在Webroot上访问和交付XML文件

Question

I'm trying to load an appcast xml file from a php file, The xml contains a file path used to display a changelog.html & gives a download path to a file. Normally, I don't want browsers to be able to access this stuff, so, the xml file, changelog & the file are all together in folder above the web root directory. The php file is inside of the webroot.

Here's my php code:

$filename = "./home/myaccountusername/folder1/folder2/appcast.xml";
    if (!file_exists ($filename)) throw new Exception("File not found");

    // Set the content type to xml
    header('Content-Type: text/xml');
    header('Content-Disposition: attachment; filename="' . basename($filename) . '"');
    header('Content-Length: ' . filesize($filename));
    // Tell the user-agent (Stacks) not to cache the file
    header('Expires: 0');
    header('Cache-Control: must-revalidate');
    header('Pragma: public');
    // Flush the output buffer
    ob_clean();
    flush();
    // Read the data and send the file
    //throw new Exception("FileName: " . $filename);
    readfile($filename);
    exit; 

It's throwing exception: File not found

How do I write the paths to look above the webroot & when passed to my final display interface, allows the changelog.html to be opened & the file to be downloaded?

Note: I've tried the beginning of the path to be /home... and home... & even ../../../folder1/ ...

Is this possible to set up in php? Can't figure it out.

Update1: Here's a tree of server:

- public_html 
  - appcastsecure  
    - productfolder  
     - appcast.xml  
     - changelog.html  
     - productzipfile.zip  

  - company_folder  
      - secureappcast  
         - appcastfile.php  (start here for pathing)  

I'm using DIR in appcastfile.php which gives path to appcast.xml:

$filename = /home/userdir/public_html/company_folder/secureappcast/../../appcastsecure/productfolder/appcast.xml

My problem is appcast.xml is pushed to clients on their server, so I can't figure out how to set up pathing in appcast.xml so it will point to changelog & productzipfile on my server (all are outside of public_html)

Answer 1

Firstly, the one in your example is trying to access the a folder relative to the current directory...

$filename = "./home/myaccountusername/folder1/folder2/appcast.xml";

The first dot shouldn't be there anyway.

If you want to access a file that is relative to a directory, you can use __DIR__, which gives the directory of the script your currently in. This then depends on where the file your trying to access is relative to the current script. So

$filename = __DIR__."/../appcast.xml";

Is a file in the directory above the one containing this script. You will have to adjust this depending on your particular requirements.