How does one send a REST request to an annotated GRPC endpoint? - rest

Question

I am not receiving a valid response when curling the REST annotated endpoint from the GRPC protobuf
I'm currently running the bookstore server from here
I've been able to hit the endpoint successfully via GRPC using the provided client.
$ python bookstore_client.py
ListShelves: shelves {
id: 1
theme: "Fiction"
}
shelves {
id: 2
theme: "Fantasy"
}
When I try to hit the corresponding REST endpoint, it gives me back a non-text (i.e. not JSON) response
$ curl --raw --http2 localhost:8000/v1/shelves 2>/dev/null | xxd
00000000: 0000 1804 0000 0000 0000 0400 4000 0000 ............#...
00000010: 0500 4000 0000 0600 0020 00fe 0300 0000 ..#...... ......
00000020: 0100 0004 0800 0000 0000 003f 0001 0000 ...........?....
00000030: 0806 0000 0000 0000 0000 0000 0000 00 ...............
I receive this response no matter what the uri is i.e. /v1/foobar gives the same result
Here are the relevant lines from the protobuf
rpc ListShelves(google.protobuf.Empty) returns (ListShelvesResponse) {
// Define HTTP mapping.
// Client example (Assuming your service is hosted at the given 'DOMAIN_NAME'):
// curl http://DOMAIN_NAME/v1/shelves
option (google.api.http) = { get: "/v1/shelves" };
}
I expected the same response that the python client gave me but I'm receiving a non-text response from the GRPC server.

Answer 1

In that example, port 8000 is the gRPC, not the REST endpoint.
To run the endpoint that follows the annotations you need to run the Extensible Service Proxy, from the docs:
"Cloud Endpoints supports protocol transcoding so that clients can access your gRPC API by using HTTP/JSON. The Extensible Service Proxy (ESP) transcodes HTTP/JSON to gRPC."
The REST endpoint will be served on a different port via ESP --http_port option.