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Server streaming RPC

We have a protobuf file with Server streaming RPC GetByAge defined. It returns a stream of employees of a certain age:

syntax = "proto3";

package Examples.Grpc;

service EmployeeService {
  rpc GetByAge(AgeRangeRequest) returns (stream Employee);
}

message Employee {
  string guid = 1;
  string full_name = 2;
  string position = 3;
  int32 age = 4;
}

message AgeRangeRequest {
  int32 from = 1;
  int32 to = 2;
}

Call Server streaming RPC

Let's get employees aged 35 to 38:

csharp
GrpcHost
	.CreateClient<EmployeeService.EmployeeServiceClient>()
	.ServerStreaming
	    .Call(x=>x.GetByAge(new AgeRangeRequest { From = 35, To = 38}))

Then we check that each age of each employee in the stream matches the requested one:

csharp
GrpcHost
	.CreateClient<EmployeeService.EmployeeServiceClient>()
	.ServerStreaming
		.Call(x=>x.GetByAge(new AgeRangeRequest { From = 35, To = 38}))
		.ResponseStream
			.AssertForEach(e=>e.Age.Should().BeInRange(30, 38));

The AssertForEach method will call the passed lambda for every response in the stream.

You can also check each response individually:

csharp
GrpcHost
	.CreateClient<EmployeeService.EmployeeServiceClient>()
	.ServerStreaming
		.Call(x=>x.GetByAge(new AgeRangeRequest { From = 35, To = 38}))
		.ResponseStream
			.Next()
			.AssertCurrent(employee => employee.Age.Should().Be(35))
			.Next()
			.AssertCurrent(employee => employee.Age.Should().Be(37))
			.AssertEndOfStream();

Handling Errors

Let's try calling the same method with the wrong argument, where From is greater than To. After trying to get the first response, the RPC should return an InvalidArgument error. You can test it like this:

csharp
GrpcHost
	.CreateClient<EmployeeService.EmployeeServiceClient>()
	.ServerStreaming
		.Call(x=>x.GetByAge(new AgeRangeRequest { From = 90, To = 10}))
		.ResponseStream
			.Next()
			.AssertStatusCode(StatusCode.InvalidArgument);