Message Service API (gRPC)

Introduction

This project implements a gRPC-based message service using C#. The server facilitates the exchange of messages between clients, managing user streams and message persistence. The client communicates with the server using the gRPC protocol to send and receive messages.

The server uses the gRPC web middleware from .NET, and handles both normal gRPC clients and web based clients.

Message Service Implementation

The MessageServiceImplementation class serves as the core component of the server. It extends MessageService.MessageServiceBase and provides implementations for two gRPC service methods: sendMessageToUser and openMessageStream.

sendMessageToUser:
This method handles the sending of messages from one user to another. It ensures database persistence and checks for open streams before delivering the message.

openMessageStream:
This method is called when a client opens a stream to listen for incoming messages. It manages the client's connection, sends stored messages, and handles client disconnection.

Usage

To run the server, make sure to install all dependencies, then run the following command:

dotnet run

C# Client Implementation

This C# client implementation initializes a gRPC channel, sets up the client, and opens a stream for incoming messages. Users can interact with the server by sending messages to each other.

Usage

Make sure that the server is running before starting the client. To start the client, run the following command:

dotnet run

Enter a user ID and username when prompted by the client. Users can send messages by providing the receiver's ID and message content. All send messages will be stored. If you restart your client and enter with the same id you will receive al previously send messages.

Exit: Press 'e' to exit the client. The server handles disconnection appropriately.

Browser (javascript) Client implementation

This browser client makes use of gRPC web to connect to the server. There is no need to set up a proxy, the server uses the Grpc.AspNetCore.Web package to handle http1.1 connections. Do note that client to server streams are not possible in the browser.

Usage

install dependencies:

npm install

Generate code from the .proto file:
Install protoc for javascript here
Install the generator for gRPC-Web here

Make sure that both these files are added to your path variables!

Run the following commands to generate the files:

protoc -I="./Proto" ./Proto/protobuf.proto --js_out=import_style=commonjs:"./src" --grpc-web_out=import_style=commonjs,mode=grpcwebtext:"./src"

The GrpcClient.js file needs to be compiled to a library, this way other scripts inside the browser can use its functions. To do this run the following command:

npx webpack 

Run client:

python -m http.server 8080

Notes

Update the server address in the client code to match your server configuration. You can find the server port in the appsettings.json file inside the Properties folder. for normal gRPC clients (Http2), the default is https://localhost:6061. For browser based clients (Http1), the default is https://localhost:6060