Protobuf Collections
Learn about the workings of collections in Protobuf and the use of the repeated keyword.
Any programming language can bundle items of the same data type together into one coherent collection of a variable length. The same is true for messaging format. We can use collections in JSON. We can have collections of repeated elements inside an XML or any other popular messaging format.
Protobuf is not an exception. The protocol supports collections via the use of the repeated keyword. All we have to do is place this keyword before a field definition inside a message structure. This is what we'll look at next.
Applying the repeated keyword in Protobuf
We'll use the code widget below to modify the gRPC client and server applications that we built previously:
syntax = "proto3";
option csharp_namespace = "BasicGrpcService";
package basic_grpc_service;
service Chatbot {
rpc SendMessage (ChatRequest) returns (ChatReply);
}
message ChatRequest {
string name = 1;
string message = 2;
}
message ChatReply {
string message = 1;
bool answer_found = 2;
bytes reply_in_bytes = 3;
NumericPayload payload = 4;
}
message NumericPayload
{
float float_demo = 1;
double double_demo = 2;
int32 int32_demo = 3;
int64 int64_demo = 4;
uint32 uint32_demo = 5;
uint64 uint64_demo = 6;
sint32 sint32_demo = 7;
sint64 sint64_demo = 8;
fixed32 fixed32_demo = 9;
fixed64 fixed64_demo = 10;
sfixed32 sfixed32_demo = 11;
sfixed64 sfixed64_demo = 12;
}To demonstrate the use of the repeated keyword, we'll modify our chatbot.proto file. We'll only do it inside the BasicGrpcService project folder while ...