Displaying Random Images

Thanks for an interesting question, which breaks down into three parts. I will answer each part in turn.

First, you wrote “Would it be possible to create a widget with MLA …“. You can place the [mla_gallery] shortcode in any widget that accepts and processes shortcodes. In particular, you can use the “MLA Text” shortcode provided by MLA itself. Navigate to the Appearance/Widgets admin submenu and look for the “MLA Text” widget. Add it to the sidebar or widget area of your choice, then open it up and add the [mla_gallery] shortcode and any other content you need.

Second, you want to “link the image to the post that contains the respective image“. This is one of the examples given in the “Gallery Display Content” section of the Settings/Media Library Assistant Documentation tab. You can use the mla_link_href parameter to change the link behind each gallery item. For your application, the parameter would be:

mla_link_href='{+site_url+}/?page_id={+parent+}'

Finally, you want to “display random images from recently uploaded images“, and display only those images already attached to a post. This is the most challenging part of your question because “display random images” and “recently uploaded images” both require limiting the number of items and sorting them in a different way. The SQL query required for this application is beyond the capability of the WordPress WP_Query class that MLA uses to select items for [mla_gallery].

You can use the hooks MLA provides to substitute your own custom SQL query and accomplish your goal. I have developed the code required and added it to one of the example plugins included with MLA. The example code is activated by a custom shortcode parameter that specifies how many items are considered “recent” and optionally, how many of those to display. For example, to display just one of the six most recent items you would code recent_random_uploads="6"' or to display two of them you would coderecent_random_uploads=”6,2″`.

The shortcode you would add to your widget would be:

[mla_gallery recent_random_uploads="6,2" mla_link_href='{+site_url+}/?page_id={+parent+}']

You can add the PHP code required to perform the query to your theme’s functions.php file or use a custom plugin such as the /plugins/media-library-assistant/examples/mla-hooks-example.php.txt example plugin. Here is an excerpt of the example plugin with just the code required for your application:

<?php
class MLAGalleryHooksExample {
    public static function initialize() {
        if ( is_admin() )
            return;

        add_filter( 'mla_gallery_attributes', 'MLAGalleryHooksExample::mla_gallery_attributes_filter', 10, 1 );
        add_filter( 'mla_gallery_query_arguments', 'MLAGalleryHooksExample::mla_gallery_query_arguments_filter', 10, 1 );
    }

    private static $shortcode_attributes = array();

    public static function mla_gallery_attributes_filter( $shortcode_attributes ) {
        self::$shortcode_attributes = $shortcode_attributes;
        return $shortcode_attributes;
    } // mla_gallery_attributes_filter

    public static function mla_gallery_query_arguments_filter( $all_query_parameters ) {
        if ( isset( self::$shortcode_attributes['recent_random_uploads'] ) ) {
            global $wpdb;

            // Extract the number of "recent posts" to consider and the (optional) number to display
            $limits = explode( ',', self::$shortcode_attributes['recent_random_uploads'] );
            $recent_limit = absint( $limits[0] );
            if ( 0 == $recent_limit ) {
                return $all_query_parameters;
            }

            $display_limit = isset( $limits[1] ) ? absint( $limits[1] ) : 1;
            if ( 0 == $display_limit ) {
                $display_limit = 1;
            }

            // Build an array of SQL clauses
            $query = array();
            $query_parameters = array();

            $query[] = "SELECT p.ID FROM (";
            $query[] = "SELECT ID FROM {$wpdb->posts} WHERE (";
            $query[] = "( post_type = 'attachment' )";
            $query[] = "AND ( post_status = 'inherit' )";
            $query[] = "AND ( post_parent > 0 )";
            $query[] = "AND ( post_mime_type LIKE 'image/%%' )";
            $query[] = ") ORDER BY post_date DESC";

            $query[] = "LIMIT %d";
            $query_parameters[] = $recent_limit;

            $query[] = ") AS p ORDER BY RAND()";

            $query[] = "LIMIT %d";
            $query_parameters[] = $display_limit;

            $query =  join(' ', $query);
            $ids = $wpdb->get_results( $wpdb->prepare( $query, $query_parameters ) );
            if ( is_array( $ids ) ) {
                $includes = array();
                foreach ( $ids as $id ) {
                    $includes[] = $id->ID;
                }
                $all_query_parameters['include'] = implode( ',', $includes );
            } else {
                $all_query_parameters['include'] = '1'; // return no images
            }

            // Remove redundant parameters from the final query
            $all_query_parameters['post_mime_type'] = 'all';
            $all_query_parameters['orderby'] = 'none';
            $all_query_parameters['post_status'] = 'all'; 

            return $all_query_parameters;
        } // parameter "recent_random_uploads" is present

        return $all_query_parameters;
    } // mla_gallery_query_arguments_filter
} // Class MLAGalleryHooksExample
add_action('init', 'MLAGalleryHooksExample::initialize');
?>

If you add the above code to your theme’s functions.php file or another suitable file you will get the recent_random_uploads feature. You can instead install and activate the example plugin if you want to separate this feature from other code on your site. The example plugin has additional functions and lots of documenting comments I have removed from the above code.

I have uploaded a new MLA Development Version dated 20160325 that contains the above code in the mla-hooks-example.php.txt example plugin. To get the Development Version, follow the instructions in this earlier topic:

Shortcode not working in (special) widget

You can follow the instructions in the “MLA Gallery Filters and Actions (Hooks)” section of the /Settings/Media Library Assistant Documentation tab to access the example. I can also send you a copy if that would be easier for you to use. You can give me your contact information using the Contact Us page at the FTJ web site:

Fair Trade Judaica/Contact Us

Do not post your e-mail address in the forum; personal details in a public forum violates WordPress guidelines. If you have trouble accessing the FTJ site, post a note here with your country of origin and I can temporarily unblock it.

I am marking this topic resolved, but please update it if you have any problems or further questions regarding the example I developed. Thanks for your interest in the plugin.

David,
Thank You so much. I turned the php code you provided into a plugin and it seems like it’s working fine.
Ok, now to fine tune the display in the widget I assume I’ll edit the MLA short code?

Thanks for your update with the good news.

Yes, you can make many format adjustments with the “Gallery Display Style” and “Gallery Display Content” parameters for the [mla_gallery] shortcode. You can gain complete control over the styles and markup by using “Style and Markup Templates”. All of these options are covered in the Documentation tab. If you have problems or questions, update this topic or start a new topic.

I have uploaded an MLA Development Version dated 20160802 that contains a completely new approach to browsing and installing the MLA Example Plugins. If you navigate to the Settings/Media library Assistant Documentation tab and click the “Example Plugins” button you will see a new submenu that lists all the example plugins and give you a “one-click” action for installing them. I hope this will make future installations of the example plugins more convenient for all MLA users. Thanks for helping to inspire this MLA enhancement.

Thanks David.
As soon as I have some time I will look into this.