Header parameters describing an API with Swagger - swagger

Question

I'm trying to use Swagger to create the spec for a Connexion API (Python+Flask). Great tools. I know that HTTP Request Headers** are not passed to the handler functions as regular parameters but I need to be able to get request headers from the operations. I read https://connexion.readthedocs.io/en/latest/request.html#header-parameters . I used the Swagger Editor to generate a minimal python server (proof of concept) but it doesn't work from the scratch, it may be a problem in requirements:
The default requirements.txt doesn't allow me to launch the server, showing this error message:
$ python3 -m swagger_server
Traceback (most recent call last):
File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
"__main__", mod_spec)
File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "/home/agalindodev/tmp/python-flask-server/swagger_server/__main__.py", line 3, in <module>
import connexion
File "/home/agalindodev/tmp/python-flask-server/venv/lib/python3.6/site-packages/connexion/__init__.py", line 3, in <module>
from .apis import AbstractAPI # NOQA
File "/home/agalindodev/tmp/python-flask-server/venv/lib/python3.6/site-packages/connexion/apis/__init__.py", line 1, in <module>
from .abstract import AbstractAPI # NOQA
File "/home/agalindodev/tmp/python-flask-server/venv/lib/python3.6/site-packages/connexion/apis/abstract.py", line 14, in <module>
from ..operation import Operation
File "/home/agalindodev/tmp/python-flask-server/venv/lib/python3.6/site-packages/connexion/operation.py", line 7, in <module>
from .decorators import validation
File "/home/agalindodev/tmp/python-flask-server/venv/lib/python3.6/site-packages/connexion/decorators/validation.py", line 9, in <module>
from werkzeug import FileStorage
ImportError: cannot import name 'FileStorage'
and modifing requirements.txt moving from connexion==1.1.15 to connexion==2.6.0 it launches but I finaly get:
TypeError: my_job_create() missing 1 required positional argument: 'my_session'
This is my environment:
1. OS and runtime:
python 3.6.9 on Ubuntu 18.04
2. requirements.txt
# connexion == 1.1.15
connexion == 2.4.0
python_dateutil == 2.6.0
setuptools >= 21.0.0
3. Complete swagger spec:
swagger: "2.0"
basePath: /api
info:
title: "Just a swagger test API"
version: "1.0.0"
paths:
/my_jobs:
post:
operationId: my_job.create
tags:
- MyJob
summary: "Create a job"
consumes:
- "application/json"
produces:
- "application/json"
parameters:
- name: "my_session"
in: "header"
description: "Session id that's creating the job"
required: True
type: string
responses:
"201":
description: "Successfully created a job"
schema:
$ref: "#/definitions/MyJob"
definitions:
MyJob:
type: "object"
properties:
id:
type: "string"
4. the error:
Using the modified requirements.txt I simply tried to POST a creation, passing the header but it generates an error:
$ curl -v -X POST --header 'Content-Type: application/json' --header 'Accept: application/problem+json' --header 'my_session: { "id": "xxxxx" }' 'http://0.0.0.0:8080/api/my_jobs'
* Trying 0.0.0.0...
* TCP_NODELAY set
* Connected to 0.0.0.0 (127.0.0.1) port 8080 (#0)
> POST /api/my_jobs HTTP/1.1
> Host: 0.0.0.0:8080
> User-Agent: curl/7.58.0
> Content-Type: application/json
> Accept: application/problem+json
> my_session: { "id": "xxxxx" }
>
* HTTP 1.0, assume close after body
< HTTP/1.0 500 INTERNAL SERVER ERROR
< Content-Type: application/problem+json
< Content-Length: 252
< Server: Werkzeug/0.12.2 Python/3.6.9
< Date: Sun, 02 Aug 2020 10:39:58 GMT
<
{
"detail": "The server encountered an internal error and was unable to complete your request. Either the server is overloaded or there is an error in the application.",
"status": 500,
"title": "Internal Server Error",
"type": "about:blank"
}
* Closing connection 0
the generated swagger server dumps this output:
[2020-07-31 14:08:50,078] ERROR in app: Exception on /api/my_jobs [POST]
Traceback (most recent call last):
File "/.../python-flask-server/venv/lib/python3.6/site-packages/flask/app.py", line 2447, in wsgi_app
response = self.full_dispatch_request()
File "/.../python-flask-server/venv/lib/python3.6/site-packages/flask/app.py", line 1952, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/.../python-flask-server/venv/lib/python3.6/site-packages/flask/app.py", line 1821, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/.../python-flask-server/venv/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
raise value
File "/.../python-flask-server/venv/lib/python3.6/site-packages/flask/app.py", line 1950, in full_dispatch_request
rv = self.dispatch_request()
File "/.../python-flask-server/venv/lib/python3.6/site-packages/flask/app.py", line 1936, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/.../python-flask-server/venv/lib/python3.6/site-packages/connexion/decorators/decorator.py", line 48, in wrapper
response = function(request)
File "/.../python-flask-server/venv/lib/python3.6/site-packages/connexion/decorators/uri_parsing.py", line 173, in wrapper
response = function(request)
File "/.../python-flask-server/venv/lib/python3.6/site-packages/connexion/decorators/validation.py", line 388, in wrapper
return function(request)
File "/.../python-flask-server/venv/lib/python3.6/site-packages/connexion/decorators/parameter.py", line 126, in wrapper
return function(**kwargs)
TypeError: my_job_create() missing 1 required positional argument: 'my_session'
127.0.0.1 - - [31/Jul/2020 14:08:50] "POST /api/my_jobs HTTP/1.1" 500 -
How can I make it work?
Many thanks!!!

Answer 1

Header parameters are not passed to the handler functions as parameters
https://connexion.readthedocs.io/en/latest/request.html#header-parameters.
You cant use
parameters:
- name: "my_session"
in: "header"
description: "Session id that's creating the job"
required: True
type: string
You must use connexion.request.headers['my_session']