includes/libs/virtualrest/VirtualRESTServiceClient.php

   1 <?php
   2 /**
   3  * Virtual HTTP service client
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 /**
  24  * Virtual HTTP service client loosely styled after a Virtual File System
  25  *
  26  * Services can be mounted on path prefixes so that virtual HTTP operations
  27  * against sub-paths will map to those services. Operations can actually be
  28  * done using HTTP messages over the wire or may simple be emulated locally.
  29  *
  30  * Virtual HTTP request maps are arrays that use the following format:
  31  *   - method   : GET/HEAD/PUT/POST/DELETE
  32  *   - url      : HTTP/HTTPS URL or virtual service path with a registered prefix
  33  *   - query    : <query parameter field/value associative array> (uses RFC 3986)
  34  *   - headers  : <header name/value associative array>
  35  *   - body     : source to get the HTTP request body from;
  36  *                this can simply be a string (always), a resource for
  37  *                PUT requests, and a field/value array for POST request;
  38  *                array bodies are encoded as multipart/form-data and strings
  39  *                use application/x-www-form-urlencoded (headers sent automatically)
  40  *   - stream   : resource to stream the HTTP response body to
  41  * Request maps can use integer index 0 instead of 'method' and 1 instead of 'url'.
  42  *
  43  * @since 1.23
  44  */
  45 class VirtualRESTServiceClient {
  46         /** @var MultiHttpClient */
  47         private $http;
  48         /** @var array Map of (prefix => VirtualRESTService|array) */
  49         private $instances = [];
  50
  51         const VALID_MOUNT_REGEX = '#^/[0-9a-z]+/([0-9a-z]+/)*$#';
  52
  53         /**
  54          * @param MultiHttpClient $http
  55          */
  56         public function __construct( MultiHttpClient $http ) {
  57                 $this->http = $http;
  58         }
  59
  60         /**
  61          * Map a prefix to service handler
  62          *
  63          * If $instance is in array, it must have these keys:
  64          *   - class : string; fully qualified VirtualRESTService class name
  65          *   - config : array; map of parameters that is the first __construct() argument
  66          *
  67          * @param string $prefix Virtual path
  68          * @param VirtualRESTService|array $instance Service or info to yield the service
  69          */
  70         public function mount( $prefix, $instance ) {
  71                 if ( !preg_match( self::VALID_MOUNT_REGEX, $prefix ) ) {
  72                         throw new UnexpectedValueException( "Invalid service mount point '$prefix'." );
  73                 } elseif ( isset( $this->instances[$prefix] ) ) {
  74                         throw new UnexpectedValueException( "A service is already mounted on '$prefix'." );
  75                 }
  76                 if ( !( $instance instanceof VirtualRESTService ) ) {
  77                         if ( !isset( $instance['class'] ) || !isset( $instance['config'] ) ) {
  78                                 throw new UnexpectedValueException( "Missing 'class' or 'config' ('$prefix')." );
  79                         }
  80                 }
  81                 $this->instances[$prefix] = $instance;
  82         }
  83
  84         /**
  85          * Unmap a prefix to service handler
  86          *
  87          * @param string $prefix Virtual path
  88          */
  89         public function unmount( $prefix ) {
  90                 if ( !preg_match( self::VALID_MOUNT_REGEX, $prefix ) ) {
  91                         throw new UnexpectedValueException( "Invalid service mount point '$prefix'." );
  92                 } elseif ( !isset( $this->instances[$prefix] ) ) {
  93                         throw new UnexpectedValueException( "No service is mounted on '$prefix'." );
  94                 }
  95                 unset( $this->instances[$prefix] );
  96         }
  97
  98         /**
  99          * Get the prefix and service that a virtual path is serviced by
 100          *
 101          * @param string $path
 102          * @return array (prefix,VirtualRESTService) or (null,null) if none found
 103          */
 104         public function getMountAndService( $path ) {
 105                 $cmpFunc = function ( $a, $b ) {
 106                         $al = substr_count( $a, '/' );
 107                         $bl = substr_count( $b, '/' );
 108                         return $bl <=> $al; // largest prefix first
 109                 };
 110
 111                 $matches = []; // matching prefixes (mount points)
 112                 foreach ( $this->instances as $prefix => $unused ) {
 113                         if ( strpos( $path, $prefix ) === 0 ) {
 114                                 $matches[] = $prefix;
 115                         }
 116                 }
 117                 usort( $matches, $cmpFunc );
 118
 119                 // Return the most specific prefix and corresponding service
 120                 return $matches
 121                         ? [ $matches[0], $this->getInstance( $matches[0] ) ]
 122                         : [ null, null ];
 123         }
 124
 125         /**
 126          * Execute a virtual HTTP(S) request
 127          *
 128          * This method returns a response map of:
 129          *   - code    : HTTP response code or 0 if there was a serious cURL error
 130          *   - reason  : HTTP response reason (empty if there was a serious cURL error)
 131          *   - headers : <header name/value associative array>
 132          *   - body    : HTTP response body or resource (if "stream" was set)
 133          *   - error   : Any cURL error string
 134          * The map also stores integer-indexed copies of these values. This lets callers do:
 135          * @code
 136          *     list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $client->run( $req );
 137          * @endcode
 138          * @param array $req Virtual HTTP request maps
 139          * @return array Response array for request
 140          */
 141         public function run( array $req ) {
 142                 return $this->runMulti( [ $req ] )[0];
 143         }
 144
 145         /**
 146          * Execute a set of virtual HTTP(S) requests concurrently
 147          *
 148          * A map of requests keys to response maps is returned. Each response map has:
 149          *   - code    : HTTP response code or 0 if there was a serious cURL error
 150          *   - reason  : HTTP response reason (empty if there was a serious cURL error)
 151          *   - headers : <header name/value associative array>
 152          *   - body    : HTTP response body or resource (if "stream" was set)
 153          *   - error   : Any cURL error string
 154          * The map also stores integer-indexed copies of these values. This lets callers do:
 155          * @code
 156          *     list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $responses[0];
 157          * @endcode
 158          *
 159          * @param array $reqs Map of Virtual HTTP request maps
 160          * @return array $reqs Map of corresponding response values with the same keys/order
 161          * @throws Exception
 162          */
 163         public function runMulti( array $reqs ) {
 164                 foreach ( $reqs as $index => &$req ) {
 165                         if ( isset( $req[0] ) ) {
 166                                 $req['method'] = $req[0]; // short-form
 167                                 unset( $req[0] );
 168                         }
 169                         if ( isset( $req[1] ) ) {
 170                                 $req['url'] = $req[1]; // short-form
 171                                 unset( $req[1] );
 172                         }
 173                         $req['chain'] = []; // chain or list of replaced requests
 174                 }
 175                 unset( $req ); // don't assign over this by accident
 176
 177                 $curUniqueId = 0;
 178                 $armoredIndexMap = []; // (original index => new index)
 179
 180                 $doneReqs = []; // (index => request)
 181                 $executeReqs = []; // (index => request)
 182                 $replaceReqsByService = []; // (prefix => index => request)
 183                 $origPending = []; // (index => 1) for original requests
 184
 185                 foreach ( $reqs as $origIndex => $req ) {
 186                         // Re-index keys to consecutive integers (they will be swapped back later)
 187                         $index = $curUniqueId++;
 188                         $armoredIndexMap[$origIndex] = $index;
 189                         $origPending[$index] = 1;
 190                         if ( preg_match( '#^(http|ftp)s?://#', $req['url'] ) ) {
 191                                 // Absolute FTP/HTTP(S) URL, run it as normal
 192                                 $executeReqs[$index] = $req;
 193                         } else {
 194                                 // Must be a virtual HTTP URL; resolve it
 195                                 list( $prefix, $service ) = $this->getMountAndService( $req['url'] );
 196                                 if ( !$service ) {
 197                                         throw new UnexpectedValueException( "Path '{$req['url']}' has no service." );
 198                                 }
 199                                 // Set the URL to the mount-relative portion
 200                                 $req['url'] = substr( $req['url'], strlen( $prefix ) );
 201                                 $replaceReqsByService[$prefix][$index] = $req;
 202                         }
 203                 }
 204
 205                 // Function to get IDs that won't collide with keys in $armoredIndexMap
 206                 $idFunc = function () use ( &$curUniqueId ) {
 207                         return $curUniqueId++;
 208                 };
 209
 210                 $rounds = 0;
 211                 do {
 212                         if ( ++$rounds > 5 ) { // sanity
 213                                 throw new Exception( "Too many replacement rounds detected. Aborting." );
 214                         }
 215                         // Track requests executed this round that have a prefix/service.
 216                         // Note that this also includes requests where 'response' was forced.
 217                         $checkReqIndexesByPrefix = [];
 218                         // Resolve the virtual URLs valid and qualified HTTP(S) URLs
 219                         // and add any required authentication headers for the backend.
 220                         // Services can also replace requests with new ones, either to
 221                         // defer the original or to set a proxy response to the original.
 222                         $newReplaceReqsByService = [];
 223                         foreach ( $replaceReqsByService as $prefix => $servReqs ) {
 224                                 $service = $this->getInstance( $prefix );
 225                                 foreach ( $service->onRequests( $servReqs, $idFunc ) as $index => $req ) {
 226                                         // Services use unique IDs for replacement requests
 227                                         if ( isset( $servReqs[$index] ) || isset( $origPending[$index] ) ) {
 228                                                 // A current or original request which was not modified
 229                                         } else {
 230                                                 // Replacement request that will convert to original requests
 231                                                 $newReplaceReqsByService[$prefix][$index] = $req;
 232                                         }
 233                                         if ( isset( $req['response'] ) ) {
 234                                                 // Replacement requests with pre-set responses should not execute
 235                                                 unset( $executeReqs[$index] );
 236                                                 unset( $origPending[$index] );
 237                                                 $doneReqs[$index] = $req;
 238                                         } else {
 239                                                 // Original or mangled request included
 240                                                 $executeReqs[$index] = $req;
 241                                         }
 242                                         $checkReqIndexesByPrefix[$prefix][$index] = 1;
 243                                 }
 244                         }
 245                         // Run the actual work HTTP requests
 246                         foreach ( $this->http->runMulti( $executeReqs ) as $index => $ranReq ) {
 247                                 $doneReqs[$index] = $ranReq;
 248                                 unset( $origPending[$index] );
 249                         }
 250                         $executeReqs = [];
 251                         // Services can also replace requests with new ones, either to
 252                         // defer the original or to set a proxy response to the original.
 253                         // Any replacement requests executed above will need to be replaced
 254                         // with new requests (eventually the original). The responses can be
 255                         // forced by setting 'response' rather than actually be sent over the wire.
 256                         $newReplaceReqsByService = [];
 257                         foreach ( $checkReqIndexesByPrefix as $prefix => $servReqIndexes ) {
 258                                 $service = $this->getInstance( $prefix );
 259                                 // $doneReqs actually has the requests (with 'response' set)
 260                                 $servReqs = array_intersect_key( $doneReqs, $servReqIndexes );
 261                                 foreach ( $service->onResponses( $servReqs, $idFunc ) as $index => $req ) {
 262                                         // Services use unique IDs for replacement requests
 263                                         if ( isset( $servReqs[$index] ) || isset( $origPending[$index] ) ) {
 264                                                 // A current or original request which was not modified
 265                                         } else {
 266                                                 // Replacement requests with pre-set responses should not execute
 267                                                 $newReplaceReqsByService[$prefix][$index] = $req;
 268                                         }
 269                                         if ( isset( $req['response'] ) ) {
 270                                                 // Replacement requests with pre-set responses should not execute
 271                                                 unset( $origPending[$index] );
 272                                                 $doneReqs[$index] = $req;
 273                                         } else {
 274                                                 // Update the request in case it was mangled
 275                                                 $executeReqs[$index] = $req;
 276                                         }
 277                                 }
 278                         }
 279                         // Update index of requests to inspect for replacement
 280                         $replaceReqsByService = $newReplaceReqsByService;
 281                 } while ( count( $origPending ) );
 282
 283                 $responses = [];
 284                 // Update $reqs to include 'response' and normalized request 'headers'.
 285                 // This maintains the original order of $reqs.
 286                 foreach ( $reqs as $origIndex => $req ) {
 287                         $index = $armoredIndexMap[$origIndex];
 288                         if ( !isset( $doneReqs[$index] ) ) {
 289                                 throw new UnexpectedValueException( "Response for request '$index' is NULL." );
 290                         }
 291                         $responses[$origIndex] = $doneReqs[$index]['response'];
 292                 }
 293
 294                 return $responses;
 295         }
 296
 297         /**
 298          * @param string $prefix
 299          * @return VirtualRESTService
 300          */
 301         private function getInstance( $prefix ) {
 302                 if ( !isset( $this->instances[$prefix] ) ) {
 303                         throw new RuntimeException( "No service registered at prefix '{$prefix}'." );
 304                 }
 305
 306                 if ( !( $this->instances[$prefix] instanceof VirtualRESTService ) ) {
 307                         $config = $this->instances[$prefix]['config'];
 308                         $class = $this->instances[$prefix]['class'];
 309                         $service = new $class( $config );
 310                         if ( !( $service instanceof VirtualRESTService ) ) {
 311                                 throw new UnexpectedValueException( "Registered service has the wrong class." );
 312                         }
 313                         $this->instances[$prefix] = $service;
 314                 }
 315
 316                 return $this->instances[$prefix];
 317         }
 318 }