Merge "API: Add support for selected HTTP precondition headers"
authorjenkins-bot <jenkins-bot@gerrit.wikimedia.org>
Thu, 10 Sep 2015 16:42:48 +0000 (16:42 +0000)
committerGerrit Code Review <gerrit@wikimedia.org>
Thu, 10 Sep 2015 16:42:48 +0000 (16:42 +0000)
RELEASE-NOTES-1.26
includes/api/ApiBase.php
includes/api/ApiMain.php
tests/phpunit/includes/api/ApiMainTest.php

index 12b973a..b5d9d5a 100644 (file)
@@ -110,10 +110,17 @@ production.
   rnfilterredir parameter that also allows for listing both redirects and
   non-redirects.
 * list=random now supports continuation.
+* API responses to GET requests may now include ETag and Last-Modified headers,
+  and will honor corresponding If-None-Match and If-Modified-Since on such
+  requests.
 
 === Action API internal changes in 1.26 ===
 * New metadata item ApiResult::META_KVP_MERGE to allow for merging the KVP key
   into the value when the value is an assoc.
+* API action modules may now provide values for the RFC 7232 ETag and
+  Last-Modified headers. The API will check these against If-None-Match and
+  If-Modified-Since request headers on GET requests and avoid executing the
+  module when appropriate.
 
 === Languages updated in 1.26 ===
 
index 7b71e6c..d53797b 100644 (file)
@@ -345,6 +345,22 @@ abstract class ApiBase extends ContextSource {
                return null;
        }
 
+       /**
+        * Returns data for HTTP conditional request mechanisms.
+        *
+        * @since 1.26
+        * @param string $condition Condition being queried:
+        *  - last-modified: Return a timestamp representing the maximum of the
+        *    last-modified dates for all resources involved in the request. See
+        *    RFC 7232 § 2.2 for semantics.
+        *  - etag: Return an entity-tag representing the state of all resources involved
+        *    in the request. Quotes must be included. See RFC 7232 § 2.3 for semantics.
+        * @return string|boolean|null As described above, or null if no value is available.
+        */
+       public function getConditionalRequestData( $condition ) {
+               return null;
+       }
+
        /**@}*/
 
        /************************************************************************//**
index f2059d7..c558c2b 100644 (file)
@@ -425,13 +425,16 @@ class ApiMain extends ApiBase {
 
                // In case an error occurs during data output,
                // clear the output buffer and print just the error information
+               $obLevel = ob_get_level();
                ob_start();
 
                $t = microtime( true );
                try {
                        $this->executeAction();
+                       $isError = false;
                } catch ( Exception $e ) {
                        $this->handleException( $e );
+                       $isError = true;
                }
 
                // Log the request whether or not there was an error
@@ -439,9 +442,13 @@ class ApiMain extends ApiBase {
 
                // Send cache headers after any code which might generate an error, to
                // avoid sending public cache headers for errors.
-               $this->sendCacheHeaders();
+               $this->sendCacheHeaders( $isError );
 
-               ob_end_flush();
+               // Executing the action might have already messed with the output
+               // buffers.
+               while ( ob_get_level() > $obLevel ) {
+                       ob_end_flush();
+               }
        }
 
        /**
@@ -532,7 +539,7 @@ class ApiMain extends ApiBase {
 
                // Log the request and reset cache headers
                $main->logRequest( 0 );
-               $main->sendCacheHeaders();
+               $main->sendCacheHeaders( true );
 
                ob_end_flush();
        }
@@ -701,7 +708,12 @@ class ApiMain extends ApiBase {
                return "/^https?:\/\/$wildcard$/";
        }
 
-       protected function sendCacheHeaders() {
+       /**
+        * Send caching headers
+        * @param boolean $isError Whether an error response is being output
+        * @since 1.26 added $isError parameter
+        */
+       protected function sendCacheHeaders( $isError ) {
                $response = $this->getRequest()->response();
                $out = $this->getOutput();
 
@@ -711,6 +723,19 @@ class ApiMain extends ApiBase {
                        $out->addVaryHeader( 'X-Forwarded-Proto' );
                }
 
+               if ( !$isError && $this->mModule &&
+                       ( $this->getRequest()->getMethod() === 'GET' || $this->getRequest()->getMethod() === 'HEAD' )
+               ) {
+                       $etag = $this->mModule->getConditionalRequestData( 'etag' );
+                       if ( $etag !== null ) {
+                               $response->header( "ETag: $etag" );
+                       }
+                       $lastMod = $this->mModule->getConditionalRequestData( 'last-modified' );
+                       if ( $lastMod !== null ) {
+                               $response->header( 'Last-Modified: ' . wfTimestamp( TS_RFC2822, $lastMod ) );
+                       }
+               }
+
                // The logic should be:
                // $this->mCacheControl['max-age'] is set?
                //    Use it, the module knows better than our guess.
@@ -993,6 +1018,121 @@ class ApiMain extends ApiBase {
                return true;
        }
 
+       /**
+        * Check selected RFC 7232 precondition headers
+        *
+        * RFC 7232 envisions a particular model where you send your request to "a
+        * resource", and for write requests that you can read "the resource" by
+        * changing the method to GET. When the API receives a GET request, it
+        * works out even though "the resource" from RFC 7232's perspective might
+        * be many resources from MediaWiki's perspective. But it totally fails for
+        * a POST, since what HTTP sees as "the resource" is probably just
+        * "/api.php" with all the interesting bits in the body.
+        *
+        * Therefore, we only support RFC 7232 precondition headers for GET (and
+        * HEAD). That means we don't need to bother with If-Match and
+        * If-Unmodified-Since since they only apply to modification requests.
+        *
+        * And since we don't support Range, If-Range is ignored too.
+        *
+        * @since 1.26
+        * @param ApiBase $module Api module being used
+        * @return bool True on success, false should exit immediately
+        */
+       protected function checkConditionalRequestHeaders( $module ) {
+               if ( $this->mInternalMode ) {
+                       // No headers to check in internal mode
+                       return true;
+               }
+
+               if ( $this->getRequest()->getMethod() !== 'GET' && $this->getRequest()->getMethod() !== 'HEAD' ) {
+                       // Don't check POSTs
+                       return true;
+               }
+
+               $return304 = false;
+
+               $ifNoneMatch = array_diff(
+                       $this->getRequest()->getHeader( 'If-None-Match', WebRequest::GETHEADER_LIST ) ?: array(),
+                       array( '' )
+               );
+               if ( $ifNoneMatch ) {
+                       if ( $ifNoneMatch === array( '*' ) ) {
+                               // API responses always "exist"
+                               $etag = '*';
+                       } else {
+                               $etag = $module->getConditionalRequestData( 'etag' );
+                       }
+               }
+               if ( $ifNoneMatch && $etag !== null ) {
+                       $test = substr( $etag, 0, 2 ) === 'W/' ? substr( $etag, 2 ) : $etag;
+                       $match = array_map( function ( $s ) {
+                               return substr( $s, 0, 2 ) === 'W/' ? substr( $s, 2 ) : $s;
+                       }, $ifNoneMatch );
+                       $return304 = in_array( $test, $match, true );
+               } else {
+                       $value = trim( $this->getRequest()->getHeader( 'If-Modified-Since' ) );
+
+                       // Some old browsers sends sizes after the date, like this:
+                       //  Wed, 20 Aug 2003 06:51:19 GMT; length=5202
+                       // Ignore that.
+                       $i = strpos( $value, ';' );
+                       if ( $i !== false ) {
+                               $value = trim( substr( $value, 0, $i ) );
+                       }
+
+                       if ( $value !== '' ) {
+                               try {
+                                       $ts = new MWTimestamp( $value );
+                                       if (
+                                               // RFC 7231 IMF-fixdate
+                                               $ts->getTimestamp( TS_RFC2822 ) === $value ||
+                                               // RFC 850
+                                               $ts->format( 'l, d-M-y H:i:s' ) . ' GMT' === $value ||
+                                               // asctime (with and without space-padded day)
+                                               $ts->format( 'D M j H:i:s Y' ) === $value ||
+                                               $ts->format( 'D M  j H:i:s Y' ) === $value
+                                       ) {
+                                               $lastMod = $module->getConditionalRequestData( 'last-modified' );
+                                               if ( $lastMod !== null ) {
+                                                       // Mix in some MediaWiki modification times
+                                                       $modifiedTimes = array(
+                                                               'page' => $lastMod,
+                                                               'user' => $this->getUser()->getTouched(),
+                                                               'epoch' => $this->getConfig()->get( 'CacheEpoch' ),
+                                                       );
+                                                       if ( $this->getConfig()->get( 'UseSquid' ) ) {
+                                                               // T46570: the core page itself may not change, but resources might
+                                                               $modifiedTimes['sepoch'] = wfTimestamp(
+                                                                       TS_MW, time() - $this->getConfig()->get( 'SquidMaxage' )
+                                                               );
+                                                       }
+                                                       Hooks::run( 'OutputPageCheckLastModified', array( &$modifiedTimes ) );
+                                                       $lastMod = max( $modifiedTimes );
+                                                       $return304 = wfTimestamp( TS_MW, $lastMod ) <= $ts->getTimestamp( TS_MW );
+                                               }
+                                       }
+                               } catch ( TimestampException $e ) {
+                                       // Invalid timestamp, ignore it
+                               }
+                       }
+               }
+
+               if ( $return304 ) {
+                       $this->getRequest()->response()->statusHeader( 304 );
+
+                       // Avoid outputting the compressed representation of a zero-length body
+                       MediaWiki\suppressWarnings();
+                       ini_set( 'zlib.output_compression', 0 );
+                       MediaWiki\restoreWarnings();
+                       wfClearOutputBuffers();
+
+                       return false;
+               }
+
+               return true;
+       }
+
        /**
         * Check for sufficient permissions to execute
         * @param ApiBase $module An Api module
@@ -1083,6 +1223,10 @@ class ApiMain extends ApiBase {
                        return;
                }
 
+               if ( !$this->checkConditionalRequestHeaders( $module ) ) {
+                       return;
+               }
+
                if ( !$this->mInternalMode ) {
                        $this->setupExternalResponse( $module, $params );
                }
index ee1a954..94b741d 100644 (file)
@@ -79,4 +79,173 @@ class ApiMainTest extends ApiTestCase {
                        );
                }
        }
+
+       /**
+        * Test HTTP precondition headers
+        *
+        * @covers ApiMain::checkConditionalRequestHeaders
+        * @dataProvider provideCheckConditionalRequestHeaders
+        * @param array $headers HTTP headers
+        * @param array $conditions Return data for ApiBase::getConditionalRequestData
+        * @param int $status Expected response status
+        * @param bool $post Request is a POST
+        */
+       public function testCheckConditionalRequestHeaders( $headers, $conditions, $status, $post = false ) {
+               $request = new FauxRequest( array( 'action' => 'query', 'meta' => 'siteinfo' ), $post );
+               $request->setHeaders( $headers );
+               $request->response()->statusHeader( 200 ); // Why doesn't it default?
+
+               $api = new ApiMain( $request );
+               $priv = TestingAccessWrapper::newFromObject( $api );
+               $priv->mInternalMode = false;
+
+               $module = $this->getMockBuilder( 'ApiBase' )
+                       ->setConstructorArgs( array( $api, 'mock' ) )
+                       ->setMethods( array( 'getConditionalRequestData' ) )
+                       ->getMockForAbstractClass();
+               $module->expects( $this->any() )
+                       ->method( 'getConditionalRequestData' )
+                       ->will( $this->returnCallback( function ( $condition ) use ( $conditions ) {
+                               return isset( $conditions[$condition] ) ? $conditions[$condition] : null;
+                       } ) );
+
+               $ret = $priv->checkConditionalRequestHeaders( $module );
+
+               $this->assertSame( $status, $request->response()->getStatusCode() );
+               $this->assertSame( $status === 200, $ret );
+       }
+
+       public static function provideCheckConditionalRequestHeaders() {
+               $now = time();
+
+               return array(
+                       // Non-existing from module is ignored
+                       array( array( 'If-None-Match' => '"foo", "bar"' ), array(), 200 ),
+                       array( array( 'If-Modified-Since' => 'Tue, 18 Aug 2015 00:00:00 GMT' ), array(), 200 ),
+
+                       // No headers
+                       array(
+                               array(),
+                               array(
+                                       'etag' => '""',
+                                       'last-modified' => '20150815000000',
+                               ),
+                               200
+                       ),
+
+                       // Basic If-None-Match
+                       array( array( 'If-None-Match' => '"foo", "bar"' ), array( 'etag' => '"bar"' ), 304 ),
+                       array( array( 'If-None-Match' => '"foo", "bar"' ), array( 'etag' => '"baz"' ), 200 ),
+                       array( array( 'If-None-Match' => '"foo"' ), array( 'etag' => 'W/"foo"' ), 304 ),
+                       array( array( 'If-None-Match' => 'W/"foo"' ), array( 'etag' => '"foo"' ), 304 ),
+                       array( array( 'If-None-Match' => 'W/"foo"' ), array( 'etag' => 'W/"foo"' ), 304 ),
+
+                       // Pointless, but supported
+                       array( array( 'If-None-Match' => '*' ), array(), 304 ),
+
+                       // Basic If-Modified-Since
+                       array( array( 'If-Modified-Since' => wfTimestamp( TS_RFC2822, $now ) ),
+                               array( 'last-modified' => wfTimestamp( TS_MW, $now - 1 ) ), 304 ),
+                       array( array( 'If-Modified-Since' => wfTimestamp( TS_RFC2822, $now ) ),
+                               array( 'last-modified' => wfTimestamp( TS_MW, $now ) ), 304 ),
+                       array( array( 'If-Modified-Since' => wfTimestamp( TS_RFC2822, $now ) ),
+                               array( 'last-modified' => wfTimestamp( TS_MW, $now + 1 ) ), 200 ),
+
+                       // If-Modified-Since ignored when If-None-Match is given too
+                       array( array( 'If-None-Match' => '""', 'If-Modified-Since' => wfTimestamp( TS_RFC2822, $now ) ),
+                               array( 'etag' => '"x"', 'last-modified' => wfTimestamp( TS_MW, $now - 1 ) ), 200 ),
+                       array( array( 'If-None-Match' => '""', 'If-Modified-Since' => wfTimestamp( TS_RFC2822, $now ) ),
+                               array( 'last-modified' => wfTimestamp( TS_MW, $now - 1 ) ), 304 ),
+
+                       // Ignored for POST
+                       array( array( 'If-None-Match' => '"foo", "bar"' ), array( 'etag' => '"bar"' ), 200, true ),
+                       array( array( 'If-Modified-Since' => wfTimestamp( TS_RFC2822, $now ) ),
+                               array( 'last-modified' => wfTimestamp( TS_MW, $now - 1 ) ), 200, true ),
+
+                       // Other date formats allowed by the RFC
+                       array( array( 'If-Modified-Since' => gmdate( 'l, d-M-y H:i:s', $now ) . ' GMT' ),
+                               array( 'last-modified' => wfTimestamp( TS_MW, $now - 1 ) ), 304 ),
+                       array( array( 'If-Modified-Since' => gmdate( 'D M j H:i:s Y', $now ) ),
+                               array( 'last-modified' => wfTimestamp( TS_MW, $now - 1 ) ), 304 ),
+
+                       // Old browser extension to HTTP/1.0
+                       array( array( 'If-Modified-Since' => wfTimestamp( TS_RFC2822, $now ) . '; length=123' ),
+                               array( 'last-modified' => wfTimestamp( TS_MW, $now - 1 ) ), 304 ),
+
+                       // Invalid date formats should be ignored
+                       array( array( 'If-Modified-Since' => gmdate( 'Y-m-d H:i:s', $now ) . ' GMT' ),
+                               array( 'last-modified' => wfTimestamp( TS_MW, $now - 1 ) ), 200 ),
+               );
+       }
+
+       /**
+        * Test conditional headers output
+        * @dataProvider provideConditionalRequestHeadersOutput
+        * @param array $conditions Return data for ApiBase::getConditionalRequestData
+        * @param array $headers Expected output headers
+        * @param bool $isError $isError flag
+        * @param bool $post Request is a POST
+        */
+       public function testConditionalRequestHeadersOutput( $conditions, $headers, $isError = false, $post = false ) {
+               $request = new FauxRequest( array( 'action' => 'query', 'meta' => 'siteinfo' ), $post );
+               $response = $request->response();
+
+               $api = new ApiMain( $request );
+               $priv = TestingAccessWrapper::newFromObject( $api );
+               $priv->mInternalMode = false;
+
+               $module = $this->getMockBuilder( 'ApiBase' )
+                       ->setConstructorArgs( array( $api, 'mock' ) )
+                       ->setMethods( array( 'getConditionalRequestData' ) )
+                       ->getMockForAbstractClass();
+               $module->expects( $this->any() )
+                       ->method( 'getConditionalRequestData' )
+                       ->will( $this->returnCallback( function ( $condition ) use ( $conditions ) {
+                               return isset( $conditions[$condition] ) ? $conditions[$condition] : null;
+                       } ) );
+               $priv->mModule = $module;
+
+               $priv->sendCacheHeaders( $isError );
+
+               foreach ( array( 'Last-Modified', 'ETag' ) as $header ) {
+                       $this->assertEquals(
+                               isset( $headers[$header] ) ? $headers[$header] : null,
+                               $response->getHeader( $header ),
+                               $header
+                       );
+               }
+       }
+
+       public static function provideConditionalRequestHeadersOutput() {
+               return array(
+                       array(
+                               array(),
+                               array()
+                       ),
+                       array(
+                               array( 'etag' => '"foo"' ),
+                               array( 'ETag' => '"foo"' )
+                       ),
+                       array(
+                               array( 'last-modified' => '20150818000102' ),
+                               array( 'Last-Modified' => 'Tue, 18 Aug 2015 00:01:02 GMT' )
+                       ),
+                       array(
+                               array( 'etag' => '"foo"', 'last-modified' => '20150818000102' ),
+                               array( 'ETag' => '"foo"', 'Last-Modified' => 'Tue, 18 Aug 2015 00:01:02 GMT' )
+                       ),
+                       array(
+                               array( 'etag' => '"foo"', 'last-modified' => '20150818000102' ),
+                               array(),
+                               true,
+                       ),
+                       array(
+                               array( 'etag' => '"foo"', 'last-modified' => '20150818000102' ),
+                               array(),
+                               false,
+                               true,
+                       ),
+               );
+       }
+
 }