MediaWiki Visual Editor Parsoid 404 Error

...OK, sometimes one can get so wrapped up in the complexities of an issue the simple basic things are missed. And in this instance, among all the really good technical suggestions I read for correcting the issue, no one ever broached the below simple idea idea.

The Issue

I had successfully installed MediaWiki, an additional WYSIWYG editor, and as a final step I wanted to also configure the Visual Editor. To do that, one also needs to install the Parsoid service (daemon, well in CentOS 7, they seem to now favor the term service) and get them 'talking' together. So I did. I got the Parsoid service working, and...

Wait, two three side notes here. In my attempts to get the Parsoid service working I noticed that in my instance I could start the service and even if it didn't start correctly, it wouldn't notify me there was an error. I had to manually check the status to discover it wasn't actually started. So watch out for that item. For me in CentOS 7.4, the command is: systemctl status parsoid

Another item I noticed was that the config.yaml (for the Parsoid service) file was oddly picky about the spaces and tabs on every line, and if it wasn't happy, it wouldn't start. I had to copy and paste the tabs or spaces that preceded lines from other configuration lines where I had erased it on other lines.

OK, that reminds me, there's a third item I noticed too, which was that a lot of the documentation I was reading had configuration references that were for older versions. I was working with WikiMedia 1.3 and the Parsoid version available on 1.14.2018. A lot of the documentation I read referred to the localsettings.js file (Parsoid service configuration) which appears to have been deprecated at some point in favor of the config.yaml file.

Anyway, I got the Parsoid service installed and working (tested it in all the methods recommended), but it just would not 'talk' with the MediaWiki site. It kept coming up with a 404 (not found) error. Nothing I did made a dent in the issue. Plus there were different suggestions from different sites that had radically different configurations settings that on the surface would seem to suggest there was no way one of these methods ever actually worked. But I tried them anyway to no success. After I got everything working (spoiler alert), I chalked this part of the adventure up to different versions of the Visual Editor, Parsoid, and different 'flavors' of linux.

The Research

And so I googled what I wrote as the title to this page; mediawiki visual editor parsoid 404 error, and started there. As I mentioned earlier, there were a lot of good suggestions on how to fix it, but nothing worked for me.

Well, it really isn't a solution per se, but rather a suggestion in the form of a question. 

The Question

Have you checked your apache / HTTPD configuration?

I hadn't. And it turns out that was the issue. It had nothing to do with the MediaWiki or Parsoid configuration at all. Specifically I had a simple typo in my httpd.conf file (I'm using CentOS 7.4, so the location and name of your Apache / HTTPD configuration file may vary. It may even be in multiple files.) that allowed me to view any page on the site, but didn't allow for editing with the Visual Editor. As near as I could figure out it has something to do with absolute and relative paths. But for the life of me I couldn't figure out how anything had worked at all with that typo, so I gave up on that and just fixed it.

My configuration

For my config.yaml (Parsoid service configuration) file, just two lines;

 

uri: '[[Http://FullQualifiedDomainNameAndPath/api.php'|http://FullyQualifiedDomainNameAndPath/api.php']]
domain: 'localhost'

For my LocalSettings.php (MediaWiki configuration) file, the following code, using the same fully qualified domain name and path, plus the port number of the Parsoid service (8000 in my case).

wfLoadExtension( 'VisualEditor' );

//Enable VisualEditor by default for everybody
$wgDefaultUserOptions['visualeditor-enable'] = 1;

// Optional: Set VisualEditor as the default for anonymous users
// otherwise they will have to switch to VE
// $wgDefaultUserOptions['visualeditor-editor'] = "visualeditor";

// Don't allow users to disable it
$wgHiddenPrefs[] = 'visualeditor-enable';

// OPTIONAL: Enable VisualEditor's experimental code features
#$wgDefaultUserOptions['visualeditor-enable-experimental'] = 1;

// Parsoid configuration
$wgVirtualRestConfig['modules']['parsoid'] = array(
// URL to the Parsoid instance
// Use port 8142 if you use the Debian package
// url must not end in a slash, otherwise it might give a 404 error
'url' => 'http://DomainNameAndPath:8000',
// Parsoid "domain", see below (optional)
'domain' => 'localhost',
// Parsoid "prefix", see below (optional)
//'prefix' => 'wiki.terrabase.info',
//If you run a private wiki then you have to set the following variable to true:
'forwardCookies' => true
);

Also, I noticed a dash ( - ) in front of a comment hash tag ( # ) that I thought was a typo, but some people actually referenced it as it was supposed to be there. It worked, so I left it.

The Conclusion

And then everything worked.

Sorry if you were looking for some really detailed instructions or a summary on all the stuff I learned, but my intent was to just share my story and solution. Hopefully it helps someone.

Final Thoughts

One other item I ran into was logging for the Parsoid service. At the stage where I was trying to get that service working I figured I'd just check the log files. A large number of sites referred to the log file location at /var/log/parsoid/parsoid.log, but that didn't exist for me. Long story short, I went down the logging rabbit hole for about an hour and ended up giving up as I could never get the service to actually log anything. So if anyone has a 'how to' on that, specifically for CentOS, please write something on that subject. Thanks in advance.