HTTP Status Codes and Their Meanings

HTTP Status Codes and Their Meanings

Topic Description: HTTP status codes are three-digit identifiers that represent the server's response to a client's request. They are divided into five categories, each indicating a different type of response status. Understanding the meaning of these status codes is crucial for web development, API debugging, and network troubleshooting.

Problem-Solving Process:

  1. Basics of Status Code Categories

    • 1xx (Informational): The request has been received and processing continues.
    • 2xx (Success): The request was successfully received, understood, and accepted by the server.
    • 3xx (Redirection): The client needs to take further action to complete the request.
    • 4xx (Client Error): There is an error in the client's request.
    • 5xx (Server Error): The server encountered an error while processing the request.

  2. Detailed Explanation of Common Status Codes

    • 200 OK: The request was successful, and the response contains the requested result.
    • 201 Created: The request has been fulfilled, and a new resource has been created (commonly used for POST requests).
    • 204 No Content: The request was successful, but the response does not contain a body.

  3. Redirection Status Codes

    • 301 Moved Permanently: Permanent redirect; the resource has permanently moved to a new location.
    • 302 Found: Temporary redirect; the resource is temporarily served from a different location.
    • 304 Not Modified: The resource has not been modified, and the cached version can be used.

  4. Client Error Status Codes

    • 400 Bad Request: The request message contains a syntax error.
    • 401 Unauthorized: Authentication is required.
    • 403 Forbidden: The server refuses the request.
    • 404 Not Found: The server cannot find the requested resource.

  5. Server Error Status Codes

    • 500 Internal Server Error: An internal server error occurred.
    • 502 Bad Gateway: The gateway or proxy server received an invalid response from the upstream server.
    • 503 Service Unavailable: The server is temporarily unavailable.

  6. Practical Application Tips

    • Quickly identify the type of issue during development based on status codes.
    • Choose appropriate status codes when designing APIs.
    • Monitor the distribution of status codes in monitoring systems to detect system issues.