Develop Reference

Adding methods gives a 'index out of range error'?

When adding a vital component of methods=["POST", "GET"], my code gives the error:
Line 127, in PatientDashboard
""".format(Data[0][0]))
IndexError: list index out of range
I understand what this error normally means but I don't understand how adding methods affect the size of my list.
#app.route("/PatientDashboard.html", methods=["GET", "POST"])
def PatientDashboard():
Username = (request.args.get("Username"))
Connection = sqlite3.connect(DB)
Cursor = Connection.cursor()
Data = Cursor.execute("""
SELECT *
FROM PatientTable
WHERE Username = '{}'
""".format(Username))
Data = Data.fetchall()
AllAppointments = Cursor.execute("""
SELECT Title, Firstname, Surname, TimeSlot, Date, Status
FROM AppointmentTable
INNER JOIN DoctorTable ON AppointmentTable.DoctorID = DoctorTable.DoctorID
WHERE PatientID = '{}'
""".format(Data[0][0]))
AllAppointments = AllAppointments.fetchall()
The SQL statements work perfectly (database isn't empty) and when adding print(Data) after the first SQL statement there is an output of a nested list.
I have tried troubleshooting by looking at various other questions on stackoverflow but with no luck.
Thank you ever so much in advance.
EDIT 1:
Username = (request.args.get("Username"))
print("Username: ", Username)
Gives the correct output, e.g. Username: nx_prv but after using the POST request the output becomes Username: None.
EDIT 2:
I have managed to fix this using flask.sessions. The problem was that the request.args.get("Username") was getting 'reset' every time.

The scenario I envision: the route was tested with a GET method (because there was not methods argument), and everything was fine. The methods argument was added so a POST could be tested, and it "stopped working". But it really didn't stop working, it's just not built to handle a POST request.
From flask doc on request object the two salient attributes are:
form
A MultiDict with the parsed form data from POST or PUT requests. Please keep in mind that file uploads will not end up here, but
instead in the files attribute.
args
A MultiDict with the parsed contents of the query string. (The part in the URL after the question mark).
So a GET request will "populate" args and a POST request, form. Username will be None from this line Username = (request.args.get("Username")) on a POST request.
You can determine which method by interrogating the method attribute of the request object.
method
The current request method (POST, GET etc.)

tornado reverse url with post request

I have a report service in tornado application.
I would like to re-use the function that creates reports from a report Json.
Meaning, in the new handler that "regenerate" existing report, I would like to reuse an existing handler that knows how to create reports from a Json.
server.py:
def create_server():
return tornado.web.Application([
(r"/task", generator.GenHandler),
(r"/task/(.+)", generator.GenHandler),
url(r"/regenerate_task", generator.GenHandler, name="regenerate_task"),
url(r"/regenerate_task/(.+)", generator.GenHandler, name="regenerate_task"),
(r"/report_status/regenerate", report_status.Regenerate)
genHandler.class:
class GenHandler(tornado.web.RequestHandler):
async def post(self):
try:
LOGGER.info(str(self.request.body))
gen_args = self.parsed_body
# create here report using the parsed body
and this is the handler I am trying to create.
It will take a saved json from DB and create a completely new report with the original report logic.
class Regenerate(tornado.web.RequestHandler):
async def post(self):
rep_id = self.request.arguments.get('rep_id')[0].decode("utf-8") if self.request.arguments.get('rep_id') \
else 0
try:
report = db_handler.get_report_by_id(rep_id)
if *REPORT IS VALID*:
return self.reverse_url("regenerate_task", report)
else:
report = dict(success=True, report_id=rep_id, report=[])
except Exception as ex:
report = dict(success=False, report_id=rep_id, report=[], error=str(ex))
finally:
self.write(report)
Right now, nothing happens. I just get the JSON I needed, but no entry for GenHandler and no report being regenerated

reverse_url returns a url for specified alias, but doesn't invoke it.
You have such problem where you have to invoke another handler because you have poor code organisation. Storing a report generation code (i.e. business logic) in handler is a bad practice and you should move it to a separate class (which is usually called a Controller in a MVC pattern and handler is a View) or at least separate method and then reuse it in your Renegate handler.

Require login in a Django Channels socket?

I'm trying out Channels in Django 1.10 and set up a few consumers.
I tried creating a login_required decorator for it that closes the connection before executing it to prevent guests from entering this private socket. Also integrated unit tests afterwards to test it and they keep failing because it keeps letting guests in (AnonymousUser errors everywhere).
Also, sometimes when logging in and logging out the session doesn't clear and it lets the old user in.
The decorator:
def login_required_websocket(func):
"""
If user is not logged in, close connection immediately.
"""
#functools.wraps(func)
def inner(message, *args, **kwargs):
if not message.user.is_authenticated():
message.reply_channel.send({'close': True})
return func(message, *args, **kwargs)
return inner
Here's the consumer code:
def ws_connect(message, slug):
message.reply_channel.send({ 'accept': True })
client = message.reply_channel
client.send(signal.message("Welcome"))
try:
# import pdb; pdb.set_trace()
Room.objects.get(name=slug)
except Room.DoesNotExist:
room = Room.objects.create(name=slug)
room.users.add(message.user)
room.turn = message.user.id
room.save()
story = Story(room=room)
story.save()
# We made sure it exists.
room = Room.objects.get(name=slug)
message.channel_session['room'] = room.name
# Check if user is allowed here.
if not room.user_allowed(message.user):
# Close the connection. User is not allowed.
client.send(Signal.error("User isn't allowed in this room."))
client.send({'close': True})
The strange thing is, when commenting out all the logic between client.send(signal.message)) forwards, it works just fine and unit tests pass (meaning guests are blocked and auth code does not run [hence AnonymousUser errors]). Any ideas?
Here's the tests too:
class RoomsTests(ChannelTestCase):
def test_reject_guest(self):
"""
This tests whether the login_required_websocket decorator is rejecting guests.
"""
client = HttpClient()
user = User.objects.create_user(
username='test', password='password')
client.send_and_consume('websocket.connect',
path='/rooms/test_room', check_accept=False)
self.assertEqual(client.receive(), {'close': True})
def test_accept_logged_in(self):
"""
This tests whether the connection is accepted when a user is logged in.
"""
client = HttpClient()
user = User.objects.create_user(
username='test', password='password')
client.login(username='test', password='password')
client.send_and_consume('websocket.connect', path='/rooms/test_room')
Am I approaching this wrong, and if I am, how do I do this (require auth) properly?
EDIT: Integrated an actions system to try something out, looks like Django channels is simply not picking up any sessions from HTTP at all.
#enforce_ordering
#channel_session_user_from_http
def ws_connect(message, slug):
message.reply_channel.send({'accept': True})
message.reply_channel.send(Action.info(message.user.is_authenticated()).to_send())
Just returns false.
EDIT2: I see it works now, I tried changing localhost to 127.0.0.1 and turns out it works now. Is there a way to make it detect localhost as a valid domain so it ports over the sessions?
EDIT3: Turns out I found the localhost vs 127.0.0.1 cookie issue haha. To not waste the bounty, how would you personally implement auth login_required in messages/channels?
edit4: While I still don't know why the thing didn't work, here's how I eventually changed my app around the issue:
I created an actions system. When entering in, the socket does nothing until you send it an AUTHENTICATE action through JSON. I separated logged in actions in guest_actions and user_actions. Once authenticated, it sets the session and you are able to use user_actions.

Django Channels already supports session authentication:
# In consumers.py
from channels import Channel, Group
from channels.sessions import channel_session
from channels.auth import channel_session_user, channel_session_user_from_http
# Connected to websocket.connect
#channel_session_user_from_http
def ws_add(message):
# Accept connection
message.reply_channel.send({"accept": True})
# Add them to the right group
Group("chat-%s" % message.user.username[0]).add(message.reply_channel)
# Connected to websocket.receive
#channel_session_user
def ws_message(message):
Group("chat-%s" % message.user.username[0]).send({
"text": message['text'],
})
# Connected to websocket.disconnect
#channel_session_user
def ws_disconnect(message):
Group("chat-%s" % message.user.username[0]).discard(message.reply_channel)
http://channels.readthedocs.io/en/stable/getting-started.html#authentication

Your function worked "as-is" for me. Before I walk through the details, there was a bug (now resolved) that was preventing sessions from being closed which may explain your other issue.
I use scarce quotes around "as-is" because I was using a class-based consumer so I had to add self to the whole stack of decorators to test it explicitly:
class MyRouter(WebsocketDemultiplexer):
# WebsocketDemultiplexer calls raw_connect for websocket.connect
#channel_session_user_from_http
#login_required_websocket
def raw_connect(self, message, **kwargs):
...
After adding some debug messages to verify the sequence of execution:
>>> ws = create_connection("ws://localhost:8085")
# server logging
channel_session_user_from_http.run
login_required_websocket.run
user: AnonymousUser
# client logging
websocket._exceptions.WebSocketBadStatusException: Handshake status 403
>>> ws = create_connection("ws://localhost:8085", cookie='sessionid=43jxki76cdjl97b8krco0ze2lsqp6pcg')
# server logging
channel_session_user_from_http.run
login_required_websocket.run
user: admin
As you can see from my snippet, you need to call #channel_session_user_from_http first. For function-based consumers, you can simplify this by including it in your decorator:
def login_required_websocket(func):
#channel_session_user_from_http
#functools.wraps(func)
def inner(message, *args, **kwargs):
...
On class-based consumers, this is handled internally (and in the right order) by setting http_user_and_session:
class MyRouter(WebsocketDemultiplexer):
http_user_and_session = True
Here's the full code for a self-respecting decorator that would be used with it:
def login_required_websocket(func):
"""
If user is not logged in, close connection immediately.
"""
#functools.wraps(func)
def inner(self, message, *args, **kwargs):
if not message.user.is_authenticated():
message.reply_channel.send({'close': True})
return func(self, message, *args, **kwargs)
return inner

My suggestion is that you can require a session key or even better take the username/password input within your consumer method. Then call the authenticate method to check if the user exists. On valid user object return, you can broadcast the message or return and invalid login details message.
from django.contrib.auth import authenticate
#channel_session_user
def ws_message(message):
user = authenticate(username=message.username, password=message.password')
if user is not None:
Group("chat-%s" % message.user.username[0]).send({
"text": message['text'],
})
else:
# User is not authenticated so return an error message.

Django Test Client does not create database entries

I'm creating unit tests for my views using Django's built-in Test Client to create mock requests.
The view I'm calling should create an object in the database. However, when I query the database from within the test method the object isn't there - it either hasn't been created or has been discarded on returning from the view.
Here's the view:
def apply_to_cmp(request, campaign_id):
""" Creates a new Application to 'campaign_id' for request.user """
campaign = Campaign.objects.get(pk = campaign_id)
if not Application.objects\
.filter(campaign = campaign, user = request.user)\
.exists():
application = Application(**{'campaign' : campaign,
'user' : request.user})
application.save()
return HttpResponseRedirect(request.META.get('HTTP_REFERER'))
This is the test that calls it:
def test_create_campaign_app(self):
""" Calls the method apply_to_cmp in .views """
c = Client()
c.login(username = self.username, password = self.password)
url = '/campaign/' + self.campaign.id + '/apply/'
response = c.get(url)
# Check whether request was successful (should return 302: redirect)
self.assertEqual(response.status_code, 302)
# Verify that an Application object was created
app_count = Application.objects\
.filter(user = self.user, campaign = self.campaign)\
.count()
self.assertEqual(app_count, 1)
This is the output from the running the test:
Traceback (most recent call last):
File "/test_views.py", line 40, in test_create_campaign_app
self.assertEqual(app_count, 1)
AssertionError: 0 != 1
The method apply_to_cmp is definitely being called, since response.status_code == 302, but still the Application object is not created. What am I doing wrong?
Edit: Solution
Client.login failed because the login system was not properly initialised in the setUp method. I fixed this by calling call_command('loaddata', 'initial_data.json') with initial_data.json containing the setup for the login system. Also, HttpResponseRedirect(request.META.get('HTTP_REFERER')) didn't work for obvious reasons. I changed that bit to
if request.META.get('HTTP_REFERER'):
return HttpResponseRedirect(request.META.get('HTTP_REFERER'))
return HttpResponse()
And therefore the test to
self.assertEqual(response.status_code, 200)
Thanks for your help!

Nothing stands out as particularly wrong with your code - but clearly either your test case or the code your are testing is not working the way you think. It is now time to question your assumptions.
The method apply_to_cmp is definitely being called, since response.status_code == 302
This is your first assumption, and it may not be correct. You might get a better picture of what is happening if you examine other details in the response object. For example, check the response.redirect_chain and confirm that it actually redirects where you expect it to:
response = c.get(url, follow=True)
self.assertEqual(response.redirect_chain, [<expected output here>])
What about other details? I can't see where self.username and self.password are defined from the code you provided. Are you 100% sure that your test code to login worked? c.login() returns 'True' or 'False' to indicate if the login was successful. In my test cases, I like to confirm that the login succeeds.
login_success = c.login(username = self.username, password = self.password)
self.assertTrue(login_success)
You can also be a bit more general. You find nothing if you check Application.objects.filter(user=self.user, campaign=self.campaign), but what about checking Application.objects.all()? You know that a specific item isn't in your database, but do you know what is stored in the database (if anything at all) in the test code at that time? Do you expect other items in there? Check to confirm that what you expect is true.
I think you can solve this one, but you'll need to be a bit more aggressive in your analysis of your test case, rather than just seeing that your app_count variable doesn't equal 1. Examine your response object, put in some debug statements, and question every assumption.

First of all, if you are subclassing from django.test.TestCase, please take in consideration the fact that each test is wrapped into transactions (official docs).
Then, you can add db logging to your project to see whether there was a hit to the database or not (official docs).
And finally be sure that you're using correct lookups at this line: filter(user = self.user, campaign = self.campaign)

How do I return the Instagram Realtime subscription challenge?

I'm trying to subscribe to a tag. It appears that the callback URL is being called correctly with a hub.challenge and hub.mode, and I figured out how to access the challenge using self.request.get('hub.challenge'). I thought I was just supposed to echo the challenge, but that doesn't appear to work since I receive the following errors in the GAE logs:
InstagramAPIError: (400) APISubscriptionError-Challenge verification failed. Sent "647bf6dbed31465093ee970577ce1b72", received "
647bf6dbed31465093ee970577ce1b72
".
Here is the full handler:
class InstagramHandler(BaseHandler):
def get(self):
def process_tag_update(update):
update = update
mode = self.request.get('hub.mode')
challenge = self.request.get('hub.challenge')
verify_token = self.request.get('hub.verify_token')
if challenge:
template_values = {'challenge':challenge}
path = os.path.join(os.path.dirname(__file__), '../templates/instagram.html')
html = template.render(path, template_values)
self.response.out.write(html)
else:
reactor = subscriptions.SubscriptionsReactor()
reactor.register_callback(subscriptions.SubscriptionType.TAG, process_tag_update)
x_hub_signature = self.request.headers.get('X-Hub-Signature')
raw_response = self.request.data
try:
reactor.process('INSTAGRAM_SECRET', raw_response, x_hub_signature)
except subscriptions.SubscriptionVerifyError:
logging.error('Instagram signature mismatch')

So returning it as a string worked. I should have payed closer attention to the error message, but it took a helpful person on the Python IRC to point out the extra line breaks in the message. Once I put the template files on one line, it seemed to work. I can now confirm that my app is authorized via Instagram's list subscription URL.