Beginnings of multisite support

[jrfoell]

I started looking at multisite support for this, at first it didn't seem promising b/c ms-files.php doesn't have any hooks available to plugins... Then I found this ticket: http://core.trac.wordpress.org/ticket/19235 and this article: http://halfelf.org/2012/dumping-ms-files/

So if I force my local system to use the new style multisite files by adding to wp-config.php:

define( 'UBP_SITEURL', 'http://example.com' );
define( 'UPLOADBLOGSDIR', 'wp-content/uploads/sites' );

and removing this rule from my .htaccess:
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]

I could get uploads by proxy to retrieve the files from the live site and put them in the new wp-content/uploads/sites structure.

I also added a "UBP Site URL" setting to the site settings in wp-admin/network/ -> Sites -> All Sites -> Edit -> Settings Tab (very bottom). This will override the UBP_SITEURL define if present, incase someone wants to have a multisite setup where subsites point to completely unrelated live sites.

I haven't (yet) tested subdomains.

[pdclark]

Wow! This is really awesome to see!!! I'm swamped between WPSessions and WordCamp Los Angeles right now, but I've made a note to read through your code as soon as possible. Thank you for submitting this! I've wanted to see true network support in UBP for a long time!

[jrfoell]

So there's a problem with sub-folder multi-site that happens with the default .htaccess that WP generates. I don't know if it is actually an Apache problem or a WP problem, but you can read more here: https://core.trac.wordpress.org/ticket/20746

I came up with a workaround and added the instructions to the readme. Hopefully smart(er) WP core contributors will come up with a better solution.

With the workaround, it seems to work good on both sub-folder and sub-domain multi-site installs.

My fork should be synced with the latest changes from your master as of 2/22/14.

[jrfoell]

Hi @pdclark, just wanted to check in and see if you could merge this pull request. I'm going to submit another for a non-multisite issue fix, but realized this one was still in waiting :)