TranslationWebService.php

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<?php
abstract class TranslationWebService {
    /* Public api */

    public static function factory( $name, $config ) {
        $handlers = array(
            'microsoft' => 'MicrosoftWebService',
            'apertium' => 'ApertiumWebService',
            'yandex' => 'YandexWebService',
            'ttmserver' => 'RemoteTTMServerWebService',
        );

        if ( !isset( $config['timeout'] ) ) {
            $config['timeout'] = 3;
        }

        if ( isset( $handlers[$config['type']] ) ) {
            $class = $handlers[$config['type']];

            return new $class( $name, $config );
        }

        return null;
    }

    public function getSuggestions( $translations, $sourceLanguage, $targetLanguage ) {
        if ( $this->checkTranslationServiceFailure() ) {
            return array();
        }

        $from = $this->mapCode( $sourceLanguage );
        $to = $this->mapCode( $targetLanguage );

        try {
            $results = array();

            // Try to use the source language when possible.
            $supported = $this->getSupportedLanguagePairs();
            if ( isset( $supported[$from][$to] ) && isset( $translations[$from] ) ) {
                // Delete all the other languages.
                // Use the unmapped code to avoid double mapping
                $translations = array( $sourceLanguage => $translations[$from] );
            }

            // Loop of the the translations we have to see which can be used as source
            // @todo: Support setting priority of languages like Yandex used to have
            foreach ( $translations as $language => $text ) {
                $from = $this->mapCode( $language );

                if ( isset( $supported[$from][$to] ) ) {
                    $sug = $this->doRequest( $text, $from, $to );
                    if ( strval( $sug === '' ) ) {
                        continue;
                    }

                    $results[] = array(
                        'target' => $sug,
                        'service' => $this->service,
                        'source_language' => $language,
                        'source' => $text,
                    );
                }

                if ( count( $results ) >= 3 ) {
                    break;
                }
            }

            return $results;
        } catch ( Exception $e ) {
            $this->reportTranslationServiceFailure( $e );

            return array();
        }
    }

    /* Service api */

    abstract protected function mapCode( $code );

    abstract protected function doPairs();

    abstract protected function doRequest( $text, $from, $to );

    /* Default implementation */

    protected $service;

    protected $config;

    protected function __construct( $service, $config ) {
        $this->service = $service;
        $this->config = $config;
    }

    protected function getSupportedLanguagePairs() {
        $key = wfMemckey( 'translate-tmsug-pairs-' . $this->service );
        $pairs = wfGetCache( CACHE_ANYTHING )->get( $key );
        if ( !is_array( $pairs ) ) {
            $pairs = $this->doPairs();
            // Cache the result for a day
            wfGetCache( CACHE_ANYTHING )->set( $key, $pairs, 60 * 60 * 24 );
        }

        return $pairs;
    }

    protected function wrapUntranslatable( $text ) {
        $pattern = '~%[^% ]+%|\$\d|{VAR:[^}]+}|{?{(PLURAL|GRAMMAR|GENDER):[^|]+\||%(\d\$)?[sd]~';
        $text = str_replace( "\n", "!N!", $text );
        $wrap = '<span class="notranslate" translate="no">\0</span>';
        $text = preg_replace( $pattern, $wrap, $text );

        return $text;
    }

    protected function unwrapUntranslatable( $text ) {
        $pattern = '~<span class="notranslate" translate="no">(.*?)</span>~';
        $text = str_replace( '!N!', "\n", $text );
        $text = preg_replace( $pattern, '\1', $text );

        return $text;
    }

    /* Failure handling and suspending */

    protected $serviceFailureCount = 5;
    protected $serviceFailurePeriod = 900;

    public function checkTranslationServiceFailure() {
        $service = $this->service;
        $key = wfMemckey( "translate-service-$service" );
        $value = wfGetCache( CACHE_ANYTHING )->get( $key );
        if ( !is_string( $value ) ) {
            return false;
        }
        list( $count, $failed ) = explode( '|', $value, 2 );

        if ( $failed + ( 2 * $this->serviceFailurePeriod ) < wfTimestamp() ) {
            if ( $count >= $this->serviceFailureCount ) {
                wfDebugLog( 'translationservices', "Translation service $service (was) restored" );
            }
            wfGetCache( CACHE_ANYTHING )->delete( $key );

            return false;
        } elseif ( $failed + $this->serviceFailurePeriod < wfTimestamp() ) {
            /* We are in suspicious mode and one failure is enough to update
             * failed timestamp. If the service works however, let's use it.
             * Previous failures are forgotten after another failure period
             * has passed */
            return false;
        }

        // Check the failure count against the limit
        return $count >= $this->serviceFailureCount;
    }

    protected function reportTranslationServiceFailure( Exception $e ) {
        $service = $this->service;
        wfDebugLog(
            'translationservices',
            "Translation service $service problem: " . $e->getMessage()
        );

        $key = wfMemckey( "translate-service-$service" );
        $value = wfGetCache( CACHE_ANYTHING )->get( $key );
        if ( !is_string( $value ) ) {
            $count = 0;
        } else {
            list( $count, ) = explode( '|', $value, 2 );
        }

        $count += 1;
        $failed = wfTimestamp();
        wfGetCache( CACHE_ANYTHING )->set(
            $key,
            "$count|$failed",
            $this->serviceFailurePeriod * 5
        );

        if ( $count == $this->serviceFailureCount ) {
            wfDebugLog( 'translationservices', "Translation service $service suspended" );
        } elseif ( $count > $this->serviceFailureCount ) {
            wfDebugLog( 'translationservices', "Translation service $service still suspended" );
        }
    }
}