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Flask WTForms - Retrieve form data when submitting to a different route, i.e. a different POST route than the GET route which renders the form

I would like to set up my URLs/endpoints according to REST as closely as possible, while still utilising Flask-WTForms.
I would like my form to render at GET /posts/new, and submit to POST /post.
With Flask-WTForms I can only work out how to get it to GET/POST to the same URL.
My current code looks like this:
#post_bp.route('/posts/new', methods=['GET', 'POST'])
def show_post_form():
create_post_form = CreatePostForm()
if create_post_form.validate_on_submit():
return 'success'
return render_template('create_post_form.html', form=create_post_form)
However I would like to be able to make it look something more like this, but I just can't seem to work it out:
#post_bp.route('/posts/new', methods=['GET'])
def show_post_form():
create_post_form = CreatePostForm()
return render_template('create_post_form.html', form=create_post_form)
this route only shows the form
the form submits a POST request to /post
<form action="{{url_for('shipment.C_shipment')}}" method="POST" novalidate>
the POST /post route handles the submitted form and if there are errors for example, then it redirects back to GET /posts/new:
#post_bp.route('/post', methods=['POST'])
def create_post():
create_post_form = CreatePostForm()
if create_post_form.validate_on_submit():
return "success!"
if len(create_post_form.errors) != 0:
for error in create_shipment_form.errors:
for msg in create_shipment_form.errors[error]:
flash(msg)
return redirect(url_for('shipment.show_create_shipment_form'))
i guess creating a new CreatePostForm() object here doesn't really work..
Any suggestions?

Creating a new CreatePostForm is correct as it parses the submitted form data for you. This allows you to call validate_on_submit() on the form object.
I don't think you're generating the correct URL for the form action in your HTML snippet. The argument to url_for() should be the desired endpoint (see docs) which should be <post_bp>.create_post. This would be similar to your call
return redirect(url_for('shipment.show_create_shipment_form'))
If this does not fix the issue, please provide both frontend and backend error messages you receive when trying to send the data to /post.

Django: how to pass request object from one view to another?

Is there a way to pass request object from one view to another? Or do I have to dissect the request into individual parts or use request.__dict__ and pass those?
Currenlty, because the request cannot be serialized, the below code:
def explorer(request):
collect_activities_init(request)
return render(request, 'explorer/explorer.html')
def collect_activities_init(request):
task = collect_activities.delay(request)
return JsonResponse({'status_url': reverse('explorer:collect_activities_status', kwargs={'task_id': task.id})})
#celery.task(bind=True)
def collect_activities(self, request):
api = StravaApi()
code = request.GET.get('code', '') # extract code from redirect URL query string
Will give:
WSGIRequest: GET
'/explorer/?state=&code=3ba4hgh5ad99ea3cf8e52d8&scope='>
is not JSON serializable
But I need to have the request data from the first function in the last one, because its code extracts some data from the request.

The problem you're having is not passing request between those functions, but rather that celery requires arguments passed to a celery task to be serialized.
The simple solution here would be to pull out the attributes you need from the request then pass those to the task.
So instead of
task = collect_activities.delay(request)
Do
code = request.GET.get('code', '')
task = collect_activities.delay(code)
Of course, you'll need to change the collect_activities task definition to accept the code as an argument, rather than a request object.

I found this: Django pass object from view to next for processing
The top answer uses sessions in order to pass the save the object and retrieve it later:
def first_view(request):
my_thing = {'foo' : 'bar'}
request.session['my_thing'] = my_thing
return render(request, 'some_template.html')
def second_view(request):
my_thing = request.session.get('my_thing', None)
return render(request, 'some_other_template.html', {'my_thing' : my_thing})

How should I continue a Python Social Auth Partial Pipeline

The application I am working has an overwritten endpoint for the Python Social Auth /complete/<backend>/ endpoint.
within our urls.py:
urlspatterns = [
...
# Override of social_auth
url(r'^api/v1/auth/oauth/complete/(?P<backend>[^/]+)/$',
social_auth_complete,
name='social_complete'),
...
]
within views.py:
from social_django.views import complete
def social_auth_complete(request, backend, *args, **kwargs):
"""Overwritten social_auth_complete."""
# some custom logic getting variables from session (Unrelated).
response = complete(request, backend, *args, **kwargs)
# Some custom logic adding args to the redirect (Unrelated).
We are attempting to implement a partial pipeline method. The first time the endpoint is called everything works as expected.
#partial
def required_info(strategy, details, user=None, is_new=False, *args, **kwargs):
"""Verify the user has all the required information before proceeding."""
if not is_new:
return
for field in settings.SOCIAL_USER_REQUIRED_DATA:
if not details.get(field):
data = strategy.request_data().get(field)
if not data:
current_partial = kwargs.get('current_partial')
social_provider = kwargs.get('backend')
return strategy.redirect(f'.../?partial_token={partial_token}&provider={social_provider}'
else:
details[field] = data
This redirects the user to the front end in which they fill out a form which calls a POST request to orginal API api/v1/auth/oauth/complete/(?P<backend>[^/]+)/ with the following in the data:
{
'required_fieldX': 'data',
...
'partial_token': '',
}
Key Issues
Two things go wrong; When I pdb into required_info there is never any data within strategy.request_data(). There is still data within the kwargs['request'].body and I can take the data out there.
However
But I am afraid that the second time around we never get into this block of code from social-core:
partial = partial_pipeline_data(backend, user, *args, **kwargs)
if partial:
user = backend.continue_pipeline(partial)
# clean partial data after usage
backend.strategy.clean_partial_pipeline(partial.token)
else:
user = backend.complete(user=user, *args, **kwargs)
I know this to be true because when I interrogate the database the original Partial object still exists as if backend.strategy.clean_partial_pipeline(partial.token) was never called.
Final Questions
Why is the social_django.views.complete not processing the POST request as expected and as it appears to be in all the example applications. Is there an issue from our overwriting it? Should I just create a separate endpoint to handle the POST request and if so how do mimic all that goes on within #psa such that I can call backend.continue_pipeline(partial)?

I think there's only one issue here, and that's that the Django strategy doesn't look into request.body when loading the request data, you can see the method in charge here. There you can see that it looks for request.GET and/or request.POST, but not body.
You can easily overcome this by defining your custom strategy that extends from the built-in one, and override the request_data method to look for the values in request.body. Then define the SOCIAL_AUTH_STRATEGY to point to your class.

django-rest-framework: Rendering both HTML and JSON with the same ModelViewSet

I'm using Django==1.10.5 and djangorestframework==3.5.3.
I have a few ModelViewSets that handle JSON API requests properly. Now, I'd like to use TemplateRenderer to add HTML rendering to those same ModelViewSets. I started with the list endpoint, and created a simple template that lists the available objects. I implemented the get_template_names to return the template I created.
Accessing that endpoint through the browser works fine when there are no objects to list, so everything related to setting up HTML renderers alongside APIs seems to work.However, when tere are objects to return the same endpoint fails with the following error:
ValueError: dictionary update sequence element #0 has length XX; 2 is required
Where XX is the number of attributes the object has.
This documentation section suggests the view function should act slightly differently when returning an HTML Response object, but I assume this is done by DRF's builtin views when necessary, so I don't think that's the issue.
This stackoverflow Q/A also looks relevant but I'm not quite sure it's the right solution to my problem.
How can I make my ModelViewSets work with both HTML and JSON renderers?
Thanks!

DRF has a brief explanation of how to do this in their documentation.
I think you'd do something like this...
On the client side, tell your endpoint what type of response you want:
fetch(yourAPIUrl, {
headers: {
'Accept': 'application/json'
// or 'Accept': 'text/html'
}
})
In your view, just check that and act accordingly:
class FlexibleAPIView(APIView):
"""
API view that can render either JSON or HTML.
"""
renderer_classes = [TemplateHTMLRenderer, JSONRenderer]
def get(self, request, *args, **kwargs):
queryset = Things.objects.all()
# If client wants HTML, give them HTML.
if request.accepted_renderer.format == 'html':
return Response({'things': queryset}, template_name='example.html')
# Otherwise, the client likely wants JSON so serialize the data.
serializer = ThingSerializer(instance=queryset)
data = serializer.data
return Response(data)

Flask example with POST

Suppose the following route which accesses an xml file to replace the text of a specific tag with a given xpath (?key=):
#app.route('/resource', methods = ['POST'])
def update_text():
# CODE
Then, I would use cURL like this:
curl -X POST http://ip:5000/resource?key=listOfUsers/user1 -d "John"
The xpath expreesion listOfUsers/user1 should access the tag <user1> to change its current text to "John".
I have no idea on how to achieve this because I'm just starting to learn Flask and REST and I can't find any good example for this specific case. Also, I'd like to use lxml to manipulate the xml file since I already know it.
Could somebody help and provide an example to guide me?

Before actually answering your question:
Parameters in a URL (e.g. key=listOfUsers/user1) are GET parameters and you shouldn't be using them for POST requests. A quick explanation of the difference between GET and POST can be found here.
In your case, to make use of REST principles, you should probably have:
http://ip:5000/users
http://ip:5000/users/<user_id>
Then, on each URL, you can define the behaviour of different HTTP methods (GET, POST, PUT, DELETE). For example, on /users/<user_id>, you want the following:
GET /users/<user_id> - return the information for <user_id>
POST /users/<user_id> - modify/update the information for <user_id> by providing the data
PUT - I will omit this for now as it is similar enough to `POST` at this level of depth
DELETE /users/<user_id> - delete user with ID <user_id>
So, in your example, you want do a POST to /users/user_1 with the POST data being "John". Then the XPath expression or whatever other way you want to access your data should be hidden from the user and not tightly couple to the URL. This way, if you decide to change the way you store and access data, instead of all your URL's changing, you will simply have to change the code on the server-side.
Now, the answer to your question:
Below is a basic semi-pseudocode of how you can achieve what I mentioned above:
from flask import Flask
from flask import request
app = Flask(__name__)
#app.route('/users/<user_id>', methods = ['GET', 'POST', 'DELETE'])
def user(user_id):
if request.method == 'GET':
"""return the information for <user_id>"""
.
.
.
if request.method == 'POST':
"""modify/update the information for <user_id>"""
# you can use <user_id>, which is a str but could
# changed to be int or whatever you want, along
# with your lxml knowledge to make the required
# changes
data = request.form # a multidict containing POST data
.
.
.
if request.method == 'DELETE':
"""delete user with ID <user_id>"""
.
.
.
else:
# POST Error 405 Method Not Allowed
.
.
.
There are a lot of other things to consider like the POST request content-type but I think what I've said so far should be a reasonable starting point. I know I haven't directly answered the exact question you were asking but I hope this helps you. I will make some edits/additions later as well.
Let me know if I have gotten something wrong.

Here is the example in which you can easily find the way to use Post,GET method and use the same way to add other curd operations as well..
#libraries to include
import os
from flask import request, jsonify
from app import app, mongo
import logger
ROOT_PATH = os.environ.get('ROOT_PATH')<br>
#app.route('/get/questions/', methods=['GET', 'POST','DELETE', 'PATCH'])
def question():
# request.args is to get urls arguments
if request.method == 'GET':
start = request.args.get('start', default=0, type=int)
limit_url = request.args.get('limit', default=20, type=int)
questions = mongo.db.questions.find().limit(limit_url).skip(start);
data = [doc for doc in questions]
return jsonify(isError= False,
message= "Success",
statusCode= 200,
data= data), 200
# request.form to get form parameter
if request.method == 'POST':
average_time = request.form.get('average_time')
choices = request.form.get('choices')
created_by = request.form.get('created_by')
difficulty_level = request.form.get('difficulty_level')
question = request.form.get('question')
topics = request.form.get('topics')
##Do something like insert in DB or Render somewhere etc. it's up to you....... :)