Add ability to upload a logo + favicon, and add custom header HTML

Closes #268. Not going to bother with a preview SVG or anything fancy for now – we can think about that as part of #746. Right now it's just good to finally get this functionality in!

Also need to think about apple-touch-icon, msTile stuff, and social sharing image. Not sure if this is all too much for core, but it's definitely too much for the current Appearance page layout. Again, something to think about as part of #746.

Code is a bit rough around the edges, but figured there's not much point in using the command bus properly since #870.

js/admin/src/components/AppearancePage.js

@@ -2,6 +2,8 @@ import Page from 'flarum/components/Page';
 import Button from 'flarum/components/Button';
 import Switch from 'flarum/components/Switch';
 import EditCustomCssModal from 'flarum/components/EditCustomCssModal';
+import EditCustomHeaderModal from 'flarum/components/EditCustomHeaderModal';
+import UploadImageButton from 'flarum/components/UploadImageButton';
 import saveSettings from 'flarum/utils/saveSettings';
 
 export default class AppearancePage extends Page {
@@ -51,6 +53,34 @@ export default class AppearancePage extends Page {
             </fieldset>
           </form>
 
+          <fieldset>
+            <legend>{app.translator.trans('core.admin.appearance.logo_heading')}</legend>
+            <div className="helpText">
+              {app.translator.trans('core.admin.appearance.logo_text')}
+            </div>
+            <UploadImageButton name="logo"/>
+          </fieldset>
+
+          <fieldset>
+            <legend>{app.translator.trans('core.admin.appearance.favicon_heading')}</legend>
+            <div className="helpText">
+              {app.translator.trans('core.admin.appearance.favicon_text')}
+            </div>
+            <UploadImageButton name="favicon"/>
+          </fieldset>
+
+          <fieldset>
+            <legend>{app.translator.trans('core.admin.appearance.custom_header_heading')}</legend>
+            <div className="helpText">
+              {app.translator.trans('core.admin.appearance.custom_header_text')}
+            </div>
+            {Button.component({
+              className: 'Button',
+              children: app.translator.trans('core.admin.appearance.edit_header_button'),
+              onclick: () => app.modal.show(new EditCustomHeaderModal())
+            })}
+          </fieldset>
+
           <fieldset>
             <legend>{app.translator.trans('core.admin.appearance.custom_styles_heading')}</legend>
             <div className="helpText">

js/admin/src/components/EditCustomHeaderModal.js

@@ -0,0 +1,24 @@
+import SettingsModal from 'flarum/components/SettingsModal';
+
+export default class EditCustomHeaderModal extends SettingsModal {
+  className() {
+    return 'EditCustomHeaderModal Modal--large';
+  }
+
+  title() {
+    return app.translator.trans('core.admin.edit_header.title');
+  }
+
+  form() {
+    return [
+      <p>{app.translator.trans('core.admin.edit_header.customize_text')}</p>,
+      <div className="Form-group">
+        <textarea className="FormControl" rows="30" bidi={this.setting('custom_header')}/>
+      </div>
+    ];
+  }
+
+  onsaved() {
+    window.location.reload();
+  }
+}

js/admin/src/components/UploadImageButton.js

@@ -0,0 +1,97 @@
+import Button from 'flarum/components/Button';
+
+export default class UploadImageButton extends Button {
+  init() {
+    this.loading = false;
+  }
+
+  view() {
+    this.props.loading = this.loading;
+    this.props.className = (this.props.className || '') + ' Button';
+
+    if (app.data.settings[this.props.name + '_path']) {
+      this.props.onclick = this.remove.bind(this);
+      this.props.children = app.translator.trans('core.admin.upload_image.remove_button');
+
+      return (
+        <div>
+          <p><img src={app.forum.attribute(this.props.name+'Url')} alt=""/></p>
+          <p>{super.view()}</p>
+        </div>
+      );
+    } else {
+      this.props.onclick = this.upload.bind(this);
+      this.props.children = app.translator.trans('core.admin.upload_image.upload_button');
+    }
+
+    return super.view();
+  }
+
+  /**
+   * Prompt the user to upload an image.
+   */
+  upload() {
+    if (this.loading) return;
+
+    const $input = $('<input type="file">');
+
+    $input.appendTo('body').hide().click().on('change', e => {
+      const data = new FormData();
+      data.append(this.props.name, $(e.target)[0].files[0]);
+
+      this.loading = true;
+      m.redraw();
+
+      app.request({
+        method: 'POST',
+        url: this.resourceUrl(),
+        serialize: raw => raw,
+        data
+      }).then(
+        this.success.bind(this),
+        this.failure.bind(this)
+      );
+    });
+  }
+
+  /**
+   * Remove the logo.
+   */
+  remove() {
+    this.loading = true;
+    m.redraw();
+
+    app.request({
+      method: 'DELETE',
+      url: this.resourceUrl()
+    }).then(
+      this.success.bind(this),
+      this.failure.bind(this)
+    );
+  }
+
+  resourceUrl() {
+    return app.forum.attribute('apiUrl') + '/' + this.props.name;
+  }
+
+  /**
+   * After a successful upload/removal, reload the page.
+   *
+   * @param {Object} response
+   * @protected
+   */
+  success(response) {
+    window.location.reload();
+  }
+
+  /**
+   * If upload/removal fails, stop loading.
+   *
+   * @param {Object} response
+   * @protected
+   */
+  failure(response) {
+    this.loading = false;
+    m.redraw();
+  }
+}