Can't get form params from an OpenAPI 2.0 generated Python-Flask application

Question

I'm trying to process a simple HTML form from a Python application described using OpenAPI 2.0 and generating the Flask-Connexion code using OpenAPI Generator v4.3.1 and v5.0.1, but I always get a response like:

"['whatever'] is not of type 'string'"

This is my OpenAPI 2.0 spec, and it seems to fit with the section "Form Parameters" of https://swagger.io/docs/specification/2-0/describing-parameters/ :

swagger: "2.0"
info:
  version: "1.0.0"
  title: "Test"
host: localhost:8080
basePath: /api
schemes:
- http
paths:
  /mytest:
    post:
      operationId: process_test_form
      consumes:
      - application/x-www-form-urlencoded
      produces:
      - text/html; charset=utf-8
      parameters:
        - name: myparam
          in: formData
          description: "my param"
          type: string
          required: True
      responses:
        "200":
          description: "Success"
          schema:
            type: string

I generate the Python application with OpenAPI Generator 4.3.1 and v5.0.1 like this:

java -jar openapi-generator-cli-4.3.1.jar generate -g python-flask -i ./spec.yml

Respecting the generated "requeriments.txt" I did "pip3 install -r requirements.txt" , so I'm finally using: Werkzeug (0.16.1) swagger-ui-bundle (0.0.8) python-dateutil (2.8.1) setuptools (39.0.1) connexion (2.7.0)

Then I run the generated code it like this:

python3 -m openapi_server

It can be easyly tested with a simple HTML form like this:

<html>
<body>
<h1>My test</h1>
<form action="http://0.0.0.0:8080/api/mytest" method="post">
<input type="text" name="myparam"><br/>
<input type="submit" name="Accept"><br/>
</form>
</body>
</html>

But it always get the error:

"['anytextentered'] is not of type 'string'"

I can't find what's wrong. The EndPoint is created and it's correctly targeted from the form, because if I omit the parameters I get an error ""'myparam' is a required property"". Maybe there's something missing in the generated requeriments.txt ?

Any help will be very appreciated. Thanks in advance! /Ángel

Edit: I tested the v3.0 spec given by Software2 and it generates the same error in my environment (I'm using the one generated by "OpenAPI Generator"). A working "requeriments.txt" would be appreciated.

Software2 Software2 · Accepted Answer · 2021-02-28T18:48:53

Swagger 2.0 is quite old. While it may be valid, it's possible there's a bug somewhere in one of the tools that consumes your spec. (Even if this doesn't solve the issue, updating to this more modern format is probably a good idea.) Try using OpenAPI 3.0. Here is your code run through an auto-converter:

openapi: 3.0.1
info:
  title: Test
  version: 1.0.0
servers:
- url: http://localhost:8080/api
paths:
  /mytest:
    post:
      operationId: process_test_form
      requestBody:
        content:
          application/x-www-form-urlencoded:
            schema:
              required:
              - myparam
              properties:
                myparam:
                  type: string
                  description: my param
        required: true
      responses:
        200:
          description: Success
          content:
            text/html; charset=utf-8:
              schema:
                type: string
components: {}

Can't get form params from an OpenAPI 2.0 generated Python-Flask application

1 Answers