media-tag accessibility and UX improvements

* preview content and prompt users to describe media when uploading
* add 'alt' attributes to rendered media-tag content if it is included in the file's encrypted metadata
* add alt attributes to some related UI elements

customize.dist/src/less2/include/modals-ui-elements.less

@@ -273,4 +273,13 @@
             }
         }
     }
+    #cp-upload-preview-container {
+        max-width: 100%;
+        media-tag {
+            max-width: 100%;
+            & > * {
+                max-width: 100%;
+            }
+        }
+    }
 }

www/common/common-ui-elements.js

@@ -1658,6 +1658,7 @@ define([
         UI.openCustomModal(modal);
     };
 
+    Messages.toolbar_userMenuAlt = "User menu"; // XXX
     UIElements.createUserAdminMenu = function (Common, config) {
         var metadataMgr = Common.getMetadataMgr();
 
@@ -1990,8 +1991,11 @@ define([
         */
 
         var $displayName = $userAdmin.find('.'+displayNameCls);
+        $userAdmin.attr({ // XXX is this on the right element?
+            alt: Messages.toolbar_userMenuAlt,
+        });
 
-        var $avatar = $userAdmin.find('> button .cp-dropdown-button-title'); // XXX alt="User menu"
+        var $avatar = $userAdmin.find('> button .cp-dropdown-button-title');
         var loadingAvatar;
         var to;
         var oldUrl = '';

www/common/media-tag.js

@@ -73,7 +73,6 @@ var factory = function () {
              * @param {object}   cfg     Object {Plugins, allowed, download, pdf} containing infos about plugins
              * @param {function} cb      Callback function: (err, pluginElement) => {}
              */
-             // XXX add alt attributes if present in metadata
             text: function (metadata, url, content, cfg, cb) {
                 var plainText = document.createElement('div');
                 plainText.className = "plain-text-reader";
@@ -88,6 +87,7 @@ var factory = function () {
             image: function (metadata, url, content, cfg, cb) {
                 var img = document.createElement('img');
                 img.setAttribute('src', url);
+                img.setAttribute('alt', metadata.alt || "");
                 img.blob = content;
                 cb(void 0, img);
             },
@@ -95,15 +95,19 @@ var factory = function () {
                 var video = document.createElement('video');
                 video.setAttribute('src', url);
                 video.setAttribute('controls', true);
+                // https://discuss.codecademy.com/t/can-we-use-an-alt-attribute-with-the-video-tag/300322/4
+                video.setAttribute('title', metadata.alt || "");
                 cb(void 0, video);
             },
             audio: function (metadata, url, content, cfg, cb) {
                 var audio = document.createElement('audio');
                 audio.setAttribute('src', url);
                 audio.setAttribute('controls', true);
+                audio.setAttribute('alt', metadata.alt || "");
                 cb(void 0, audio);
             },
             pdf: function (metadata, url, content, cfg, cb) {
+                // XXX alt text
                 var iframe = document.createElement('iframe');
                 if (cfg.pdf.viewer) { // PDFJS
                     var viewerUrl = cfg.pdf.viewer + '?file=' + url;
@@ -116,6 +120,7 @@ var factory = function () {
             download: function (metadata, url, content, cfg, cb) {
                 var btn = document.createElement('button');
                 btn.setAttribute('class', 'btn btn-default');
+                btn.setAttribute('alt', metadata.alt || "");
                 btn.innerHTML = '<i class="fa fa-save"></i>' + cfg.download.text + '<br>' +
                                 (metadata.name ? '<b>' + fixHTML(metadata.name) + '</b>' : '');
                 btn.addEventListener('click', function () {
@@ -543,7 +548,7 @@ var factory = function () {
 
     // Process
     var process = function (mediaObject, decrypted, cfg, cb) {
-        var metadata = decrypted.metadata;
+        var metadata = decrypted.metadata || {};
         var blob = decrypted.content;
 
         var mediaType = getType(mediaObject, metadata, cfg);
@@ -597,6 +602,15 @@ var factory = function () {
         });
     };
 
+    var initHandlers = function () {
+        return {
+            'progress': [],
+            'complete': [],
+            'metadata': [],
+            'error': []
+        };
+    };
+
     // Initialize a media-tag
     var init = function (el, cfg) {
         cfg = cfg || {};
@@ -614,13 +628,7 @@ var factory = function () {
             };
         }
 
-        var handlers = cfg.handlers || {
-            'progress': [],
-            'complete': [],
-            'metadata': [],
-            'error': []
-        };
-
+        var handlers = cfg.handlers || initHandlers();
         var mediaObject = el._mediaObject = {
             handlers: handlers,
             tag: el
@@ -763,6 +771,24 @@ var factory = function () {
 
     init.fetchDecryptedMetadata = fetchDecryptedMetadata;
 
+    init.preview = function (content, metadata, cfg, cb) {
+        cfg = cfg || {};
+        addMissingConfig(cfg, config);
+        var handlers = cfg.handlers || initHandlers();
+        var el = document.createElement('media-tag');
+        var mediaObject = el._mediaObject = {
+            handlers: handlers,
+            tag: el,
+        };
+        process(mediaObject, {
+            metadata: metadata,
+            content: content
+        }, cfg, function (err) {
+            if (err) { return void cb(err); }
+            cb(void 0, el);
+        });
+    };
+
     return init;
 };
 

www/common/sframe-common-file.js

@@ -11,10 +11,12 @@ define([
     '/common/hyperscript.js',
     '/customize/messages.js',
     '/customize/pages.js',
+    '/bower_components/nthen/index.js',
+    '/common/media-tag.js',
 
     '/bower_components/file-saver/FileSaver.min.js',
     '/bower_components/tweetnacl/nacl-fast.min.js',
-], function ($, ApiConfig, FileCrypto, MakeBackup, Thumb, UI, UIElements, Util, Hash, h, Messages, Pages) {
+], function ($, ApiConfig, FileCrypto, MakeBackup, Thumb, UI, UIElements, Util, Hash, h, Messages, Pages, nThen, MT) {
     var Nacl = window.nacl;
     var module = {};
 
@@ -312,7 +314,11 @@ define([
             });
             return manualStore;
         };
-        var fileUploadModal = function (defaultFileName, cb) {
+
+        Messages.upload_modal_alt = "Alt text"; // XXX
+        Messages.upload_addOptionalAlt = "Add descriptive text (optional)"; // XXX
+
+        var fileUploadModal = function (defaultFileName, cb, preview) {
             var parsedName = /^(\.?.+?)(\.[^.]+)?$/.exec(defaultFileName) || [];
             var ext = parsedName[2] || "";
 
@@ -321,9 +327,15 @@ define([
             // Ask for name, password and owner
             var content = h('div', [
                 h('h4', Messages.upload_modal_title),
+                (preview? h('div#cp-upload-preview-container', preview): undefined),
                 UIElements.setHTML(h('label', {for: 'cp-upload-name'}),
                                    Messages._getKey('upload_modal_filename', [ext])),
                 h('input#cp-upload-name', {type: 'text', placeholder: defaultFileName, value: defaultFileName}),
+
+                h('label', {for: 'cp-upload-alt'}, Messages.upload_addOptionalAlt), // XXX alt text for uploads
+                h('input#cp-upload-alt', {type: 'text', placeholder: Messages.upload_modal_alt}),
+
+
                 h('label', {for: 'cp-upload-password'}, Messages.addOptionalPassword),
                 UI.passwordInput({id: 'cp-upload-password'}),
                 h('span', {
@@ -335,7 +347,8 @@ define([
                 manualStore
             ]);
 
-            $(content).find('#cp-upload-owned').on('change', function () {
+            var $content = $(content);
+            $content.find('#cp-upload-owned').on('change', function () {
                 var val = Util.isChecked($(content).find('#cp-upload-owned'));
                 if (val) {
                     $(content).find('#cp-upload-store').prop('checked', true).prop('disabled', true);
@@ -348,8 +361,9 @@ define([
                 if (!yes) { return void cb(); }
 
                 // Get the values
-                var newName = $(content).find('#cp-upload-name').val();
-                var password = $(content).find('#cp-upload-password').val() || undefined;
+                var newName = $content.find('#cp-upload-name').val();
+                var password = $content.find('#cp-upload-password').val() || undefined;
+                var alt = $content.find('#cp-upload-alt').val() || undefined;
                 var owned = Util.isChecked($(content).find('#cp-upload-owned'));
                 var forceSave = owned || Util.isChecked($(content).find('#cp-upload-store'));
 
@@ -366,7 +380,8 @@ define([
                     name: newName,
                     password: password,
                     owned: owned,
-                    forceSave: forceSave
+                    forceSave: forceSave,
+                    alt: alt,
                 });
             });
         };
@@ -437,6 +452,8 @@ define([
             }
 
             var thumb;
+            var preview;
+            var alt;
             var file_arraybuffer;
             var name = file.name;
             var password;
@@ -447,6 +464,7 @@ define([
                     var metadata = {
                         name: name,
                         type: type,
+                        alt: alt,
                     };
                     if (thumb) { metadata.thumbnail = thumb; }
                     queue.push({
@@ -486,8 +504,9 @@ define([
                         password = obj.password;
                         owned = obj.owned;
                         forceSave = obj.forceSave;
+                        alt = obj.alt;
                         finish();
-                    });
+                    }, preview);
                 }
             };
 
@@ -495,11 +514,20 @@ define([
                 if (e) { console.error(e); }
                 file_arraybuffer = buffer;
                 if (!Thumb.isSupportedType(file)) { return getName(); }
-                // make a resized thumbnail from the image..
-                Thumb.fromBlob(file, function (e, thumb64) {
-                    if (e) { console.error(e); }
-                    if (!thumb64) { return getName(); }
-                    thumb = thumb64;
+                nThen(function (w) {
+                    // make a resized thumbnail from the image..
+                    Thumb.fromBlob(file, w(function (e, thumb64) {
+                        if (e) { console.error(e); }
+                        if (!thumb64) { return; }
+                        thumb = thumb64;
+                    }));
+                    MT.preview(buffer, {
+                        type: file.type,
+                    }, void 0, w(function (err, el) {
+                        if (err) { return void console.error(err); }
+                        preview = el;
+                    }));
+                }).nThen(function () {
                     getName();
                 });
             });

www/profile/inner.js

@@ -341,6 +341,8 @@ define([
         });
     };
 
+    Messages.profile_defaultAlt = "Default profile picture"; // XXX
+
     var displayAvatar = function (val) {
         var sframeChan = common.getSframeChannel();
         var $span = APP.$avatar;
@@ -349,7 +351,7 @@ define([
             $('<img>', {
                 src: '/customize/images/avatar.png',
                 title: Messages.profile_avatar,
-                alt: 'Avatar' // XXX translate this "Default profile picture"
+                alt: Messages.profile_defaultAlt,
             }).appendTo($span);
             return;
         }