The responsibility of the status code is to describe the result of the request returned when the client sends a request to the server. With the status code, the user can tell whether the server handled the request properly or an error occurred.

Category of status code:

2XX — indicates that the request was processed normally

1. 200 OK: The request is processed normally.

2, 204 No Content: The request is processed successfully, but No resources can be returned to the client. Generally, the request is used when only information needs to be sent from the client to the server, and No new information Content needs to be sent to the client.

206 Partial Content: a request for a part of the resource. This status code indicates that the client made the scope request and the server successfully executed the GET request for this part. The response packet contains the entity Content in the content-range Range.

3XX — indicates that the browser needs to perform some special processing to process the request correctly

301 Moved, Permanently: The URI of the resource has been updated, please update your bookmark reference, too. Permanent redirection, where the requested resource has been assigned a new URI and should later use the URI to which the resource now refers.

302: The resource URI was temporarily located elsewhere, if you already know this. Temporary redirection. Similar to 301, 302 represents a temporary, not permanent, move of resources. In other words, the URI of the moved resource may change in the future.

6, 303 See Other: The resource URI has been updated. Can you temporarily access the resource by clicking the new URI? The status code indicates that the requested resource has another URL and should be directed to the requested resource using the GET method. The 303 status code has the same function as the 302 status code. However, the 303 status code is different from the 302 status code. The 303 status code indicates that the client should use the GET method to obtain resources.

When the 301,302,303 response status code returns, almost all browsers change the POST to GET and remove the body in the request packet, after which the request is automatically resent.

7, 304 Not Modified: The resource was found but did Not meet the request. The status code indicates that when a client sends a conditional request (if-match, if-modified-since, if-none-match, if-range, The server allows the request to access the resource, but returns 304 If the request does not meet the condition.

8, 307 Temporary Redirect: Indicates the Temporary Redirect. Has the same meaning as 302.

4XX — indicates that the client is the cause of the error.

9. 400 Bad Request: The server cannot understand the Request sent by the client. Syntax errors may exist in the Request packet.

10. 401 Unauthorized: The status code indicates that the request needs HTTP authentication information (BASIC authentication and DIGEST authentication).

11, 403 Forbidden: Forbidden to access that resource. The status code indicates that access to the requested resource has been denied by the server. (Permission, unauthorized IP, etc.)

12, 404 Not Found: No requested resource was Found on the server. The path is incorrect.

5XX — The server itself has an error

13, 500 Internal Server Error: This status code indicates that an error occurred while the server was executing the request. It could also be a bug or some temporary glitch in the Web application.

Excuse me, BUT I’m busy right now. This status code indicates that the server is temporarily under load or is down for maintenance and is now unable to process requests.