Long polling is a technique used to improve the responsiveness of web applications. It allows the server to push data to the client as soon as it becomes available, without the client having to continuously poll the server for updates.
What is Long Polling?
Long polling is a variation of the traditional polling mechanism. In traditional polling, the client sends a request to the server, and if there is no new data, the server responds with an empty result and the client has to send another request immediately.
In contrast, long polling, the client sends a request to the server and the server holds the request open until new data is available. Once the data is available, the server sends the data to the client and closes the connection.
How Long Polling Works
- The client sends a request to the server.
- The server holds the request open until new data is available.
- When new data is available, the server sends the data to the client and closes the connection.
- The client receives the data and sends another request to the server.
Benefits of Long Polling
- Reduces the number of requests sent by the client, leading to better performance.
- Improves the responsiveness of web applications.
- Allows the server to push data to the client as soon as it becomes available.
Example
Here's an example of how long polling works in a chat application:
- The client sends a request to the server to receive new messages.
- The server holds the request open until a new message is received.
- When a new message is received, the server sends the message to the client and closes the connection.
- The client receives the message and sends another request to the server.
Long Polling in Action
To learn more about long polling and see it in action, you can check out our Long Polling Example.