syntax = "proto3";
package session;
option go_package = "github.com/nspcc-dev/neofs-proto/session";

import "session/types.proto";
import "github.com/gogo/protobuf/gogoproto/gogo.proto";

option (gogoproto.stable_marshaler_all) = true;


service Session {
    // Open a trusted session to manipulate an object. In order to put or
    // delete object client have to obtain session token with trusted node.
    // Trusted node will modify client's object (add missing headers, checksums,
    // homomorphic hash) and sign id with session key. Session is established
    // during 4-step handshake in one gRPC stream

    // - First client stream message SHOULD BE type of `CreateRequest_Init`.
    // - First server stream message SHOULD BE type of `CreateResponse_Unsigned`.
    // - Second client stream message SHOULD BE type of `CreateRequest_Signed`.
    // - Second server stream message SHOULD BE type of `CreateResponse_Result`.

    rpc Create (stream CreateRequest) returns (stream CreateResponse);
}


message CreateRequest {
    // Message should be one of
    oneof Message {
        // Message to init session opening. Carry:
        // owner of manipulation object;
        // ID of manipulation object;
        // token lifetime bounds.
        session.Token Init = 1;
        // Signed Init message response (Unsigned) from server with user private key
        session.Token Signed = 2;
    }
}

message CreateResponse {
    oneof Message {
        // Unsigned token with token ID and session public key generated on server side
        session.Token Unsigned = 1;
        // Resulting token which can be used for object placing through an trusted intermediary
        session.Token Result = 2;
    }
}