includes/libs/http/MultiHttpClient.php

   1 <?php
   2 /**
   3  * 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 use Psr\Log\LoggerAwareInterface;
  24 use Psr\Log\LoggerInterface;
  25 use Psr\Log\NullLogger;
  26 use MediaWiki\MediaWikiServices;
  27
  28 /**
  29  * Class to handle multiple HTTP requests
  30  *
  31  * If curl is available, requests will be made concurrently.
  32  * Otherwise, they will be made serially.
  33  *
  34  * HTTP request maps are arrays that use the following format:
  35  *   - method   : GET/HEAD/PUT/POST/DELETE
  36  *   - url      : HTTP/HTTPS URL
  37  *   - query    : <query parameter field/value associative array> (uses RFC 3986)
  38  *   - headers  : <header name/value associative array>
  39  *   - body     : source to get the HTTP request body from;
  40  *                this can simply be a string (always), a resource for
  41  *                PUT requests, and a field/value array for POST request;
  42  *                array bodies are encoded as multipart/form-data and strings
  43  *                use application/x-www-form-urlencoded (headers sent automatically)
  44  *   - stream   : resource to stream the HTTP response body to
  45  *   - proxy    : HTTP proxy to use
  46  *   - flags    : map of boolean flags which supports:
  47  *                  - relayResponseHeaders : write out header via header()
  48  * Request maps can use integer index 0 instead of 'method' and 1 instead of 'url'.
  49  *
  50  * @since 1.23
  51  */
  52 class MultiHttpClient implements LoggerAwareInterface {
  53         /** @var resource curl_multi_init() handle */
  54         protected $cmh;
  55         /** @var string|null SSL certificates path */
  56         protected $caBundlePath;
  57         /** @var float */
  58         protected $connTimeout = 10;
  59         /** @var float */
  60         protected $reqTimeout = 900;
  61         /** @var bool */
  62         protected $usePipelining = false;
  63         /** @var int */
  64         protected $maxConnsPerHost = 50;
  65         /** @var string|null proxy */
  66         protected $proxy;
  67         /** @var string */
  68         protected $userAgent = 'wikimedia/multi-http-client v1.0';
  69         /** @var LoggerInterface */
  70         protected $logger;
  71
  72         // In PHP 7 due to https://bugs.php.net/bug.php?id=76480 the request/connect
  73         // timeouts are periodically polled instead of being accurately respected.
  74         // The select timeout is set to the minimum timeout multiplied by this factor.
  75         const TIMEOUT_ACCURACY_FACTOR = 0.1;
  76
  77         /**
  78          * @param array $options
  79          *   - connTimeout     : default connection timeout (seconds)
  80          *   - reqTimeout      : default request timeout (seconds)
  81          *   - proxy           : HTTP proxy to use
  82          *   - usePipelining   : whether to use HTTP pipelining if possible (for all hosts)
  83          *   - maxConnsPerHost : maximum number of concurrent connections (per host)
  84          *   - userAgent       : The User-Agent header value to send
  85          *   - logger          : a \Psr\Log\LoggerInterface instance for debug logging
  86          *   - caBundlePath    : path to specific Certificate Authority bundle (if any)
  87          * @throws Exception
  88          */
  89         public function __construct( array $options ) {
  90                 if ( isset( $options['caBundlePath'] ) ) {
  91                         $this->caBundlePath = $options['caBundlePath'];
  92                         if ( !file_exists( $this->caBundlePath ) ) {
  93                                 throw new Exception( "Cannot find CA bundle: " . $this->caBundlePath );
  94                         }
  95                 }
  96                 static $opts = [
  97                         'connTimeout', 'reqTimeout', 'usePipelining', 'maxConnsPerHost',
  98                         'proxy', 'userAgent', 'logger'
  99                 ];
 100                 foreach ( $opts as $key ) {
 101                         if ( isset( $options[$key] ) ) {
 102                                 $this->$key = $options[$key];
 103                         }
 104                 }
 105                 if ( $this->logger === null ) {
 106                         $this->logger = new NullLogger;
 107                 }
 108         }
 109
 110         /**
 111          * Execute an HTTP(S) request
 112          *
 113          * This method returns a response map of:
 114          *   - code    : HTTP response code or 0 if there was a serious error
 115          *   - reason  : HTTP response reason (empty if there was a serious error)
 116          *   - headers : <header name/value associative array>
 117          *   - body    : HTTP response body or resource (if "stream" was set)
 118          *   - error     : Any error string
 119          * The map also stores integer-indexed copies of these values. This lets callers do:
 120          * @code
 121          *              list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $http->run( $req );
 122          * @endcode
 123          * @param array $req HTTP request array
 124          * @param array $opts
 125          *   - connTimeout     : connection timeout per request (seconds)
 126          *   - reqTimeout      : post-connection timeout per request (seconds)
 127          *   - usePipelining   : whether to use HTTP pipelining if possible (for all hosts)
 128          *   - maxConnsPerHost : maximum number of concurrent connections (per host)
 129          * @return array Response array for request
 130          */
 131         public function run( array $req, array $opts = [] ) {
 132                 return $this->runMulti( [ $req ], $opts )[0]['response'];
 133         }
 134
 135         /**
 136          * Execute a set of HTTP(S) requests.
 137          *
 138          * If curl is available, requests will be made concurrently.
 139          * Otherwise, they will be made serially.
 140          *
 141          * The maps are returned by this method with the 'response' field set to a map of:
 142          *   - code    : HTTP response code or 0 if there was a serious error
 143          *   - reason  : HTTP response reason (empty if there was a serious error)
 144          *   - headers : <header name/value associative array>
 145          *   - body    : HTTP response body or resource (if "stream" was set)
 146          *   - error   : Any error string
 147          * The map also stores integer-indexed copies of these values. This lets callers do:
 148          * @code
 149          *        list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $req['response'];
 150          * @endcode
 151          * All headers in the 'headers' field are normalized to use lower case names.
 152          * This is true for the request headers and the response headers. Integer-indexed
 153          * method/URL entries will also be changed to use the corresponding string keys.
 154          *
 155          * @param array[] $reqs Map of HTTP request arrays
 156          * @param array $opts Options
 157          *   - connTimeout     : connection timeout per request (seconds)
 158          *   - reqTimeout      : post-connection timeout per request (seconds)
 159          *   - usePipelining   : whether to use HTTP pipelining if possible (for all hosts)
 160          *   - maxConnsPerHost : maximum number of concurrent connections (per host)
 161          * @return array $reqs With response array populated for each
 162          * @throws Exception
 163          */
 164         public function runMulti( array $reqs, array $opts = [] ) {
 165                 $this->normalizeRequests( $reqs );
 166                 $opts += [ 'connTimeout' => $this->connTimeout, 'reqTimeout' => $this->reqTimeout ];
 167
 168                 if ( $this->isCurlEnabled() ) {
 169                         return $this->runMultiCurl( $reqs, $opts );
 170                 } else {
 171                         return $this->runMultiHttp( $reqs, $opts );
 172                 }
 173         }
 174
 175         /**
 176          * Determines if the curl extension is available
 177          *
 178          * @return bool true if curl is available, false otherwise.
 179          */
 180         protected function isCurlEnabled() {
 181                 return extension_loaded( 'curl' );
 182         }
 183
 184         /**
 185          * Execute a set of HTTP(S) requests concurrently
 186          *
 187          * @see MultiHttpClient::runMulti()
 188          *
 189          * @param array[] $reqs Map of HTTP request arrays
 190          * @param array $opts
 191          *   - connTimeout     : connection timeout per request (seconds)
 192          *   - reqTimeout      : post-connection timeout per request (seconds)
 193          *   - usePipelining   : whether to use HTTP pipelining if possible
 194          *   - maxConnsPerHost : maximum number of concurrent connections (per host)
 195          * @codingStandardsIgnoreStart
 196          * @phan-param array{connTimeout?:int,reqTimeout?:int,usePipelining?:bool,maxConnsPerHost?:int} $opts
 197          * @codingStandardsIgnoreEnd
 198          * @return array $reqs With response array populated for each
 199          * @throws Exception
 200          * @suppress PhanTypeInvalidDimOffset
 201          */
 202         private function runMultiCurl( array $reqs, array $opts ) {
 203                 $chm = $this->getCurlMulti( $opts );
 204
 205                 $selectTimeout = $this->getSelectTimeout( $opts );
 206
 207                 // Add all of the required cURL handles...
 208                 $handles = [];
 209                 foreach ( $reqs as $index => &$req ) {
 210                         $handles[$index] = $this->getCurlHandle( $req, $opts );
 211                         curl_multi_add_handle( $chm, $handles[$index] );
 212                 }
 213                 unset( $req ); // don't assign over this by accident
 214
 215                 $infos = [];
 216                 // Execute the cURL handles concurrently...
 217                 $active = null; // handles still being processed
 218                 do {
 219                         // Do any available work...
 220                         do {
 221                                 $mrc = curl_multi_exec( $chm, $active );
 222                                 $info = curl_multi_info_read( $chm );
 223                                 if ( $info !== false ) {
 224                                         $infos[(int)$info['handle']] = $info;
 225                                 }
 226                         } while ( $mrc == CURLM_CALL_MULTI_PERFORM );
 227                         // Wait (if possible) for available work...
 228                         if ( $active > 0 && $mrc == CURLM_OK && curl_multi_select( $chm, $selectTimeout ) == -1 ) {
 229                                 // PHP bug 63411; https://curl.haxx.se/libcurl/c/curl_multi_fdset.html
 230                                 usleep( 5000 ); // 5ms
 231                         }
 232                 } while ( $active > 0 && $mrc == CURLM_OK );
 233
 234                 // Remove all of the added cURL handles and check for errors...
 235                 foreach ( $reqs as $index => &$req ) {
 236                         $ch = $handles[$index];
 237                         curl_multi_remove_handle( $chm, $ch );
 238
 239                         if ( isset( $infos[(int)$ch] ) ) {
 240                                 $info = $infos[(int)$ch];
 241                                 $errno = $info['result'];
 242                                 if ( $errno !== 0 ) {
 243                                         $req['response']['error'] = "(curl error: $errno)";
 244                                         if ( function_exists( 'curl_strerror' ) ) {
 245                                                 $req['response']['error'] .= " " . curl_strerror( $errno );
 246                                         }
 247                                         $this->logger->warning( "Error fetching URL \"{$req['url']}\": " .
 248                                                 $req['response']['error'] );
 249                                 }
 250                         } else {
 251                                 $req['response']['error'] = "(curl error: no status set)";
 252                         }
 253
 254                         // For convenience with the list() operator
 255                         $req['response'][0] = $req['response']['code'];
 256                         $req['response'][1] = $req['response']['reason'];
 257                         $req['response'][2] = $req['response']['headers'];
 258                         $req['response'][3] = $req['response']['body'];
 259                         $req['response'][4] = $req['response']['error'];
 260                         curl_close( $ch );
 261                         // Close any string wrapper file handles
 262                         if ( isset( $req['_closeHandle'] ) ) {
 263                                 fclose( $req['_closeHandle'] );
 264                                 unset( $req['_closeHandle'] );
 265                         }
 266                 }
 267                 unset( $req ); // don't assign over this by accident
 268
 269                 return $reqs;
 270         }
 271
 272         /**
 273          * @param array &$req HTTP request map
 274          * @codingStandardsIgnoreStart
 275          * @phan-param array{url:string,proxy?:?string,query:mixed,method:string,body:string|resource,headers:string[],stream?:resource,flags:array} $req
 276          * @codingStandardsIgnoreEnd
 277          * @param array $opts
 278          *   - connTimeout : default connection timeout
 279          *   - reqTimeout : default request timeout
 280          * @return resource
 281          * @throws Exception
 282          */
 283         protected function getCurlHandle( array &$req, array $opts ) {
 284                 $ch = curl_init();
 285
 286                 curl_setopt( $ch, CURLOPT_PROXY, $req['proxy'] ?? $this->proxy );
 287                 curl_setopt( $ch, CURLOPT_CONNECTTIMEOUT_MS, intval( $opts['connTimeout'] * 1e3 ) );
 288                 curl_setopt( $ch, CURLOPT_TIMEOUT_MS, intval( $opts['reqTimeout'] * 1e3 ) );
 289                 curl_setopt( $ch, CURLOPT_FOLLOWLOCATION, 1 );
 290                 curl_setopt( $ch, CURLOPT_MAXREDIRS, 4 );
 291                 curl_setopt( $ch, CURLOPT_HEADER, 0 );
 292                 if ( !is_null( $this->caBundlePath ) ) {
 293                         curl_setopt( $ch, CURLOPT_SSL_VERIFYPEER, true );
 294                         curl_setopt( $ch, CURLOPT_CAINFO, $this->caBundlePath );
 295                 }
 296                 curl_setopt( $ch, CURLOPT_RETURNTRANSFER, 1 );
 297
 298                 $url = $req['url'];
 299                 $query = http_build_query( $req['query'], '', '&', PHP_QUERY_RFC3986 );
 300                 if ( $query != '' ) {
 301                         $url .= strpos( $req['url'], '?' ) === false ? "?$query" : "&$query";
 302                 }
 303                 curl_setopt( $ch, CURLOPT_URL, $url );
 304                 curl_setopt( $ch, CURLOPT_CUSTOMREQUEST, $req['method'] );
 305                 curl_setopt( $ch, CURLOPT_NOBODY, ( $req['method'] === 'HEAD' ) );
 306
 307                 if ( $req['method'] === 'PUT' ) {
 308                         curl_setopt( $ch, CURLOPT_PUT, 1 );
 309                         if ( is_resource( $req['body'] ) ) {
 310                                 curl_setopt( $ch, CURLOPT_INFILE, $req['body'] );
 311                                 if ( isset( $req['headers']['content-length'] ) ) {
 312                                         curl_setopt( $ch, CURLOPT_INFILESIZE, $req['headers']['content-length'] );
 313                                 } elseif ( isset( $req['headers']['transfer-encoding'] ) &&
 314                                         $req['headers']['transfer-encoding'] === 'chunks'
 315                                 ) {
 316                                         curl_setopt( $ch, CURLOPT_UPLOAD, true );
 317                                 } else {
 318                                         throw new Exception( "Missing 'Content-Length' or 'Transfer-Encoding' header." );
 319                                 }
 320                         } elseif ( $req['body'] !== '' ) {
 321                                 $fp = fopen( "php://temp", "wb+" );
 322                                 fwrite( $fp, $req['body'], strlen( $req['body'] ) );
 323                                 rewind( $fp );
 324                                 curl_setopt( $ch, CURLOPT_INFILE, $fp );
 325                                 curl_setopt( $ch, CURLOPT_INFILESIZE, strlen( $req['body'] ) );
 326                                 $req['_closeHandle'] = $fp; // remember to close this later
 327                         } else {
 328                                 curl_setopt( $ch, CURLOPT_INFILESIZE, 0 );
 329                         }
 330                         curl_setopt( $ch, CURLOPT_READFUNCTION,
 331                                 function ( $ch, $fd, $length ) {
 332                                         return (string)fread( $fd, $length );
 333                                 }
 334                         );
 335                 } elseif ( $req['method'] === 'POST' ) {
 336                         curl_setopt( $ch, CURLOPT_POST, 1 );
 337                         curl_setopt( $ch, CURLOPT_POSTFIELDS, $req['body'] );
 338                 } else {
 339                         if ( is_resource( $req['body'] ) || $req['body'] !== '' ) {
 340                                 throw new Exception( "HTTP body specified for a non PUT/POST request." );
 341                         }
 342                         $req['headers']['content-length'] = 0;
 343                 }
 344
 345                 if ( !isset( $req['headers']['user-agent'] ) ) {
 346                         $req['headers']['user-agent'] = $this->userAgent;
 347                 }
 348
 349                 $headers = [];
 350                 foreach ( $req['headers'] as $name => $value ) {
 351                         if ( strpos( $name, ': ' ) ) {
 352                                 throw new Exception( "Headers cannot have ':' in the name." );
 353                         }
 354                         $headers[] = $name . ': ' . trim( $value );
 355                 }
 356                 curl_setopt( $ch, CURLOPT_HTTPHEADER, $headers );
 357
 358                 curl_setopt( $ch, CURLOPT_HEADERFUNCTION,
 359                         function ( $ch, $header ) use ( &$req ) {
 360                                 if ( !empty( $req['flags']['relayResponseHeaders'] ) && trim( $header ) !== '' ) {
 361                                         header( $header );
 362                                 }
 363                                 $length = strlen( $header );
 364                                 $matches = [];
 365                                 if ( preg_match( "/^(HTTP\/1\.[01]) (\d{3}) (.*)/", $header, $matches ) ) {
 366                                         $req['response']['code'] = (int)$matches[2];
 367                                         $req['response']['reason'] = trim( $matches[3] );
 368                                         return $length;
 369                                 }
 370                                 if ( strpos( $header, ":" ) === false ) {
 371                                         return $length;
 372                                 }
 373                                 list( $name, $value ) = explode( ":", $header, 2 );
 374                                 $name = strtolower( $name );
 375                                 $value = trim( $value );
 376                                 if ( isset( $req['response']['headers'][$name] ) ) {
 377                                         $req['response']['headers'][$name] .= ', ' . $value;
 378                                 } else {
 379                                         $req['response']['headers'][$name] = $value;
 380                                 }
 381                                 return $length;
 382                         }
 383                 );
 384
 385                 // This works with both file and php://temp handles (unlike CURLOPT_FILE)
 386                 $hasOutputStream = isset( $req['stream'] );
 387                 curl_setopt( $ch, CURLOPT_WRITEFUNCTION,
 388                         function ( $ch, $data ) use ( &$req, $hasOutputStream ) {
 389                                 if ( $hasOutputStream ) {
 390                                         return fwrite( $req['stream'], $data );
 391                                 } else {
 392                                         // @phan-suppress-next-line PhanTypeArraySuspiciousNullable
 393                                         $req['response']['body'] .= $data;
 394
 395                                         return strlen( $data );
 396                                 }
 397                         }
 398                 );
 399
 400                 return $ch;
 401         }
 402
 403         /**
 404          * @param array $opts
 405          * @return resource
 406          * @throws Exception
 407          */
 408         protected function getCurlMulti( array $opts ) {
 409                 if ( !$this->cmh ) {
 410                         if ( !function_exists( 'curl_multi_init' ) ) {
 411                                 throw new Exception( "PHP cURL function curl_multi_init missing. " .
 412                                         "Check https://www.mediawiki.org/wiki/Manual:CURL" );
 413                         }
 414                         $cmh = curl_multi_init();
 415                         // Limit the size of the idle connection cache such that consecutive parallel
 416                         // request batches to the same host can avoid having to keep making connections
 417                         curl_multi_setopt( $cmh, CURLMOPT_MAXCONNECTS, (int)$this->maxConnsPerHost );
 418                         $this->cmh = $cmh;
 419                 }
 420
 421                 // Limit the number of in-flight requests for any given host
 422                 $maxHostConns = $opts['maxConnsPerHost'] ?? $this->maxConnsPerHost;
 423                 curl_multi_setopt( $this->cmh, CURLMOPT_MAX_HOST_CONNECTIONS, (int)$maxHostConns );
 424                 // Configure when to multiplex multiple requests onto single TCP handles
 425                 $pipelining = $opts['usePipelining'] ?? $this->usePipelining;
 426                 curl_multi_setopt( $this->cmh, CURLMOPT_PIPELINING, (int)$pipelining );
 427
 428                 return $this->cmh;
 429         }
 430
 431         /**
 432          * Execute a set of HTTP(S) requests sequentially.
 433          *
 434          * @see MultiHttpClient::runMulti()
 435          * @todo Remove dependency on MediaWikiServices: use a separate HTTP client
 436          *  library or copy code from PhpHttpRequest
 437          * @param array $reqs Map of HTTP request arrays
 438          * @param array $opts
 439          *   - connTimeout     : connection timeout per request (seconds)
 440          *   - reqTimeout      : post-connection timeout per request (seconds)
 441          * @return array $reqs With response array populated for each
 442          * @throws Exception
 443          */
 444         private function runMultiHttp( array $reqs, array $opts = [] ) {
 445                 $httpOptions = [
 446                         'timeout' => $opts['reqTimeout'] ?? $this->reqTimeout,
 447                         'connectTimeout' => $opts['connTimeout'] ?? $this->connTimeout,
 448                         'logger' => $this->logger,
 449                         'caInfo' => $this->caBundlePath,
 450                 ];
 451                 foreach ( $reqs as &$req ) {
 452                         $reqOptions = $httpOptions + [
 453                                 'method' => $req['method'],
 454                                 'proxy' => $req['proxy'] ?? $this->proxy,
 455                                 'userAgent' => $req['headers']['user-agent'] ?? $this->userAgent,
 456                                 'postData' => $req['body'],
 457                         ];
 458
 459                         $url = $req['url'];
 460                         $query = http_build_query( $req['query'], '', '&', PHP_QUERY_RFC3986 );
 461                         if ( $query != '' ) {
 462                                 $url .= strpos( $req['url'], '?' ) === false ? "?$query" : "&$query";
 463                         }
 464
 465                         $httpRequest = MediaWikiServices::getInstance()->getHttpRequestFactory()->create(
 466                                 $url, $reqOptions );
 467                         $sv = $httpRequest->execute()->getStatusValue();
 468
 469                         $respHeaders = array_map(
 470                                 function ( $v ) {
 471                                         return implode( ', ', $v );
 472                                 },
 473                                 $httpRequest->getResponseHeaders() );
 474
 475                         $req['response'] = [
 476                                 'code' => $httpRequest->getStatus(),
 477                                 'reason' => '',
 478                                 'headers' => $respHeaders,
 479                                 'body' => $httpRequest->getContent(),
 480                                 'error' => '',
 481                         ];
 482
 483                         if ( !$sv->isOK() ) {
 484                                 $svErrors = $sv->getErrors();
 485                                 if ( isset( $svErrors[0] ) ) {
 486                                         $req['response']['error'] = $svErrors[0]['message'];
 487
 488                                         // param values vary per failure type (ex. unknown host vs unknown page)
 489                                         if ( isset( $svErrors[0]['params'][0] ) ) {
 490                                                 if ( is_numeric( $svErrors[0]['params'][0] ) ) {
 491                                                         if ( isset( $svErrors[0]['params'][1] ) ) {
 492                                                                 // @phan-suppress-next-line PhanTypeInvalidDimOffset
 493                                                                 $req['response']['reason'] = $svErrors[0]['params'][1];
 494                                                         }
 495                                                 } else {
 496                                                         $req['response']['reason'] = $svErrors[0]['params'][0];
 497                                                 }
 498                                         }
 499                                 }
 500                         }
 501
 502                         $req['response'][0] = $req['response']['code'];
 503                         $req['response'][1] = $req['response']['reason'];
 504                         $req['response'][2] = $req['response']['headers'];
 505                         $req['response'][3] = $req['response']['body'];
 506                         $req['response'][4] = $req['response']['error'];
 507                 }
 508
 509                 return $reqs;
 510         }
 511
 512         /**
 513          * Normalize request information
 514          *
 515          * @param array[] $reqs the requests to normalize
 516          */
 517         private function normalizeRequests( array &$reqs ) {
 518                 foreach ( $reqs as &$req ) {
 519                         $req['response'] = [
 520                                 'code'     => 0,
 521                                 'reason'   => '',
 522                                 'headers'  => [],
 523                                 'body'     => '',
 524                                 'error'    => ''
 525                         ];
 526                         if ( isset( $req[0] ) ) {
 527                                 $req['method'] = $req[0]; // short-form
 528                                 unset( $req[0] );
 529                         }
 530                         if ( isset( $req[1] ) ) {
 531                                 $req['url'] = $req[1]; // short-form
 532                                 unset( $req[1] );
 533                         }
 534                         if ( !isset( $req['method'] ) ) {
 535                                 throw new Exception( "Request has no 'method' field set." );
 536                         } elseif ( !isset( $req['url'] ) ) {
 537                                 throw new Exception( "Request has no 'url' field set." );
 538                         }
 539                         $this->logger->debug( "{$req['method']}: {$req['url']}" );
 540                         $req['query'] = $req['query'] ?? [];
 541                         $headers = []; // normalized headers
 542                         if ( isset( $req['headers'] ) ) {
 543                                 foreach ( $req['headers'] as $name => $value ) {
 544                                         $headers[strtolower( $name )] = $value;
 545                                 }
 546                         }
 547                         $req['headers'] = $headers;
 548                         if ( !isset( $req['body'] ) ) {
 549                                 $req['body'] = '';
 550                                 $req['headers']['content-length'] = 0;
 551                         }
 552                         $req['flags'] = $req['flags'] ?? [];
 553                 }
 554         }
 555
 556         /**
 557          * Get a suitable select timeout for the given options.
 558          *
 559          * @param array $opts
 560          * @return float
 561          */
 562         private function getSelectTimeout( $opts ) {
 563                 $connTimeout = $opts['connTimeout'] ?? $this->connTimeout;
 564                 $reqTimeout = $opts['reqTimeout'] ?? $this->reqTimeout;
 565                 $timeouts = array_filter( [ $connTimeout, $reqTimeout ] );
 566                 if ( count( $timeouts ) === 0 ) {
 567                         return 1;
 568                 }
 569
 570                 $selectTimeout = min( $timeouts ) * self::TIMEOUT_ACCURACY_FACTOR;
 571                 // Minimum 10us for sanity
 572                 if ( $selectTimeout < 10e-6 ) {
 573                         $selectTimeout = 10e-6;
 574                 }
 575                 return $selectTimeout;
 576         }
 577
 578         /**
 579          * Register a logger
 580          *
 581          * @param LoggerInterface $logger
 582          */
 583         public function setLogger( LoggerInterface $logger ) {
 584                 $this->logger = $logger;
 585         }
 586
 587         function __destruct() {
 588                 if ( $this->cmh ) {
 589                         curl_multi_close( $this->cmh );
 590                 }
 591         }
 592 }