--- /dev/null
+<?php
+/**
+ * Virtual HTTP service client
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Virtual HTTP service client loosely styled after a Virtual File System
+ *
+ * Services can be mounted on path prefixes so that virtual HTTP operations
+ * against sub-paths will map to those services. Operations can actually be
+ * done using HTTP messages over the wire or may simple be emulated locally.
+ *
+ * Virtual HTTP request maps are arrays that use the following format:
+ * - method : GET/HEAD/PUT/POST/DELETE
+ * - url : HTTP/HTTPS URL or virtual service path with a registered prefix
+ * - query : <query parameter field/value associative array> (uses RFC 3986)
+ * - headers : <header name/value associative array>
+ * - body : source to get the HTTP request body from;
+ * this can simply be a string (always), a resource for
+ * PUT requests, and a field/value array for POST request;
+ * array bodies are encoded as multipart/form-data and strings
+ * use application/x-www-form-urlencoded (headers sent automatically)
+ * - stream : resource to stream the HTTP response body to
+ * Request maps can use integer index 0 instead of 'method' and 1 instead of 'url'.
+ *
+ * @since 1.23
+ */
+class VirtualRESTServiceClient {
+ /** @var MultiHttpClient */
+ private $http;
+ /** @var array Map of (prefix => VirtualRESTService|array) */
+ private $instances = [];
+
+ const VALID_MOUNT_REGEX = '#^/[0-9a-z]+/([0-9a-z]+/)*$#';
+
+ /**
+ * @param MultiHttpClient $http
+ */
+ public function __construct( MultiHttpClient $http ) {
+ $this->http = $http;
+ }
+
+ /**
+ * Map a prefix to service handler
+ *
+ * If $instance is in array, it must have these keys:
+ * - class : string; fully qualified VirtualRESTService class name
+ * - config : array; map of parameters that is the first __construct() argument
+ *
+ * @param string $prefix Virtual path
+ * @param VirtualRESTService|array $instance Service or info to yield the service
+ */
+ public function mount( $prefix, $instance ) {
+ if ( !preg_match( self::VALID_MOUNT_REGEX, $prefix ) ) {
+ throw new UnexpectedValueException( "Invalid service mount point '$prefix'." );
+ } elseif ( isset( $this->instances[$prefix] ) ) {
+ throw new UnexpectedValueException( "A service is already mounted on '$prefix'." );
+ }
+ if ( !( $instance instanceof VirtualRESTService ) ) {
+ if ( !isset( $instance['class'] ) || !isset( $instance['config'] ) ) {
+ throw new UnexpectedValueException( "Missing 'class' or 'config' ('$prefix')." );
+ }
+ }
+ $this->instances[$prefix] = $instance;
+ }
+
+ /**
+ * Unmap a prefix to service handler
+ *
+ * @param string $prefix Virtual path
+ */
+ public function unmount( $prefix ) {
+ if ( !preg_match( self::VALID_MOUNT_REGEX, $prefix ) ) {
+ throw new UnexpectedValueException( "Invalid service mount point '$prefix'." );
+ } elseif ( !isset( $this->instances[$prefix] ) ) {
+ throw new UnexpectedValueException( "No service is mounted on '$prefix'." );
+ }
+ unset( $this->instances[$prefix] );
+ }
+
+ /**
+ * Get the prefix and service that a virtual path is serviced by
+ *
+ * @param string $path
+ * @return array (prefix,VirtualRESTService) or (null,null) if none found
+ */
+ public function getMountAndService( $path ) {
+ $cmpFunc = function ( $a, $b ) {
+ $al = substr_count( $a, '/' );
+ $bl = substr_count( $b, '/' );
+ if ( $al === $bl ) {
+ return 0; // should not actually happen
+ }
+ return ( $al < $bl ) ? 1 : -1; // largest prefix first
+ };
+
+ $matches = []; // matching prefixes (mount points)
+ foreach ( $this->instances as $prefix => $unused ) {
+ if ( strpos( $path, $prefix ) === 0 ) {
+ $matches[] = $prefix;
+ }
+ }
+ usort( $matches, $cmpFunc );
+
+ // Return the most specific prefix and corresponding service
+ return $matches
+ ? [ $matches[0], $this->getInstance( $matches[0] ) ]
+ : [ null, null ];
+ }
+
+ /**
+ * Execute a virtual HTTP(S) request
+ *
+ * This method returns a response map of:
+ * - code : HTTP response code or 0 if there was a serious cURL error
+ * - reason : HTTP response reason (empty if there was a serious cURL error)
+ * - headers : <header name/value associative array>
+ * - body : HTTP response body or resource (if "stream" was set)
+ * - error : Any cURL error string
+ * The map also stores integer-indexed copies of these values. This lets callers do:
+ * @code
+ * list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $client->run( $req );
+ * @endcode
+ * @param array $req Virtual HTTP request maps
+ * @return array Response array for request
+ */
+ public function run( array $req ) {
+ return $this->runMulti( [ $req ] )[0];
+ }
+
+ /**
+ * Execute a set of virtual HTTP(S) requests concurrently
+ *
+ * A map of requests keys to response maps is returned. Each response map has:
+ * - code : HTTP response code or 0 if there was a serious cURL error
+ * - reason : HTTP response reason (empty if there was a serious cURL error)
+ * - headers : <header name/value associative array>
+ * - body : HTTP response body or resource (if "stream" was set)
+ * - error : Any cURL error string
+ * The map also stores integer-indexed copies of these values. This lets callers do:
+ * @code
+ * list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $responses[0];
+ * @endcode
+ *
+ * @param array $reqs Map of Virtual HTTP request maps
+ * @return array $reqs Map of corresponding response values with the same keys/order
+ * @throws Exception
+ */
+ public function runMulti( array $reqs ) {
+ foreach ( $reqs as $index => &$req ) {
+ if ( isset( $req[0] ) ) {
+ $req['method'] = $req[0]; // short-form
+ unset( $req[0] );
+ }
+ if ( isset( $req[1] ) ) {
+ $req['url'] = $req[1]; // short-form
+ unset( $req[1] );
+ }
+ $req['chain'] = []; // chain or list of replaced requests
+ }
+ unset( $req ); // don't assign over this by accident
+
+ $curUniqueId = 0;
+ $armoredIndexMap = []; // (original index => new index)
+
+ $doneReqs = []; // (index => request)
+ $executeReqs = []; // (index => request)
+ $replaceReqsByService = []; // (prefix => index => request)
+ $origPending = []; // (index => 1) for original requests
+
+ foreach ( $reqs as $origIndex => $req ) {
+ // Re-index keys to consecutive integers (they will be swapped back later)
+ $index = $curUniqueId++;
+ $armoredIndexMap[$origIndex] = $index;
+ $origPending[$index] = 1;
+ if ( preg_match( '#^(http|ftp)s?://#', $req['url'] ) ) {
+ // Absolute FTP/HTTP(S) URL, run it as normal
+ $executeReqs[$index] = $req;
+ } else {
+ // Must be a virtual HTTP URL; resolve it
+ list( $prefix, $service ) = $this->getMountAndService( $req['url'] );
+ if ( !$service ) {
+ throw new UnexpectedValueException( "Path '{$req['url']}' has no service." );
+ }
+ // Set the URL to the mount-relative portion
+ $req['url'] = substr( $req['url'], strlen( $prefix ) );
+ $replaceReqsByService[$prefix][$index] = $req;
+ }
+ }
+
+ // Function to get IDs that won't collide with keys in $armoredIndexMap
+ $idFunc = function () use ( &$curUniqueId ) {
+ return $curUniqueId++;
+ };
+
+ $rounds = 0;
+ do {
+ if ( ++$rounds > 5 ) { // sanity
+ throw new Exception( "Too many replacement rounds detected. Aborting." );
+ }
+ // Track requests executed this round that have a prefix/service.
+ // Note that this also includes requests where 'response' was forced.
+ $checkReqIndexesByPrefix = [];
+ // Resolve the virtual URLs valid and qualified HTTP(S) URLs
+ // and add any required authentication headers for the backend.
+ // Services can also replace requests with new ones, either to
+ // defer the original or to set a proxy response to the original.
+ $newReplaceReqsByService = [];
+ foreach ( $replaceReqsByService as $prefix => $servReqs ) {
+ $service = $this->getInstance( $prefix );
+ foreach ( $service->onRequests( $servReqs, $idFunc ) as $index => $req ) {
+ // Services use unique IDs for replacement requests
+ if ( isset( $servReqs[$index] ) || isset( $origPending[$index] ) ) {
+ // A current or original request which was not modified
+ } else {
+ // Replacement request that will convert to original requests
+ $newReplaceReqsByService[$prefix][$index] = $req;
+ }
+ if ( isset( $req['response'] ) ) {
+ // Replacement requests with pre-set responses should not execute
+ unset( $executeReqs[$index] );
+ unset( $origPending[$index] );
+ $doneReqs[$index] = $req;
+ } else {
+ // Original or mangled request included
+ $executeReqs[$index] = $req;
+ }
+ $checkReqIndexesByPrefix[$prefix][$index] = 1;
+ }
+ }
+ // Run the actual work HTTP requests
+ foreach ( $this->http->runMulti( $executeReqs ) as $index => $ranReq ) {
+ $doneReqs[$index] = $ranReq;
+ unset( $origPending[$index] );
+ }
+ $executeReqs = [];
+ // Services can also replace requests with new ones, either to
+ // defer the original or to set a proxy response to the original.
+ // Any replacement requests executed above will need to be replaced
+ // with new requests (eventually the original). The responses can be
+ // forced by setting 'response' rather than actually be sent over the wire.
+ $newReplaceReqsByService = [];
+ foreach ( $checkReqIndexesByPrefix as $prefix => $servReqIndexes ) {
+ $service = $this->getInstance( $prefix );
+ // $doneReqs actually has the requests (with 'response' set)
+ $servReqs = array_intersect_key( $doneReqs, $servReqIndexes );
+ foreach ( $service->onResponses( $servReqs, $idFunc ) as $index => $req ) {
+ // Services use unique IDs for replacement requests
+ if ( isset( $servReqs[$index] ) || isset( $origPending[$index] ) ) {
+ // A current or original request which was not modified
+ } else {
+ // Replacement requests with pre-set responses should not execute
+ $newReplaceReqsByService[$prefix][$index] = $req;
+ }
+ if ( isset( $req['response'] ) ) {
+ // Replacement requests with pre-set responses should not execute
+ unset( $origPending[$index] );
+ $doneReqs[$index] = $req;
+ } else {
+ // Update the request in case it was mangled
+ $executeReqs[$index] = $req;
+ }
+ }
+ }
+ // Update index of requests to inspect for replacement
+ $replaceReqsByService = $newReplaceReqsByService;
+ } while ( count( $origPending ) );
+
+ $responses = [];
+ // Update $reqs to include 'response' and normalized request 'headers'.
+ // This maintains the original order of $reqs.
+ foreach ( $reqs as $origIndex => $req ) {
+ $index = $armoredIndexMap[$origIndex];
+ if ( !isset( $doneReqs[$index] ) ) {
+ throw new UnexpectedValueException( "Response for request '$index' is NULL." );
+ }
+ $responses[$origIndex] = $doneReqs[$index]['response'];
+ }
+
+ return $responses;
+ }
+
+ /**
+ * @param string $prefix
+ * @return VirtualRESTService
+ */
+ private function getInstance( $prefix ) {
+ if ( !isset( $this->instances[$prefix] ) ) {
+ throw new RuntimeException( "No service registered at prefix '{$prefix}'." );
+ }
+
+ if ( !( $this->instances[$prefix] instanceof VirtualRESTService ) ) {
+ $config = $this->instances[$prefix]['config'];
+ $class = $this->instances[$prefix]['class'];
+ $service = new $class( $config );
+ if ( !( $service instanceof VirtualRESTService ) ) {
+ throw new UnexpectedValueException( "Registered service has the wrong class." );
+ }
+ $this->instances[$prefix] = $service;
+ }
+
+ return $this->instances[$prefix];
+ }
+}
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