def course_file(request,course_key):
key=Key(encoded=course_key)
course=Course.get(key)
course.downtimes=course.downtimes+1
course.put()
response = HttpResponse(mimetype='text')
response['Content-Disposition'] = 'attachment; filename='+course_key+'.cou'
response.write(course.content_blob)
return response
