SimpleExiftoolFacade.php

<?php

namespace Drupal\exif;

include_once drupal_get_path('module', 'exif') . '/ExifInterface.php';

/**
 * Helper class to handle the whole data processing of EXIF with exiftool.
 */
class SimpleExifToolFacade implements ExifInterface {
    private static $instance = NULL;
    
    /**
     *
     *
     * @return object
     */
    public static function getInstance() {
        if (is_null(self::$instance)) {
            self::$instance = new self();
        }
        return self::$instance;
    }
    public function getFieldKeys() {
        return array();
    }
    
    /**
     * Going through all the fields that have been created for a given node type
     * and try to figure out which match the naming convention -> so that we know
     * which exif information we have to read
     *
     * Naming convention are: field_exif_xxx (xxx would be the name of the exif
     * tag to read
     *
     * @param array $fields
     *   The fields to process.
     *
     * @return array
     *   A list of exif tags to read for this image.
     */
    public function getMetadataFields(array $fields = array()) {
        foreach ($fields as $drupal_field => $metadata_settings) {
            $metadata_field = $metadata_settings['metadata_field'];
            $ar = explode('_', $metadata_field);
            if (isset($ar[0])) {
                $section = $ar[0];
                unset($ar[0]);
                $fields[$drupal_field]['metadata_field'] = array(
                    'section' => $section,
                    'tag' => implode('_', $ar),
                );
            }
        }
        return $fields;
    }
    public static function checkConfiguration() {
        $exiftoolLocation = self::getExecutable();
        return isset($exiftoolLocation) && is_executable($exiftoolLocation);
    }
    public static function getExecutable() {
        return variable_get('exif_exiftool_location');
    }
    public function runTool($file, $enable_sections = TRUE, $enable_markerNote = FALSE, $enable_non_supported_tags = FALSE) {
        $params = ' -E -n -json ';
        if ($enable_sections) {
            $params .= '-g -struct ';
        }
        if ($enable_markerNote) {
            $params .= '-fast ';
        }
        else {
            $params .= '-fast2 ';
        }
        if ($enable_non_supported_tags) {
            $params .= '-u -U ';
        }
        // Escape all of the arguments passed to the function.
        // Note: If params is expanded so it is customizable, make sure that each
        // piece is passed through escapeshellarg().
        $commandline = escapeshellcmd('exiftool' . $params . escapeshellarg($file));
        $output = array();
        $returnCode = 0;
        exec($commandline, $output, $returnCode);
        if ($returnCode != 0) {
            $output = "";
            watchdog('exif', 'Exiftool returns an error. Can not extract metadata from file !file', array(
                '!file' => $file,
            ), WATCHDOG_WARNING);
        }
        return implode("\n", $output);
    }
    public function tolowerJsonResult(array $data) {
        $result = array();
        foreach ($data as $section => $values) {
            if (is_array($values)) {
                $result[strtolower($section)] = array_change_key_case($values);
            }
            else {
                $result[strtolower($section)] = $values;
            }
        }
        return $result;
    }
    public function readAllInformation($file, $enable_sections = TRUE, $enable_markerNote = FALSE, $enable_non_supported_tags = FALSE) {
        $jsonAsString = $this->runTool($file, $enable_sections, $enable_markerNote, $enable_non_supported_tags);
        $json = json_decode($jsonAsString, TRUE);
        $errorCode = json_last_error();
        if ($errorCode == JSON_ERROR_NONE) {
            return $this->tolowerJsonResult($json[0]);
        }
        else {
            $errorMessage = '';
            switch ($errorCode) {
                case JSON_ERROR_DEPTH:
                    $errorMessage = 'Maximum stack depth exceeded';
                    break;
                case JSON_ERROR_STATE_MISMATCH:
                    $errorMessage = 'Underflow or the modes mismatch';
                    break;
                case JSON_ERROR_CTRL_CHAR:
                    $errorMessage = 'Unexpected control character found';
                    break;
                case JSON_ERROR_SYNTAX:
                    $errorMessage = 'Syntax error, malformed JSON';
                    break;
                case JSON_ERROR_UTF8:
                    $errorMessage = 'Malformed UTF-8 characters, possibly incorrectly encoded';
                    break;
                default:
                    $errorMessage = 'Unknown error';
                    break;
            }
            // Logs a notice.
            watchdog('exif', 'Error reading information from exiftool for file !file: !message', array(
                '!file' => $file,
                '!message' => $errorMessage,
            ), WATCHDOG_NOTICE);
            return array();
        }
    }
    
    /**
     * $arOptions liste of options for the method :
     * # enable_sections : (default : TRUE) retrieve also sections.
     *
     * @param string $file
     * @param bool $enable_sections
     *
     * @return array $data
     */
    public function readMetadataTags($file, $enable_sections = TRUE) {
        if (!file_exists($file)) {
            return array();
        }
        $data = $this->readAllInformation($file, $enable_sections);
        return $data;
    }
    
    /**
     *
     *
     * @param array $metadata
     * @param array $tag_names
     *
     * @return array
     */
    public function filterMetadataTags(array $metadata, array $tag_names) {
        $info = array();
        foreach ($tag_names as $drupal_field => $metadata_settings) {
            $tagName = $metadata_settings['metadata_field'];
            if (!empty($metadata[$tagName['section']][$tagName['tag']])) {
                $info[$tagName['section']][$tagName['tag']] = $metadata[$tagName['section']][$tagName['tag']];
            }
        }
        return $info;
    }

}