add teacher preview mode

app.py

@@ -1313,7 +1313,8 @@ def index(level, program_id):
 
     customizations = {}
     if current_user()['username']:
-        customizations = DATABASE.get_student_class_customizations(current_user()['username'])
+        customizations = DATABASE.get_student_class_customizations(
+            current_user()['username'], preview_class_as_teacher=session.get("preview_class"))
 
     if 'levels' in customizations:
         available_levels = customizations['levels']

templates/for-teachers.html

@@ -22,6 +22,7 @@ <h2>{{_('my_classes')}}</h2>
                   <!-- This is a bucket-fix to get the first letter capitalized, should find a long-term solution -->
                   <th class="px-4 py-2">{{_('students')[0]|upper}}{{_('students')[1:]}}</th>
                   <th class="p-2">{{_('duplicate')}}</th>
+                  <th class="p-2">{{_('preview')}}</th>
                   <th class="p-2">{{_('remove')}}</th>
               </tr>
             </thead>
@@ -32,6 +33,7 @@ <h2>{{_('my_classes')}}</h2>
                   <td class="username_cell">{{class.teacher}}</td>
                   <td class="text-center p-2">{{class.students|length}}</td>
                   <td class="text-center p-2"><a class="no-underline cursor-pointer" onclick='hedyApp.duplicate_class("{{class.id}}", {{_('class_name_prompt')|default(None)|tojson}}, {% if class.teacher != username %}"{{class.name}}"{% else %}" "{% endif %})'><span class="fas fa-copy"></span></a></td>
+                  <td class="text-center p-2"><a href="for-teachers/class/{{class.id}}/preview" class="no-underline cursor-pointer preview_class" data-cy="preview_class_link">👁</a></td>
                   <td class="text-center p-2"><a class="no-underline cursor-pointer" onclick='hedyApp.delete_class("{{class.id}}", {{_('delete_class_prompt')|default(None)|tojson}})'>🗑️</a></td>
                 </tr>
               {% endfor %}

templates/layout.html

@@ -78,6 +78,12 @@
       {% if menu != False %}
         {% include "incl/menubar.html" %}
       {% endif %}
+      {% if session.preview_class %}
+      <div class="bg-red-100 border-l-4 border-red-500 text-red-700 p-4" role="alert">
+          <p class="font-bold">Preview mode</p>
+          <p>You are previewing a class as a teacher. <a href="/for-teachers/clear-preview-class">Exit preview mode</a></p>
+      </div>
+      {% endif %}
       {# Can't reindent this as it may contain preformatted code blocks whose indentation is important. #}
       {% block full_width_content %}{% endblock %}
 

website/database.py

@@ -765,7 +765,7 @@ def get_class_customizations(self, class_id):
         customizations = CUSTOMIZATIONS.get({"id": class_id})
         return customizations
 
-    def get_student_class_customizations(self, user):
+    def get_student_class_customizations(self, user, preview_class_as_teacher=None):
         """Return customizations for the very first class this user is part of.
 
         If the user is part of multiple classes, they will only get the customizations
@@ -775,6 +775,11 @@ def get_student_class_customizations(self, user):
         if student_classes:
             class_customizations = self.get_class_customizations(student_classes[0]["id"])
             return class_customizations or {}
+        elif preview_class_as_teacher:
+            for Class in self.get_teacher_classes(user):
+                if preview_class_as_teacher == Class["id"]:
+                    class_customizations = self.get_class_customizations(preview_class_as_teacher)
+                    return class_customizations or {}
         return {}
 
     def progress_by_username(self, username):

website/for_teachers.py

@@ -3,7 +3,7 @@
 import os
 import uuid
 
-from flask import g, jsonify, request, session, url_for
+from flask import g, jsonify, request, session, url_for, redirect
 from jinja_partials import render_partial
 from flask_babel import gettext
 
@@ -208,6 +208,26 @@ def get_class(self, user, class_id):
             survey_later=survey_later,
         )
 
+    @route("/class/<class_id>/preview", methods=["GET"])
+    @requires_login
+    def preview_class_as_teacher(self, user, class_id):
+        if not is_teacher(user) and not is_admin(user):
+            return utils.error_page(error=403, ui_message=gettext("retrieve_class_error"))
+        Class = self.db.get_class(class_id)
+        if not Class or (not utils.can_edit_class(user, Class) and not is_admin(user)):
+            return utils.error_page(error=404, ui_message=gettext("no_such_class"))
+        session["preview_class"] = Class["id"]
+        return redirect("/hedy")
+
+    @route("/clear-preview-class", methods=["GET"])
+    # Note: we explicitly do not need login here, anyone can exit preview mode
+    def clear_preview_class(self):
+        try:
+            del session["preview_class"]
+        except KeyError:
+            pass
+        return redirect("/for-teachers")
+
     @route("/class/<class_id>/programs/<username>", methods=["GET", "POST"])
     @requires_teacher
     def public_programs(self, user, class_id, username):