Changes in views, models, forms, urls, file_utils

- Add new view function to download course content
- Add new attribute to Lesson model
- Add new model methods to add course, module and lesson content
- Add validation in forms to check for lesson video file format
- Add functions in file_utils to add static files and templates to the zip file

5 files changed, 165 insertions, 5 deletions

diff --git a/yaksh/file_utils.py b/yaksh/file_utils.py
index 6c3fd5d..6b0340f 100644
--- a/yaksh/file_utils.py
+++ b/yaksh/file_utils.py
@@ -3,6 +3,7 @@ import os
 import zipfile
 import tempfile
 import csv
+from django.template import Context, Template
 
 
 def copy_files(file_paths):
@@ -66,3 +67,28 @@ def is_csv(document):
     except (csv.Error, UnicodeDecodeError):
         return False, None
     return True, dialect
+
+
+def write_static_files_to_zip(zipfile, course_name, current_dir):
+    relative_folders = ["css", "js", "images"]
+    static_files = {"js": ["bootstrap.js", "bootstrap.min.js",
+                           "jquery-1.9.1.min.js", "video.js"],
+                    "css": ["bootstrap.css", "bootstrap.min.css",
+                            "video-js.css"],
+                    "images": ["yaksh_banner.png"]}
+    for folder in relative_folders:
+        folder_path = os.sep.join((current_dir, "static", "yaksh", folder))
+        for file in static_files[folder]:
+            file_path = os.sep.join((folder_path, file))
+            zipfile.write(file_path, os.sep.join((course_name, "static",
+                                                  folder, file)))
+
+
+def write_templates_to_zip(zipfile, template_path, data, filename, filepath):
+    with open(template_path) as f:
+        template_data = f.read()
+        template = Template(template_data)
+        context = Context(data)
+        render = template.render(context)
+        zipfile.writestr(os.sep.join((filepath, "{0}.html".format(filename))),
+                         render)
diff --git a/yaksh/forms.py b/yaksh/forms.py
index 41c9176..66076b1 100644
--- a/yaksh/forms.py
+++ b/yaksh/forms.py
@@ -324,7 +324,19 @@ class LessonForm(forms.ModelForm):
 
     class Meta:
         model = Lesson
-        exclude = ['completed_lessons', 'creator', 'html_data']
+        exclude = ['creator', 'html_data']
+
+    def clean_video_file(self):
+        file = self.cleaned_data.get("video_file")
+        if file:
+            extension = file.name.split(".")[-1]
+            actual_extension = ["mp4", "ogv"]
+            if extension not in actual_extension:
+                raise forms.ValidationError(
+                    "Please upload video files in {0} format".format(
+                        ", ".join(actual_extension))
+                    )
+        return file
 
 
 class LessonFileForm(forms.Form):
diff --git a/yaksh/models.py b/yaksh/models.py
index 5d17dba..b97859d 100644
--- a/yaksh/models.py
+++ b/yaksh/models.py
@@ -26,7 +26,10 @@ import zipfile
 import tempfile
 from textwrap import dedent
 from ast import literal_eval
-from .file_utils import extract_files, delete_files
+from .file_utils import (
+    extract_files, delete_files, write_templates_to_zip,
+    write_static_files_to_zip
+)
 from yaksh.code_server import (
     submit, get_result as get_result_from_code_server
 )
@@ -124,7 +127,10 @@ def dict_to_yaml(dictionary):
 
 
 def get_file_dir(instance, filename):
-    upload_dir = instance.lesson.name.replace(" ", "_")
+    if isinstance(instance, LessonFile):
+        upload_dir = instance.lesson.name.replace(" ", "_")
+    else:
+        upload_dir = instance.name.replace(" ", "_")
     return os.sep.join((upload_dir, filename))
 
 
@@ -159,6 +165,11 @@ class Lesson(models.Model):
     # Activate/Deactivate Lesson
     active = models.BooleanField(default=True)
 
+    # A video file
+    video_file = models.FileField(upload_to=get_file_dir, default=None,
+                                  null=True, blank=True
+                                  )
+
     def __str__(self):
         return "{0}".format(self.name)
 
@@ -182,6 +193,37 @@ class Lesson(models.Model):
                 lesson_file_obj.file.save(file_name, django_file, save=True)
         return new_lesson
 
+    def remove_file(self):
+        if self.video_file:
+            file_path = self.video_file.path
+            if os.path.exists(file_path):
+                os.remove(file_path)
+
+    def _add_lesson_to_zip(self, module, course, zip_file, path):
+        lesson_name = self.name.replace(" ", "_")
+        course_name = course.name.replace(" ", "_")
+        module_name = module.name.replace(" ", "_")
+        sub_folder_name = os.sep.join((
+            course_name, module_name, lesson_name
+            ))
+        lesson_files = self.get_files()
+        if self.video_file:
+            video_file = os.sep.join((sub_folder_name, os.path.basename(
+                        self.video_file.name)))
+            zip_file.write(self.video_file.path, video_file)
+        for lesson_file in lesson_files:
+            if os.path.exists(lesson_file.file.path):
+                filename = os.sep.join((sub_folder_name, os.path.basename(
+                    lesson_file.file.name)))
+                zip_file.write(lesson_file.file.path, filename)
+        unit_file_path = os.sep.join((
+            path, "templates", "yaksh", "unit.html"
+            ))
+        lesson_data = {"course": course, "module": module,
+                       "lesson": self, "lesson_files": lesson_files}
+        write_templates_to_zip(zip_file, unit_file_path, lesson_data,
+                               lesson_name, sub_folder_name)
+
 
 #############################################################################
 class LessonFile(models.Model):
@@ -491,6 +533,10 @@ class LearningModule(models.Model):
         return [unit.quiz for unit in self.learning_unit.filter(
                 type="quiz")]
 
+    def get_lesson_units(self):
+        return [unit.lesson for unit in self.learning_unit.filter(
+                type="lesson").order_by("order")]
+
     def get_learning_units(self):
         return self.learning_unit.order_by("order")
 
@@ -579,6 +625,20 @@ class LearningModule(models.Model):
             new_module.learning_unit.add(new_unit)
         return new_module
 
+    def _add_module_to_zip(self, course, zip_file, path):
+        module_name = self.name.replace(" ", "_")
+        course_name = course.name.replace(" ", "_")
+        folder_name = os.sep.join((course_name, module_name))
+        lessons = self.get_lesson_units()
+        for lesson in lessons:
+            lesson._add_lesson_to_zip(self, course, zip_file, path)
+        module_file_path = os.sep.join((
+            path, "templates", "yaksh", "module.html"
+            ))
+        module_data = {"course": course, "module": self, "lessons": lessons}
+        write_templates_to_zip(zip_file, module_file_path, module_data,
+                               module_name, folder_name)
+
     def __str__(self):
         return self.name
 
@@ -819,6 +879,29 @@ class Course(models.Model):
             percentage = 0
         return percentage
 
+    def is_student(self, user):
+        return user in self.students.all()
+
+    def create_zip(self, zip_file, path):
+        course_name = self.name.replace(" ", "_")
+        modules = self.get_learning_modules()
+        file_path = os.sep.join((path, "templates", "yaksh", "index.html"))
+        write_static_files_to_zip(zip_file, course_name, path)
+        course_data = {"course": self, "modules": modules}
+        write_templates_to_zip(zip_file, file_path, course_data,
+                               "index", course_name)
+        for module in modules:
+            module._add_module_to_zip(self, zip_file, path)
+
+    def has_lessons(self):
+        modules = self.get_learning_modules()
+        status = False
+        for module in modules:
+            if module.get_lesson_units():
+                status = True
+                break
+        return status
+
     def __str__(self):
         return self.name
 
diff --git a/yaksh/urls.py b/yaksh/urls.py
index 1e1def6..6e6b8c1 100644
--- a/yaksh/urls.py
+++ b/yaksh/urls.py
@@ -200,5 +200,9 @@ urlpatterns = [
     url(r'^manage/preview_questionpaper/(?P<questionpaper_id>\d+)/$',
         views.preview_questionpaper, name="preview_questionpaper"),
     url(r'^manage/get_user_status/(?P<course_id>\d+)/(?P<student_id>\d+)/$',
-        views.get_user_data, name="get_user_data")
+        views.get_user_data, name="get_user_data"),
+    url(r'^manage/courses/download_course/(?P<course_id>\d+)/$',
+        views.download_course, name="download_course"),
+    url(r'^download_course/(?P<course_id>\d+)/$',
+        views.download_course, name="download_course"),
 ]
diff --git a/yaksh/views.py b/yaksh/views.py
index 3341aca..c5c5be1 100644
--- a/yaksh/views.py
+++ b/yaksh/views.py
@@ -2297,9 +2297,16 @@ def edit_lesson(request, lesson_id=None, course_id=None):
     context = {}
     if request.method == "POST":
         if "Save" in request.POST:
-            lesson_form = LessonForm(request.POST, instance=lesson)
+            lesson_form = LessonForm(request.POST, request.FILES,
+                                     instance=lesson)
             lesson_file_form = LessonFileForm(request.POST, request.FILES)
             lessonfiles = request.FILES.getlist('Lesson_files')
+            clear = request.POST.get("video_file-clear")
+            video_file = request.FILES.get("video_file")
+            if (clear or video_file) and lesson:
+                # Remove previous video file if new file is uploaded or
+                # if clear is selected
+                lesson.remove_file()
             if lesson_form.is_valid():
                 if lesson is None:
                     lesson_form.instance.creator = user
@@ -2314,6 +2321,7 @@ def edit_lesson(request, lesson_id=None, course_id=None):
                 return my_redirect(redirect_url)
             else:
                 context['lesson_form'] = lesson_form
+                context['error'] = lesson_form["video_file"].errors
                 context['lesson_file_form'] = lesson_file_form
 
         if 'Delete' in request.POST:
@@ -2808,3 +2816,30 @@ def get_user_data(request, course_id, student_id):
         context = Context(data)
         data = template.render(context)
     return HttpResponse(json.dumps({"user_data": data}), **response_kwargs)
+
+
+@login_required
+@email_verified
+def download_course(request, course_id):
+    user = request.user
+    course = get_object_or_404(Course, pk=course_id)
+    if (not course.is_creator(user) and not course.is_teacher(user) and not
+            course.is_student(user)):
+        raise Http404("You are not allowed to download {0} course".format(
+            course.name))
+    if not course.has_lessons():
+        raise Http404("{0} course does not have any lessons".format(
+            course.name))
+    file_name = string_io()
+    current_dir = os.path.dirname(__file__)
+    course_name = course.name.replace(" ", "_")
+    zip_file = zipfile.ZipFile(file_name, "w")
+    course.create_zip(zip_file, current_dir)
+    zip_file.close()
+    file_name.seek(0)
+    response = HttpResponse(content_type='application/zip')
+    response['Content-Disposition'] = 'attachment; filename={0}.zip'.format(
+                                            course_name
+                                            )
+    response.write(file_name.read())
+    return response