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 */
  54         protected $multiHandle = null; // curl_multi handle
  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          * @return array Response array for request
 128          */
 129         public function run( array $req, array $opts = [] ) {
 130                 return $this->runMulti( [ $req ], $opts )[0]['response'];
 131         }
 132
 133         /**
 134          * Execute a set of HTTP(S) requests.
 135          *
 136          * If curl is available, requests will be made concurrently.
 137          * Otherwise, they will be made serially.
 138          *
 139          * The maps are returned by this method with the 'response' field set to a map of:
 140          *   - code    : HTTP response code or 0 if there was a serious error
 141          *   - reason  : HTTP response reason (empty if there was a serious error)
 142          *   - headers : <header name/value associative array>
 143          *   - body    : HTTP response body or resource (if "stream" was set)
 144          *   - error   : Any error string
 145          * The map also stores integer-indexed copies of these values. This lets callers do:
 146          * @code
 147          *        list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $req['response'];
 148          * @endcode
 149          * All headers in the 'headers' field are normalized to use lower case names.
 150          * This is true for the request headers and the response headers. Integer-indexed
 151          * method/URL entries will also be changed to use the corresponding string keys.
 152          *
 153          * @param array[] $reqs Map of HTTP request arrays
 154          * @param array $opts
 155          *   - connTimeout     : connection timeout per request (seconds)
 156          *   - reqTimeout      : post-connection timeout per request (seconds)
 157          *   - usePipelining   : whether to use HTTP pipelining if possible
 158          *   - maxConnsPerHost : maximum number of concurrent connections (per host)
 159          * @return array $reqs With response array populated for each
 160          * @throws Exception
 161          */
 162         public function runMulti( array $reqs, array $opts = [] ) {
 163                 $this->normalizeRequests( $reqs );
 164                 if ( $this->isCurlEnabled() ) {
 165                         return $this->runMultiCurl( $reqs, $opts );
 166                 } else {
 167                         return $this->runMultiHttp( $reqs, $opts );
 168                 }
 169         }
 170
 171         /**
 172          * Determines if the curl extension is available
 173          *
 174          * @return bool true if curl is available, false otherwise.
 175          */
 176         protected function isCurlEnabled() {
 177                 return extension_loaded( 'curl' );
 178         }
 179
 180         /**
 181          * Execute a set of HTTP(S) requests concurrently
 182          *
 183          * @see MultiHttpClient::runMulti()
 184          *
 185          * @param array[] $reqs Map of HTTP request arrays
 186          * @param array $opts
 187          *   - connTimeout     : connection timeout per request (seconds)
 188          *   - reqTimeout      : post-connection timeout per request (seconds)
 189          *   - usePipelining   : whether to use HTTP pipelining if possible
 190          *   - maxConnsPerHost : maximum number of concurrent connections (per host)
 191          * @codingStandardsIgnoreStart
 192          * @phan-param array{connTimeout?:int,reqTimeout?:int,usePipelining?:bool,maxConnsPerHost?:int} $opts
 193          * @codingStandardsIgnoreEnd
 194          * @return array $reqs With response array populated for each
 195          * @throws Exception
 196          * @suppress PhanTypeInvalidDimOffset
 197          */
 198         private function runMultiCurl( array $reqs, array $opts = [] ) {
 199                 $chm = $this->getCurlMulti();
 200
 201                 $selectTimeout = $this->getSelectTimeout( $opts );
 202
 203                 // Add all of the required cURL handles...
 204                 $handles = [];
 205                 foreach ( $reqs as $index => &$req ) {
 206                         $handles[$index] = $this->getCurlHandle( $req, $opts );
 207                         if ( count( $reqs ) > 1 ) {
 208                                 // https://github.com/guzzle/guzzle/issues/349
 209                                 curl_setopt( $handles[$index], CURLOPT_FORBID_REUSE, true );
 210                         }
 211                 }
 212                 unset( $req ); // don't assign over this by accident
 213
 214                 $indexes = array_keys( $reqs );
 215                 if ( isset( $opts['usePipelining'] ) ) {
 216                         curl_multi_setopt( $chm, CURLMOPT_PIPELINING, (int)$opts['usePipelining'] );
 217                 }
 218                 if ( isset( $opts['maxConnsPerHost'] ) ) {
 219                         // Keep these sockets around as they may be needed later in the request
 220                         curl_multi_setopt( $chm, CURLMOPT_MAXCONNECTS, (int)$opts['maxConnsPerHost'] );
 221                 }
 222
 223                 // @TODO: use a per-host rolling handle window (e.g. CURLMOPT_MAX_HOST_CONNECTIONS)
 224                 $batches = array_chunk( $indexes, $this->maxConnsPerHost );
 225                 $infos = [];
 226
 227                 foreach ( $batches as $batch ) {
 228                         // Attach all cURL handles for this batch
 229                         foreach ( $batch as $index ) {
 230                                 curl_multi_add_handle( $chm, $handles[$index] );
 231                         }
 232                         // Execute the cURL handles concurrently...
 233                         $active = null; // handles still being processed
 234                         do {
 235                                 // Do any available work...
 236                                 do {
 237                                         $mrc = curl_multi_exec( $chm, $active );
 238                                         $info = curl_multi_info_read( $chm );
 239                                         if ( $info !== false ) {
 240                                                 $infos[(int)$info['handle']] = $info;
 241                                         }
 242                                 } while ( $mrc == CURLM_CALL_MULTI_PERFORM );
 243                                 // Wait (if possible) for available work...
 244                                 if ( $active > 0 && $mrc == CURLM_OK && curl_multi_select( $chm, $selectTimeout ) == -1 ) {
 245                                         // PHP bug 63411; https://curl.haxx.se/libcurl/c/curl_multi_fdset.html
 246                                         usleep( 5000 ); // 5ms
 247                                 }
 248                         } while ( $active > 0 && $mrc == CURLM_OK );
 249                 }
 250
 251                 // Remove all of the added cURL handles and check for errors...
 252                 foreach ( $reqs as $index => &$req ) {
 253                         $ch = $handles[$index];
 254                         curl_multi_remove_handle( $chm, $ch );
 255
 256                         if ( isset( $infos[(int)$ch] ) ) {
 257                                 $info = $infos[(int)$ch];
 258                                 $errno = $info['result'];
 259                                 if ( $errno !== 0 ) {
 260                                         $req['response']['error'] = "(curl error: $errno)";
 261                                         if ( function_exists( 'curl_strerror' ) ) {
 262                                                 $req['response']['error'] .= " " . curl_strerror( $errno );
 263                                         }
 264                                         $this->logger->warning( "Error fetching URL \"{$req['url']}\": " .
 265                                                 $req['response']['error'] );
 266                                 }
 267                         } else {
 268                                 $req['response']['error'] = "(curl error: no status set)";
 269                         }
 270
 271                         // For convenience with the list() operator
 272                         $req['response'][0] = $req['response']['code'];
 273                         $req['response'][1] = $req['response']['reason'];
 274                         $req['response'][2] = $req['response']['headers'];
 275                         $req['response'][3] = $req['response']['body'];
 276                         $req['response'][4] = $req['response']['error'];
 277                         curl_close( $ch );
 278                         // Close any string wrapper file handles
 279                         if ( isset( $req['_closeHandle'] ) ) {
 280                                 fclose( $req['_closeHandle'] );
 281                                 unset( $req['_closeHandle'] );
 282                         }
 283                 }
 284                 unset( $req ); // don't assign over this by accident
 285
 286                 // Restore the default settings
 287                 curl_multi_setopt( $chm, CURLMOPT_PIPELINING, (int)$this->usePipelining );
 288                 curl_multi_setopt( $chm, CURLMOPT_MAXCONNECTS, (int)$this->maxConnsPerHost );
 289
 290                 return $reqs;
 291         }
 292
 293         /**
 294          * @param array &$req HTTP request map
 295          * @param array $opts
 296          *   - connTimeout    : default connection timeout
 297          *   - reqTimeout     : default request timeout
 298          * @return resource
 299          * @throws Exception
 300          * @suppress PhanTypeMismatchArgumentInternal
 301          */
 302         protected function getCurlHandle( array &$req, array $opts = [] ) {
 303                 $ch = curl_init();
 304
 305                 curl_setopt( $ch, CURLOPT_CONNECTTIMEOUT_MS,
 306                         ( $opts['connTimeout'] ?? $this->connTimeout ) * 1000 );
 307                 curl_setopt( $ch, CURLOPT_PROXY, $req['proxy'] ?? $this->proxy );
 308                 curl_setopt( $ch, CURLOPT_TIMEOUT_MS,
 309                         ( $opts['reqTimeout'] ?? $this->reqTimeout ) * 1000 );
 310                 curl_setopt( $ch, CURLOPT_FOLLOWLOCATION, 1 );
 311                 curl_setopt( $ch, CURLOPT_MAXREDIRS, 4 );
 312                 curl_setopt( $ch, CURLOPT_HEADER, 0 );
 313                 if ( !is_null( $this->caBundlePath ) ) {
 314                         curl_setopt( $ch, CURLOPT_SSL_VERIFYPEER, true );
 315                         curl_setopt( $ch, CURLOPT_CAINFO, $this->caBundlePath );
 316                 }
 317                 curl_setopt( $ch, CURLOPT_RETURNTRANSFER, 1 );
 318
 319                 $url = $req['url'];
 320                 $query = http_build_query( $req['query'], '', '&', PHP_QUERY_RFC3986 );
 321                 if ( $query != '' ) {
 322                         $url .= strpos( $req['url'], '?' ) === false ? "?$query" : "&$query";
 323                 }
 324                 curl_setopt( $ch, CURLOPT_URL, $url );
 325
 326                 curl_setopt( $ch, CURLOPT_CUSTOMREQUEST, $req['method'] );
 327                 if ( $req['method'] === 'HEAD' ) {
 328                         curl_setopt( $ch, CURLOPT_NOBODY, 1 );
 329                 }
 330
 331                 if ( $req['method'] === 'PUT' ) {
 332                         curl_setopt( $ch, CURLOPT_PUT, 1 );
 333                         if ( is_resource( $req['body'] ) ) {
 334                                 curl_setopt( $ch, CURLOPT_INFILE, $req['body'] );
 335                                 if ( isset( $req['headers']['content-length'] ) ) {
 336                                         curl_setopt( $ch, CURLOPT_INFILESIZE, $req['headers']['content-length'] );
 337                                 } elseif ( isset( $req['headers']['transfer-encoding'] ) &&
 338                                         $req['headers']['transfer-encoding'] === 'chunks'
 339                                 ) {
 340                                         curl_setopt( $ch, CURLOPT_UPLOAD, true );
 341                                 } else {
 342                                         throw new Exception( "Missing 'Content-Length' or 'Transfer-Encoding' header." );
 343                                 }
 344                         } elseif ( $req['body'] !== '' ) {
 345                                 $fp = fopen( "php://temp", "wb+" );
 346                                 fwrite( $fp, $req['body'], strlen( $req['body'] ) );
 347                                 rewind( $fp );
 348                                 curl_setopt( $ch, CURLOPT_INFILE, $fp );
 349                                 curl_setopt( $ch, CURLOPT_INFILESIZE, strlen( $req['body'] ) );
 350                                 $req['_closeHandle'] = $fp; // remember to close this later
 351                         } else {
 352                                 curl_setopt( $ch, CURLOPT_INFILESIZE, 0 );
 353                         }
 354                         curl_setopt( $ch, CURLOPT_READFUNCTION,
 355                                 function ( $ch, $fd, $length ) {
 356                                         return (string)fread( $fd, $length );
 357                                 }
 358                         );
 359                 } elseif ( $req['method'] === 'POST' ) {
 360                         curl_setopt( $ch, CURLOPT_POST, 1 );
 361                         curl_setopt( $ch, CURLOPT_POSTFIELDS, $req['body'] );
 362                 } else {
 363                         if ( is_resource( $req['body'] ) || $req['body'] !== '' ) {
 364                                 throw new Exception( "HTTP body specified for a non PUT/POST request." );
 365                         }
 366                         $req['headers']['content-length'] = 0;
 367                 }
 368
 369                 if ( !isset( $req['headers']['user-agent'] ) ) {
 370                         $req['headers']['user-agent'] = $this->userAgent;
 371                 }
 372
 373                 $headers = [];
 374                 foreach ( $req['headers'] as $name => $value ) {
 375                         if ( strpos( $name, ': ' ) ) {
 376                                 throw new Exception( "Headers cannot have ':' in the name." );
 377                         }
 378                         $headers[] = $name . ': ' . trim( $value );
 379                 }
 380                 curl_setopt( $ch, CURLOPT_HTTPHEADER, $headers );
 381
 382                 curl_setopt( $ch, CURLOPT_HEADERFUNCTION,
 383                         function ( $ch, $header ) use ( &$req ) {
 384                                 if ( !empty( $req['flags']['relayResponseHeaders'] ) && trim( $header ) !== '' ) {
 385                                         header( $header );
 386                                 }
 387                                 $length = strlen( $header );
 388                                 $matches = [];
 389                                 if ( preg_match( "/^(HTTP\/1\.[01]) (\d{3}) (.*)/", $header, $matches ) ) {
 390                                         $req['response']['code'] = (int)$matches[2];
 391                                         $req['response']['reason'] = trim( $matches[3] );
 392                                         return $length;
 393                                 }
 394                                 if ( strpos( $header, ":" ) === false ) {
 395                                         return $length;
 396                                 }
 397                                 list( $name, $value ) = explode( ":", $header, 2 );
 398                                 $name = strtolower( $name );
 399                                 $value = trim( $value );
 400                                 if ( isset( $req['response']['headers'][$name] ) ) {
 401                                         $req['response']['headers'][$name] .= ', ' . $value;
 402                                 } else {
 403                                         $req['response']['headers'][$name] = $value;
 404                                 }
 405                                 return $length;
 406                         }
 407                 );
 408
 409                 if ( isset( $req['stream'] ) ) {
 410                         // Don't just use CURLOPT_FILE as that might give:
 411                         // curl_setopt(): cannot represent a stream of type Output as a STDIO FILE*
 412                         // The callback here handles both normal files and php://temp handles.
 413                         curl_setopt( $ch, CURLOPT_WRITEFUNCTION,
 414                                 function ( $ch, $data ) use ( &$req ) {
 415                                         return fwrite( $req['stream'], $data );
 416                                 }
 417                         );
 418                 } else {
 419                         curl_setopt( $ch, CURLOPT_WRITEFUNCTION,
 420                                 function ( $ch, $data ) use ( &$req ) {
 421                                         $req['response']['body'] .= $data;
 422                                         return strlen( $data );
 423                                 }
 424                         );
 425                 }
 426
 427                 return $ch;
 428         }
 429
 430         /**
 431          * @return resource
 432          * @throws Exception
 433          */
 434         protected function getCurlMulti() {
 435                 if ( !$this->multiHandle ) {
 436                         if ( !function_exists( 'curl_multi_init' ) ) {
 437                                 throw new Exception( "PHP cURL function curl_multi_init missing. " .
 438                                         "Check https://www.mediawiki.org/wiki/Manual:CURL" );
 439                         }
 440                         $cmh = curl_multi_init();
 441                         curl_multi_setopt( $cmh, CURLMOPT_PIPELINING, (int)$this->usePipelining );
 442                         curl_multi_setopt( $cmh, CURLMOPT_MAXCONNECTS, (int)$this->maxConnsPerHost );
 443                         $this->multiHandle = $cmh;
 444                 }
 445                 return $this->multiHandle;
 446         }
 447
 448         /**
 449          * Execute a set of HTTP(S) requests sequentially.
 450          *
 451          * @see MultiHttpClient::runMulti()
 452          * @todo Remove dependency on MediaWikiServices: use a separate HTTP client
 453          *  library or copy code from PhpHttpRequest
 454          * @param array $reqs Map of HTTP request arrays
 455          * @param array $opts
 456          *   - connTimeout     : connection timeout per request (seconds)
 457          *   - reqTimeout      : post-connection timeout per request (seconds)
 458          * @return array $reqs With response array populated for each
 459          * @throws Exception
 460          */
 461         private function runMultiHttp( array $reqs, array $opts = [] ) {
 462                 $httpOptions = [
 463                         'timeout' => $opts['reqTimeout'] ?? $this->reqTimeout,
 464                         'connectTimeout' => $opts['connTimeout'] ?? $this->connTimeout,
 465                         'logger' => $this->logger,
 466                         'caInfo' => $this->caBundlePath,
 467                 ];
 468                 foreach ( $reqs as &$req ) {
 469                         $reqOptions = $httpOptions + [
 470                                 'method' => $req['method'],
 471                                 'proxy' => $req['proxy'] ?? $this->proxy,
 472                                 'userAgent' => $req['headers']['user-agent'] ?? $this->userAgent,
 473                                 'postData' => $req['body'],
 474                         ];
 475
 476                         $url = $req['url'];
 477                         $query = http_build_query( $req['query'], '', '&', PHP_QUERY_RFC3986 );
 478                         if ( $query != '' ) {
 479                                 $url .= strpos( $req['url'], '?' ) === false ? "?$query" : "&$query";
 480                         }
 481
 482                         $httpRequest = MediaWikiServices::getInstance()->getHttpRequestFactory()->create(
 483                                 $url, $reqOptions );
 484                         $sv = $httpRequest->execute()->getStatusValue();
 485
 486                         $respHeaders = array_map(
 487                                 function ( $v ) {
 488                                         return implode( ', ', $v );
 489                                 },
 490                                 $httpRequest->getResponseHeaders() );
 491
 492                         $req['response'] = [
 493                                 'code' => $httpRequest->getStatus(),
 494                                 'reason' => '',
 495                                 'headers' => $respHeaders,
 496                                 'body' => $httpRequest->getContent(),
 497                                 'error' => '',
 498                         ];
 499
 500                         if ( !$sv->isOK() ) {
 501                                 $svErrors = $sv->getErrors();
 502                                 if ( isset( $svErrors[0] ) ) {
 503                                         $req['response']['error'] = $svErrors[0]['message'];
 504
 505                                         // param values vary per failure type (ex. unknown host vs unknown page)
 506                                         if ( isset( $svErrors[0]['params'][0] ) ) {
 507                                                 if ( is_numeric( $svErrors[0]['params'][0] ) ) {
 508                                                         if ( isset( $svErrors[0]['params'][1] ) ) {
 509                                                                 // @phan-suppress-next-line PhanTypeInvalidDimOffset
 510                                                                 $req['response']['reason'] = $svErrors[0]['params'][1];
 511                                                         }
 512                                                 } else {
 513                                                         $req['response']['reason'] = $svErrors[0]['params'][0];
 514                                                 }
 515                                         }
 516                                 }
 517                         }
 518
 519                         $req['response'][0] = $req['response']['code'];
 520                         $req['response'][1] = $req['response']['reason'];
 521                         $req['response'][2] = $req['response']['headers'];
 522                         $req['response'][3] = $req['response']['body'];
 523                         $req['response'][4] = $req['response']['error'];
 524                 }
 525
 526                 return $reqs;
 527         }
 528
 529         /**
 530          * Normalize request information
 531          *
 532          * @param array[] $reqs the requests to normalize
 533          */
 534         private function normalizeRequests( array &$reqs ) {
 535                 foreach ( $reqs as &$req ) {
 536                         $req['response'] = [
 537                                 'code'     => 0,
 538                                 'reason'   => '',
 539                                 'headers'  => [],
 540                                 'body'     => '',
 541                                 'error'    => ''
 542                         ];
 543                         if ( isset( $req[0] ) ) {
 544                                 $req['method'] = $req[0]; // short-form
 545                                 unset( $req[0] );
 546                         }
 547                         if ( isset( $req[1] ) ) {
 548                                 $req['url'] = $req[1]; // short-form
 549                                 unset( $req[1] );
 550                         }
 551                         if ( !isset( $req['method'] ) ) {
 552                                 throw new Exception( "Request has no 'method' field set." );
 553                         } elseif ( !isset( $req['url'] ) ) {
 554                                 throw new Exception( "Request has no 'url' field set." );
 555                         }
 556                         $this->logger->debug( "{$req['method']}: {$req['url']}" );
 557                         $req['query'] = $req['query'] ?? [];
 558                         $headers = []; // normalized headers
 559                         if ( isset( $req['headers'] ) ) {
 560                                 foreach ( $req['headers'] as $name => $value ) {
 561                                         $headers[strtolower( $name )] = $value;
 562                                 }
 563                         }
 564                         $req['headers'] = $headers;
 565                         if ( !isset( $req['body'] ) ) {
 566                                 $req['body'] = '';
 567                                 $req['headers']['content-length'] = 0;
 568                         }
 569                         $req['flags'] = $req['flags'] ?? [];
 570                 }
 571         }
 572
 573         /**
 574          * Get a suitable select timeout for the given options.
 575          *
 576          * @param array $opts
 577          * @return float
 578          */
 579         private function getSelectTimeout( $opts ) {
 580                 $connTimeout = $opts['connTimeout'] ?? $this->connTimeout;
 581                 $reqTimeout = $opts['reqTimeout'] ?? $this->reqTimeout;
 582                 $timeouts = array_filter( [ $connTimeout, $reqTimeout ] );
 583                 if ( count( $timeouts ) === 0 ) {
 584                         return 1;
 585                 }
 586
 587                 $selectTimeout = min( $timeouts ) * self::TIMEOUT_ACCURACY_FACTOR;
 588                 // Minimum 10us for sanity
 589                 if ( $selectTimeout < 10e-6 ) {
 590                         $selectTimeout = 10e-6;
 591                 }
 592                 return $selectTimeout;
 593         }
 594
 595         /**
 596          * Register a logger
 597          *
 598          * @param LoggerInterface $logger
 599          */
 600         public function setLogger( LoggerInterface $logger ) {
 601                 $this->logger = $logger;
 602         }
 603
 604         function __destruct() {
 605                 if ( $this->multiHandle ) {
 606                         curl_multi_close( $this->multiHandle );
 607                 }
 608         }
 609 }