fix: use old singe file share rendering as fallback

Only render images and videos with the viewer.
Text has its own way of handling single file shares for now.

In case viewer does not support the file format
fall back to the old way of handling single file shares.

Signed-off-by: Max <max@nextcloud.com>

apps/files_sharing/js/public.js

@@ -129,10 +129,39 @@ OCA.Sharing.PublicApp = {
 			}
 		}
 
-		if (OCA.Viewer.mimetypes.includes(mimetype)) {
+		// dynamically load image previews
+		var bottomMargin = 350;
+		var previewWidth = $(window).width();
+		var previewHeight = $(window).height() - bottomMargin;
+		previewHeight = Math.max(200, previewHeight);
+		var params = {
+			x: Math.ceil(previewWidth * window.devicePixelRatio),
+			y: Math.ceil(previewHeight * window.devicePixelRatio),
+			a: 'true',
+			file: encodeURIComponent(this.initialDir + $('#filename').val()),
+			scalingup: 0
+		};
+
+		var imgcontainer = $('<img class="publicpreview" alt="">');
+		if (hideDownload === 'false') {
+			imgcontainer = $('<a href="' + $('#previewURL').val() + '" target="_blank"></a>').append(imgcontainer);
+		}
+		var img = imgcontainer.hasClass('publicpreview')? imgcontainer: imgcontainer.find('.publicpreview');
+		img.css({
+			'max-width': previewWidth,
+			'max-height': previewHeight
+		});
+
+		if (OCA.Viewer && OCA.Viewer.mimetypes.includes(mimetype)
+			&& (mimetype.startsWith('image/') || mimetype.startsWith('video/'))) {
 			OCA.Viewer.setRootElement('#imgframe')
 			OCA.Viewer.open({ path: '/' })
 		} else if (mimetype.substr(0, mimetype.indexOf('/')) === 'text' && window.btoa) {
+			if (OC.appswebroots['files_texteditor'] !== undefined ||
+				OC.appswebroots['text'] !== undefined) {
+				// the text editor handles the previewing
+				return;
+			}
 			// Undocumented Url to public WebDAV endpoint
 			var url = parent.location.protocol + '//' + location.host + OC.linkTo('', 'public.php/webdav');
 			$.ajax({
@@ -144,6 +173,20 @@ OCA.Sharing.PublicApp = {
 			}).then(function (data) {
 				self._showTextPreview(data, previewHeight);
 			});
+		} else if ((previewSupported === 'true' && mimetype.substr(0, mimetype.indexOf('/')) !== 'video') ||
+			mimetype.substr(0, mimetype.indexOf('/')) === 'image' &&
+			mimetype !== 'image/svg+xml') {
+			img.attr('src', OC.generateUrl('/apps/files_sharing/publicpreview/' + token + '?' + OC.buildQueryString(params)));
+			imgcontainer.appendTo('#imgframe');
+		} else if (mimetype.substr(0, mimetype.indexOf('/')) !== 'video') {
+			img.attr('src', mimetypeIcon);
+			img.attr('width', 128);
+			// "#imgframe" is either empty or it contains an audio preview that
+			// the icon should appear before, so the container should be
+			// prepended to the frame.
+			imgcontainer.prependTo('#imgframe');
+		} else if (previewSupported === 'true') {
+			$('#imgframe > video').attr('poster', OC.generateUrl('/apps/files_sharing/publicpreview/' + token + '?' + OC.buildQueryString(params)));
 		}
 
 		if (this.fileList) {