Add section to docs showing how to use connexion as a Blueprint

[jasonrhaas]

Description

It would be nice to add a section in the docs that describes how to use connexion using the api.blueprint like in #188. I think a lot of people use Flask Blueprint to manage their different endpoints, so this I think would increase adoption of the connexion framework.

Also #393 is another reference, with an example gist.

[jasonrhaas]

Also, I am happy to submit a PR for this if the maintainers agree with this addition.

[hjacobs]

@jasonrhaas adding a section to the docs sounds awesome! 😄

[mvalkon]

@jasonrhaas I don't see any reason why we would be against a PR of this nature so feel free to contribute, it's more than welcome. Just add a section of it's own so it's clear that it's Flask specific as we're trying to move Connexion to a more framework agnostic model (#380). Thanks!

[zerox1212]

It would be great to have an example that uses blueprints. For example a regular flask web app endpoint (/) along side an API endpoint (/api). This seems like a common requirement for a typical web + mobiles + api use case.

[sxslex]

"""Implement load api from swagger using template import yam."""
import yaml
import connexion
from jinja2 import FileSystemLoader
from jinja2.environment import Environment


def connexion_register_blueprint(app, swagger_file, **kwargs):
    con = connexion.FlaskApp("api", app.instance_path)
    env = Environment(loader=FileSystemLoader(
        app.config.get('SWAGGER_ROOT_TEMPLATE') or
        app.config['PROJECT_ROOT']
    ))
    swagger_string = env.get_template(swagger_file).render(**kwargs)
    specification = yaml.safe_load(swagger_string)
    api = super(connexion.FlaskApp, con).add_api(specification, **kwargs)
    app.register_blueprint(api.blueprint)
    return api

...
connexion_register_blueprint(app, 'api/v1/swagger/main.yaml')
...

[varqasim]

Correct me If I am wrong but by using connexion.FlaskApp.add_api already does this? It actually registers a blueprint. For example:

app.add_api('users.yaml', arguments={
                'api_local': 'local_value'}, validate_responses=True)

the add_api method from connexion.FlaskApp

def add_api(self, specification, **kwargs):
        api = super(FlaskApp, self).add_api(specification, **kwargs)
        self.app.register_blueprint(api.blueprint)
        return api

[ghost]

I needed to use the after_request decorator on the connexion api blueprint. Thus, I had to access the connexion blueprint before the blueprint was registered in the app. Here's how I've done it, thanks to the comment above :

connexion_app = connexion.FlaskApp(__name__, specification_dir="./api/openapi/")
connexion_api = super(connexion.FlaskApp, connexion_app).add_api("openapi.yaml")

@connexion_api.blueprint.after_request
def after_request(response):
    # your logic
    return response

# Register the api blueprint
connexion_app.app.register_blueprint(connexion_api.blueprint)