Allow users to remove images they have uploaded

In your earlier topic Show images uploaded by current user you stated that the users in question were logged in and had been assigned a custom Role, “Participant”. If this role grants the “delete_post” capability to the items uploaded by the user they can delete their own images using the MLA Media/Assistant screen or the WordPress Media/Library screen. For example, the standard “Author” role works this way. Does that work in your application?

I am not quite sure what you mean by “delete their own images from the gallery on their profile.” Can you give me more details about how the application should work?

Hi David,
The setup works like –
User registers as Participant. He has his profile on which ‘upload photos’ functionality is there. Once he uploads his photos, he has ‘view gallery’ option. This is actually MLA shortcode that you provided in earlier topic.

Is there anyway that we can show ‘delete’ option next to each photo that he sees through photos populated by this MLA shortcode.

It would be really great if you could register yourself on https://www.angadjoshi.com/register/
and then check this first hand.

Thanks for your update and for your patience in awaiting my reply. I’ve just remembered that this question has come up before:

delete option on front end?

I will have a look at your site to see your user interface. Then, I will see if I can adapt the code from the earlier topic to the “current user” example plugin created for your earlier, related topic.

I am traveling for a few days so there will be some delay in progress. I hope to have something for you within week.

I created an account on your site and uploaded an image to populate the “Gallery”. I think The solution below will work for you.

I have updated the example plugin created for your earlier topic to support file deletion. To enable the new feature you must add another parameter to your [mla_gallery] shortcode, e.g.:

[mla_gallery author=current my_filter='allow file deletion']

Once that’s done the file name will be displayed below each thumbnail image with a link labeled “Delete this file.” If you click on the link, the associated file will be deleted and the gallery display will refresh with an appropriate message above the gallery.

Here is the complete source code for the updated plugin:

<?php
/*
Plugin Name: MLA Current User Example
Plugin URI: https://fairtradejudaica.org/media-library-assistant-a-wordpress-plugin/
Description: Uses the current logged in user to supply an "Author" parameter for the query
Author: David Lingren
Version: 1.01
Author URI: https://fairtradejudaica.org/our-story/staff/

Copyright 2016 David Lingren

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You can get a copy of the GNU General Public License by writing to the
    Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110, USA
*/

/**
 * Class MLA Current User Example uses the current logged in user to supply an "Author" parameter for the query
 *
 * @package MLA Current User Example
 * @since 1.00
 */
class MLACurrentUserExample {
    /**
     * Initialization function, similar to __construct()
     *
     * @since 1.00
     */
    public static function initialize() {
        // The filters are only useful for front-end posts/pages; exit if in the admin section
        if ( is_admin() )
            return;

        add_filter( 'mla_gallery_raw_attributes', 'MLACurrentUserExample::mla_gallery_raw_attributes_filter', 10, 1 );
        add_filter( 'mla_gallery_attributes', 'MLACurrentUserExample::mla_gallery_attributes_filter', 10, 1 );
        add_filter( 'mla_gallery_open_template', 'MLACurrentUserExample::mla_gallery_open_template_filter', 10, 1 );
        add_filter( 'mla_gallery_item_values', 'MLACurrentUserExample::mla_gallery_item_values_filter', 10, 1 );
    }

    /**
     * Save the shortcode attributes
     *
     * @since 1.01
     *
     * @var    array
     */
    private static $shortcode_attributes = array();

    /**
     * MLA Gallery Raw (Display) Attributes
     *
     * @since 1.01
     *
     * @param    array    the raw shortcode parameters passed in to the shortcode
     */
    public static function mla_gallery_raw_attributes_filter( $shortcode_attributes ) {
        error_log( 'MLAGalleryHooksExample::mla_gallery_raw_attributes_filter $shortcode_attributes = ' . var_export( $shortcode_attributes, true ), 0 );

        // Delete the selected file.
        if ( isset( $shortcode_attributes['my_filter'] ) && 'allow file deletion' == $shortcode_attributes['my_filter'] ) {
            if ( isset( $_REQUEST['attachment_ID'] ) ) {
                $id = (integer) $_REQUEST['attachment_ID'];
                if ( current_user_can( 'delete_post', $id ) ) {
                    $result = wp_delete_attachment( $id );
                } else {
                    $result = false;
                }

                if ( ( false === $result ) || ( NULL === $result ) ) {
                    $shortcode_attributes['gallery_open_message'] = "Could not delete attachment_ID '{$id}'.";
                } else {
                    $result = (array) $result; // Some wp_delete_attachment calls return an object
                    $shortcode_attributes['gallery_open_message'] = "Attachment '{$result['post_title']}' (ID {$id}) has been deleted.";
                }

                unset( $_REQUEST['attachment_ID'] );
            }
        }

        return $shortcode_attributes;
    } // mla_gallery_raw_attributes_filter

    /**
     * MLA Gallery (Display) Attributes
     *
     * @since 1.00
     *
     * @param    array    the shortcode parameters passed in to the shortcode
     */
    public static function mla_gallery_attributes_filter( $shortcode_attributes ) {
        global $wpdb;

        // ignore shortcodes without the author parameter set to "current"
        if ( empty( $shortcode_attributes['author'] ) || ( 'current' !== $shortcode_attributes['author'] ) ) {
            return $shortcode_attributes;
        }

        // ignore shortcodes with no logged in user
        $current_user = wp_get_current_user();
        if ( !( $current_user instanceof WP_User ) || ( 0 == $current_user->ID ) ) {
            unset ( $shortcode_attributes['author'] );
        } else {
            $shortcode_attributes['author'] = $current_user->ID;
        }

        // Save the attributes for use in the later filters
        self::$shortcode_attributes = $shortcode_attributes;

        return $shortcode_attributes;
    } // mla_gallery_attributes_filter

    /**
     * Replace the caption value and update captiontag_content as well
     *
     * @since 1.01
     *
     * @param    array    parameter_name => parameter_value pairs
     * @param    string    New value for Caption
     *
     * @return    array    item_values with updated 'caption' and 'captiontag_content'
     */
    private static function _update_caption( $item_values, $new_caption ) {
        $old_caption = $item_values['caption'];
        $item_values['caption'] = $new_caption;

        if ( !empty( $item_values['captiontag_content'] ) ) {
            $item_values['captiontag_content'] = str_replace( $old_caption, $new_caption, $item_values['captiontag_content'] );
        } else {
            if ( $item_values['captiontag'] ) {
                $item_values['captiontag_content'] = '<' . $item_values['captiontag'] . " class='wp-caption-text gallery-caption' id='" . $item_values['selector'] . '-' . $item_values['attachment_ID'] . "'>\n\t\t" . $new_caption . "\n\t</" . $item_values['captiontag'] . ">\n";
            } else {
                $item_values['captiontag_content'] = $new_caption;
            }
        }

        return $item_values;
    } // _update_caption

    /**
     * MLA Gallery Open Template
     *
     * @since 1.01
     *
     * @param    string    template used to generate the HTML markup
     */
    public static function mla_gallery_open_template_filter( $open_template ) {
        // Check for a display message
        if ( isset( self::$shortcode_attributes['gallery_open_message'] ) ) {
            $open_template = '<p><strong>' . self::$shortcode_attributes['gallery_open_message'] . '</strong></p>' . $open_template;
        }

        return $open_template;
    } // mla_gallery_open_template_filter

    /**
     * MLA Gallery Item Values
     *
     * @since 1.01
     *
     * @param    array    parameter_name => parameter_value pairs
     */
    public static function mla_gallery_item_values_filter( $item_values ) {
        error_log( 'MLAGalleryHooksExample::mla_gallery_item_values_filter $item_values = ' . var_export( $item_values, true ), 0 );

        if ( isset( self::$shortcode_attributes['my_filter'] ) && ( 'allow file deletion' == self::$shortcode_attributes['my_filter'] ) ) {
            $id = (integer) $item_values['attachment_ID'];
        error_log( 'MLAGalleryHooksExample::mla_gallery_item_values_filter $id = ' . var_export( $id, true ), 0 );
            if ( current_user_can( 'delete_post', $id ) ) {
                // Compose a new caption, adding the deletion link.
                $mla_link_href = "{$item_values['page_url']}?attachment_ID={$id}";
                $item_values = self::_update_caption( $item_values, sprintf( '%1$s<br><a href="%2$s" title="Click to delete">Delete this file</a>', $item_values['base_file'], $mla_link_href ) );
            } else {
                $item_values = self::_update_caption( $item_values, sprintf( '%1$s', $item_values['base_file'] ) );
            }
        }

        return $item_values;
    } // mla_gallery_item_values_filter
} // Class MLACurrentUserExample

/*
 * Install the filters at an early opportunity
 */
add_action('init', 'MLACurrentUserExample::initialize');
?>

Give it a try and let me know how it works for you. I am marking this topic resolved, but please update it if you have any problems or further questions regarding the updated example plugin.