'Can I define a grpc call with a null request or response?
Does the rpc syntax in proto3 allow null requests or responses?
e.g. I want the equivalent of the following:
rpc Logout;
rpc Status returns (Status);
rpc Log (LogData);
Or should I just create a null type?
message Null {};
rpc Logout (Null) returns (Null);
rpc Status (Null) returns (Status);
rpc Log (LogData) returns (Null);
Solution 1:[1]
Kenton's comment below is sound advice:
... we as developers are really bad at guessing what we might want in the future. So I recommend being safe by always defining custom params and results types for every method, even if they are empty.
Answering my own question:
Looking through the default proto files, I came across Empty that is exactly like the Null type I suggested above :)
excerpt from that file:
// A generic empty message that you can re-use to avoid defining duplicated
// empty messages in your APIs. A typical example is to use it as the request
// or the response type of an API method. For instance:
//
// service Foo {
// rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty);
// }
//
message Empty {
}
Solution 2:[2]
You also can use predefined:
import "google/protobuf/empty.proto";
package MyPackage;
service MyService {
rpc Check(google.protobuf.Empty) returns (google.protobuf.Empty) {}
}
Solution 3:[3]
you can also use another bool property inside the Reply structure. like this
message Reply {
string result = 1;
bool found = 2;
}
so if you dont find the result or some error happened you can return from the service class this
return new Reply()
{
Found = false
};
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
Solution | Source |
---|---|
Solution 1 | Ryan M |
Solution 2 | hdnn |
Solution 3 | dkokkinos |