Connexion uses the operationId
from each Operation Object to
identify which Python function should handle each URL.
Explicit Routing:
paths:
/hello_world:
post:
operationId: myapp.api.hello_world
If you provided this path in your specification POST requests to
http://MYHOST/hello_world
, it would be handled by the function
hello_world
in myapp.api
module. Optionally, you can include
x-swagger-router-controller
in your operation definition, making
operationId
relative:
paths:
/hello_world:
post:
x-swagger-router-controller: myapp.api
operationId: hello_world
Keep in mind that Connexion follows how HTTP methods work in Flask
and therefore HEAD requests will be handled by the operationId
specified
under GET in the specification. If both methods are supported,
connexion.request.method
can be used to determine which request was made.
By default, Connexion strictly enforces the presence of a handler
function for any path defined in your specification. Because of this, adding
new paths without implementing a corresponding handler function will produce
runtime errors and your application will not start. To allow new paths to be
added to your specification, e.g. in an API design first workflow, set the
resolver_error
to configure Connexion to provide an error response for
paths that are not yet implemented:
app = connexion.FlaskApp(__name__)
app.add_api('swagger.yaml', resolver_error=501)
To customize this behavior, Connexion can use alternative
Resolvers
—for example, RestyResolver
. The RestyResolver
will compose an operationId
based on the path and HTTP method of
the endpoints in your specification:
from connexion.resolver import RestyResolver
app = connexion.FlaskApp(__name__)
app.add_api('swagger.yaml', resolver=RestyResolver('api'))
paths:
/:
get:
# Implied operationId: api.get
/foo:
get:
# Implied operationId: api.foo.search
post:
# Implied operationId: api.foo.post
'/foo/{id}':
get:
# Implied operationId: api.foo.get
put:
# Implied operationId: api.foo.put
copy:
# Implied operationId: api.foo.copy
delete:
# Implied operationId: api.foo.delete
'/foo/{id}/bar':
get:
# Implied operationId: api.foo.bar.search
'/foo/{id}/bar/{name}':
get:
# Implied operationId: api.foo.bar.get
# Handler signature: `def get(id, name): ...`
RestyResolver
will give precedence to any operationId
encountered in the specification. It will also respect
x-swagger-router-controller
. You may import and extend
connexion.resolver.Resolver
to implement your own operationId
(and function) resolution algorithm.
Note that when using multiple parameters in the path, they will be
collected and all passed to the endpoint handlers.
MethodViewResolver
is an customised Resolver based on RestyResolver
to take advantage of MethodView structure of building Flask APIs.
The MethodViewResolver
will compose an operationId
based on the path and HTTP method of
the endpoints in your specification. The path will be based on the path you provide in the app.add_api and the path provided in the URL endpoint (specified in the swagger or openapi3).
from connexion.resolver import MethodViewResolver
app = connexion.FlaskApp(__name__)
app.add_api('swagger.yaml', resolver=MethodViewResolver('api'))
And associated YAML
paths:
/foo:
get:
# Implied operationId: api.FooView.search
post:
# Implied operationId: api.FooView.post
'/foo/{id}':
get:
# Implied operationId: api.FooView.get
put:
# Implied operationId: api.FooView.put
copy:
# Implied operationId: api.FooView.copy
delete:
# Implied operationId: api.FooView.delete
The structure expects a Class to exists inside the directory api
that conforms to the naming <<Classname with Capitalised name>>View
.
In the above yaml the necessary MethodView implementation is as follows:
import datetime
from connexion import NoContent
from flask import request
from flask.views import MethodView
class PetsView(MethodView):
""" Create Pets service
"""
method_decorators = []
pets = {}
def post(self):
body= request.json
name = body.get("name")
tag = body.get("tag")
count = len(self.pets)
pet = {}
pet['id'] = count + 1
pet["tag"] = tag
pet["name"] = name
pet['last_updated'] = datetime.datetime.now()
self.pets[pet['id']] = pet
return pet, 201
def put(self, petId):
body = request.json
name = body["name"]
tag = body.get("tag")
id_ = int(petId)
pet = self.pets.get(petId, {"id": id_})
pet["name"] = name
pet["tag"] = tag
pet['last_updated'] = datetime.datetime.now()
self.pets[id_] = pet
return self.pets[id_], 201
def delete(self, petId):
id_ = int(petId)
if self.pets.get(id_) is None:
return NoContent, 404
del self.pets[id_]
return NoContent, 204
def get(self, petId):
id_ = int(petId)
if self.pets.get(id_) is None:
return NoContent, 404
return self.pets[id_]
def search(self, limit=100):
# NOTE: we need to wrap it with list for Python 3 as dict_values is not JSON serializable
return list(self.pets.values())[0:limit]
and a __init__.py file to make the Class visible in the api directory.
from .petsview import PetsView
MethodViewResolver
will give precedence to any operationId
encountered in the specification. It will also respect
x-swagger-router-controller
. You may import and extend
connexion.resolver.MethodViewResolver
to implement your own operationId
(and function) resolution algorithm.
The names of query and form parameters, as well as the name of the body parameter are sanitized by removing characters that are not allowed in Python symbols. I.e. all characters that are not letters, digits or the underscore are removed, and finally characters are removed from the front until a letter or an under-score is encountered. As an example:
>>> re.sub('^[^a-zA-Z_]+', '', re.sub('[^0-9a-zA-Z_]', '', '$top'))
'top'
Without this sanitation it would e.g. be impossible to implement an OData API.
Connexion supports Flask's int
, float
, and path
route parameter
variable converters.
Specify a route parameter's type as integer
or number
or its type as
string
and its format as path
to use these converters. For example:
paths:
/greeting/{name}:
# ...
parameters:
- name: name
in: path
required: true
type: string
format: path
will create an equivalent Flask route /greeting/<path:name>
, allowing
requests to include forward slashes in the name
url variable.
Setting a base path is useful for versioned APIs. An example of
a base path would be the 1.0
in http://MYHOST/1.0/hello_world
.
If you are using OpenAPI 3.x.x, you set your base URL path in the servers block of the specification. You can either specify a full URL, or just a relative path.
servers:
- url: https://MYHOST/1.0
description: full url example
- url: /1.0
description: relative path example
paths:
...
If you are using OpenAPI 2.0, you can define a basePath
on the top level
of your OpenAPI 2.0 specification.
basePath: /1.0
paths:
...
If you don't want to include the base path in your specification, you can provide it when adding the API to your application:
app.add_api('my_api.yaml', base_path='/1.0')
Swagger UI is available at /ui/
by default.
You can choose another path through options:
options = {'swagger_url': '/'}
app = connexion.App(__name__, options=options)
Connexion makes the OpenAPI/Swagger specification in JSON format
available from swagger.json
in the base path of the API.
You can disable the Swagger JSON at the application level:
app = connexion.FlaskApp(__name__, specification_dir='swagger/',
swagger_json=False)
app.add_api('my_api.yaml')
You can also disable it at the API level:
app = connexion.FlaskApp(__name__, specification_dir='swagger/')
app.add_api('my_api.yaml', swagger_json=False)