[BUG][Python-Flask] securitySchemes: Endpoint module/function is not generated

Description

• We define a (securitySchemes) type: apiKey for in: header in our OpenAPI v3.0.1 yaml file.
• We generate the python-flask code.

When we start the server, it shows a warning: ... x-apikeyInfoFunc missing.
This definition is required by connexion to identify the module/function which performs the apiKey authorization/authentication. See also what changed in #546 - Rework security flow.

It looks like openapi-generator(-cli) does not generate this key in the scheme.
Is this intended?

The result is that authentication always fails and the server returns 401 - Unauthorized (No authorization token provided). See also release notes for Connexion 2.0:

If unsupported security requirements are defined or x-tokenInfoFunc/x-tokenInfoUrl is missing, connexion now denies requests instead of allowing access without security-check.

When we add the x-apikeyInfoFunc ourselves, and implement the endpoint, it works fine.

The same issue may probably occur with x-basicInfoFunc, x-bearerInfoFunc, etc.
See also Security - Connexion 2.0 documentation

openapi-generator version

I used OpenAPI generator CLI version 4.0.0-SNAPSHOT:
https://oss.sonatype.org/content/repositories/snapshots/org/openapitools/openapi-generator-cli/4.0.0-SNAPSHOT/openapi-generator-cli-4.0.0-20181210.103357-85.jar

OpenAPI declaration file content or url

See python-flask-security-endpoint.yaml in the attached zip-file:
python-flask-security-endpoint.zip

Command line used for generation

java -jar openapi-generator-cli-4.x.jar generate -i ./python-flask-security-endpoint.yaml -g python-flask -o ./python-flask-security-endpoint/

Steps to reproduce

1. Generate the server code

   ./python-flask-security-endpoint.sh
   

2. Start the server

   (cd ./python-flask-security-endpoint && python3 -m openapi_server)
   

3. Perform a client request

   curl -X GET "http://localhost:8080/data" -H  "accept: application/json" -H  "X-Full-Access-Token: 123"
   

   Returns:

   {
     "detail": "No authorization token provided",
     "status": 401,
     "title": "Unauthorized",
     "type": "about:blank"
   }
   

Related issues/PRs

I have not found any.

Suggest a fix

1. If the x-apikeyInfoFunc (or any of the others mentioned) is not defined by the user, the openapi-generator-cli should generate the endpoint. I expect similar behavior like is done for the path operation endpoints.
2. The endpoint module/function itself should also be generated.

Note: there may also be need for backward-compatibility with the deprecated x-tokenInfoUrl.
See also Security - Connexion 2.0 documentation

Start by reproducing the report with python-flask-security-endpoint.yaml and the shown openapi-generator CLI command, then inspect the generated server and its Connexion security setup. Compare the generated result with the x-apikeyInfoFunc behavior described in the issue, including the related security hook names. Done means the generated server exposes the required authorization endpoint configuration and the curl request no longer fails solely because that configuration is missing.