Changing how audio embed shortcodes are generated in Wordpress

Question

I have a rather annoying problem: I have a wordpress website that, among other things, serves audio files. Wordpress does a nice job of filtering any media inserts to a post and putting a player in, but this isn't much good for allowing downloads of the file as well. Ideally I'd want to change the code that generates the audio player shortcode and add <a href="URL">Click here to download mp3.</a> after the [/audio] tag, but my PHP is pretty much non-existent.

My current approach is to use python (which I know well) to write an hourly cron script which plays with the mysql database directly using the python mysql connector. If it runs hourly and looks for posts made in the last hour which contain the string [/audio], pulls out the url for the audio file, and uses it to construct a link to append afterwards. The effect of this is the same, with a maximum time delay of one hour between the post being made and the link being available. When I've finished coding it it should work, but I'm sure it's not the best approach.

Any suggestions?

Answer 1

This should do it (add this to your functions.php file)

function wp_audio_shortcode_dowload_link( $html, $atts, $audio, $post_id, $library ) {
    $html .='<br><a href="'.$atts['src'].'">Download</a>';
    return $html;

}
add_filter( 'wp_audio_shortcode','wp_audio_shortcode_dowload_link',5,10);

Answer 2

In this snippet you have the original code for [audio] shortcode.
It is located in wp-includes/media.php and begins at line 2171. The code in this snippet:

2171            function wp_audio_shortcode( $attr, $content = '' ) {
2172	        $post_id = get_post() ? get_the_ID() : 0;
2173	
2174	        static $instance = 0;
2175	        $instance++;
2176	
2177	        /**
2178	         * Filter the default audio shortcode output.
2179	         *
2180	         * If the filtered output isn't empty, it will be used instead of generating the default audio template.
2181	         *
2182	         * @since 3.6.0
2183	         *
2184	         * @param string $html     Empty variable to be replaced with shortcode markup.
2185	         * @param array  $attr     Attributes of the shortcode. @see wp_audio_shortcode()
2186	         * @param string $content  Shortcode content.
2187	         * @param int    $instance Unique numeric ID of this audio shortcode instance.
2188	         */
2189	        $override = apply_filters( 'wp_audio_shortcode_override', '', $attr, $content, $instance );
2190	        if ( '' !== $override ) {
2191	                return $override;
2192	        }
2193	
2194	        $audio = null;
2195	
2196	        $default_types = wp_get_audio_extensions();
2197	        $defaults_atts = array(
2198	                'src'      => '',
2199	                'loop'     => '',
2200	                'autoplay' => '',
2201	                'preload'  => 'none',
2202	                'class'    => 'wp-audio-shortcode',
2203	                'style'    => 'width: 100%; visibility: hidden;'
2204	        );
2205	        foreach ( $default_types as $type ) {
2206	                $defaults_atts[$type] = '';
2207	        }
2208	
2209	        $atts = shortcode_atts( $defaults_atts, $attr, 'audio' );
2210	
2211	        $primary = false;
2212	        if ( ! empty( $atts['src'] ) ) {
2213	                $type = wp_check_filetype( $atts['src'], wp_get_mime_types() );
2214	                if ( ! in_array( strtolower( $type['ext'] ), $default_types ) ) {
2215	                        return sprintf( '<a class="wp-embedded-audio" href="%s">%s</a>', esc_url( $atts['src'] ), esc_html( $atts['src'] ) );
2216	                }
2217	                $primary = true;
2218	                array_unshift( $default_types, 'src' );
2219	        } else {
2220	                foreach ( $default_types as $ext ) {
2221	                        if ( ! empty( $atts[ $ext ] ) ) {
2222	                                $type = wp_check_filetype( $atts[ $ext ], wp_get_mime_types() );
2223	                                if ( strtolower( $type['ext'] ) === $ext ) {
2224	                                        $primary = true;
2225	                                }
2226	                        }
2227	                }
2228	        }
2229	
2230	        if ( ! $primary ) {
2231	                $audios = get_attached_media( 'audio', $post_id );
2232	                if ( empty( $audios ) ) {
2233	                        return;
2234	                }
2235	
2236	                $audio = reset( $audios );
2237	                $atts['src'] = wp_get_attachment_url( $audio->ID );
2238	                if ( empty( $atts['src'] ) ) {
2239	                        return;
2240	                }
2241	
2242	                array_unshift( $default_types, 'src' );
2243	        }
2244	
2245	        /**
2246	         * Filter the media library used for the audio shortcode.
2247	         *
2248	         * @since 3.6.0
2249	         *
2250	         * @param string $library Media library used for the audio shortcode.
2251	         */
2252	        $library = apply_filters( 'wp_audio_shortcode_library', 'mediaelement' );
2253	        if ( 'mediaelement' === $library && did_action( 'init' ) ) {
2254	                wp_enqueue_style( 'wp-mediaelement' );
2255	                wp_enqueue_script( 'wp-mediaelement' );
2256	        }
2257	
2258	        /**
2259	         * Filter the class attribute for the audio shortcode output container.
2260	         *
2261	         * @since 3.6.0
2262	         *
2263	         * @param string $class CSS class or list of space-separated classes.
2264	         */
2265	        $atts['class'] = apply_filters( 'wp_audio_shortcode_class', $atts['class'] );
2266	
2267	        $html_atts = array(
2268	                'class'    => $atts['class'],
2269	                'id'       => sprintf( 'audio-%d-%d', $post_id, $instance ),
2270	                'loop'     => wp_validate_boolean( $atts['loop'] ),
2271	                'autoplay' => wp_validate_boolean( $atts['autoplay'] ),
2272	                'preload'  => $atts['preload'],
2273	                'style'    => $atts['style'],
2274	        );
2275	
2276	        // These ones should just be omitted altogether if they are blank
2277	        foreach ( array( 'loop', 'autoplay', 'preload' ) as $a ) {
2278	                if ( empty( $html_atts[$a] ) ) {
2279	                        unset( $html_atts[$a] );
2280	                }
2281	        }
2282	
2283	        $attr_strings = array();
2284	        foreach ( $html_atts as $k => $v ) {
2285	                $attr_strings[] = $k . '="' . esc_attr( $v ) . '"';
2286	        }
2287	
2288	        $html = '';
2289	        if ( 'mediaelement' === $library && 1 === $instance ) {
2290	                $html .= "<!--[if lt IE 9]><script>document.createElement('audio');</script><![endif]-->\n";
2291	        }
2292	        $html .= sprintf( '<audio %s controls="controls">', join( ' ', $attr_strings ) );
2293	
2294	        $fileurl = '';
2295	        $source = '<source type="%s" src="%s" />';
2296	        foreach ( $default_types as $fallback ) {
2297	                if ( ! empty( $atts[ $fallback ] ) ) {
2298	                        if ( empty( $fileurl ) ) {
2299	                                $fileurl = $atts[ $fallback ];
2300	                        }
2301	                        $type = wp_check_filetype( $atts[ $fallback ], wp_get_mime_types() );
2302	                        $url = add_query_arg( '_', $instance, $atts[ $fallback ] );
2303	                        $html .= sprintf( $source, $type['type'], esc_url( $url ) );
2304	                }
2305	        }
2306	
2307	        if ( 'mediaelement' === $library ) {
2308	                $html .= wp_mediaelement_fallback( $fileurl );
2309	        }
2310	        $html .= '</audio>';
2311	
2312	        /**
2313	         * Filter the audio shortcode output.
2314	         *
2315	         * @since 3.6.0
2316	         *
2317	         * @param string $html    Audio shortcode HTML output.
2318	         * @param array  $atts    Array of audio shortcode attributes.
2319	         * @param string $audio   Audio file.
2320	         * @param int    $post_id Post ID.
2321	         * @param string $library Media library used for the audio shortcode.
2322	         */
2323	        return apply_filters( 'wp_audio_shortcode', $html, $atts, $audio, $post_id, $library );
2324	}
2325	add_shortcode( 'audio', 'wp_audio_shortcode' );

The idea is to create your own custom version [audio] shortcode, copying and customizing the original code in the function.php file of your active child theme or theme.

You should use first remove_shortcode( 'audio' ); before registering your custom [audio] shortcode.