This repository presents an example application that consists of a Python gRPC server and a NodeJS gRPC client. ProtocolBuffer service definition is located in protos directory.

NodeJS application has two flavours:

• index.js - is a simple NodeJS gRPC client that shows examples of unary calls, one with successful response and one with error response.
• websocket-server.js - is a NodeJS WebSocket server that utilizes gRPC client to send a validation request to Python server, and streams responses from the server all the way to WebSocket client.

First run the Python server application:

cd python-app
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt
python server.py

Next in a new terminal window initialize NodeJS application:

cd node-app
npm install

Afterwards run the NodeJS simple client application:

node index.js

This will perform an unary call to the Python server and will print the response. One call will succeed, and another one will fail to show how errors are propagated.

Another example we can run is a NodeJS WebSocket server application:

node websocket-server.js

This initializes a simple NodeJS WebSocket server, that accepts arguments as input, and streams back argument validation results from the Python server all the way down to the WebSocket client.

To test this server, you can perform following steps:

npm install -g wscat
wscat -c ws://localhost:8080

And then try sending those arguments to the server:

• Is this argument valid?
• Blimey what a lot of food!
• sdfigojsuignsiugn

cd python-app
python -m grpc_tools.protoc -I../protos --python_out=. --grpc_python_out=. ../protos/echo.proto