How do I use HTML5 to download from a non web folder? - php

Question

I have a webpage for that is for internal use only. It is going to be hosted on a server that is primarily running other processes that generate log files in the /opt/appname/logs/ dir. I have been tasked with making a web interface that will allow these log files to be downloaded to any computer on our network. I am using Apache on Debian. This is what I have so far:
<details>
<summary><b>Download Log Files</b></summary>
<?php
foreach (glob("/opt/appname/logs/*.log") as $filename) {
$file_info = explode("/logs/", $filename);
?>
<a href="<?php echo $filename ?>" download><?php echo $file_info[1] ?></a>
<br>
<?php } ?>
</details>
When I try and download a log file the download looks like it starts but then gives me the message "Failed No file". I have found many posts on line that say you can or can't do this but none of them provide adequate examples. I realize that there are issues with accessing anything outside of the web folders but there has to be some way to do this. I am really at a loss here so any suggestions would be great. Lastly I am self taught so if you see any errors or things that I am not doing best practice please let me know. I am always trying to improve.

Answer 1

It's a security related thing, that only files which are in certain paths on the server can be accessed by a browser, so there should not be a 'simple' solution to this.
What you can do:
Define an alias to the path or file in your web server configuration
or
Write a small program which is called instead and which reads the file from the desired location and send it as output.
In the latter case, you should remember that giving the path via parameters is like an open door for all those who like to read all files on your server!

Answer 2

You could create a file download.php. This file can look something like:
Download.php
$fn = $_GET["filename"];
if (is_readable($fn)) {
header('Content-Description: File Transfer');
header('Content-Type: text/plain');
header('Content-Disposition: attachment; filename="'.$fn.'"');
readfile($fn);
} else {
//return a 404 error perhaps.
}
You could then modify your original listing code to:
<details>
<summary><b>Download Log Files</b></summary>
<?php
foreach (glob("/opt/appname/logs/*.log") as $filename) {
$file_info = explode("/logs/", $filename);
?>
<a href="download.php?filename=<?php echo $filename ?>" download><?php echo $file_info[1] ?></a>
<br>
<?php } ?>
</details>
I personally like this method because you can also add extra checks and exceptions in the "download manager".