Protocol Buffers (protobuf) is a language-neutral format for serializing structured messages and defining service interfaces. In a gRPC board-game API, a .proto file becomes the shared contract between client and server, replacing JSON with compact binary messages. section 10.3 section 10.3.4
A practical ASP.NET Core implementation follows this sequence:
- Create a /gRPC/ directory and add grpc.proto using proto3 syntax. section 10.3.4
- Describe services, methods, request messages, and response messages in the protobuf contract. section 10.3.4
- Reference the file in the project file so the .NET compiler generates client and server base classes. section 10.3.4
- Extend the generated server base class and implement methods against application data, such as EF Core. section 10.3.4
- Register gRPC services and map the implementation into the ASP.NET Core HTTP pipeline. section 10.3.4
Board-game lookup contract
A grpc.proto contract can declare a Grpc service with a GetBoardGame method, accepting BoardGameRequest and returning BoardGameResponse. The request carries an integer id; the response carries id, name, and year fields. These protobuf messages serve a role similar to C# DTOs while generating strongly typed service accessors. section 10.3.4
Listing 10.7 /gRPC/grpc.proto file
syntax = "proto3";
option csharp_namespace = "MyBGList.gRPC";
package Grpc;
service Grpc {
rpc GetBoardGame (BoardGameRequest) returns (BoardGameResponse); #1
}
message BoardGameRequest { #2
int32 id = 1;
}
message BoardGameResponse { #3
int32 id = 1;
string name = 2;
int32 year = 3;
}
Inspect the complete grpc.proto example to see proto3 syntax, the service declaration, RPC method, message types, and field numbering together. section 10.3.4
