Introduction to Memcached

Memcached is a high-performance, distributed memory caching system, commonly used to speed up dynamic web applications by reducing the database load. Memcached stores data in-memory and serves it from there until cache expiration, offering rapid data retrieval.

Core APIs of Memcached

Below are some of the most commonly used APIs of Memcached, illustrated with code snippets in Python, using the popular pymemcache library:

1. Connect to Memcached

      
      from pymemcache.client import base

      client = base.Client(('localhost', 11211))
      
    

2. Set a Value

      
      client.set('key', 'value')
      
    

3. Get a Value

      
      value = client.get('key')
      print(value)
      
    

4. Delete a Value

      
      client.delete('key')
      
    

5. Increment a Value

      
      client.incr('counter', 1)
      
    

6. Decrement a Value

      
      client.decr('counter', 1)
      
    

7. Check Key Existence

      
      exists = client.get('key') is not None
      print(exists)
      
    

8. Add a Value (Only if it Doesn’t Exist)

      
      client.add('new_key', 'new_value')
      
    

9. Replace a Value (Only if it Exists)

      
      client.replace('existing_key', 'new_value')
      
    

10. Append to a Value

      
      client.append('key', 'additional_value')
      
    

11. Prepend to a Value

      
      client.prepend('key', 'initial_value')
      
    

Example Application Using Memcached

Let’s create a simple web application using Flask, a lightweight WSGI web application framework, to showcase the use of Memcached:

      
      from flask import Flask, request
      from pymemcache.client import base

      app = Flask(__name__)
      client = base.Client(('localhost', 11211))

      @app.route('/')
      def index():
          return 'Welcome to the Memcached Example App!'

      @app.route('/set')
      def set_value():
          key = request.args.get('key')
          value = request.args.get('value')
          client.set(key, value)
          return f'Set {key} to {value}'

      @app.route('/get')
      def get_value():
          key = request.args.get('key')
          value = client.get(key)
          return f'The value of {key} is {value}'

      @app.route('/delete')
      def delete_value():
          key = request.args.get('key')
          client.delete(key)
          return f'Deleted {key}'

      if __name__ == '__main__':
          app.run(debug=True)
      
    

In this example, we’ve created an application that can set, get, and delete values from Memcached. You can run the Flask app and test the functionalities via your web browser or tools like Postman.