The reason why header function returns 404 failure

The failure of the header function to return 404 is caused by the resource not existing, URL address case error, server configuration error, redirection problem or network connection problem, etc. The solution is as follows: 1. The resource does not exist, check whether the requested URL address is correct, and ensure that the resource exists on the server; 2. The URL address is case-incorrect, convert all URL addresses to lowercase or uppercase, and resend the request; 3. Server configuration error, try to restart the server to apply the new configuration; 4. Redirection problems, etc.

The header function is a commonly used method in programming, used to send HTTP requests to the server and obtain the server's response header information. When using the header function, sometimes a 404 failure is returned. This article will explore several possible reasons why the header function fails to return 404 and provide corresponding solutions.

1. The resource does not exist:

The most common reason is that the requested resource does not exist on the server. When we use the header function to send a request, we need to ensure that the requested URL address is correct and that the resource does exist on the server. If the resource does not exist, the server will return a 404 error code.

Solution: Check whether the requested URL address is correct and ensure that the resource exists on the server. You can manually try to access the URL address in the browser to confirm whether the resource exists.

2. URL address case error:

URL address is case-sensitive. If the case of the URL address does not match the resource on the server during the request, , the server will return a 404 error code.

Solution: Check whether the case of the URL address matches the resource on the server. You can try converting the URL address to all lowercase or uppercase and resend the request.

3. Server configuration error:

Sometimes, there may be a problem with the server's configuration that prevents the request from being processed correctly. This may be caused by errors in the server configuration file, permission issues, or other configuration issues.

Solution: Contact the server administrator or developer to check the server's configuration file and make sure it is configured correctly. You can try restarting the server to apply the new configuration.

4. Redirection issues:

Sometimes, the server redirects requests to other URL addresses, but we fail to handle the redirection correctly. This may cause the header function to return a 404 error code.

Solution: When using the header function, you need to set the third parameter to false to disable automatic redirection. The redirected URL can then be obtained by checking the "Location" field in the response header and processed further as needed.

5. Network connection problems:

When sending a request, you may encounter network connection problems, resulting in the inability to establish a connection with the server or failure to send the request. This may cause the header function to return a 404 error code.

Solution: Check whether the network connection is normal. You can try to reconnect to the network, or use another network connection method, such as switching to a mobile data network or using another network connection device.

Summary:

When using the header function to send a request, if a 404 failure is returned, it may be because the resource does not exist, the URL address case is incorrect, or the server configuration is incorrect. Caused by reasons such as redirection issues or network connection issues. By checking the correctness of the URL address, server configuration, redirect settings, network connection, etc., you can solve the problem of header function returning 404 failure. .

The above is the detailed content of The reason why header function returns 404 failure. For more information, please follow other related articles on the PHP Chinese website!