Let’s talk about how to use php to manage uploaded files

In the process of web development, file upload is a very common requirement, and as a popular back-end programming language, PHP naturally provides support for file upload. But sometimes, we need to operate or manage the uploaded files, so we need to modify the PHP uploaded files.

PHP’s uploaded file management mainly includes the following aspects:

1. Restrict uploaded file types

When uploading files in PHP, uploaded files should be restricted type to prevent illegal file uploads. We can use the type attribute of the $_FILES array to get the MIME type of the uploaded file. When determining the uploaded file type, you can use the in_array() function to determine whether it is an allowed file type.

2. Limit the size of uploaded files

The size of uploaded files should also be limited. In PHP, you can control the size of uploaded files through upload_max_filesize and post_max_size in the php.ini file. When the file size exceeds the limit, an error will be reported. Therefore, before uploading the file, the current file size limit should be obtained through PHP's ini_get() function in order to prompt the user to upload the file when the size exceeds the limit.

3. Upload file storage

Uploaded files need to be saved in the specified directory. In PHP, you can use the move_uploaded_file() function to save the file. This function accepts two parameters. The first parameter is the temporary path of the uploaded file, and the second parameter is the path and file name of the saved file. Before saving the file, you should check whether the file already exists to avoid overwriting files with the same name.

4. Uploaded file information record

When managing uploaded files, we need to record the uploaded files and store the information of the uploaded files. You can use a database such as MySQL to store information about uploaded files, or you can use a file system to store it. If you use file system storage, you need to use the fopen() function to open the file, and use the fwrite() function to write the uploaded file information into the file.

5. Download and delete uploaded files

When managing uploaded files, we need to provide functions such as downloading and deleting. To download a file, you need to use the header() function to output the file to the browser. To delete a file, you need to use the unlink() function to delete the specified file.

Summary

In web development, file upload is a very common requirement. Although PHP provides a powerful file upload function, we also need to carry out relevant management and some logical restrictions and optimizations on uploaded files. The above aspects provide some reference, I hope it can be helpful to everyone.

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