Ticket #33772: add-iptc-keywords-to-attachment-metadata.php

<?php
/**
 * Get extended image metadata, exif or iptc as available.
 *
 * Retrieves the EXIF metadata aperture, credit, camera, caption, copyright, iso
 * created_timestamp, focal_length, shutter_speed, and title.
 *
 * The IPTC metadata that is retrieved is APP13, credit, byline, created date
 * and time, caption, copyright, and title. Also includes FNumber, Model,
 * DateTimeDigitized, FocalLength, ISOSpeedRatings, and ExposureTime.
 *
 * @todo Try other exif libraries if available.
 * @since 2.5.0
 *
 * @param string $file
 * @return bool|array False on failure. Image metadata array on success.
 */
function wp_read_image_metadata( $file ) {
        if ( ! file_exists( $file ) )
                return false;

        list( , , $sourceImageType ) = getimagesize( $file );

        /*
         * EXIF contains a bunch of data we'll probably never need formatted in ways
         * that are difficult to use. We'll normalize it and just extract the fields
         * that are likely to be useful. Fractions and numbers are converted to
         * floats, dates to unix timestamps, and everything else to strings.
         */
        $meta = array(
                'aperture' => 0,
                'credit' => '',
                'camera' => '',
                'caption' => '',
                'created_timestamp' => 0,
                'copyright' => '',
                'focal_length' => 0,
                'iso' => 0,
                'shutter_speed' => 0,
                'title' => '',
                'orientation' => 0,
        );

        /*
         * Read IPTC first, since it might contain data not available in exif such
         * as caption, description etc.
         */
        if ( is_callable( 'iptcparse' ) ) {
                getimagesize( $file, $info );

                if ( ! empty( $info['APP13'] ) ) {
                        $iptc = iptcparse( $info['APP13'] );
                        
                        apply_filters( 'wp_parse_image_iptc', $meta, $iptc, $file, $sourceImageType );

                        // Headline, "A brief synopsis of the caption."
                        if ( ! empty( $iptc['2#105'][0] ) ) {
                                $meta['title'] = trim( $iptc['2#105'][0] );
                        /*
                         * Title, "Many use the Title field to store the filename of the image,
                         * though the field may be used in many ways."
                         */
                        } elseif ( ! empty( $iptc['2#005'][0] ) ) {
                                $meta['title'] = trim( $iptc['2#005'][0] );
                        }

                        if ( ! empty( $iptc['2#120'][0] ) ) { // description / legacy caption
                                $caption = trim( $iptc['2#120'][0] );

                                mbstring_binary_safe_encoding();
                                $caption_length = strlen( $caption );
                                reset_mbstring_encoding();

                                if ( empty( $meta['title'] ) && $caption_length < 80 ) {
                                        // Assume the title is stored in 2:120 if it's short.
                                        $meta['title'] = $caption;
                                }

                                $meta['caption'] = $caption;
                        }

                        if ( ! empty( $iptc['2#110'][0] ) ) // credit
                                $meta['credit'] = trim( $iptc['2#110'][0] );
                        elseif ( ! empty( $iptc['2#080'][0] ) ) // creator / legacy byline
                                $meta['credit'] = trim( $iptc['2#080'][0] );

                        if ( ! empty( $iptc['2#055'][0] ) && ! empty( $iptc['2#060'][0] ) ) // created date and time
                                $meta['created_timestamp'] = strtotime( $iptc['2#055'][0] . ' ' . $iptc['2#060'][0] );

                        if ( ! empty( $iptc['2#116'][0] ) ) // copyright
                                $meta['copyright'] = trim( $iptc['2#116'][0] );
                                
                        if ( ! empty( $iptc['2#025'][0] ) ) // keywords array
                                $meta['keywords'] = array_values( $iptc['2#025'] );
                 }
        }

        /**
         * Filter the image types to check for exif data.
         *
         * @since 2.5.0
         *
         * @param array $image_types Image types to check for exif data.
         */
        if ( is_callable( 'exif_read_data' ) && in_array( $sourceImageType, apply_filters( 'wp_read_image_metadata_types', array( IMAGETYPE_JPEG, IMAGETYPE_TIFF_II, IMAGETYPE_TIFF_MM ) ) ) ) {
                $exif = @exif_read_data( $file );

                if ( ! empty( $exif['ImageDescription'] ) ) {
                        mbstring_binary_safe_encoding();
                        $description_length = strlen( $exif['ImageDescription'] );
                        reset_mbstring_encoding();

                        if ( empty( $meta['title'] ) && $description_length < 80 ) {
                                // Assume the title is stored in ImageDescription
                                $meta['title'] = trim( $exif['ImageDescription'] );
                        }

                        if ( empty( $meta['caption'] ) && ! empty( $exif['COMPUTED']['UserComment'] ) ) {
                                $meta['caption'] = trim( $exif['COMPUTED']['UserComment'] );
                        }

                        if ( empty( $meta['caption'] ) ) {
                                $meta['caption'] = trim( $exif['ImageDescription'] );
                        }
                } elseif ( empty( $meta['caption'] ) && ! empty( $exif['Comments'] ) ) {
                        $meta['caption'] = trim( $exif['Comments'] );
                }

                if ( empty( $meta['credit'] ) ) {
                        if ( ! empty( $exif['Artist'] ) ) {
                                $meta['credit'] = trim( $exif['Artist'] );
                        } elseif ( ! empty($exif['Author'] ) ) {
                                $meta['credit'] = trim( $exif['Author'] );
                        }
                }

                if ( empty( $meta['copyright'] ) && ! empty( $exif['Copyright'] ) ) {
                        $meta['copyright'] = trim( $exif['Copyright'] );
                }
                if ( ! empty( $exif['FNumber'] ) ) {
                        $meta['aperture'] = round( wp_exif_frac2dec( $exif['FNumber'] ), 2 );
                }
                if ( ! empty( $exif['Model'] ) ) {
                        $meta['camera'] = trim( $exif['Model'] );
                }
                if ( empty( $meta['created_timestamp'] ) && ! empty( $exif['DateTimeDigitized'] ) ) {
                        $meta['created_timestamp'] = wp_exif_date2ts( $exif['DateTimeDigitized'] );
                }
                if ( ! empty( $exif['FocalLength'] ) ) {
                        $meta['focal_length'] = (string) wp_exif_frac2dec( $exif['FocalLength'] );
                }
                if ( ! empty( $exif['ISOSpeedRatings'] ) ) {
                        $meta['iso'] = is_array( $exif['ISOSpeedRatings'] ) ? reset( $exif['ISOSpeedRatings'] ) : $exif['ISOSpeedRatings'];
                        $meta['iso'] = trim( $meta['iso'] );
                }
                if ( ! empty( $exif['ExposureTime'] ) ) {
                        $meta['shutter_speed'] = (string) wp_exif_frac2dec( $exif['ExposureTime'] );
                }
                if ( ! empty( $exif['Orientation'] ) ) {
                        $meta['orientation'] = $exif['Orientation'];
                }
        }

        foreach ( array( 'title', 'caption', 'credit', 'copyright', 'camera', 'iso' ) as $key ) {
                if ( $meta[ $key ] && ! seems_utf8( $meta[ $key ] ) ) {
                        $meta[ $key ] = utf8_encode( $meta[ $key ] );
                }
        }

        foreach ( $meta as &$value ) {
                if ( is_string( $value ) ) {
                        $value = wp_kses_post( $value );
                }
        }

        /**
         * Filter the array of meta data read from an image's exif data.
         *
         * @since 2.5.0
         *
         * @param array  $meta            Image meta data.
         * @param string $file            Path to image file.
         * @param int    $sourceImageType Type of image.
         */
        return apply_filters( 'wp_read_image_metadata', $meta, $iptc, $file, $sourceImageType );

}