What's this

• for studying grpc
• implement server side by golang
• implement client side by golang and flutter

reference

• grpc quickstart guide

feature

• GetFeature Simple RPC
• ListFeatures Server-side streaming RPC
• RecordRoute Client-side streaming RPC
• RouteChat Bidirectional streaming RPC

how to implement

1. create .proto file like simple_grpc.proto
2. run

   protoc --go_out=. --go_opt=paths=source_relative \
   --go-grpc_out=. --go-grpc_opt=paths=source_relative \
   simplegrpc/simple_grpc.proto

3. server implements SimpleGrpcServer interface and client implements SimpleGrpcClient interface. These files are in simplegrpc/simple_grpc_grpc.pb.go
4. start the server

   grpcServer := grpc.NewServer(opts...)
   pb.RegisterSimpleGrpcServer(grpcServer, newServer())
   grpcServer.Serve(lis)

5. create the channel on client

   var opts []grpc.DialOption
   conn, err := grpc.Dial(*serverAddr, opts...)
   if err != nil {
   ...
   }
   defer conn.Close()
   client := pb.NewRouteGuideClient(conn)

6. client can call our service methods via client val

how to run

• run the server go run server/server.go
• run the client go run client/client.go

you will see following outputs

Getting feature for point (409146138, -746188906)
name:"Berkshire Valley Management Area Trail, Jefferson, NJ, USA" location:<latitude:409146138 longitude:-746188906 >
Getting feature for point (0, 0)
location:<>
Looking for features within lo:<latitude:400000000 longitude:-750000000 > hi:<latitude:420000000 longitude:-730000000 >
name:"Patriots Path, Mendham, NJ 07945, USA" location:<latitude:407838351 longitude:-746143763 >
...
name:"3 Hasta Way, Newton, NJ 07860, USA" location:<latitude:410248224 longitude:-747127767 >
Traversing 56 points.
Route summary: point_count:56 distance:497013163
Got message First message at point(0, 1)
Got message Second message at point(0, 2)
Got message Third message at point(0, 3)
Got message First message at point(0, 1)
Got message Fourth message at point(0, 1)
Got message Second message at point(0, 2)
Got message Fifth message at point(0, 2)
Got message Third message at point(0, 3)
Got message Sixth message at point(0, 3)

For Flutter Client (only native)

how to set up for Flutter (only native)

• reference
• install grpc package
• install protoc-gen-dart

  dart pub global activate protoc_plugin
  

• generate client stub

  protoc --dart_out=grpc:client/flutter_client/lib/generated -Isimplegrpc simplegrpc/simple_grpc.proto

how to test

1. run golang server go run server/server.go
2. run flutter app
3. tap button

For React Client (TODO)

how to set up for React

• it seems there is a bug