GA-Server is a simple script that works as a server, it receives audio chunks from a client and it forwards them to Google Assistant. This script can be used (with a client) when you want to integrate GA into a device that is not powerful enough or in a device where the SDK couldn't be installed.

Steps from 1 to 5 are needed only if you don't have a registered project or the credentials

1. Create/open a project in the Actions Console
2. Register a device model
3. Download credentials.json
4. Install the google-oauthlib-tool in a Python 3 virtual environment:

python3 -m venv env
env/bin/python -m pip install --upgrade pip setuptools
env/bin/pip install --upgrade "google-auth-oauthlib[tool]"

5. Use the google-oauthlib-tool to generate credentials:

env/bin/google-oauthlib-tool --scope https://www.googleapis.com/auth/assistant-sdk-prototype \ 
--save --headless --client-secrets credentials.json

6. Download the project and open it
7. Run npm install
8. Open index.js and edit the host, port, input/output sample rate if needed (Default settings are: accept connections from all IPv4 addresses on the local machine on port 4000, audio with 16000Hz sample rate)
9. Run node index.js

If all it's working, it should appear a message with "TCP server listen on address: x.w.y.z:p" . That means that the server is ready to receive audio chunks from a client.

A client sends microphone data to this server and waits for a JSON that contains the GA answer, an internet connection is needed where the server is.

1. A client starts recording microphone's audio and every bits it's sent to the server trough a TCP stream
2. The server start a connection with GA and it forwards microphone's audio sent by the client
3. GA sends the response packets to the server
4. When GA sends an "END_OF_UTTERANCE", the server send a JSON to the client that contains: the transcription of the user input, the text response, the microphone mode and the conversation state (see the documentation for more information)
5. The client receive the JSON response

If you want to test the project without writing a client, you can use the example python client located in the test folder. You just need to open it and edit the ip/port and put there the one of the server (eg. 127.0.0.1 and 4000). It can be run simply with python test_send_file.py.

The python script sends whoisobama.wav to the server, the server forward it to GA and send back to the client a JSON with the answer. That answer will be written by the client.

Choregraphe-GA (Robot connected to Google Assistant)

ZAGA