services doc : redis doc

Docs/Services/Redis.md

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+# 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()
+```
+