How to download a file and modify its name using PHP

PHP is a server-side programming language that provides many convenient functions to operate files. In web applications, sometimes you need to download a file and save it to the user's device. In some cases, users may wish to rename downloaded files for easier management and identification. In this article, we will explore how to download a file and modify its name using PHP.

File Download

In PHP, you can download any type of file using a special function called "header". When using the header function, you must ensure that nothing is produced before any output. In addition, a correct Content-Disposition header needs to be set to instruct the browser to download the file. The following is a sample code for downloading a file using PHP:

<?php $file_url = &#39;http://example.com/file.pdf&#39;;
header(&#39;Content-Type: application/octet-stream&#39;);
header("Content-Transfer-Encoding: Binary"); 
header("Content-disposition: attachment; filename=\"" . basename($file_url) . "\""); 
readfile($file_url);
?>

The above code will download a PDF file named "file.pdf". To download different types of files, you can change the Content-Type. For example, for image files, you can use Content-Type: image/jpeg or Content-Type: image/png.

This code uses the readfile function to download the file to the user device. When dealing with larger files, it is recommended to use more efficient methods, such as reading the file block by block and outputting the data.

File Renaming

To download a file and rename it, you can add some code to modify the filename in the Content-Disposition header. Typically, the Content-Disposition header specifies the original name of the downloaded file. Here is a code example:

<?php $file_url = &#39;http://example.com/file.pdf&#39;;
header(&#39;Content-Type: application/octet-stream&#39;);
header("Content-Transfer-Encoding: Binary"); 
header("Content-disposition: attachment; filename=\"new_name.pdf\"");
readfile($file_url);
?>

You can replace "new_name.pdf" with any file name you want. This will ensure that the new filename is used when downloading the file, rather than the original filename.

If you want to dynamically generate file names, you can use some functions in PHP. For example, you can add the current date/time to the file name:

<?php $file_url = &#39;http://example.com/file.pdf&#39;;
$date = date("Y-m-d");
$new_filename = $date . "_new_file.pdf";
header(&#39;Content-Type: application/octet-stream&#39;);
header("Content-Transfer-Encoding: Binary"); 
header("Content-disposition: attachment; filename=\"$new_filename\"");
readfile($file_url);
?>

In the above example, the code adds the current date to the file name so that the downloaded file name looks like "2022-01-01_new_file .pdf".

Conclusion

PHP provides many features to web application developers to handle files. Downloading files is one of the common requirements in web applications and can be easily achieved using features in PHP. By setting the Content-Disposition header, you can control the downloaded file name. In this article, we show you how to download a file and change the file name, hope it helps.

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