Long Polling vs WebSockets

Difference Between Long Polling vs WebSockets

• Long polling is an efficient technique now day uses HTTP protocol; in which the server is going to send data to the client; among them, there is no delay in events.
• Using this technique, sever can hold the client’s connection open as much time as possible and only send the data whenever there is actual need.
• Whereas WebSocket is a technique in which the browser is built, the server gets notified by the browser whenever the browser sends something to the server.
• This is the process that establishes full-duplex communication with the help of a single protocol called TCP. This is a two-way process for communication between client and server.

Head to Head Comparisons Between Long Polling vs WebSockets (Infographics)

Below are the top 7 comparisons between Long Polling vs WebSockets:

Key Differences Between Long Polling vs WebSockets

There is some key differences point which makes both the things like long polling and WebSockets separate from each other,  let’s see in details one by one:

Long Polling

• As we know, long polling is the technique in which there are two entities; one is a client, and another is a server. So in the process of communication client want to know some data or information from the server.
• So it does the request for the needed information to the server without doing any immediate response to the server; after that, it will hold the connection as an open, which gives permission to the server to respond later on.
• Using AJAX call in long polling forces the server to keep checking whether any new data comes into the connection or not, which is for a very short time period.
• Here, using HTTP protocol does not mean that keeping the connection open doesn’t mean the server wants to send frequent data or the information to its related client.
• In between this process, a connection is created to the server, and it will keep this connection open where the client can receive data from the related server.

Long polling is the process that is based on an event-based algorithm which includes processes like:

• In the initial step, the client will send an ajax request through the AJAX.
• After that in the next step server will check for the changes which are done within the data.
• The next step determines the algorithm’s actual condition in which it will check if changes are done within data means it will return the value yes, then changed data will be displayed, and control will go back to #1.
• If the previous step fails means, there is no any changes with data, though the server will wait on short time period, and controls will go back to the #2

This method is only helpful whenever you are processing your data for very close to real-time. This is because it believes and waits until it makes some move rather than keep waiting for the timer. So this is treated as a long time-based process due to server-side script rather than in quick short timestamp.

WebSockets

• Web sockets are the connection stream based on a single-layer protocol called TCP/IP. This is used to create a connection to the server, and the main interesting is to keep waiting as much time as needed, which exactly differs from the long polling.
• Once all processes or events are done from the connection, either the client or the server can easily terminate it. The main interesting feature of it is the user can do bidirectional communication among client and server; this means simultaneously in both directions like the client to server and from server to client as well.
• Because of this scenario, the process of sending messages frequently becomes very efficient. Data encryption is also done in a very simple manner.
• The performance rate is obtusely high in WebSocket programming as compared to long polling due to all features mentioned earlier.
• This is also beneficial because it utilizes resources that were wasted in long polling due to the use of HTTP protocol, which is very disadvantaging and also causes the difficulty of connection time out.
• Compatibility is one of the major factors for the webpage; for solving compatibility issues, WebSockets uses an HTTP upgrade header to replace HTTP protocol, so a new HTTP protocol is going to support WebSocket.
• WebSocket is treated as frame-based, where other is considering as stream-based. So it’s treated differently for the actual delivery of data.

Comparison Table of Long Polling vs WebSockets

Let’s look at the top comparisons between Long Polling and WebSockets.

Sr. No	Long Polling	WebSockets
1.	Long Pooling programming is a unidirectional data transfer process that means the user can do only one-way connection communication at a single time.	WebSockets programming is a bidirectional process that means one can send data from client to server or from server to client in both directions at a time.
2.	It uses an HTTP protocol for connection purposes.	It uses TCP/IP as a single layer protocol for establishing a connection.
3.	While using the HTTP protocol, this method will wait for a shorter time for getting data updates from the server.	In this method, TCP/IP protocol till waiting whenever updates are not getting from the server. Once it’s done, it will do further process.
4.	This is responsible for the wastage of resources as well as the frequent connection timeout process.	It will wait for the update until getting an update from the server is beneficial for resource utilization purposes.
5.	It is an easy method to implement.	As compare to Long polling, it is difficult to implement.
6.	It’s having latency problems.	This method overcomes the latency problems from long polling.
7.	Headers are sent along with HTTP for every interchange.	Here, no headers are sent for every interchange.

Conclusion

From the above information, we came to know that both are the connection stream used for data transmission, in which Long Polling is for unidirectional whereas WebSockets for two way transmission. Long polling easy in processing using HTTP. WebSockets require an explicit method to close the connection once the task has done.

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