MDL-75401 core: sticky footer component

lib/classes/output/sticky_footer.php

@@ -0,0 +1,130 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle 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 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle 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 should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace core\output;
+
+use renderable;
+
+/**
+ * Class to render a sticky footer element.
+ *
+ * Sticky footer can be rendered at any moment if the page (even inside a form) but
+ * it will be displayed at the bottom of the page.
+ *
+ * Important: note that pages can only display one sticky footer at once.
+ *
+ * Important: not all themes are compatible with sticky footer. If the current theme
+ * is not compatible it will be rendered as a standard div element.
+ *
+ * @package    core
+ * @category   output
+ * @copyright  2022 Ferran Recio <ferran@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class sticky_footer implements named_templatable, renderable {
+
+    /**
+     * @var string content of the sticky footer.
+     */
+    protected $stickycontent = '';
+
+    /**
+     * @var string extra CSS classes. By default, elements are justified to the end.
+     */
+    protected $stickyclasses = 'justify-content-end';
+
+    /**
+     * @var array extra HTML attributes (attribute => value).
+     */
+    protected $attributes = [];
+
+    /**
+     * Constructor.
+     *
+     * @param string $stickycontent the footer content
+     * @param string|null $stickyclasses extra CSS classes
+     * @param array $attributes extra html attributes (attribute => value)
+     */
+    public function __construct(string $stickycontent = '', ?string $stickyclasses = null, array $attributes = []) {
+        $this->stickycontent = $stickycontent;
+        if ($stickyclasses !== null) {
+            $this->stickyclasses = $stickyclasses;
+        }
+        $this->attributes = $attributes;
+    }
+
+    /**
+     * Set the footer contents.
+     *
+     * @param string $stickycontent the footer content
+     */
+    public function set_content(string $stickycontent) {
+        $this->stickycontent = $stickycontent;
+    }
+
+    /**
+     * Add extra classes to the sticky footer.
+     *
+     * @param string $stickyclasses the extra classes
+     */
+    public function add_classes(string $stickyclasses) {
+        if (!empty($this->stickyclasses)) {
+            $this->stickyclasses .= ' ';
+        }
+        $this->stickyclasses = $stickyclasses;
+    }
+
+    /**
+     * Add extra attributes to the sticky footer element.
+     *
+     * @param string $atribute the attribute
+     * @param string $value the value
+     */
+    public function add_attribute(string $atribute, string $value) {
+        $this->attributes[$atribute] = $value;
+    }
+
+    /**
+     * Export this data so it can be used as the context for a mustache template (core/inplace_editable).
+     *
+     * @param renderer_base $output typically, the renderer that's calling this function
+     * @return array data context for a mustache template
+     */
+    public function export_for_template(\renderer_base $output) {
+        $extras = [];
+        foreach ($this->attributes as $attribute => $value) {
+            $extras[] = [
+                'attribute' => $attribute,
+                'value' => $value,
+            ];
+        }
+        return [
+            'stickycontent' => (string)$this->stickycontent,
+            'stickyclasses' => $this->stickyclasses,
+            'extras' => $extras,
+        ];
+    }
+
+    /**
+     * Get the name of the template to use for this templatable.
+     *
+     * @param \renderer_base $renderer The renderer requesting the template name
+     * @return string the template name
+     */
+    public function get_template_name(\renderer_base $renderer): string {
+        return 'core/sticky_footer';
+    }
+}

lib/templates/sticky_footer.mustache

@@ -0,0 +1,47 @@
+{{!
+    This file is part of Moodle - http://moodle.org/
+
+    Moodle 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 3 of the License, or
+    (at your option) any later version.
+
+    Moodle 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 should have received a copy of the GNU General Public License
+    along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+}}
+{{!
+    @template core/sticky_footer
+
+    Displays a page sticky footer element.
+
+    Sticky footer behaviour depends on the theme. The default template is
+    a regular element.
+
+    Example context (json):
+    {
+        "stickycontent" : "<a href=\"#\">Moodle</a>",
+        "extras" : [
+            {
+                "attribute" : "data-example",
+                "value" : "stickyfooter"
+            }
+        ],
+        "stickyclasses" : "extraclasses"
+    }
+}}
+<div
+    id="sticky-footer"
+    class="{{$ stickyclasses }}{{stickyclasses}}{{/ stickyclasses }}"
+    {{#extras}}
+    {{attribute}}="{{value}}"
+    {{/extras}}
+>
+    {{$ stickycontent }}
+        {{{stickycontent}}}
+    {{/ stickycontent }}
+</div>