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Difference between Polling and WebSockets

Polling and WebSockets are two different techniques for client-server communication, particularly useful for real-time applications. Here's a detailed comparison between the two, along with their use cases and examples:

Polling

Polling is a method where the client repeatedly requests data from the server at regular intervals.

How It Works:

Types of Polling:

  1. Regular Polling:

    • The client sends requests at fixed intervals regardless of whether new data is available.
    • Example: Sending a request every 5 seconds.
  2. Long Polling:

    • The client sends a request and the server holds the connection open until new data is available or a timeout occurs.
    • Once the server responds, the client immediately sends another request, creating a near-real-time connection.

Advantages:

Disadvantages:

Example (Regular Polling in JavaScript):

function poll() {
    setInterval(async () => {
        const response = await fetch('/api/data');
        const data = await response.json();
        console.log(data);
    }, 5000); // Poll every 5 seconds
}

poll();

WebSockets

WebSockets provide a full-duplex communication channel over a single, long-lived connection between the client and the server.

How It Works:

Advantages:

Disadvantages:

Example (WebSockets in JavaScript):

const socket = new WebSocket('ws://example.com/socket');

socket.onopen = function(event) {
    console.log('WebSocket connection opened.');
    socket.send('Hello Server!');
};

socket.onmessage = function(event) {
    console.log('Message from server:', event.data);
};

socket.onclose = function(event) {
    console.log('WebSocket connection closed.');
};

socket.onerror = function(event) {
    console.error('WebSocket error:', event);
};

Comparison Table

FeaturePollingWebSockets
CommunicationClient initiates each requestFull-duplex, bidirectional
LatencyHigher latencyLow latency
EfficiencyLess efficient (frequent requests)More efficient (persistent connection)
ImplementationSimpleComplex
CompatibilityWorks with any HTTP serverRequires WebSocket-compatible server
Use CaseSuitable for less frequent updates or simpler applicationsIdeal for real-time applications (chat, live updates)

Use Cases

Polling:

WebSockets:

Published on: Jul 08, 2024, 09:19 PM  
 

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