Analysis of HTTP status code differences

In network communication, the HTTP protocol is one of the most commonly used application layer protocols. During the HTTP communication process, the server will return a status code in the response message. This status code is used to inform the processing status of the request. HTTP status codes are divided into five categories, namely 1xx, 2xx, 3xx, 4xx and 5xx.

First, let’s take a look at the 1xx status code. 1xx status codes are informational status codes used to inform the client that the request was received but is still being processed. The most common one is the 100 Continue status code. When the client sends a request, if the server receives the request header and determines that the request can continue to be processed, it will return the 100 Continue status code, indicating that the client can continue to send the request body.

Next is the 2xx status code. This type of status code indicates that the request is successful. The most common is the 200 OK status code, which indicates that the request was successfully processed and the requested response was returned. In addition, the 204 No Content status code indicates that the server has successfully processed the request, but does not need to return any entity content in the response. The 206 Partial Content status code indicates that the server successfully processed part of the request, and the response message contains part of the entity content, which is generally used for resumed transmission or audio and video downloads.

Then there are 3xx status codes, which indicate that further operations are required to complete the request. The most common is the 302 Found status code, which indicates that the requested resource has been temporarily moved to a new URL. In addition, the 301 Moved Permanently status code indicates that the requested resource has been permanently moved to a new URL. The 304 Not Modified status code indicates that the requested resource has not been modified on the server.

Next is the 4xx status code, which indicates an error on the client side. The most common is the 400 Bad Request status code, which means that the server cannot understand the syntax of the request. In addition, the 403 Forbidden status code indicates that the server refuses to execute the request, usually because the requested resource does not have the corresponding permissions. The 404 Not Found status code indicates that the requested resource does not exist on the server.

The last is the 5xx status code. This type of status code indicates a server error. The most common is the 500 Internal Server Error status code, which means that the server encountered an error that cannot be handled. In addition, the 503 Service Unavailable status code indicates that the server is temporarily unable to process the request, usually because the server is overloaded or under maintenance.

By analyzing different HTTP status codes, we can have a deeper understanding of the server's processing under various circumstances in network communication. In actual development, it is very important to understand and handle these status codes, which can help us quickly locate and solve problems and improve the reliability and stability of the system. Therefore, as developers, we need to have a clear understanding of HTTP status codes, and reasonably process and utilize the status code information in actual use.

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