Fix DDG: allow using conversations and improve UX for incorrect usage

[0dminnimda]

The vqd-4 changes for each continuation of the converation, thus allowing stepping back or branching, but this contradicts the initial authors assumption. The logic is as such: first status update gives us first empty chat id, the successive chat queries send the new conversation id, we just got to read it and return the new one to the user.

Before that I was getting this if I were to use a conversation (DDG does not allow more than one message without it):

Traceback (most recent call last):
    ...
  File "C:\Users\ASUS\AppData\Roaming\Python\Python312\site-packages\g4f\client\client.py", line 29, in iter_response
    for idx, chunk in enumerate(response):
  File "C:\Users\ASUS\AppData\Roaming\Python\Python312\site-packages\g4f\providers\base_provider.py", line 223, in create_completion
    yield loop.run_until_complete(await_callback(gen.__anext__))
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python3.12.4\Lib\asyncio\base_events.py", line 687, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "C:\Users\ASUS\AppData\Roaming\Python\Python312\site-packages\g4f\providers\base_provider.py", line 52, in await_callback
    return await callback()
           ^^^^^^^^^^^^^^^^
  File "C:\Python\projects\experiments\gpt4free\DDG.py", line 110, in create_async_generator
    await raise_for_status(response)
  File "C:\Users\ASUS\AppData\Roaming\Python\Python312\site-packages\g4f\requests\raise_for_status.py", line 28, in raise_for_status_async
    raise ResponseStatusError(f"Response {response.status}: {message}")
g4f.errors.ResponseStatusError: Response 400: {"action":"error","status":400,"type":"ERR_INVALID_VQD"}

Also it's better to make user track messages, rather than half-tracking present in here (does not track llm answer, so user have to add it to conversation messages for some reason ...) and AFAIC if a user wants to do anything useful with llm, they have to manage the messages history.

[0dminnimda]

Should I raise an exception if we could not get the conversation id, but the user requested it? Currently it's not a silent error, the user can detect an absence of the Converation chunk.

[TheFirstNoob]

If i correclty remeber ddg site give 50 messages Converation and after need press "Fire" (clear button).
Maybe need add checking for >49 like

[github-actions]

Bumping this pull request because it has been open for 7 days with no activity. Closing automatically in 7 days unless it becomes active again.

[kqlio67]

Thank you for these valuable improvements and the detailed explanation about vqd-4 behavior. Your changes significantly enhance error handling and conversation management. I appreciate your efforts in improving the DDG provider. These enhancements make the provider more robust and efficient.

[TheFirstNoob]

DDG: ValueError: More than one message requires using conversation.

This happening after first message sended or if some "bots" use conversation saving well we have error to

[0dminnimda]

DDG: ValueError: More than one message requires using conversation.

Yes, otherwise you'll get an error I referenced in the ticket description.