Limitations of HTTP
HTTP stands for Hypertext Transfer Protocol. It is one of the protocols used in the Application Layer for communication.
It works using the HTTP Protocol. It uses a request/response mechanism, and data flow is unidirectional. It uses the half-duplex mode of communication.
The drawback of HTTP Protocols leads to the use and emergence of WebSockets. Let us look at them:
Data Integrity
No encryption methods are used in HTTP Protocol, making the data vulnerable to alteration. Therefore, it is considered an insecure method.
Data Privacy
Relating to Data Integrity, Data Privacy is another issue with HTTP. If any third party intercepts the Client’s request, they can read and access the data and gain confidential information.
Server Availability
The client does not take any measure to terminate the established connection with the server even if the HTTP has received all the data required. This makes the Server unavailable during that period.
Administrative Overhead
Multiple connections must be created to transmit a web page leading to administrative overhead.
Delay in Responses
As it works on the request/respond mechanism, it takes time from the time the client requests from the server, and the server sends the required information.
IoT Device Support
As HTTP requires more system resources, it leads to more power consumption.
Also see, Difference Between Verilog and Vhdl
What do WebSockets offer?
The idea behind WebSocket was thought to overcome the limitations of HTTP Protocols. In HTTP, a client requests resources, and then the server responds with the requested information, which is strictly unidirectional protocol.
Although long polling comes to the rescue with longer timeouts but keeps the resources tied up during that whole time, even if no data is available to send.
At this point, WebSockets enable sending data with utmost data integrity and privacy, providing reliability. WebSockets utilize HTTP in the initial transport mechanism but keep the TCP connection established to send data between client and server.
WebSocket URLs use a new scheme, that is, ws: , for more secure WebSocket wss:. And the other part of the URL is similar to HTTP URI, that is, a host, port, path, and query parameters. The format is something like this:
“ws:””//”host[“.”post]path[“?”query] //For ws
“wss:””//”host[“.”post]path[“?”query] //For wss
WebSocket connections can only be created to URIs that have this scheme. This means that both client and server should follow the WebSocket connection protocol to follow the WebSocket specification.
The most essential feature of WebSockets is its network compatibility.
In WebSocket, data is continuously communicated into the same connection which is already open, that is why WebSocket is faster and improves the application performance.
How does WebSocket work?
To understand how WebSocket actually works, let’s first see how web pages get displayed on our browsers.
Web pages are transferred via the HTTP protocol. So, a request is sent to the server for every click you make on the website. The server then responds with appropriate action or data. This is what is called a request-and-respond model. A significant drawback of this model is the huge delay.
In WebSockets, things happen differently; all the calls and responses are sent in real-time. They follow a dynamic follow-up procedure. It uses the handshake mechanism, which is a part of the WebSocket protocol.
The handshake begins with an HTTP request or response, enabling servers to handle HTTP and WebSocket connections on the same port. Once the connection is created, communication switches to a bidirectional protocol, which is different from the HTTP protocol. The handshake has all of the identification information needed for data exchange.
After the handshake is done, the channel is kept open, allowing almost continuous communication. The server can independently send data to the client without the client requesting it again and again. The server sends any new information to the client without needing a specific request from the client-side.
To begin communication, the client sends a request like with HTTP, but an open connection is maintained via TCP. The content of the handshake between the client and the server is as follows:
The client sends the request:
GET /chatService HTTP/1.1
Host: server.example.com
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: dGhlIHNhbXBsZLBub25jZQ==
Sec-WebSocket-Origin: http://codein.com
Sec-WebSocket-Protocol: chat, superchat
Sec-WebSocket-Version: 13
The server answers:
HTTP/1.1 101 Switching Protocols
Upgrade: WebSocket
Connection: Upgrade
Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=
Sec-WebSocket-Protocol: superchat
The new URL scheme for WebSocket websites is ws and not http or wss for a more secure one.
WebSockets in IoT
IoT stands for Internet of Things. You can refer here to get a better understanding of IoT.
The IoT system must be able to present Data and Information from the sensor to the administrator or user in real-time. That is, the delay from the sensors to the user's screen should not be more than 300ms. Also, along with bandwidth speed, another problem is the technique of displaying data and information from the server to the user. There are numerous ways to send data and information from the sensor to the database server and display it on a laptop or smartphone. WebSocket method is a suitable method for exchanging data between the web server and mobile devices in IoT systems to support real-time applications, specifically for the smart home.
WebSocket communication is a suitable protocol for the IoT environment where lots of data are communicated continuously within multiple devices. A WebSocket allows server and device communication efficient. A server requires a WebSocket library to be installed and the WebSocket client and web browser installed on the client or device that supports WebSocket. The messages are transmitted using binary data that is encoded using JSON.
Applications of WebSockets
Because of so many properties of WebSockets, it has a lot of applications. Some of them are as follows:
Multiplayer games
In online games in which are many players and they are playing together a multi-player game, the changes need to be reflected for all the players very quickly. In those cases, WebSockets come in use as they have low latency.
Collaborative coding or editing
For distributed professional teams, who need to work on a single copy of a document or project, a collaborative solution like WebSockets makes it efficient and easy, without making any confusion. This
saves time and allows for greater collaboration.
Social feeds
Apps like Twitter, Instagram, Facebook, Whatsapp, etc., use WebSockets to immediately update the information on their feed, keeping users up to date( or up to second).
Clickstream data
Analyzing how users interact with your website is critical to improving it. The cost of HTTP has forced to prioritize and collect only the most critical data. So, using WebSockets makes it easy and takes less space.
Limitations of Websockets
A few limitations of Websockets are:
- WebSockets do not automatically recover when connections are closed, they need to be implemented explicitly.
- Browsers older than 2011 cannot support WebSocket connections. However, this is being worked upon.
- WebSocket is a very heavy protocol and has really complex hardware requirements.
- WebSocket requires HTTP implementation along with TCP implementation for initial connection setup.
Frequently Asked Questions
What are the different communication modes?
There are mainly three modes of communication: Simplex, Half-duplex and Full-duplex.
What are the different Computer network Models?
There are two popular computer Network Modesl namely: OSI(Open Systems Interconnection) Model and Internet Model
Which browsers support WebSockets?
WebSocket is currently supported by the following browsers:
- Internet Explorer: version 10 or later
- Firefox: version 6 or later
- Opera: version 12.10 or later
- Safari: version 6 or later
- Chrome: version 14 or later
Conclusion
This article extensively discusses WebSockets, its working and other properties.
We hope that this blog has helped you enhance your knowledge regarding WebSockets, and if you would like to learn more, check out our articles on Coding Ninjas Blogs.
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