MultiHttpClient.php

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<?php
use Psr\Log\LoggerAwareInterface;
use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;
use MediaWiki\MediaWikiServices;

class MultiHttpClient implements LoggerAwareInterface {
    protected $multiHandle = null; // curl_multi handle
    protected $caBundlePath;
    protected $connTimeout = 10;
    protected $reqTimeout = 900;
    protected $usePipelining = false;
    protected $maxConnsPerHost = 50;
    protected $proxy;
    protected $userAgent = 'wikimedia/multi-http-client v1.0';
    protected $logger;

    // In PHP 7 due to https://bugs.php.net/bug.php?id=76480 the request/connect
    // timeouts are periodically polled instead of being accurately respected.
    // The select timeout is set to the minimum timeout multiplied by this factor.
    const TIMEOUT_ACCURACY_FACTOR = 0.1;

    public function __construct( array $options ) {
        if ( isset( $options['caBundlePath'] ) ) {
            $this->caBundlePath = $options['caBundlePath'];
            if ( !file_exists( $this->caBundlePath ) ) {
                throw new Exception( "Cannot find CA bundle: " . $this->caBundlePath );
            }
        }
        static $opts = [
            'connTimeout', 'reqTimeout', 'usePipelining', 'maxConnsPerHost',
            'proxy', 'userAgent', 'logger'
        ];
        foreach ( $opts as $key ) {
            if ( isset( $options[$key] ) ) {
                $this->$key = $options[$key];
            }
        }
        if ( $this->logger === null ) {
            $this->logger = new NullLogger;
        }
    }

    public function run( array $req, array $opts = [] ) {
        return $this->runMulti( [ $req ], $opts )[0]['response'];
    }

    public function runMulti( array $reqs, array $opts = [] ) {
        $this->normalizeRequests( $reqs );
        if ( $this->isCurlEnabled() ) {
            return $this->runMultiCurl( $reqs, $opts );
        } else {
            return $this->runMultiHttp( $reqs, $opts );
        }
    }

    protected function isCurlEnabled() {
        return extension_loaded( 'curl' );
    }

    private function runMultiCurl( array $reqs, array $opts = [] ) {
        $chm = $this->getCurlMulti();

        $selectTimeout = $this->getSelectTimeout( $opts );

        // Add all of the required cURL handles...
        $handles = [];
        foreach ( $reqs as $index => &$req ) {
            $handles[$index] = $this->getCurlHandle( $req, $opts );
            if ( count( $reqs ) > 1 ) {
                // https://github.com/guzzle/guzzle/issues/349
                curl_setopt( $handles[$index], CURLOPT_FORBID_REUSE, true );
            }
        }
        unset( $req ); // don't assign over this by accident

        $indexes = array_keys( $reqs );
        if ( isset( $opts['usePipelining'] ) ) {
            curl_multi_setopt( $chm, CURLMOPT_PIPELINING, (int)$opts['usePipelining'] );
        }
        if ( isset( $opts['maxConnsPerHost'] ) ) {
            // Keep these sockets around as they may be needed later in the request
            curl_multi_setopt( $chm, CURLMOPT_MAXCONNECTS, (int)$opts['maxConnsPerHost'] );
        }

        // @TODO: use a per-host rolling handle window (e.g. CURLMOPT_MAX_HOST_CONNECTIONS)
        $batches = array_chunk( $indexes, $this->maxConnsPerHost );
        $infos = [];

        foreach ( $batches as $batch ) {
            // Attach all cURL handles for this batch
            foreach ( $batch as $index ) {
                curl_multi_add_handle( $chm, $handles[$index] );
            }
            // Execute the cURL handles concurrently...
            $active = null; // handles still being processed
            do {
                // Do any available work...
                do {
                    $mrc = curl_multi_exec( $chm, $active );
                    $info = curl_multi_info_read( $chm );
                    if ( $info !== false ) {
                        $infos[(int)$info['handle']] = $info;
                    }
                } while ( $mrc == CURLM_CALL_MULTI_PERFORM );
                // Wait (if possible) for available work...
                if ( $active > 0 && $mrc == CURLM_OK && curl_multi_select( $chm, $selectTimeout ) == -1 ) {
                    // PHP bug 63411; https://curl.haxx.se/libcurl/c/curl_multi_fdset.html
                    usleep( 5000 ); // 5ms
                }
            } while ( $active > 0 && $mrc == CURLM_OK );
        }

        // Remove all of the added cURL handles and check for errors...
        foreach ( $reqs as $index => &$req ) {
            $ch = $handles[$index];
            curl_multi_remove_handle( $chm, $ch );

            if ( isset( $infos[(int)$ch] ) ) {
                $info = $infos[(int)$ch];
                $errno = $info['result'];
                if ( $errno !== 0 ) {
                    $req['response']['error'] = "(curl error: $errno)";
                    if ( function_exists( 'curl_strerror' ) ) {
                        $req['response']['error'] .= " " . curl_strerror( $errno );
                    }
                    $this->logger->warning( "Error fetching URL \"{$req['url']}\": " .
                        $req['response']['error'] );
                }
            } else {
                $req['response']['error'] = "(curl error: no status set)";
            }

            // For convenience with the list() operator
            $req['response'][0] = $req['response']['code'];
            $req['response'][1] = $req['response']['reason'];
            $req['response'][2] = $req['response']['headers'];
            $req['response'][3] = $req['response']['body'];
            $req['response'][4] = $req['response']['error'];
            curl_close( $ch );
            // Close any string wrapper file handles
            if ( isset( $req['_closeHandle'] ) ) {
                fclose( $req['_closeHandle'] );
                unset( $req['_closeHandle'] );
            }
        }
        unset( $req ); // don't assign over this by accident

        // Restore the default settings
        curl_multi_setopt( $chm, CURLMOPT_PIPELINING, (int)$this->usePipelining );
        curl_multi_setopt( $chm, CURLMOPT_MAXCONNECTS, (int)$this->maxConnsPerHost );

        return $reqs;
    }

    protected function getCurlHandle( array &$req, array $opts = [] ) {
        $ch = curl_init();

        curl_setopt( $ch, CURLOPT_CONNECTTIMEOUT_MS,
            ( $opts['connTimeout'] ?? $this->connTimeout ) * 1000 );
        curl_setopt( $ch, CURLOPT_PROXY, $req['proxy'] ?? $this->proxy );
        curl_setopt( $ch, CURLOPT_TIMEOUT_MS,
            ( $opts['reqTimeout'] ?? $this->reqTimeout ) * 1000 );
        curl_setopt( $ch, CURLOPT_FOLLOWLOCATION, 1 );
        curl_setopt( $ch, CURLOPT_MAXREDIRS, 4 );
        curl_setopt( $ch, CURLOPT_HEADER, 0 );
        if ( !is_null( $this->caBundlePath ) ) {
            curl_setopt( $ch, CURLOPT_SSL_VERIFYPEER, true );
            curl_setopt( $ch, CURLOPT_CAINFO, $this->caBundlePath );
        }
        curl_setopt( $ch, CURLOPT_RETURNTRANSFER, 1 );

        $url = $req['url'];
        $query = http_build_query( $req['query'], '', '&', PHP_QUERY_RFC3986 );
        if ( $query != '' ) {
            $url .= strpos( $req['url'], '?' ) === false ? "?$query" : "&$query";
        }
        curl_setopt( $ch, CURLOPT_URL, $url );

        curl_setopt( $ch, CURLOPT_CUSTOMREQUEST, $req['method'] );
        if ( $req['method'] === 'HEAD' ) {
            curl_setopt( $ch, CURLOPT_NOBODY, 1 );
        }

        if ( $req['method'] === 'PUT' ) {
            curl_setopt( $ch, CURLOPT_PUT, 1 );
            if ( is_resource( $req['body'] ) ) {
                curl_setopt( $ch, CURLOPT_INFILE, $req['body'] );
                if ( isset( $req['headers']['content-length'] ) ) {
                    curl_setopt( $ch, CURLOPT_INFILESIZE, $req['headers']['content-length'] );
                } elseif ( isset( $req['headers']['transfer-encoding'] ) &&
                    $req['headers']['transfer-encoding'] === 'chunks'
                ) {
                    curl_setopt( $ch, CURLOPT_UPLOAD, true );
                } else {
                    throw new Exception( "Missing 'Content-Length' or 'Transfer-Encoding' header." );
                }
            } elseif ( $req['body'] !== '' ) {
                $fp = fopen( "php://temp", "wb+" );
                fwrite( $fp, $req['body'], strlen( $req['body'] ) );
                rewind( $fp );
                curl_setopt( $ch, CURLOPT_INFILE, $fp );
                curl_setopt( $ch, CURLOPT_INFILESIZE, strlen( $req['body'] ) );
                $req['_closeHandle'] = $fp; // remember to close this later
            } else {
                curl_setopt( $ch, CURLOPT_INFILESIZE, 0 );
            }
            curl_setopt( $ch, CURLOPT_READFUNCTION,
                function ( $ch, $fd, $length ) {
                    $data = fread( $fd, $length );
                    $len = strlen( $data );
                    return $data;
                }
            );
        } elseif ( $req['method'] === 'POST' ) {
            curl_setopt( $ch, CURLOPT_POST, 1 );
            // Don't interpret POST parameters starting with '@' as file uploads, because this
            // makes it impossible to POST plain values starting with '@' (and causes security
            // issues potentially exposing the contents of local files).
            curl_setopt( $ch, CURLOPT_SAFE_UPLOAD, true );
            curl_setopt( $ch, CURLOPT_POSTFIELDS, $req['body'] );
        } else {
            if ( is_resource( $req['body'] ) || $req['body'] !== '' ) {
                throw new Exception( "HTTP body specified for a non PUT/POST request." );
            }
            $req['headers']['content-length'] = 0;
        }

        if ( !isset( $req['headers']['user-agent'] ) ) {
            $req['headers']['user-agent'] = $this->userAgent;
        }

        $headers = [];
        foreach ( $req['headers'] as $name => $value ) {
            if ( strpos( $name, ': ' ) ) {
                throw new Exception( "Headers cannot have ':' in the name." );
            }
            $headers[] = $name . ': ' . trim( $value );
        }
        curl_setopt( $ch, CURLOPT_HTTPHEADER, $headers );

        curl_setopt( $ch, CURLOPT_HEADERFUNCTION,
            function ( $ch, $header ) use ( &$req ) {
                if ( !empty( $req['flags']['relayResponseHeaders'] ) && trim( $header ) !== '' ) {
                    header( $header );
                }
                $length = strlen( $header );
                $matches = [];
                if ( preg_match( "/^(HTTP\/1\.[01]) (\d{3}) (.*)/", $header, $matches ) ) {
                    $req['response']['code'] = (int)$matches[2];
                    $req['response']['reason'] = trim( $matches[3] );
                    return $length;
                }
                if ( strpos( $header, ":" ) === false ) {
                    return $length;
                }
                list( $name, $value ) = explode( ":", $header, 2 );
                $name = strtolower( $name );
                $value = trim( $value );
                if ( isset( $req['response']['headers'][$name] ) ) {
                    $req['response']['headers'][$name] .= ', ' . $value;
                } else {
                    $req['response']['headers'][$name] = $value;
                }
                return $length;
            }
        );

        if ( isset( $req['stream'] ) ) {
            // Don't just use CURLOPT_FILE as that might give:
            // curl_setopt(): cannot represent a stream of type Output as a STDIO FILE*
            // The callback here handles both normal files and php://temp handles.
            curl_setopt( $ch, CURLOPT_WRITEFUNCTION,
                function ( $ch, $data ) use ( &$req ) {
                    return fwrite( $req['stream'], $data );
                }
            );
        } else {
            curl_setopt( $ch, CURLOPT_WRITEFUNCTION,
                function ( $ch, $data ) use ( &$req ) {
                    $req['response']['body'] .= $data;
                    return strlen( $data );
                }
            );
        }

        return $ch;
    }

    protected function getCurlMulti() {
        if ( !$this->multiHandle ) {
            if ( !function_exists( 'curl_multi_init' ) ) {
                throw new Exception( "PHP cURL function curl_multi_init missing. " .
                    "Check https://www.mediawiki.org/wiki/Manual:CURL" );
            }
            $cmh = curl_multi_init();
            curl_multi_setopt( $cmh, CURLMOPT_PIPELINING, (int)$this->usePipelining );
            curl_multi_setopt( $cmh, CURLMOPT_MAXCONNECTS, (int)$this->maxConnsPerHost );
            $this->multiHandle = $cmh;
        }
        return $this->multiHandle;
    }

    private function runMultiHttp( array $reqs, array $opts = [] ) {
        $httpOptions = [
            'timeout' => $opts['reqTimeout'] ?? $this->reqTimeout,
            'connectTimeout' => $opts['connTimeout'] ?? $this->connTimeout,
            'logger' => $this->logger,
            'caInfo' => $this->caBundlePath,
        ];
        foreach ( $reqs as &$req ) {
            $reqOptions = $httpOptions + [
                'method' => $req['method'],
                'proxy' => $req['proxy'] ?? $this->proxy,
                'userAgent' => $req['headers']['user-agent'] ?? $this->userAgent,
                'postData' => $req['body'],
            ];

            $url = $req['url'];
            $query = http_build_query( $req['query'], '', '&', PHP_QUERY_RFC3986 );
            if ( $query != '' ) {
                $url .= strpos( $req['url'], '?' ) === false ? "?$query" : "&$query";
            }

            $httpRequest = MediaWikiServices::getInstance()->getHttpRequestFactory()->create(
                $url, $reqOptions );
            $sv = $httpRequest->execute()->getStatusValue();

            $respHeaders = array_map(
                function ( $v ) {
                    return implode( ', ', $v );
                },
                $httpRequest->getResponseHeaders() );

            $req['response'] = [
                'code' => $httpRequest->getStatus(),
                'reason' => '',
                'headers' => $respHeaders,
                'body' => $httpRequest->getContent(),
                'error' => '',
            ];

            if ( !$sv->isOk() ) {
                $svErrors = $sv->getErrors();
                if ( isset( $svErrors[0] ) ) {
                    $req['response']['error'] = $svErrors[0]['message'];

                    // param values vary per failure type (ex. unknown host vs unknown page)
                    if ( isset( $svErrors[0]['params'][0] ) ) {
                        if ( is_numeric( $svErrors[0]['params'][0] ) ) {
                            if ( isset( $svErrors[0]['params'][1] ) ) {
                                $req['response']['reason'] = $svErrors[0]['params'][1];
                            }
                        } else {
                            $req['response']['reason'] = $svErrors[0]['params'][0];
                        }
                    }
                }
            }

            $req['response'][0] = $req['response']['code'];
            $req['response'][1] = $req['response']['reason'];
            $req['response'][2] = $req['response']['headers'];
            $req['response'][3] = $req['response']['body'];
            $req['response'][4] = $req['response']['error'];
        }

        return $reqs;
    }

    private function normalizeRequests( array &$reqs ) {
        foreach ( $reqs as &$req ) {
            $req['response'] = [
                'code'     => 0,
                'reason'   => '',
                'headers'  => [],
                'body'     => '',
                'error'    => ''
            ];
            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] );
            }
            if ( !isset( $req['method'] ) ) {
                throw new Exception( "Request has no 'method' field set." );
            } elseif ( !isset( $req['url'] ) ) {
                throw new Exception( "Request has no 'url' field set." );
            }
            $this->logger->debug( "{$req['method']}: {$req['url']}" );
            $req['query'] = $req['query'] ?? [];
            $headers = []; // normalized headers
            if ( isset( $req['headers'] ) ) {
                foreach ( $req['headers'] as $name => $value ) {
                    $headers[strtolower( $name )] = $value;
                }
            }
            $req['headers'] = $headers;
            if ( !isset( $req['body'] ) ) {
                $req['body'] = '';
                $req['headers']['content-length'] = 0;
            }
            $req['flags'] = $req['flags'] ?? [];
        }
    }

    private function getSelectTimeout( $opts ) {
        $connTimeout = $opts['connTimeout'] ?? $this->connTimeout;
        $reqTimeout = $opts['reqTimeout'] ?? $this->reqTimeout;
        $timeouts = array_filter( [ $connTimeout, $reqTimeout ] );
        if ( count( $timeouts ) === 0 ) {
            return 1;
        }

        $selectTimeout = min( $timeouts ) * self::TIMEOUT_ACCURACY_FACTOR;
        // Minimum 10us for sanity
        if ( $selectTimeout < 10e-6 ) {
            $selectTimeout = 10e-6;
        }
        return $selectTimeout;
    }

    public function setLogger( LoggerInterface $logger ) {
        $this->logger = $logger;
    }

    function __destruct() {
        if ( $this->multiHandle ) {
            curl_multi_close( $this->multiHandle );
        }
    }
}