Server-side conversion of documents is a fairly common task. On Linux/Apache, doing so should be easy: you should just be able to run LibreOffice or OpenOffice in headless mode. If you’re really adventurous, you can install unoconv, which makes document conversion better. Anyway, you’ll be delighted to know that you can invoke any of those programs from your terminal. You won’t be delighted to know that they will return error code 77 when Apache tries to invoke them to actually convert a document. That means your server will probably return a 500 error to your users, and that means you’ll get a phone call at 3:00 in the morning from a crying user. Nobody wants to get a 3 AM phone call from a crying user.
To save yourself from such punishment, there is actually a very simple fix. First, create a new home directory for your Apache user (www-data):
sudo mkdir /home/www-data && sudo chown www-data /home/www-data
Then, you’ll need to edit your /etc/passwd file (scary stuff, right) to change the Apache user’s home directory and default shell. Doing so magically gets rid of your error code 77 troubles (I can’t explain further than that).
sudo nano /etc/passwd
Scroll down to the line that starts with “www-data.” It will look something like “www-data:x:[a number]:[a number]:[a string]:[user's home directory]:[path to user's default shell].” Obviously, we only care about the last two parts. Change the default directory to /home/www-data and then change the default shell to /bin/bash. You may need to move some of your website’s files around–I’m not sure because I use Django with mod_wsgi for GradeSolve so my files are stored elsewhere and I’m still an Apache noob.