", status_code=status.HTTP_201_CREATED)
+def create_user(name: str, age: int):
+    new_user = {"name": name, "age": age}
+    users.append(new_user)
+    return {"msg": f"user {name} with age {age} created"}
+
+
+@app.put("/update_user/{target_name}", status_code=status.HTTP_202_ACCEPTED)
+def update_user(target_name: str, age: int):
+    for user in users:
+        if user["name"] == target_name:
+            user["age"] = age
+            return {"msg": f"user {target_name} updated"}
+    raise HTTPException(
+        status_code=status.HTTP_404_NOT_FOUND,
+        detail="User not found"
+    )
+
+
+@app.delete("/delete_user/{target_name}", status_code=status.HTTP_204_NO_CONTENT)
+def delete_user(target_name: str):
+    for user in users:
+        if user["name"] == target_name:
+            users.remove(user)
+            return
+    raise HTTPException(
+        status_code=status.HTTP_404_NOT_FOUND,
+        detail="User not found"
+    )
+```
+
+---
+
+## Status Code Overview
+
+HTTP status codes communicate the result of an API request to clients and monitoring systems.
+
+| Code | Meaning    | Usage                             |
+| ---- | ---------- | --------------------------------- |
+| 200  | OK         | Successful GET requests           |
+| 201  | Created    | Resource successfully created     |
+| 202  | Accepted   | Update request accepted           |
+| 204  | No Content | Resource deleted successfully     |
+| 404  | Not Found  | Requested resource does not exist |
+
+---
+
+## Endpoint Behavior
+
+### Root Endpoint
+
+```http
+GET /
+```
+
+* Returns HTTP **200 OK**
+* Used as a health check
+
+---
+
+### Create User
+
+```http
+POST /create_user
+```
+
+* Returns HTTP **201 Created**
+* Indicates successful resource creation
+
+---
+
+### Update User
+
+```http
+PUT /update_user/{target_name}
+```
+
+* Returns HTTP **202 Accepted** on success
+* Raises HTTP **404 Not Found** if user does not exist
+
+---
+
+### Delete User
+
+```http
+DELETE /delete_user/{target_name}
+```
+
+* Returns HTTP **204 No Content** on success
+* Returns no response body
+* Raises HTTP **404 Not Found** if user does not exist
+
+---
+
+## Error Handling with `HTTPException`
+
+```python
+raise HTTPException(
+    status_code=status.HTTP_404_NOT_FOUND,
+    detail="User not found"
+)
+```
+
+* Immediately stops request processing
+* Returns structured error responses
+* Automatically serialized by FastAPI
+
+**Error Response Example:**
+
+```json
+{
+  "detail": "User not found"
+}
+```
+
+---
+
+## Example Requests
+
+### Create User
+
+```bash
+curl -X POST "http://localhost:8000/create_user?name=ali&age=25"
+```
+
+### Update User
+
+```bash
+curl -X PUT "http://localhost:8000/update_user/ali?age=30"
+```
+
+### Delete User
+
+```bash
+curl -X DELETE "http://localhost:8000/delete_user/ali"
+```
+
+---
+
+## Running the Application
+
+Start the application using `uvicorn`:
+
+```bash
+uvicorn main:app --reload
+```
+
+---
+
+## Best Practices
+
+* Always return meaningful HTTP status codes
+* Use `status` module instead of hard-coded numbers
+* Use `HTTPException` for predictable error handling
+* Do not return response bodies with `204 No Content`
+* Align status codes with REST conventions
+* Ensure monitoring systems rely on status codes, not messages
+* Standardize error formats across services
+
--- a/Docs/Libs/FastAPI/09-Json-Responce.md
+++ b/Docs/Libs/FastAPI/09-Json-Responce.md
@@ -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
+
--- a/Docs/Libs/FastAPI/10-Query-Path--AdvancedParm.md
+++ b/Docs/Libs/FastAPI/10-Query-Path--AdvancedParm.md
@@ -0,0 +1,238 @@
+# FastAPI – Advanced Path and Query Parameters
+
+This document demonstrates advanced usage of **path parameters** and **query parameters** in FastAPI, including:
+
+* Validation rules
+* Aliases
+* Descriptions for OpenAPI
+* Deprecation flags
+* Clear separation of responsibilities between path and query parameters
+
+---
+
+## Example Application
+
+Create or update `main.py` with the following content:
+
+```python
+from fastapi import FastAPI, Query, Path, status
+from fastapi.responses import JSONResponse
+
+app = FastAPI()
+
+users_db = [
+    {"id": "1", "name": "radin"}
+]
+
+
+@app.get("/user/{target_id}")
+def get_user_by_path(
+    target_id: int = Path(
+        ...,
+        alias="User ID",
+        description="Enter target unique ID",
+        deprecated=True,
+    )
+):
+    for item in users_db:
+        if int(item["id"]) == target_id:
+            return JSONResponse(
+                content={"msg": f"Your target user name is {item['name']}"},
+                status_code=status.HTTP_200_OK,
+            )
+
+    return JSONResponse(
+        content={"msg": "user not found"},
+        status_code=status.HTTP_404_NOT_FOUND,
+    )
+
+
+@app.get("/user")
+def get_user_by_query(
+    target: int | None = Query(
+        default=None,
+        gt=0,
+        alias="User ID",
+        description="Enter target unique ID",
+    )
+):
+    for item in users_db:
+        if item["id"] == str(target):
+            return JSONResponse(
+                content={"msg": f"Your target user name is {item['name']}"},
+                status_code=status.HTTP_200_OK,
+            )
+
+    return JSONResponse(
+        content={"msg": "user not found"},
+        status_code=status.HTTP_404_NOT_FOUND,
+    )
+```
+
+---
+
+## Path Parameter Example
+
+### Endpoint
+
+```http
+GET /user/{target_id}
+```
+
+**Example Request:**
+
+```
+/user/1
+```
+
+### Characteristics
+
+* Always required
+* Defined as part of the route
+* Used to identify a specific resource
+* Missing value results in **404 Not Found**
+* Supports validation, aliases, and documentation metadata
+
+---
+
+## Query Parameter Example
+
+### Endpoint
+
+```http
+GET /user?User%20ID=1
+```
+
+### Characteristics
+
+* Optional by default
+* Used for filtering and searching
+* Not part of the route path
+* Supports validation and documentation metadata
+* Uses default values when not provided
+
+---
+
+## Advanced Parameter Configuration
+
+### `Path()` Example
+
+```python
+Path(
+    ...,
+    alias="User ID",
+    description="Enter target unique ID",
+    deprecated=True
+)
+```
+
+* `...` → parameter is required
+* `alias` → custom name in documentation and URL
+* `description` → shown in Swagger UI
+* `deprecated` → marked as deprecated in OpenAPI
+
+---
+
+### `Query()` Example
+
+```python
+Query(
+    default=None,
+    gt=0,
+    alias="User ID",
+    description="Enter target unique ID"
+)
+```
+
+* `gt=0` → value must be greater than zero
+* Optional parameter with validation rules
+* Appears in API documentation
+
+---
+
+## Path vs Query Parameters
+
+### 1. Path Parameters
+
+**What they are**
+Values embedded directly in the URL path that identify a specific resource.
+
+**When to use**
+When the parameter is mandatory and uniquely identifies a resource.
+
+**Example URL**
+
+```
+/users/42
+```
+
+**FastAPI Example**
+
+```python
+@app.get("/users/{user_id}")
+def get_user(user_id: int):
+    return {"user_id": user_id}
+```
+
+**Key Points**
+
+* Always required
+* Part of the route definition
+* Used for IDs and unique identifiers
+* Missing value → 404 error
+
+---
+
+### 2. Query Parameters
+
+**What they are**
+Key-value pairs appended to the URL after `?`.
+
+**When to use**
+For optional filtering, searching, sorting, and pagination.
+
+**Example URL**
+
+```
+/users?limit=10&active=true
+```
+
+**FastAPI Example**
+
+```python
+@app.get("/users")
+def list_users(limit: int = 10, active: bool = True):
+    return {"limit": limit, "active": active}
+```
+
+**Key Points**
+
+* Optional by default
+* Not part of the route path
+* Used to modify or filter results
+* Defaults are used when missing
+
+---
+
+## Side-by-Side Comparison
+
+| Feature       | Path Parameter      | Query Parameter                   |
+| ------------- | ------------------- | --------------------------------- |
+| Location      | Inside URL path     | After `?`                         |
+| Required      | Yes                 | No (by default)                   |
+| Purpose       | Identify a resource | Filter or modify results          |
+| Example       | `/items/5`          | `/items?limit=10`                 |
+| Missing Value | 404 Not Found       | Default value or validation error |
+
+---
+
+## Best Practices
+
+* Use path parameters for resource identification
+* Use query parameters for filtering and modifiers
+* Avoid spaces in parameter aliases for production APIs
+* Deprecate parameters instead of removing them
+* Use validation (`gt`, `lt`, `regex`) for safer APIs
+* Keep URL design consistent across services
+* Prefer response models over manual JSON responses when possible
+
--- a/Docs/Libs/FastAPI/11-Post-Types.md
+++ b/Docs/Libs/FastAPI/11-Post-Types.md
@@ -0,0 +1,226 @@
+# POST Request Types and Content Types
+
+This document explains the **body types of POST requests** and the most common **Content-Types** used in APIs.
+Understanding these formats is essential for building interoperable and production-ready FastAPI services.
+
+---
+
+## POST Request Body Types
+
+A POST request sends data to the server in the **request body**.
+The format of this data is defined by the **Content-Type** header.
+
+---
+
+## 1. Form Data
+
+### Description
+
+Used primarily for HTML form submissions. Common in browser-based applications.
+
+### Content-Type
+
+```
+application/x-www-form-urlencoded
+```
+
+or
+
+```
+multipart/form-data
+```
+
+### Characteristics
+
+* Key-value pairs
+* Supports file uploads (multipart)
+* Common in login and upload forms
+
+### Example
+
+```http
+POST /login
+Content-Type: application/x-www-form-urlencoded
+
+username=admin&password=secret
+```
+
+---
+
+## 2. JSON
+
+### Description
+
+The most common data format for REST APIs.
+
+### Content-Type
+
+```
+application/json
+```
+
+### Characteristics
+
+* Structured, readable, and language-independent
+* Easily parsed and validated
+* Default choice for FastAPI APIs
+
+### Example
+
+```json
+{
+  "name": "abbas",
+  "age": 25
+}
+```
+
+---
+
+## 3. XML
+
+### Description
+
+An older but still widely used data format in enterprise systems and legacy APIs.
+
+### Content-Type
+
+```
+application/xml
+```
+
+or
+
+```
+text/xml
+```
+
+### Characteristics
+
+* Verbose and schema-driven
+* Common in SOAP-based services
+* Less common in modern REST APIs
+
+### Example
+
+```xml
+<user>
+  <name>abbas</name>
+  <age>25</age>
+</user>
+```
+
+---
+
+## 4. Plain Text
+
+### Description
+
+Used when sending raw text without structure.
+
+### Content-Type
+
+```
+text/plain
+```
+
+### Characteristics
+
+* No schema or structure
+* Useful for logs, messages, or simple payloads
+* Requires custom parsing on the server
+
+### Example
+
+```
+Hello FastAPI
+```
+
+---
+
+## 5. Binary Data
+
+### Description
+
+Used for sending non-textual data such as images, videos, or files.
+
+### Content-Type
+
+```
+application/octet-stream
+```
+
+### Characteristics
+
+* Raw binary format
+* Common for file uploads and downloads
+* Requires stream handling
+
+### Example
+
+```
+(binary file data)
+```
+
+---
+
+## 6. GraphQL
+
+### Description
+
+GraphQL uses POST requests to execute queries and mutations.
+
+### Content-Type
+
+```
+application/json
+```
+
+### Characteristics
+
+* Single endpoint
+* Flexible client-driven queries
+* Requires GraphQL server support
+
+### Example
+
+```json
+{
+  "query": "query { users { id name } }"
+}
+```
+
+---
+
+## Common Content Types Summary
+
+| Content-Type                        | Usage                      |
+| ----------------------------------- | -------------------------- |
+| `application/json`                  | REST APIs (default)        |
+| `application/x-www-form-urlencoded` | HTML forms                 |
+| `multipart/form-data`               | Forms with file uploads    |
+| `application/xml`                   | Legacy / SOAP APIs         |
+| `text/plain`                        | Raw text                   |
+| `application/octet-stream`          | Binary data                |
+| `application/graphql`               | GraphQL (rare, often JSON) |
+
+---
+
+## FastAPI Considerations
+
+* JSON is the recommended default for FastAPI
+* Use Pydantic models for JSON validation
+* Use `Form()` and `File()` for form and file uploads
+* Always validate content type in production APIs
+* Document supported content types clearly
+
+---
+
+## Best Practices
+
+* Choose the simplest format that meets requirements
+* Prefer `application/json` for APIs
+* Avoid XML unless required by integration
+* Secure file uploads (size limits, scanning)
+* Validate all incoming request bodies
+* Be explicit about supported Content-Types
+
--- a/Docs/Libs/FastAPI/12-From-Post.md
+++ b/Docs/Libs/FastAPI/12-From-Post.md
@@ -0,0 +1,165 @@
+# FastAPI – POST Requests with Form Data
+
+This document demonstrates how to handle **form-based POST requests** in FastAPI using the `Form()` dependency.
+Form data is commonly used in **HTML forms**, authentication flows, and legacy systems.
+
+---
+
+## Example Application
+
+Create or update `main.py` with the following content:
+
+```python
+from fastapi import FastAPI, Form, status
+from fastapi.responses import JSONResponse
+
+app = FastAPI()
+
+users_db = [
+    {"id": "1", "name": "radin", "password": "123"}
+]
+
+
+@app.post("/user/")
+def get_user_from_form(
+    target: int = Form(
+        ...,
+        gt=0,
+        alias="User ID",
+        description="Enter target unique ID",
+    )
+):
+    for item in users_db:
+        if item["id"] == str(target):
+            return JSONResponse(
+                content={"msg": f"Your target user name is {item['name']}"},
+                status_code=status.HTTP_200_OK,
+            )
+
+    return JSONResponse(
+        content={"msg": "user not found"},
+        status_code=status.HTTP_404_NOT_FOUND,
+    )
+```
+
+---
+
+## Form Data Overview
+
+### What is Form Data
+
+Form data is sent in the request body using:
+
+```
+Content-Type: application/x-www-form-urlencoded
+```
+
+or
+
+```
+multipart/form-data
+```
+
+FastAPI requires the `Form()` dependency to explicitly declare form inputs.
+
+---
+
+## Endpoint Behavior
+
+### Endpoint
+
+```http
+POST /user/
+```
+
+### Request Body (Form Data)
+
+```
+User ID=1
+```
+
+### Example Using `curl`
+
+```bash
+curl -X POST "http://localhost:8000/user/" \
+  -H "Content-Type: application/x-www-form-urlencoded" \
+  -d "User ID=1"
+```
+
+---
+
+## Response Examples
+
+### Success Response
+
+```json
+{
+  "msg": "Your target user name is radin"
+}
+```
+
+Status Code: **200 OK**
+
+---
+
+### Failure Response
+
+```json
+{
+  "msg": "user not found"
+}
+```
+
+Status Code: **404 Not Found**
+
+---
+
+## `Form()` Parameter Configuration
+
+```python
+Form(
+    ...,
+    gt=0,
+    alias="User ID",
+    description="Enter target unique ID"
+)
+```
+
+| Parameter     | Description                     |
+| ------------- | ------------------------------- |
+| `...`         | Field is required               |
+| `gt=0`        | Value must be greater than zero |
+| `alias`       | Custom form field name          |
+| `description` | Displayed in API docs           |
+
+---
+
+## Swagger / OpenAPI Behavior
+
+* Form fields appear as input fields
+* Aliases are reflected in the UI
+* Validation rules are enforced automatically
+* Errors are returned with clear messages
+
+---
+
+## Running the Application
+
+Start the service using `uvicorn`:
+
+```bash
+uvicorn main:app --reload
+```
+
+---
+
+## Best Practices
+
+* Use form data only when required (e.g. HTML forms)
+* Prefer JSON for APIs and services
+* Avoid exposing sensitive fields in plain form data
+* Use HTTPS for all form submissions
+* Validate and sanitize all inputs
+* Use authentication and hashing for passwords
+* Do not store credentials in plain text
+
--- a/Docs/Libs/FastAPI/13-Body-Post.md
+++ b/Docs/Libs/FastAPI/13-Body-Post.md
@@ -0,0 +1,161 @@
+# FastAPI – POST Requests with JSON Body (`Body`)
+
+This document demonstrates how to receive data from the **request body** using `Body()` in FastAPI.
+This approach is commonly used when clients send **JSON payloads**.
+
+---
+
+## Example Application
+
+Create or update `main.py` with the following content:
+
+```python
+from fastapi import FastAPI, Body, status
+from fastapi.responses import JSONResponse
+
+app = FastAPI()
+
+users_db = [
+    {"id": "1", "name": "radin", "password": "123"}
+]
+
+
+@app.post("/user/")
+def get_user_from_body(
+    target: int = Body(
+        ...,
+        embed=True,
+        gt=0,
+        alias="User ID",
+        description="Enter target unique ID",
+    )
+):
+    for item in users_db:
+        if item["id"] == str(target):
+            return JSONResponse(
+                content={"msg": f"Your target user name is {item['name']}"},
+                status_code=status.HTTP_200_OK,
+            )
+
+    return JSONResponse(
+        content={"msg": "user not found"},
+        status_code=status.HTTP_404_NOT_FOUND,
+    )
+```
+
+---
+
+## JSON Body Overview
+
+### What Is a Request Body
+
+The request body contains structured data sent by the client, most commonly as **JSON**.
+
+**Content-Type:**
+
+```
+application/json
+```
+
+---
+
+## Request Format
+
+### Example JSON Payload
+
+```json
+{
+  "User ID": 1
+}
+```
+
+* `embed=True` requires the value to be wrapped inside a JSON object
+* The key name is controlled by the `alias`
+
+---
+
+## Example Request Using `curl`
+
+```bash
+curl -X POST "http://localhost:8000/user/" \
+  -H "Content-Type: application/json" \
+  -d '{"User ID": 1}'
+```
+
+---
+
+## Response Examples
+
+### Success Response
+
+```json
+{
+  "msg": "Your target user name is radin"
+}
+```
+
+Status Code: **200 OK**
+
+---
+
+### Failure Response
+
+```json
+{
+  "msg": "user not found"
+}
+```
+
+Status Code: **404 Not Found**
+
+---
+
+## `Body()` Parameter Configuration
+
+```python
+Body(
+    ...,
+    embed=True,
+    gt=0,
+    alias="User ID",
+    description="Enter target unique ID"
+)
+```
+
+| Parameter     | Purpose                          |
+| ------------- | -------------------------------- |
+| `...`         | Field is required                |
+| `embed=True`  | Wraps the value in a JSON object |
+| `gt=0`        | Validates input value            |
+| `alias`       | Custom JSON key name             |
+| `description` | Shown in API documentation       |
+
+---
+
+## Swagger / OpenAPI Behavior
+
+* JSON schema is automatically generated
+* Validation errors are returned if rules are violated
+* Aliases and descriptions appear in Swagger UI
+* Request body is clearly documented
+
+---
+
+## Running the Application
+
+Start the service using `uvicorn`:
+
+```bash
+uvicorn main:app --reload
+```
+
+---
+
+## Best Practices
+
+* Prefer request body over query parameters for POST requests
+* Use Pydantic models instead of raw `Body()` for complex payloads
+* Keep JSON structures consistent
+* Avoid spaces in JSON keys for production APIs
+* Never send sensitive data in plain text
+* Use HTTPS for all JSON-based APIs
--- a/Docs/Libs/FastAPI/14-File-Post.md
+++ b/Docs/Libs/FastAPI/14-File-Post.md
@@ -0,0 +1,167 @@
+# FastAPI – POST Requests with File Uploads
+
+This document demonstrates how to handle **file uploads** in FastAPI.
+File uploads are essential for APIs that need to receive **images, documents, or binary data** from clients.
+
+---
+
+## Example Application
+
+Create or update `main.py` with the following content:
+
+```python
+from fastapi import FastAPI, File, UploadFile, status
+from fastapi.responses import JSONResponse
+from typing import List
+
+app = FastAPI()
+
+users_db = [
+    {"id": "1", "name": "radin", "password": "123"}
+]
+
+
+@app.post("/file")
+def upload_file_bytes(file: bytes = File(...)):
+    """
+    Receive file as raw bytes.
+    Returns the size of the uploaded file.
+    """
+    return {"file_size": len(file)}
+
+
+@app.post("/uploadfile")
+def upload_file_uploadfile(file: UploadFile):
+    """
+    Receive file as UploadFile.
+    Returns filename, content type, and size.
+    """
+    content = file.read()
+    return {
+        "filename": file.filename,
+        "content_type": file.content_type,
+        "file_size": len(content)
+    }
+
+
+@app.post("/uploadmultifile")
+def upload_multiple_files(files: List[UploadFile]):
+    """
+    Receive multiple files as UploadFile list.
+    Returns filenames and content types.
+    """
+    return [
+        {"filename": file.filename, "content_type": file.content_type}
+        for file in files
+    ]
+```
+
+---
+
+## File Upload Methods
+
+### 1. `File` as Bytes
+
+* Accepts the uploaded file as raw bytes
+* Suitable for small files or direct in-memory processing
+* Fast but lacks metadata (filename, content type)
+
+**Example Request (curl):**
+
+```bash
+curl -X POST "http://localhost:8000/file" \
+  -F "file=@example.txt"
+```
+
+**Response:**
+
+```json
+{
+  "file_size": 128
+}
+```
+
+---
+
+### 2. `UploadFile`
+
+* Accepts file as `UploadFile` object
+* Provides metadata: `filename` and `content_type`
+* Supports `.read()`, `.write()`, and `.seek()` operations
+* More efficient for large files (uses spooled temporary files)
+
+**Example Request (curl):**
+
+```bash
+curl -X POST "http://localhost:8000/uploadfile" \
+  -F "file=@example.txt"
+```
+
+**Response:**
+
+```json
+{
+  "filename": "example.txt",
+  "content_type": "text/plain",
+  "file_size": 128
+}
+```
+
+---
+
+### 3. Multiple File Uploads
+
+* Accepts a list of `UploadFile`
+* Allows uploading multiple files in one request
+* Useful for batch uploads or form submissions
+
+**Example Request (curl):**
+
+```bash
+curl -X POST "http://localhost:8000/uploadmultifile" \
+  -F "files=@file1.txt" \
+  -F "files=@file2.txt"
+```
+
+**Response:**
+
+```json
+[
+  {"filename": "file1.txt", "content_type": "text/plain"},
+  {"filename": "file2.txt", "content_type": "text/plain"}
+]
+```
+
+---
+
+## Content-Type
+
+For file uploads, the request must include:
+
+```
+Content-Type: multipart/form-data
+```
+
+* Each file is sent as a separate part in the multipart request
+
+---
+
+## Running the Application
+
+Start the service using `uvicorn`:
+
+```bash
+uvicorn main:app --reload
+```
+
+---
+
+## Best Practices
+
+* Use `UploadFile` for large or multiple files
+* Validate file type and size on the server
+* Avoid loading very large files fully into memory
+* Use HTTPS for secure file transfer
+* Store files in dedicated storage (S3, local disk, or DB)
+* Return clear metadata (filename, size, content type) to clients
+* Support multiple files when needed for batch operations
--- a/Docs/Libs/FastAPI/15-Life-Span.md
+++ b/Docs/Libs/FastAPI/15-Life-Span.md
@@ -0,0 +1,121 @@
+    # FastAPI – Application Lifespan (Startup & Shutdown Events)
+
+FastAPI allows you to run code when your application **starts up** or **shuts down**.
+This is useful for initializing resources, database connections, caches, or background tasks.
+
+---
+
+## Deprecated Method: `@app.on_event`
+
+Older FastAPI versions use the `@app.on_event` decorator for lifecycle events:
+
+```python
+from fastapi import FastAPI
+
+app = FastAPI()
+
+
+@app.on_event("startup")
+def on_startup():
+    print("App is loading")
+
+
+@app.on_event("shutdown")
+def on_shutdown():
+    print("App is shutting down")
+```
+
+### Characteristics
+
+* `startup` runs once when the app starts
+* `shutdown` runs once when the app is stopped
+* Works for synchronous and asynchronous functions
+* Still supported but **deprecated** in favor of the `lifespan` parameter
+
+---
+
+## Recommended Modern Approach: `lifespan` with `asynccontextmanager`
+
+FastAPI now recommends using the `lifespan` parameter in the `FastAPI` constructor.
+This uses Python's `asynccontextmanager` to define a **single lifecycle context**.
+
+```python
+from fastapi import FastAPI
+from contextlib import asynccontextmanager
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    # Code to run before the app starts
+    print("App is loading")
+    yield  # Application runs after this point
+    # Code to run after the app stops
+    print("App is shutting down")
+
+app = FastAPI(lifespan=lifespan)
+```
+
+### How It Works
+
+1. Code **before `yield`** executes on startup
+2. Code **after `yield`** executes on shutdown
+3. Supports async operations, e.g., connecting to a database
+
+---
+
+## Example: Using Lifespan for Database Initialization
+
+```python
+from fastapi import FastAPI
+from contextlib import asynccontextmanager
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    app.state.db = await connect_to_db()
+    print("Database connected")
+    yield
+    await app.state.db.close()
+    print("Database disconnected")
+
+app = FastAPI(lifespan=lifespan)
+```
+
+* `app.state` is used to store shared resources
+* Clean startup and shutdown handling
+* Ensures proper resource cleanup
+
+---
+
+## Benefits of the Lifespan Approach
+
+* Centralized lifecycle management
+* Cleaner async support
+* Avoids multiple scattered `@app.on_event` decorators
+* Better for testing and production-ready apps
+
+---
+
+## Running the Application
+
+Start the service with `uvicorn`:
+
+```bash
+uvicorn main:app --reload
+```
+
+* On startup, `App is loading` prints to the console
+* On shutdown (Ctrl+C), `App is shutting down` prints to the console
+
+---
+
+## Best Practices
+
+* Always use `lifespan` for new applications
+* Use `app.state` to store shared resources
+* Close database connections, caches, or background services in shutdown
+* Keep startup logic lightweight to avoid blocking the server
+* Avoid printing in production; use logging instead
+
+---
+
+This approach provides a **modern, production-ready pattern** for managing application startup and shutdown events in FastAPI.
+
--- a/Docs/Libs/Redis/Redis.md
+++ b/Docs/Libs/Redis/Redis.md
@@ -0,0 +1,172 @@
+# Python + Redis Quick Guide
+
+This document explains how to set up Python, connect to Redis, and perform basic cache operations.
+
+---
+
+## 1. Setup
+
+Install Python and create a virtual environment:
+
+```bash
+sudo apt install python3-full
+python3 -m venv .venv
+source .venv/bin/activate
+```
+
+---
+
+## 2. Connect and Test Redis Connection
+
+```python
+import redis
+
+r = redis.Redis(host='localhost', port=6379, db=0)
+print(r.ping())  # Should print True
+```
+
+**Expected Output:**
+
+```
+True
+```
+
+---
+
+## 3. Caching Scenario Example
+
+This example demonstrates caching data in Redis with a TTL (Time To Live).
+
+```python
+import redis
+import time
+
+r = redis.Redis(host='localhost', port=6379, db=0)
+
+def get_data_from_db():
+    print("Fetching from DB...")
+    time.sleep(2)  # Simulate slow query
+    return {"user": "alice", "age": 30}
+
+def get_user(user_id):
+    cache_key = f"user:{user_id}"
+    
+    # Check cache first
+    cached = r.get(cache_key)
+    if cached:
+        print("Cache hit")
+        return eval(cached)
+    
+    # Fetch from DB
+    data = get_data_from_db()
+    
+    # Store in Redis with TTL (10 seconds)
+    r.set(cache_key, str(data), ex=10)
+    return data
+
+print(get_user(1))
+print(get_user(1))  # Should hit cache
+```
+
+---
+
+## 4. Connect, Set, and Get Example
+
+```python
+import redis
+
+r = redis.Redis(host="192.168.6.160", port=6379, db=0)
+
+r.set('name', 'radin')
+
+name = r.get('name')
+print(name)
+print(name.decode("utf-8"))
+```
+
+---
+
+## 5. Interactive Read/Write Example
+
+```python
+import redis
+
+method = int(input("Enter Method: (1.Read/2.Write) "))
+
+r = redis.Redis(host="192.168.6.160", port=6379, db=0)
+
+if method == 1:
+    key = str(input("Enter key name: "))
+    value = r.get(key)
+    if value is None:
+        print("Undefined Key")
+    else:
+        print(value)
+elif method == 2:
+    key = str(input("Enter key name: "))
+    value = str(input("Enter value: "))
+    r.set(key, value)
+else:
+    print("Incorrect Input")
+```
+
+---
+
+## 6. Professional Version (Improved Code)
+
+```python
+import redis
+import sys
+
+def connect_redis(host="192.168.6.160", port=6379, db=0):
+    """Establish a connection to Redis."""
+    try:
+        client = redis.Redis(host=host, port=port, db=db, decode_responses=True)
+        # Test connection
+        client.ping()
+        return client
+    except redis.ConnectionError as e:
+        print(f"Error connecting to Redis: {e}")
+        sys.exit(1)
+
+def read_key(client):
+    """Read a key from Redis."""
+    key = input("Enter key name: ").strip()
+    value = client.get(key)
+    if value is None:
+        print("Undefined Key")
+    else:
+        print(f"Value: {value}")
+
+def write_key(client):
+    """Write a key-value pair to Redis."""
+    key = input("Enter key name: ").strip()
+    value = input("Enter value: ").strip()
+    client.set(key, value)
+    print(f"Successfully set key '{key}' with value '{value}'.")
+
+def main():
+    client = connect_redis()
+
+    print("Select Method:")
+    print("1. Read")
+    print("2. Write")
+    
+    try:
+        method = int(input("Enter method (1 or 2): ").strip())
+    except ValueError:
+        print("Invalid input. Please enter 1 or 2.")
+        sys.exit(1)
+
+    if method == 1:
+        read_key(client)
+    elif method == 2:
+        write_key(client)
+    else:
+        print("Incorrect input. Please enter 1 or 2.")
+        sys.exit(1)
+
+if __name__ == "__main__":
+    main()
+```
+