HTTP server status codes are three-digit codes returned in HTTP responses that indicate the server's processing of the request. These status codes provide information about the status of the request, such as success, redirect, client error, and server error. Parsing an HTTP server status code usually requires looking at the hundreds digit of the code to determine which status category it belongs to.
Here are some common HTTP server status codes and their interpretation:
1xx - Informational status codes: These status codes indicate that the server is processing the request, but needs more information to complete the request. For example, a 100 (Continue) status code indicates that the client can continue sending the remainder of the request.
2xx - Success status codes: These status codes indicate that the request was successfully received, understood, and accepted. The most common one is 200(OK), which means the request was completed successfully.
3xx - Redirect status codes: These status codes indicate that the client needs to take further action to complete the request. For example, the 301 (Permanent Redirect) status code indicates that the resource has been permanently moved to a new location and the client should update its link.
4xx - Client Error Status Codes: These status codes indicate that the request made by the client contained an error or could not be completed. For example, a 404 (Not Found) status code indicates that the server cannot find the requested resource.
5xx - Server Error Status Codes: These status codes indicate that the server encountered an error while processing the request. For example, the 500 (Internal Server Error) status code indicates that the server encountered an unexpected error.
The usual way to parse HTTP server status codes is to look at the status line in the response, which contains the HTTP version and status code. For example:
HTTP/1.1 200 OK
In this example, "200" in the status line represents a success status code, and "OK" provides a more detailed description.
Understanding HTTP server status codes is important for debugging and troubleshooting HTTP request and response issues. Different status codes can help you determine why problems occurred so you can better handle and fix them.