class_docstr: A simple command channel based on HTTP.
  
  Check the server for details. (``ts/nni_manager/common/command_channel/http.ts``)
code: def receive(self) -> Command | None:
      while True:
          r = requests.get(self._url)
          if r.status_code == 200:
              return r.json()
          if r.status_code == 408:
              continue
          if r.status_code == 410:
              return None
          _logger.error("Bad status %s %s", r.status_code, r.text)
          raise IOError(
              f"HTTP command channel received unexpected status code {r.status_code}"
          )
  
file_path: nni/nni/runtime/command_channel/http.py
imports: from __future__ import annotations
  import logging
  import requests
  from .base import Command, CommandChannel
label_desc: Use image node_id 3 for calling the HttpChannel obj's underlying member method code with example usage: obj.receive() and returns: r, None