How to Automate File Downloads in PHP Using Headers?

How to Trigger Automatic File Downloads in PHP

When designing websites or web applications, it's often desirable to allow users to download files directly from the server. Unlike with browsing, this process requires an additional step to prompt the user to save the file to their local machine. This article delves into a code snippet that automates this download process in PHP.

Solution:

To automatically initiate a file download upon clicking a link, you can employ the following header declarations:

header("Content-Disposition: attachment; filename=\"" . basename($File) . "\"");
header("Content-Type: application/octet-stream");
header("Content-Length: " . filesize($File));
header("Connection: close");

Explanation:

1. Content-Disposition: This header specifies that the response should be handled as an attachment, and the filename parameter sets the default filename for the user to save.
2. Content-Type: Here, application/octet-stream is used to indicate that the response represents a binary file. By default, browsers expect an HTML document and may not handle non-HTML files correctly.
3. Content-Length: This header informs the browser of the file size, allowing it to display an accurate progress bar during the download.
4. Connection: close: Setting this header prevents the browser from reusing the connection for subsequent requests, ensuring that the download is completed without interference.

By using these headers in conjunction with serving the file content, you can create a seamless file download experience for your users, similar to functionality seen on popular download sites.

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