Explain Long Polling.
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Long polling is a web communication technique used to achieve real-time updates or asynchronous data retrieval between a web client (typically a browser) and a server. It is often used when there is a need for near-real-time updates from the server to the client without the continuous overhead of repeated polling.
Here's how long polling works:
Client Request: The client (usually a web browser) initiates a request to the server for some data or updates. This request is made using a standard HTTP request, just like any other request for a web page or resource.
Server Processing: The server receives the client's request and starts processing it. Instead of immediately responding with the requested data, the server "hangs" the request, meaning it does not send a response back right away.
Event or Data Availability: The server waits until there is new data or an event that the client is interested in. This could be new chat messages, stock price changes, or any other type of real-time information. When this data or event becomes available, the server prepares a response.
Server Response: Once the data or event is ready, the server sends a response back to the client. This response typically contains the updated data or information the client was waiting for.
Client Handling: The client receives the response and processes the data. After processing the response, the client immediately initiates a new request to the server, effectively starting the process over again.
Loop: This cycle of request, delayed response, and new request continues as long as the client wants to receive updates or until a predetermined condition is met.
