nodejs-express-server - Auto-populate URL_PORT, URL_PATH, BASE_VERSION from schema servers url

Created by: kmturley

Is your feature request related to a problem? Please describe.

Under the v3.0 spec, you can configure the server url, port and base API path, as shown here

openapi: 3.0.0
info:
  title: Sample title
  description: Sample description
  version: 0.1.9
servers:
  - url: http://0.0.0.0:5000/v3
    description: Local server

https://swagger.io/docs/specification/basic-structure/

However when generated using nodejs-express-server the settings are not used. They seem to be hardcoded:

const config = {
  ROOT_DIR: __dirname,
  URL_PORT: 3000,
  URL_PATH: 'http://localhost',
  BASE_VERSION: 'v2',
  CONTROLLER_DIRECTORY: path.join(__dirname, 'controllers'),
  PROJECT_DIR: __dirname,
};

https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/resources/nodejs-express-server/config.mustache#L5

However in other generators the settings are dynamic: http://localhost:{{serverPort}}{{contextPath}}/ui/ https://github.com/OpenAPITools/openapi-generator/search?l=HTML%2BDjango&p=2&q=serverPort

Describe the solution you'd like

Config to be generated using the yaml services url: http://0.0.0.0:5000/v3

const config = {
  ROOT_DIR: __dirname,
  URL_PORT: 5000,
  URL_PATH: 'http://0.0.0.0',
  BASE_VERSION: 'v3',
  CONTROLLER_DIRECTORY: path.join(__dirname, 'controllers'),
  PROJECT_DIR: __dirname,
};

It seems this can be achieve by modifying ./src/main/java/org/openapitools/codegen/languages/NodeJSExpressServerCodegen.java

if (additionalProperties.containsKey(SERVER_HOST)) {
    host = additionalProperties.get(SERVER_HOST).toString();
}
this.additionalProperties.put(SERVER_HOST, host);

if (additionalProperties.containsKey(SERVER_PORT)) {
    port = additionalProperties.get(SERVER_PORT).toString();
}
this.additionalProperties.put(SERVER_PORT, port);

and also ./src/main/resources/nodejs-express-server/config.mustache

const config = {
  ROOT_DIR: __dirname,
  URL_PORT: {{#serverPort}}{{serverPort}}{{/serverPort}}{{^serverPort}}1234{{/serverPort}},
  URL_PATH: '{{#serverHost}}{{serverHost}}{{/serverHost}}{{^serverHost}}http://localhost{{/serverHost}}',
  BASE_VERSION: '{{#contextPath}}{{contextPath}}{{/contextPath}}{{^contextPath}}v2{{/contextPath}}',
  CONTROLLER_DIRECTORY: path.join(__dirname, 'controllers'),
  PROJECT_DIR: __dirname,
};

Describe alternatives you've considered

1. Manually making the change after the template has been generated
2. Using bash to update the string after the template has been created

These aren't ideal as every time the API spec changes we may want to regenerate the service, and have to repeat these steps manually. Also if we are generating multiple services they all have the same url/port settings...