After a seriously OBSCENE amount of time, I finally managed to get this to work. The process of getting selfoss to work on Arch is ridiculously tedious and complicated, so I'm going to leave a little guide for future readers.

Bear in mind that I spent several hours over a few days trying to get this to work, so I might have forgotten to document some steps and they might be out of order.

Setup with nginx and sqlite
1.) In addition to installing the necessary dependencies listed in the AUR selfoss package, ensure that you also install php-fpm.

2.) Do NOT upload selfoss to /var/www/ - instead, you must upload to /usr/share/webapps/. You have the choice of a few other directories; /usr/share/webapps/ just happens to be one of the locations that works. Unzip selfoss in /usr/share/webapps/selfoss and then delete the zip file if you wish.

3.) Make absolutely sure that you set the proper permissions on the appropriate directories as outlined in the official selfoss documentation.

4.) In your php.ini file (should be /etc/php/php.ini), there should be a line like `listen = /var/run/php5-fpm.sock`. Comment this line and then uncomment the line that reads `listen = 127.0.0.1:9000`.

5.) While you are in the php.ini file, uncomment the line that reads `extension=pdo_sqlite.so`.

6.) Restart the php-fpm service.

7.) Create your selfoss.conf file using the example provided in the wiki guide. Exclude the `upstream` block when you copy/paste. In addition to changing `server_name` to the appropriate value for your domain, make the following changes as well:

• root /var/www/selfoss/; -> root /usr/share/webapps/selfoss
  
• fastcgi_pass backend; -> fastcgi_pass 127.0.0.1:9000;

Again, don't forgot to exclude the upstream block!! Just copy/paste the server block and make the above changes.

8.) Finish the nginx part of the setup process and restart the nginx service. Everything should be working now. If you are still having issues, check /var/log/nginx/rss.error.log for any funny business. Mess around with the selfoss config.ini file and enjoy the great software.

I encountered some issues while using selfoss and it turns out `extension=gd.so` needs to be uncommented as well in php.ini. Don't forget to do this in steps 4/5.