gRPC

gRPC - GRPC Remote Procedure Call. The “G” could also just stand for “Google” which is one of the main drive forces behind the protocol. It’s a high performance, open-source universal RPC framework. gRPC uses Protocol Buffers v3.

Highlights

high serialization/deserialization performance (especially deserialization when compared to JSON)
wide adoption in programming languages
binary communication (no JSON, XML, whatever) - small size
contract-based
requires HTTP/2 (HTTPS by default)
uni- and bi-directional streaming
great for low-power devices (IoT)

Usage

backend-to-backend communication, e.g. between microservices

Usage on the frontend is not as straightforward as with REST.

Contracts

The Server and the Client are generated using the ProtoBuf.

ProtoBuf

Protocol Buffers (ProtoBuf) is a language for defining interfaces.

language/platform neutral
extensible
serializable
not specific to gRPC

It comes with its own set of types for defining data.

Example

Request:

1: 100
2: "Hello There"

Response:

1: 94.5
2: 15.4
3: .5

Streaming

Thanks to HTTP/2 base, gRPC supports streaming. It’s very similar to how websockets work. The streaming works in any direction (client -> server or server -> client), it can also be both ways at the same time.

To support streaming, the protobuf file needs to explicitly contain such information attached to the input of the chosen rpc.

Usage

.NET

Read here.

gRPC-Web

gRPC-Web is the way to call gRPC servers from the frontend layer (from JS). ASP.NET Core supports it via an additional NuGet package.

Tools

BloomRPC- “Postman” for gRPC

References

← Server Name Indication