Why does the dot in the file name become an underscore when uploading a file in PHP?

PHP file upload: Why dot numbers in file names become underscores?

During the process of uploading files by PHP, some users encounter an exception in which the dot (.) in the file name is replaced by underscore (_). This is not a function of the PHP move_uploaded_file() function itself, but a result of the logic processing of the code. The move_uploaded_file() function retains the original file name unless there is special processing in the code.

The following situations can cause this problem:

1. Improper string replacement: functions such as str_replace() or preg_replace() may be used in the code, and the dot number is replaced with underscore. This may be to avoid illegal characters or enhance security, but the implementation is flawed.

2. Custom file name generation: The code may not use the upload file name directly, but generate a new file name based on timestamps, user IDs, etc. In this process, the dot number is handled or ignored by errors.

3. Server-side security mechanism (less likely): Server-side security software or firewall may filter or modify file names, but this is usually accompanied by other error messages or logging.

Solution:

Carefully check the PHP upload file processing code, especially the file name processing part. Find and modify or remove the code for replacing the dot number to ensure that the original file name is saved correctly. It is recommended to print the actual saved file name after uploading for debugging to quickly locate the problem.

The above is the detailed content of Why does the dot in the file name become an underscore when uploading a file in PHP?. For more information, please follow other related articles on the PHP Chinese website!