From 378313317329648792ef4ac4c5f7ae21dac8f90f Mon Sep 17 00:00:00 2001
From: Alex Vanin <alexey@nspcc.ru>
Date: Tue, 15 Sep 2020 13:49:20 +0300
Subject: [PATCH] [#144] sdk/client: Add RPC to create session token

Signed-off-by: Alex Vanin <alexey@nspcc.ru>
---
 pkg/client/opts.go    |   1 +
 pkg/client/session.go | 112 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 113 insertions(+)
 create mode 100644 pkg/client/session.go

diff --git a/pkg/client/opts.go b/pkg/client/opts.go
index de37e2c5..4de58238 100644
--- a/pkg/client/opts.go
+++ b/pkg/client/opts.go
@@ -41,6 +41,7 @@ type (
 		conn               *grpc.ClientConn
 		v2ContainerClient  *v2container.Client
 		v2AccountingClient *v2accounting.Client
+		v2SessionClient    *v2session.Client
 
 		objectClientV2 *v2object.Client
 	}
diff --git a/pkg/client/session.go b/pkg/client/session.go
new file mode 100644
index 00000000..fee9e7f1
--- /dev/null
+++ b/pkg/client/session.go
@@ -0,0 +1,112 @@
+package client
+
+import (
+	"context"
+
+	"github.com/nspcc-dev/neofs-api-go/pkg/owner"
+	"github.com/nspcc-dev/neofs-api-go/pkg/token"
+	"github.com/nspcc-dev/neofs-api-go/v2/client"
+	v2session "github.com/nspcc-dev/neofs-api-go/v2/session"
+	v2signature "github.com/nspcc-dev/neofs-api-go/v2/signature"
+	"github.com/pkg/errors"
+)
+
+func (c Client) CreateSession(ctx context.Context, expiration uint64, opts ...CallOption) (*token.SessionToken, error) {
+	switch c.remoteNode.Version.GetMajor() {
+	case 2:
+		return c.createSessionV2(ctx, expiration, opts...)
+	default:
+		return nil, unsupportedProtocolErr
+	}
+}
+
+func (c Client) createSessionV2(ctx context.Context, expiration uint64, opts ...CallOption) (*token.SessionToken, error) {
+	// apply all available options
+	callOptions := defaultCallOptions()
+	for i := range opts {
+		opts[i].apply(&callOptions)
+	}
+
+	w, err := owner.NEO3WalletFromPublicKey(&c.key.PublicKey)
+	if err != nil {
+		return nil, err
+	}
+
+	ownerID := new(owner.ID)
+	ownerID.SetNeo3Wallet(w)
+
+	reqBody := new(v2session.CreateRequestBody)
+	reqBody.SetOwnerID(ownerID.ToV2())
+	reqBody.SetExpiration(expiration)
+
+	req := new(v2session.CreateRequest)
+	req.SetBody(reqBody)
+	req.SetMetaHeader(v2MetaHeaderFromOpts(callOptions))
+
+	err = v2signature.SignServiceMessage(c.key, req)
+	if err != nil {
+		return nil, err
+	}
+
+	switch c.remoteNode.Protocol {
+	case GRPC:
+		cli, err := v2SessionClientFromOptions(c.opts)
+		if err != nil {
+			return nil, errors.Wrap(err, "can't create grpc client")
+		}
+
+		resp, err := cli.Create(ctx, req)
+		if err != nil {
+			return nil, errors.Wrap(err, "transport error")
+		}
+
+		err = v2signature.VerifyServiceMessage(resp)
+		if err != nil {
+			return nil, errors.Wrap(err, "can't verify response message")
+		}
+
+		body := resp.GetBody()
+		if body == nil {
+			return nil, errors.New("malformed response body")
+		}
+
+		sessionToken, err := token.CreateSessionToken(body.GetID(), body.GetSessionKey())
+		if err != nil {
+			return nil, errors.Wrap(err, "malformed response body")
+		}
+
+		return sessionToken, nil
+	default:
+		return nil, unsupportedProtocolErr
+	}
+}
+
+func v2SessionClientFromOptions(opts *clientOptions) (cli *v2session.Client, err error) {
+	switch {
+	case opts.grpcOpts.v2SessionClient != nil:
+		// return value from client cache
+		return opts.grpcOpts.v2SessionClient, nil
+
+	case opts.grpcOpts.conn != nil:
+		cli, err = v2session.NewClient(v2session.WithGlobalOpts(
+			client.WithGRPCConn(opts.grpcOpts.conn)),
+		)
+
+	case opts.addr != "":
+		cli, err = v2session.NewClient(v2session.WithGlobalOpts(
+			client.WithNetworkAddress(opts.addr)),
+		)
+
+	default:
+		return nil, errors.New("lack of sdk client options to create accounting client")
+	}
+
+	// check if client correct and save in cache
+	if err != nil {
+		return nil, err
+	}
+
+	opts.grpcOpts.v2SessionClient = cli
+
+	return cli, nil
+}