Download Helper

The Download Helper allows you to force a file to be downloaded by the user’s browser. It generates the appropriate headers and streams the file content in chunks, supporting partial downloads via HTTP range requests.

Note

This helper relies on PHP’s native file functions such as fopen(), fread(), filesize(), and mime_content_type(). Make sure your server has proper read permissions for the files you intend to download.

Function Summary

Function	Description
`force_download()`	Sends headers and streams a file to the browser for download.

Available Functions

force_download($file, $name, $mime_type = '')

Forces a download of a specified file by sending appropriate HTTP headers.

Parameters:

$file (string) – The full path to the file to be downloaded.
$name (string) – The filename to display in the browser download dialog.
$mime_type (string) – Optional. MIME type to send (default: auto-detected from the file).

Returns:

void — The function outputs file content directly and does not return a value.

Raises:

Exception — Throws an exception if the file cannot be read.

Behavior:

Checks if the file exists and is readable; if not, execution stops with an error.
Detects MIME type if none is provided.
Handles output buffering and disables zlib.output_compression to prevent corruption.
Supports HTTP range requests for partial content download.
Streams the file in 1 MB chunks to manage memory usage efficiently.

Example Usage:

<?php
try {
    // Force the download of a file
    force_download('/path/to/file.zip', 'myfile.zip');
} catch (Exception $e) {
    echo 'Error: ' . $e->getMessage();
}

Additional Notes

This function automatically cleans any output buffer to avoid corrupting the downloaded file.
Partial download support is implemented using HTTP Range headers, allowing resume of interrupted downloads.
Ensure that your PHP script has sufficient memory and execution time limits for large file downloads.