fembooru/ext/view/main.php

<?php
/*
 * Name: Image Viewer
 * Author: Shish
 * Description: Allows users to see uploaded images
 */

/*
 * DisplayingImageEvent:
 *   $image -- the image being displayed
 *   $page  -- the page to display on
 *
 * Sent when an image is ready to display. Extensions who
 * wish to appear on the "view" page should listen for this,
 * which only appears when an image actually exists.
 */
class DisplayingImageEvent extends Event
{
    /** @var Image  */
    public $image;

    public function __construct(Image $image)
    {
        $this->image = $image;
    }

    public function get_image(): Image
    {
        return $this->image;
    }
}

class ImageInfoBoxBuildingEvent extends Event
{
    /** @var array  */
    public $parts = [];
    /** @var Image  */
    public $image;
    /** @var User  */
    public $user;

    public function __construct(Image $image, User $user)
    {
        $this->image = $image;
        $this->user = $user;
    }

    public function add_part(string $html, int $position=50)
    {
        while (isset($this->parts[$position])) {
            $position++;
        }
        $this->parts[$position] = $html;
    }
}

class ImageInfoSetEvent extends Event
{
    /** @var Image */
    public $image;

    public function __construct(Image $image)
    {
        $this->image = $image;
    }
}

class ImageAdminBlockBuildingEvent extends Event
{
    /** @var string[] */
    public $parts = [];
    /** @var ?Image  */
    public $image = null;
    /** @var ?User  */
    public $user = null;

    public function __construct(Image $image, User $user)
    {
        $this->image = $image;
        $this->user = $user;
    }

    public function add_part(string $html, int $position=50)
    {
        while (isset($this->parts[$position])) {
            $position++;
        }
        $this->parts[$position] = $html;
    }
}

class ViewImage extends Extension
{
    public function onPageRequest(PageRequestEvent $event)
    {
        global $page, $user;

        if ($event->page_matches("post/prev") ||	$event->page_matches("post/next")) {
            $image_id = int_escape($event->get_arg(0));

            if (isset($_GET['search'])) {
                $search_terms = explode(' ', $_GET['search']);
                $query = "#search=".url_escape($_GET['search']);
            } else {
                $search_terms = [];
                $query = null;
            }

            $image = Image::by_id($image_id);
            if (is_null($image)) {
                $this->theme->display_error(404, "Image not found", "Image $image_id could not be found");
                return;
            }

            if ($event->page_matches("post/next")) {
                $image = $image->get_next($search_terms);
            } else {
                $image = $image->get_prev($search_terms);
            }

            if (is_null($image)) {
                $this->theme->display_error(404, "Image not found", "No more images");
                return;
            }

            $page->set_mode(PageMode::REDIRECT);
            $page->set_redirect(make_link("post/view/{$image->id}", $query));
        } elseif ($event->page_matches("post/view")) {
            if (!is_numeric($event->get_arg(0))) {
                // For some reason there exists some very broken mobile client
                // who follows up every request to '/post/view/123' with
                // '/post/view/12300000000000Image 123: tags' which spams the
                // database log with 'integer out of range'
                $this->theme->display_error(404, "Image not found", "Invalid image ID");
                return;
            }

            $image_id = int_escape($event->get_arg(0));

            $image = Image::by_id($image_id);

            if (!is_null($image)) {
                send_event(new DisplayingImageEvent($image));
                $iabbe = new ImageAdminBlockBuildingEvent($image, $user);
                send_event($iabbe);
                ksort($iabbe->parts);
                $this->theme->display_admin_block($page, $iabbe->parts);
            } else {
                $this->theme->display_error(404, "Image not found", "No image in the database has the ID #$image_id");
            }
        } elseif ($event->page_matches("post/set")) {
            if (!isset($_POST['image_id'])) {
                return;
            }

            $image_id = int_escape($_POST['image_id']);

            send_event(new ImageInfoSetEvent(Image::by_id($image_id)));

            $page->set_mode(PageMode::REDIRECT);
            $page->set_redirect(make_link("post/view/$image_id", url_escape(@$_POST['query'])));
        }
    }

    public function onDisplayingImage(DisplayingImageEvent $event)
    {
        global $user;
        $iibbe = new ImageInfoBoxBuildingEvent($event->get_image(), $user);
        send_event($iibbe);
        ksort($iibbe->parts);
        $this->theme->display_meta_headers($event->get_image());
        $this->theme->display_page($event->get_image(), $iibbe->parts);
    }
}