Using A Query string value in my AWS Lambda function - python

So I have followed this gudie from another stack question:
The steps to get this working are:
go to Resources -> Integration Request
click on the plus or edit icon next to templates dropdown (odd I know since the template field is already open and the button here looks greyed out)
Explicitly type application/json in the content-type field even though it shows a default (if you don't do this it will not save and will not give you an error message)
Put this in the input mapping { "name": "$input.params('name')" }
click on the check box next to the templates dropdown (I'm assuming this is what finally saves it)
I understand this however I don't understand how I can then use this parameter within my lambda function (Python)
I have tried input.name with no success.

You can use query strings like this:
UserName = event["UserName"]
Here is an example with Python:
def lambda_handler(event, context):
import boto3
import json
import decimal
# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
def default(self, o):
if isinstance(o, decimal.Decimal):
if o % 1 > 0:
return float(o)
else:
return int(o)
return super(DecimalEncoder, self).default(o)
dynamodb = boto3.resource('dynamodb', region_name='ap-southeast-1', endpoint_url="http://dynamodb.ap-southeast-1.amazonaws.com")
table = dynamodb.Table('TableUsers')
UserName =event["UserName"]
UserId = event["UserId"]
UserPassword=event["UserPassword"]
response = table.put_item(
Item={
'UserName': UserName,
'UserId': UserId,
'UserPassword':UserPassword
}
)
return "Register Successfully"

Related

multiple functions in one endpoint fastapi

I am trying to create an audio server where I can upload various audio files, I have a requirement that I can only create one endpoint for creating, I have come up with this but it does show the request form to input data.
class AudioType(str, Enum):
Song = "Song"
Podcast = "Podcast"
Audiobook = "Audiobook"
#app.post("/{audio_type}", status_code=status.HTTP_200_OK)
def audio(audio_type: AudioType):
if audio_type == AudioType.Song:
def create_song(request: schemas.Song, db: Session = Depends(database.get_db)):
new_song = models.Song(name=request.name, duration=request.duration, uploadTime=request.uploadTime)
db.add(new_song)
db.commit()
db.refresh(new_song)
return new_song
elif audio_type == AudioType.Podcast:
def create_podcast(request: schemas.Podcast, db: Session = Depends(database.get_db)):
new_podcast = models.Podcast(name=request.name, duration=request.duration, uploadTime=request.uploadTime, host=request.host)
db.add(new_podcast)
db.commit()
db.refresh(new_podcast)
return new_podcast
elif audio_type == AudioType.Audiobook:
def create_audiobook(request: schemas.Audiobook, db: Session = Depends(database.get_db)):
new_audiobook = models.Audiobook(titile=request.title, author=request.author, narrator=request.narrator, duration=request.duration, uploadTime=request.uploadTime)
db.add(new_audiobook)
db.commit()
db.refresh(new_audiobook)
return new_audiobook
Your method doesn't accept the request object but only the audio_type.
Also from what I understand from your code, you may have multiple request bodies (schemas as you refer to them)
There are 2 options to what you want:
You need to declare your endpoint as follows:
from typing import Union
#app.post("/{audio_type}", status_code=status.HTTP_200_OK)
def audio(
request: Union[schemas.Song, schemas.Podcast,
schemas.Audiobook], audio_type: AudioType
):
... Your method ...
But the auto swagger of fastapi will not provide a schema example and you will have to provide examples manually, (which may or may not be possible, I don't really know and haven't tried it :/)
OR you can have a schema that can accept everything as Optional and the audio_type parameter:
from typing import Optional
class EndpointSchema(BaseModel):
audio_type: AudioType
song: Optional[schemas.Song]
podcast: Optional[schemas.Podcast]
audiobook: Optional[schemas.Audiobook]
#app.post("/audio", status_code=status.HTTP_200_OK)
def audio(request_body: EndpointSchema):
if request_body.audio_type == AudioType.Song:
... Continue with your request processing ...
Finally, very important: You are declaring internal methods (create_song etc.) that you are not calling afterward, so your code will do nothing. You don't need to do that, use the code you want to create a song, podcast, or audiobook directly inside the if, elif ... blocks!

What is the type annotation for a Flask view?

I want to add type annotations to a view function that returns a call to redirect. What does redirect return, and how do I add an annotation for that to my view function?
I thought it might be str, or the redirect function, but I'm not sure.
def setalarm() -> redirect:
# Retrieves the information to create new alarms.
return redirect("/")
The straightforward answer is to annotate your view with whatever you're writing it to return. In your specific example, redirect returns an instance of werkzeug.wrappers.Response.
from werkzeug.wrappers import Response
def set_alarm() -> Response:
return redirect()
Rather than figuring out what any given function returns in order to annotate your view, it might seem easier to come up with a Union annotation that represents anything a Flask view is allowed to return. However, Flask doesn't provide typing information, and its dynamic nature makes representing the possibilities difficult.
By default, a Flask view can return:
A str or bytes.
A subclass of werkzeug.wrappers.BaseResponse.
A tuple in one of these forms, where data is any of the other types a Flask view can return:
(data,)
(data, status), where status can be either an int or a str or bytes.
(data, headers), where headers is either a dict, iterable of (key, value) tuples, or a werkzeug.datastructures.Headers object.
(data, status, headers)
A dict to be converted to JSON. The values should be types that app.json_encoder supports.
A WSGI callable.
Flask can support more or different return types by overriding the Flask.make_response method. The data it can serialize to JSON can be extended by overriding Flask.json_encoder. If you have customized Flask's behavior you'll need to customize the type information as well.
Here's a view_return_type that represents the possible return types from a Flask view, ignoring JSON typing. Once you define the type, you can annotate any view with it.
import typing as t
from werkzeug.datastructures import Headers
from werkzeug.wrappers import BaseResponse
_str_bytes = t.Union[str, bytes]
_data_type = t.Union[
_str_bytes,
BaseResponse,
t.Dict[str, t.Any],
t.Callable[
[t.Dict[str, t.Any], t.Callable[[str, t.List[t.Tuple[str, str]]], None]], t.Iterable[bytes]
],
]
_status_type = t.Union[int, _str_bytes]
_headers_type = t.Union[
Headers, t.Dict[_str_bytes, _str_bytes], t.Iterable[t.Tuple[_str_bytes, _str_bytes]],
]
view_return_type = t.Union[
_data_type,
t.Tuple[_data_type],
t.Tuple[_data_type, _status_type],
t.Tuple[_data_type, _headers_type],
t.Tuple[_data_type, _status_type, _headers_type],
]
#app.route("/users/<int:id>/")
def user_detail(id: int) -> view_return_type:
...
In Flask 2 you can use flask.typing.ResponseReturnValue.
from flask.typing import ResponseReturnValue
#app.get("/")
def index() -> ResponseReturnValue:
return "OK"

Passing objects through Flask URL's

I am working on a site using Flask that is pulling data from an API, processing it into JSON, and then dynamically loading it throughout the site as needed. I am having an issue with matching the URL appropriately while at the same time efficiently loading what data I need.
Here is my main file:
import requests
from flask import Flask, render_template
app = Flask(__name__)
url = 'https://omgvamp-hearthstone-v1.p.mashape.com/cards'
myHeaders={
"X-Mashape-Key": 'key-here',
"Accept": "application/json"
}
r = requests.get(url, headers=myHeaders)
cards = r.json()
badSets = ['Promo', 'Hall of Fame', 'Tavern Brawl', 'Hero Skins', ' Missions', 'Credits', 'System', 'Debug']
#app.route('/')
def index():
return render_template('index.html', cards=cards, badSets=badSets)
#app.route('/<setName>', methods=['GET'])
def set(setName):
return render_template('set.html', cards=cards, setName=setName, badSets=badSets)
#app.route('/<setName>/<cardName>', methods=['GET'])
def individualCard(setName, cardName):
return render_template('card.html', cards=cards, setName=setName, cardName=cardName, badSets=badSets)
First, I'd prefer to not have to pass each html page all of my data. Is there some way to pull only what is needed and ignore the rest?
Second, I would like to pass a dictionary object i.e.
if card['name'] == card[setName][--index--][cardName]:
pass card object to html page here
How could this be achieved, and is it possible without having to use a for-loop through all of my data?
I'm happy to load my html pages if needed.
Assuming the basic structure of your parsed json data looks like this (a dictionary with lists of dictionaries):
{
"Basic": [{"cardId": 4711, ...}, {"cardId": 4712, ...}, ...],
"Fancy": [...],
...
}
You could rewrite:
#app.route('/<setName>', methods=['GET'])
def set(setName):
cardset = cards.get(setName)
return render_template('set.html', cardset=cardset)
This extracts the card set we are looking for by the dictionary key, according to the assumed data structure above.
Then in the template, instead of cardName, pass the cardId and rewrite the other route:
#app.route('/<setName>/<cardId>', methods=['GET'])
def individualCard(setName, cardId):
cardset = cards.get(setName)
matches = [x for x in cardset if x['cardId'] == cardId]
card = matches[0]
return render_template('card.html', card=card)
This uses list comprehension to extract a list of matches (everything that has the cardId we are looking for) from our selected cardset, and should be a list with a single element. We return the first element to the template for rendering.
Now this obviously does not do any error checking, for example the dictionary key we passed might be wrong and not be found, the cardId might not be found, or more interestingly there might be more than one result for the cardId we passed.
But this would be the general idea on how to approach this.
Also note I've left out badSets for clarity in the example, I'm assuming this are card sets that are forbidden, or for testing purposes.
For this case, you'd want to check the dictionary key first before looking up the set, and show an error page or something maybe:
#app.route('/<setName>', methods=['GET'])
def set(setName):
if setName in badSets:
return render_template('error.html')
cardset = cards.get(setName)
return render_template('set.html', cardset=cardset)
Disclaimer: This is coming purely from memory and it is late, so there might be an error here or there...

Google App Engine Datastore Query to JSON with Python

How can I get a JSON Object in python from getting data via Google App Engine Datastore?
I've got model in datastore with following field:
id
key_name
object
userid
created
Now I want to get all objects for one user:
query = Model.all().filter('userid', user.user_id())
How can I create a JSON object from the query so that I can write it?
I want to get the data via AJAX call.
Not sure if you got the answer you were looking for, but did you mean how to parse the model (entry) data in the Query object directly into a JSON object? (At least that's what I've been searching for).
I wrote this to parse the entries from Query object into a list of JSON objects:
def gql_json_parser(query_obj):
result = []
for entry in query_obj:
result.append(dict([(p, unicode(getattr(entry, p))) for p in entry.properties()]))
return result
You can have your app respond to AJAX requests by encoding it with simplejson e.g.:
query_data = MyModel.all()
json_query_data = gql_json_parser(query_data)
self.response.headers['Content-Type'] = 'application/json'
self.response.out.write(simplejson.dumps(json_query_data))
Your app will return something like this:
[{'property1': 'value1', 'property2': 'value2'}, ...]
Let me know if this helps!
If I understood you correctly I have implemented a system that works something like this. It sounds like you want to store an arbitrary JSON object in a GAE datastore model. To do this you need to encode the JSON into a string of some sort on the way into the database and decode it from a string into a python datastructure on the way out. You will need to use a JSON coder/decoder to do this. I think the GAE infrastructure includes one. For example you could use a "wrapper class" to handle the encoding/decoding. Something along these lines...
class InnerClass(db.Model):
jsonText = db.TextProperty()
def parse(self):
return OuterClass(self)
class Wrapper:
def __init__(self, storage=None):
self.storage = storage
self.json = None
if storage is not None:
self.json = fromJsonString(storage.jsonText)
def put(self):
jsonText = ToJsonString(self.json)
if self.storage is None:
self.storage = InnerClass()
self.storage.jsonText = jsonText
self.storage.put()
Then always operate on parsed wrapper objects instead of the inner class
def getall():
all = db.GqlQuery("SELECT * FROM InnerClass")
for x in all:
yield x.parse()
(untested). See datastoreview.py for some model implementations that work like this.
I did the following to convert the google query object to json. I used the logic in jql_json_parser above as well except for the part where everything is converted to unicode. I want to preserve the data-types like integer, floats and null.
import json
class JSONEncoder(json.JSONEncoder):
def default(self, obj):
if hasattr(obj, 'isoformat'): #handles both date and datetime objects
return obj.isoformat()
else:
return json.JSONEncoder.default(self, obj)
class BaseResource(webapp2.RequestHandler):
def to_json(self, gql_object):
result = []
for item in gql_object:
result.append(dict([(p, getattr(item, p)) for p in item.properties()]))
return json.dumps(result, cls=JSONEncoder)
Now you can subclass BaseResource and call self.to_json on the gql_object

How to find user id from session_data from django_session table?

In django_session table session_data is stored which is first pickled using pickle module of Python and then encoded in base64 by using base64 module of Python.
I got the decoded pickled session_data.
session_data from django_session table:
gAJ9cQEoVQ9fc2Vzc2lvbl9leHBpcnlxAksAVRJfYXV0aF91c2VyX2JhY2tlbmRxA1UpZGphbmdvLmNvbnRyaWIuYXV0aC5iYWNrZW5kcy5Nb2RlbEJhY2tlbmRxBFUNX2F1dGhfdXNlcl9pZHEFigECdS5iZmUwOWExOWI0YTZkN2M0NDc2MWVjZjQ5ZDU0YjNhZA==
after decoding it by base64.decode(session_data):
\x80\x02}q\x01(U\x0f_session_expiryq\x02K\x00U\x12_auth_user_backendq\x03U)django.contrib.auth.backends.ModelBackendq\x04U\r_auth_user_idq\x05\x8a\x01\x02u.bfe09a19b4a6d7c44761ecf49d54b3ad
I want to find out the value of auth_user_id from auth_user_idq\x05\x8a\x01\x02u.
I had trouble with Paulo's method (see my comment on his answer), so I ended up using this method from a scottbarnham.com blog post:
from django.contrib.sessions.models import Session
from django.contrib.auth.models import User
session_key = '8cae76c505f15432b48c8292a7dd0e54'
session = Session.objects.get(session_key=session_key)
uid = session.get_decoded().get('_auth_user_id')
user = User.objects.get(pk=uid)
print user.username, user.get_full_name(), user.email
NOTE: format changed since original answer, for 1.4 and above see the update below
import pickle
data = pickle.loads(base64.decode(session_data))
>>> print data
{'_auth_user_id': 2L, '_auth_user_backend': 'django.contrib.auth.backends.ModelBackend',
'_session_expiry': 0}
[update]
My base64.decode requires filename arguments, so then I tried base64.b64decode, but this returned "IndexError: list assignment index out of range".
I really don't know why I used the base64 module, I guess because the question featured it.
You can just use the str.decode method:
>>> pickle.loads(session_data.decode('base64'))
{'_auth_user_id': 2L, '_auth_user_backend': 'django.contrib.auth.backends.ModelBackend',
'_session_expiry': 0}
I found a work-around (see answer below), but I am curious why this doesn't work.
Loading pickled data from user sources (cookies) is a security risk, so the session_data format was changed since this question was answered (I should go after the specific issue in Django's bug tracker and link it here, but my pomodoro break is gone).
The format now (since Django 1.4) is "hash:json-object" where the first 40 byte hash is a crypto-signature and the rest is a JSON payload. For now you can ignore the hash (it allows checking if the data was not tampered by some cookie hacker).
>>> json.loads(session_data.decode('base64')[41:])
{u'_auth_user_backend': u'django.contrib.auth.backends.ModelBackend',
u'_auth_user_id': 1}
If you want to learn more about it and know how does encode or decode work, there are some relevant code.
By the way the version of Django that i use is 1.9.4.
django/contrib/sessions/backends/base.py
class SessionBase(object):
def _hash(self, value):
key_salt = "django.contrib.sessions" + self.__class__.__name__
return salted_hmac(key_salt, value).hexdigest()
def encode(self, session_dict):
"Returns the given session dictionary serialized and encoded as a string."
serialized = self.serializer().dumps(session_dict)
hash = self._hash(serialized)
return base64.b64encode(hash.encode() + b":" + serialized).decode('ascii')
def decode(self, session_data):
encoded_data = base64.b64decode(force_bytes(session_data))
try:
# could produce ValueError if there is no ':'
hash, serialized = encoded_data.split(b':', 1)
expected_hash = self._hash(serialized)
if not constant_time_compare(hash.decode(), expected_hash):
raise SuspiciousSession("Session data corrupted")
else:
return self.serializer().loads(serialized)
except Exception as e:
# ValueError, SuspiciousOperation, unpickling exceptions. If any of
# these happen, just return an empty dictionary (an empty session).
if isinstance(e, SuspiciousOperation):
logger = logging.getLogger('django.security.%s' %
e.__class__.__name__)
logger.warning(force_text(e))
return {}
django/contrib/sessions/serializer.py
class JSONSerializer(object):
"""
Simple wrapper around json to be used in signing.dumps and
signing.loads.
"""
def dumps(self, obj):
return json.dumps(obj, separators=(',', ':')).encode('latin-1')
def loads(self, data):
return json.loads(data.decode('latin-1'))
Let's focus on SessionBase's encode function.
Serialize the session dictionary to a json
create a hash salt
add the salt to serialized session , base64 the concatenation
So, decode is inverse.
We can simplify the decode function in the following code.
import json
import base64
session_data = 'YTUyYzY1MjUxNzE4MzMxZjNjODFiNjZmZmZmMzhhNmM2NWQzMTllMTp7ImNvdW50Ijo0fQ=='
encoded_data = base64.b64decode(session_data)
hash, serialized = encoded_data.split(b':', 1)
json.loads(serialized.decode('latin-1'))
And that what session.get_decoded() did.
from django.conf import settings
from django.contrib.auth.models import User
from django.utils.importlib import import_module
def get_user_from_sid(session_key):
django_session_engine = import_module(settings.SESSION_ENGINE)
session = django_session_engine.SessionStore(session_key)
uid = session.get('_auth_user_id')
return User.objects.get(id=uid)
I wanted to do this in pure Python with the latest version of DJango (2.05). This is what I did:
>>> import base64
>>> x = base64.b64decode('OWNkOGQxYjg4NzlkN2ZhOTc2NmU1ODY0NWMzZmQ4YjdhMzM4OTJhNjp7Im51bV92aXNpdHMiOjJ9')
>>> print(x)
b'9cd8d1b8879d7fa9766e58645c3fd8b7a33892a6:{"num_visits":2}'
>>> import json
>>> data = json.loads(x[41:])
>>> print(data)
{'num_visits': 2}
I just had to solve something like this on a Django install. I knew the ID (36) of the user and wanted to delete the session data for that specific user. I wanted to put this code out as a prototype to build from for finding a user in session data:
from django.contrib.sessions.models import Session
TARGET_USER = 36 # edit this to match target user.
TARGET_USER = str(TARGET_USER) # type found to be a string
for session in Session.objects.all():
raw_session= session.get_decoded()
uid = session.get_decoded().get('_auth_user_id')
if uid == TARGET_USER: # this could be a list also if multiple users
print(session)
# session.delete() # uncomment to delete session data associated with the user
Hope this helps anyone out there.

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