将 HTTP/JSON 转码为 gRPC，如何为 enum 指定查询参数

Question

I have setup http-grpc transcoding for my service (see https://cloud.google.com/endpoints/docs/grpc/transcoding ). It has an rpc DoSomething defined as follows:

service MyService {
  // Determine experiments and treatments for a user across multiple namespaces.
  rpc DoSomething (RpcRequest) returns (RpcResponse) {
    option (google.api.http) = {
      get: "/my-service/do-something"
    };
  };
}

message RpcRequest {
  // Metadata associated with this request.
  RequestContext request_context = 1;
}

message RequestContext {

  // DeviceID for identifying user.
  string device_id = 1;

  // Just added this, but don't know how to pass in this value as query parameter!
  Country country = 2;

}

// Just added this
enum Country {
  UNKNOWN_COUNTRY = 0;
  US = 1;
  CA = 2;
  AF = 3;
  AX = 4;
  // ... etc.
}

When I first implemented this, RequestContext only had device_id, so this REST URL worked fine: GET https://example.com/my-service/do-something?request_context.device_id=abc123 . It executed the operation and returned the correct response as expected.

Now I need to add an enum country to RequestContext , but I'm not sure how to pass in that information in the query string of the URL. I've tried GET https://example.com/my-service/do-something?request_context.device_id=abc123&request_context.country=US , but that does not forward the country onto the GRPC service; it just assigns the default value 0, which is "UNKNOWN_COUNTRY", to country . I have not found any guidance on Google's documentation about this.

What is the correct way to specify an enum in the query parameter? Thanks in advance!

Answer 1

It should work passing enum value as the string defined in the proto file regardless in the query parameters or in the json body. You can also pass enum value as integer too.

You may have some typo and trailing space that causing the conversion code not finding the match value. If mis-matched, enum value default to 0.