Support of Proxy settings

Problem/Motivation

I would like to use the Drupal's proxy configuration when I'm calling a service through HTTP_CLIENT_MANAGER.

Steps to reproduce

Create a custom module using HTTP_CLIENT_MANAGER. (ex: test_proxy)

• Define the proxy's settings on your Drupal's settings file.
  

  $settings['http_client_config']['proxy']['http'] = 'https://<user>:<password>@<location>:<port>';
  $settings['http_client_config']['proxy']['https'] = 'https://<user>:<password>@<location>:<port>';
  $settings['http_client_config']['proxy']['no'] = ['127.0.0.1', 'localhost'];
  

• Create modules/custom/test_proxy/test_proxy.http_services_api.yml

  beh_services.httpbin:
    title: "[Services] Httpbin"
    api_path: "/src/api/httpbin.yml"
    config:
      base_uri: "https://httpbin.org"
  

• Create modules/custom/test_proxy/src/api/httpbin.yml

  name: "[Services] Httpbin"
  apiVersion: "1.0"
  description: "Client wrapper Httpbin API."
  imports:
    - "resources/httpbin/content.yml"
  

• Create modules/custom/test_proxy/src/api/resources/httpbin/content.yml

  operations:
  
    GetContent:
      httpMethod: "GET"
      uri: "/get"
      summary: "Gets the origin."
      responseModel: "ContentData"
  
  models:
  
    ContentData:
      type: "object"
      location: "json"
      properties:
        args:
          type: "json"
          location: "json"
        headers:
          type: "json"
          location: "json"
        origin:
          type: "string"
          location: "json"
        url:
          type: "string"
          location: "json"
  

When I'm testing the service, through the UI, the Origin in the httpbin response is my network IP. It should be the proxy's.

Proposed resolution

TBD.