def post(self):
import json
from model import Student, Lesson
from all_exceptions import StudentLoginException
from datetime import datetime
from helpers import log
try:
self.load_search_party_context(user_type="student")
# Get CGI form fields.
lesson_code = self.request.get('lesson_code')
student_nickname = self.request.get('student_nickname')
ext = int(self.request.get('ext', 0))
# Normalize whitespace in student name.
# Replace any string of >=1 whitespace with a single space (equivalent to s/\s+/ /g).
student_nickname = " ".join(student_nickname.split())
if not lesson_code:
# No lesson code
raise StudentLoginException("Please enter a lesson code.",
"lesson_code==%r"%lesson_code)
# If no student nickname, generate an anonymous one
anonymous = False
if not student_nickname:
import random, string
alphabet = string.letters + string.digits
anonymous_student = None
for i in range(8):
random_nickname = "".join(random.choice(alphabet) for i in range(10))
key_name = Student.make_key_name(student_nickname=random_nickname, lesson_code=lesson_code)
anonymous_student = Student.get_by_key_name(key_name)
if anonymous_student is None:
student_nickname = random_nickname
anonymous = True
break
if anonymous and not student_nickname:
# No student name
raise StudentLoginException("Could not login as anonymous student.",
"student_nickname==%r"%student_nickname)
# if not lesson_code and not student_nickname:
# # Blank form
# raise StudentLoginException("Please enter a lesson code and a student name.",
# "lesson_code==%r, student_nickname==%r"%(lesson_code, student_nickname))
# elif not lesson_code:
# # No lesson code
# raise StudentLoginException("Please enter a lesson code.",
# "lesson_code==%r"%lesson_code)
# elif not student_nickname:
# # No student name
# raise StudentLoginException("Please enter a student name.",
# "student_nickname==%r"%student_nickname)
lesson = Lesson.get_by_key_name(lesson_code)
# Retrieve lesson from DB
# - If lesson does not exist, this will return None.
# - If lesson existed but is disabled, it will return the lesson, but lesson.is_active will be False.
# - If lesson existed but was deleted (hidden), it will return the lesson, but lesson.is_deleted will be True.
# (Deleting lessons is done lazily. Actually, they are merely hidden from the teacher's view.)
if lesson is None or lesson.is_deleted:
# Lesson does not exist or was deleted (hidden).
raise StudentLoginException("Please check the lesson code.",
"lesson retrieved from datastore with lesson_code %r is None"%lesson_code)
elif not lesson.is_active:
# Lesson has been disabled by teacher. Students are not allowed to work on it anymore.
raise StudentLoginException("This lesson is finished. You cannot work on it now.",
"lesson_code %r has is_active=False"%lesson_code)
# Fetch student from DB.
# - Might return None if nobody has ever logged in with this nickname+lesson combination.
key_name = Student.make_key_name(student_nickname=student_nickname, lesson_code=lesson_code)
student = Student.get_by_key_name(key_name)
login_timestamp = datetime.now()
if student is not None:
# Found the student.
student.session_sid=self.session.sid
student.latest_login_timestamp = login_timestamp
student.latest_logout_timestamp = None
if not student.first_login_timestamp:
student.first_login_timestamp = login_timestamp
else:
student = Student(
key_name=key_name,
nickname=student_nickname,
teacher=lesson.teacher_key,
lesson=lesson,
task_idx=self.INITIAL_TASK_IDX,
first_login_timestamp=login_timestamp,
latest_login_timestamp=login_timestamp,
latest_logout_timestamp=None,
session_sid=self.session.sid,
anonymous=anonymous,
client_ids=[]
)
assert student.session_sid is not None
student.put()
self.set_person(student)
displayName = "Anonymous" if self.is_student and self.person.anonymous else self.person.nickname
self.session['msg'] = "Student logged in: Hello " + displayName
self.response.headers.add_header('Content-Type', 'application/json', charset='utf-8')
self.response.out.write(json.dumps({"status":"logged_in", "ext":ext}))
log( "=> LOGIN SUCCESS" )
except StudentLoginException, e:
e.log()
self.set_person(None)
msg = e.args[0]
self.session['msg'] = msg
self.response.headers.add_header('Content-Type', 'application/json', charset='utf-8')
self.response.out.write(json.dumps({"status":"logged_out", "error":msg}))
log( "=> LOGIN FAILURE: %s"%msg )
def _attempt_to_identify_as_student(self):
from model import Student
from helpers import log
# Initialize student
# We still store changes to student record only, if any, but we don't want to store
# the record needlessly, since that consumes billable resources.
student = None
student_is_dirty = False
# There are two ways to identify a student: nickname + lesson code sent via CGI,
# or the session ID. We will try them in that order.
# Get CGI form values
lesson_code = self.request.get("lesson_code", None)
student_nickname = self.request.get("student_nickname", None)
if lesson_code is not None and student_nickname is not None:
# 1. Fetch student by nickname+lesson
student_nickname = self.htmlunquote(student_nickname)
key_name = Student.make_key_name(student_nickname=student_nickname, lesson_code=lesson_code)
student = Student.get_by_key_name(key_name)
log("=> SEARCHING BY NAME AND LESSON CODE: {0}, {1}, {2}".format(student_nickname, lesson_code, key_name))
if student is not None and self.session.sid != student.session_sid:
if student.is_logged_in:
# Prevent login if student already logged in to another session
# GAE limits # of channels so we don't want to allow too many student windows
from all_exceptions import StudentLoginException
raise StudentLoginException(
"Please choose another name. Someone is already logged in as %s."
% (student_nickname.encode("ascii", "xmlcharrefreplace")),
"Session ID doesn't match.",
student.session_sid,
self.session.sid,
student.latest_login_timestamp,
student.latest_logout_timestamp,
)
# else:
# # Need to update session id if student was logged into another browser previously (and then logged out)
# student.session_sid = self.session.sid
# student_is_dirty = True
else:
# 2. Fetch student by session id
student = Student.all().filter("session_sid =", self.session.sid).get()
log("=> SEARCHING FOR STUDENT BY SESSION ID {0}".format(self.session.sid))
if student is not None and not student.is_logged_in:
# Passively log student in again.
# At some point this student logged into this browser but logged out passively.
from datetime import datetime
student.latest_login_timestamp = datetime.now()
student.latest_logout_timestamp = None
student_is_dirty = True
log("=> PASSIVE STUDENT LOGIN AFTER PASSIVE LOGOUT")
if student_is_dirty:
# Store changes to student record, if any.
student.put()
if student is not None and not student.is_logged_in:
log("=> STUDENT IS **NOT** LOGGED IN")
return student