Understanding WebSockets and Their Distinction from HTTP
HTTP and WebSocket are both communication protocols used in client-server communication.
HTTP Protocol
HTTP operates in a unidirectional manner where the client sends a request and the server provides a response. For example, when a user sends a request to the server, it is transmitted via HTTP or HTTPS. Upon receiving the request, the server returns a response to the client. Each request corresponds to a specific response, and after the response is sent, the connection closes. Every HTTP or HTTPS request establishes a new connection to the server, which automatically terminates once the response is received.
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HTTP is a stateless protocol built on TCP, a connection-oriented protocol that ensures data packet delivery through three-way handshaking and retransmits lost packets. HTTP can operate over any reliable connection-oriented protocol like TCP or SCTP. When a client sends an HTTP request to the server, a TCP connection is established between them, which closes after the response is received.
Each HTTP request initiates a separate TCP connection to the server; for instance, if the client sends 10 requests, 10 separate TCP connections will be opened and closed after each response.
HTTP message information is encoded in ASCII. Each HTTP request message consists of the HTTP protocol version (HTTP/1.1, HTTP/2), HTTP methods (GET/POST, etc.), HTTP headers (content type, content length), host information, and the body containing the actual message sent to the server. HTTP headers typically range from 200 bytes to 2 KB, with a common size of 700-800 bytes. When a web application uses more cookies and other client-side tools that expand the agent's storage capabilities, it reduces the HTTP header payload.
WebSocket
WebSocket is a bidirectional, full-duplex protocol used in client-server communication scenarios, differing from HTTP as it begins with ws:// or wss://. It is a stateful protocol, meaning the connection between the client and server remains active until terminated by either party.
Once the connection is closed by either the client or server, it is terminated on both sides. For example, in client-server communication, with a web browser as the client and a server, when a connection is initiated, the client and server perform a handshake to establish a new connection, which stays active until either party ends it.
Understanding WebSockets and Their Distinction from HTTP
Communication occurs over this established connection channel until termination. After the handshake, the client and server agree to maintain this new connection, known as a WebSocket. Once the communication link is set up and connections are open, messages can be exchanged bidirectionally as long as the connection lasts.
If either the client or server fails or decides to close the connection, it is closed by both parties. The operation of WebSockets differs slightly from HTTP, with status code 101 indicating a protocol switch in WebSocket.
When is it appropriate to use a WebSocket?
Real-time web applications: WebSockets are utilized in real-time web applications to display data on the client side that is continuously transmitted by the backend server. Since WebSockets allow data to be continuously pushed through an already open connection, they are faster and enhance application performance.
For example, in trading platforms or bitcoin trading websites, price fluctuations and movement data are continuously pushed from the backend server to the client via a WebSocket channel.
Understanding WebSockets and Their Distinction from HTTP
Gaming applications: In gaming applications, data is continuously received by the server, and the user interface is updated automatically without the need to refresh or establish a new connection. This feature is particularly beneficial in gaming environments.
Chat applications: Chat applications employ WebSockets to establish a single connection for exchanging, publishing, and broadcasting messages among subscribers. The same WebSocket connection is reused for sending and receiving messages and for one-to-one message transfers.
When is it not advisable to use a WebSocket?
WebSockets are suitable for real-time updates or continuous data streams transmitted over the network. However, if the requirement is to fetch historical data or retrieve data only once for application processing, the HTTP protocol is preferred. Historical data that is infrequently required or fetched only once can be accessed via a simple HTTP request. In such cases, it is advisable not to use WebSockets.
Differences between HTTP and WebSocket Connection
WebSocket Connection | HTTP Connection |
WebSocket is a bidirectional communication protocol that can send the data from the client to the server or from the server to the client by reusing the established connection channel. The connection is kept alive until terminated by either the client or the server. | The HTTP protocol is a unidirectional protocol that works on top of TCP protocol which is a connection-oriented transport layer protocol, we can create the connection by using HTTP request methods after getting the response HTTP connection get closed. |
Almost all the real-time applications like (trading, monitoring, notification) services use WebSocket to receive the data on a single communication channel. | Simple RESTful application uses HTTP protocol which is stateless. |
All the frequently updated applications used WebSocket because it is faster than HTTP Connection. | It is used when we do not want to retain a connection for a particular amount of time or reuse the connection for transmitting data; An HTTP connection is slower than WebSockets. |
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