MediaWiki.php: Redirect non-standard title urls to canonical

Urls that use the page's title and no extra query parameters now redirect
to the standard url format.

Previously we only did this for variations of the title value (e.g. "Foo%20Bar"),
not for variations of the overall url structure (like title=Foo -> /wiki/Foo).

Existing redirect (unchanged):
 /wiki/Foo%20Bar
 /w/index.php?title=Foo%20Bar

New redirects:
 /wiki/Foo_Bar?action=view
 /w/index.php?title=Foo_Bar
 /w/index.php?title=Foo_Bar&action=view

Any intentional (or unintentional) ways a url can be rewritten by the server,
such as "/?title=Foo_Bar" in case of Wikimedia, are redirected as well.

While this has been a problem for many years, it went unnoticed until
recently when Google started to index significantly more results of
the "/?title=<name>" form. This query returns "About 3,220,000 results":
https://google.com/search?q=site:en.wikipedia.org+inurl:title+-intitle:title

The only change in logic is that the titlekey comparison is now no longer a
factor in deciding whether to redirect. Instead the existing comparison for the
entire url is used to cover this.

However I kept titlekey comparison in the redirect-loop check as otherwise this
check would throw on all canonical page views where no redirect can be made.
Added a comment explaining how this redirect loop was possible.

Bug: T67402
Change-Id: I88ed3525141c765910e66188427b9aab36b958a9

diff --git a/includes/MediaWiki.php b/includes/MediaWiki.php
index 932dea2..5510d35 100644 (file)
--- a/includes/MediaWiki.php
+++ b/includes/MediaWiki.php
@@ -279,6 +279,8 @@ class MediaWiki {
         * - Normalise empty title:
         *   /wiki/ -> /wiki/Main
         *   /w/index.php?title= -> /wiki/Main
+        * - Normalise non-standard title urls:
+        *   /w/index.php?title=Foo_Bar -> /wiki/Foo_Bar
         * - Don't redirect anything with query parameters other than 'title' or 'action=view'.
         *
         * @return bool True if a redirect was set.
@@ -289,8 +291,6 @@ class MediaWiki {
 
                if ( $request->getVal( 'action', 'view' ) != 'view'
                        || $request->wasPosted()
-                       || ( $request->getVal( 'title' ) !== null
-                               && $title->getPrefixedDBkey() == $request->getVal( 'title' ) )
                        || count( $request->getValueNames( array( 'action', 'title' ) ) )
                        || !Hooks::run( 'TestCanonicalRedirect', array( $request, $title, $output ) )
                ) {
@@ -305,7 +305,19 @@ class MediaWiki {
                }
                // Redirect to canonical url, make it a 301 to allow caching
                $targetUrl = wfExpandUrl( $title->getFullURL(), PROTO_CURRENT );
-               if ( $targetUrl == $request->getFullRequestURL() ) {
+
+               if ( $targetUrl != $request->getFullRequestURL() ) {
+                       $output->setSquidMaxage( 1200 );
+                       $output->redirect( $targetUrl, '301' );
+                       return true;
+               }
+
+               // If there is no title, or the title is in a non-standard encoding, we demand
+               // a redirect. If cgi somehow changed the 'title' query to be non-standard while
+               // the url is standard, the server is misconfigured.
+               if ( $request->getVal( 'title' ) === null
+                       || $title->getPrefixedDBkey() != $request->getVal( 'title' )
+               ) {
                        $message = "Redirect loop detected!\n\n" .
                                "This means the wiki got confused about what page was " .
                                "requested; this sometimes happens when moving a wiki " .
@@ -327,9 +339,7 @@ class MediaWiki {
                        }
                        throw new HttpError( 500, $message );
                }
-               $output->setSquidMaxage( 1200 );
-               $output->redirect( $targetUrl, '301' );
-               return true;
+               return false;
        }
 
        /**

diff --git a/tests/phpunit/includes/MediaWikiTest.php b/tests/phpunit/includes/MediaWikiTest.php
index df94d3e..e196243 100644 (file)
--- a/tests/phpunit/includes/MediaWikiTest.php
+++ b/tests/phpunit/includes/MediaWikiTest.php
@@ -34,7 +34,7 @@ class MediaWikiTest extends MediaWikiTestCase {
                                'url' => 'http://example.org/w/index.php?title=Foo_Bar',
                                'query' => array( 'title' => 'Foo_Bar' ),
                                'title' => 'Foo_Bar',
-                               'redirect' => false,
+                               'redirect' => 'http://example.org/wiki/Foo_Bar',
                        ),
                        array(
                                // View: Script path with implicit title from page id
@@ -76,21 +76,21 @@ class MediaWikiTest extends MediaWikiTestCase {
                                'url' => 'http://example.org/w/?title=Foo_Bar',
                                'query' => array( 'title' => 'Foo_Bar' ),
                                'title' => 'Foo_Bar',
-                               'redirect' => false,
+                               'redirect' => 'http://example.org/wiki/Foo_Bar',
                        ),
                        array(
                                // View: Root path with escaped title
                                'url' => 'http://example.org/?title=Foo_Bar',
                                'query' => array( 'title' => 'Foo_Bar' ),
                                'title' => 'Foo_Bar',
-                               'redirect' => false,
+                               'redirect' => 'http://example.org/wiki/Foo_Bar',
                        ),
                        array(
                                // View: Canonical with redundant query
                                'url' => 'http://example.org/wiki/Foo_Bar?action=view',
                                'query' => array( 'action' => 'view' ),
                                'title' => 'Foo_Bar',
-                               'redirect' => false,
+                               'redirect' => 'http://example.org/wiki/Foo_Bar',
                        ),
                        array(
                                // Edit: Canonical view url with action query
@@ -104,7 +104,7 @@ class MediaWikiTest extends MediaWikiTestCase {
                                'url' => 'http://example.org/w/index.php?title=Foo_Bar&action=view',
                                'query' => array( 'title' => 'Foo_Bar', 'action' => 'view' ),
                                'title' => 'Foo_Bar',
-                               'redirect' => false,
+                               'redirect' => 'http://example.org/wiki/Foo_Bar',
                        ),
                        array(
                                // Edit: Index with action query