public static function toJSON($content) {
    // Note: deliberatly creating JSON string "manually" to improve performance
    return
      '{"title":' . (isset($content->title) ? json_encode($content->title) : 'null') .
      ',"authors":' . (isset($content->authors) ? $content->authors : 'null') .
      ',"source":' . (isset($content->source) ? '"' . $content->source . '"' : 'null') .
      ',"license":' . (isset($content->license) ? '"' . $content->license . '"' : 'null') .
      ',"licenseVersion":' . (isset($content->license_version) ? '"' . $content->license_version . '"' : 'null') .
      ',"licenseExtras":' . (isset($content->license_extras) ? json_encode($content->license_extras) : 'null') .
      ',"yearFrom":' . (isset($content->year_from) ? $content->year_from : 'null') .
      ',"yearTo":' .  (isset($content->year_to) ? $content->year_to : 'null') .
      ',"changes":' . (isset($content->changes) ? $content->changes : 'null') .
      ',"defaultLanguage":' . (isset($content->default_language) ? '"' . $content->default_language . '"' : 'null') .
      ',"authorComments":' . (isset($content->author_comments) ? json_encode($content->author_comments) : 'null') . '}';
  }
public static function toJSON($content) {
    // Note: deliberatly creating JSON string "manually" to improve performance
    return
      '{"title":' . (isset($content->title) ? json_encode($content->title) : 'null') .
      ',"authors":' . (isset($content->authors) ? $content->authors : 'null') .
      ',"source":' . (isset($content->source) ? '"' . $content->source . '"' : 'null') .
      ',"license":' . (isset($content->license) ? '"' . $content->license . '"' : 'null') .
      ',"licenseVersion":' . (isset($content->license_version) ? '"' . $content->license_version . '"' : 'null') .
      ',"licenseExtras":' . (isset($content->license_extras) ? json_encode($content->license_extras) : 'null') .
      ',"yearFrom":' . (isset($content->year_from) ? $content->year_from : 'null') .
      ',"yearTo":' .  (isset($content->year_to) ? $content->year_to : 'null') .
      ',"changes":' . (isset($content->changes) ? $content->changes : 'null') .
      ',"defaultLanguage":' . (isset($content->default_language) ? '"' . $content->default_language . '"' : 'null') .
      ',"authorComments":' . (isset($content->author_comments) ? json_encode($content->author_comments) : 'null') . '}';
  }
public static function toJSON ( $ content ) { // Note: deliberatly creating JSON string "manually" to improve performance return '{"title":' . ( isset ( $ content -> title ) ? json_encode ( $ content -> title ) : 'null' ) . ',"authors":' . ( isset ( $ content -> authors ) ? $ content -> authors : 'null' ) . ',"source":' . ( isset ( $ content -> source ) ? '"' . $ content -> source . '"' : 'null' ) . ',"license":' . ( isset ( $ content -> license ) ? '"' . $ content -> license . '"' : 'null' ) . ',"licenseVersion":' . ( isset ( $ content -> license_version ) ? '"' . $ content -> license_version . '"' : 'null' ) . ',"licenseExtras":' . ( isset ( $ content -> license_extras ) ? json_encode ( $ content -> license_extras ) : 'null' ) . ',"yearFrom":' . ( isset ( $ content -> year_from ) ? $ content -> year_from : 'null' ) . ',"yearTo":' . ( isset ( $ content -> year_to ) ? $ content -> year_to : 'null' ) . ',"changes":' . ( isset ( $ content -> changes ) ? $ content -> changes : 'null' ) . ',"defaultLanguage":' . ( isset ( $ content -> default_language ) ? '"' . $ content -> default_language . '"' : 'null' ) . ',"authorComments":' . ( isset ( $ content -> author_comments ) ? json_encode ( $ content -> author_comments ) : 'null' ) . '}' ; }
JSON encode metadata

@param object $content
@return string
JSON encode metadata