[#62] client: move package from neofs-api-go

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>

client/session.go

@@ -0,0 +1,79 @@
+package client
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/nspcc-dev/neofs-api-go/rpc/client"
+	rpcapi "github.com/nspcc-dev/neofs-api-go/v2/rpc"
+	v2session "github.com/nspcc-dev/neofs-api-go/v2/session"
+	v2signature "github.com/nspcc-dev/neofs-api-go/v2/signature"
+	"github.com/nspcc-dev/neofs-sdk-go/owner"
+	"github.com/nspcc-dev/neofs-sdk-go/session"
+)
+
+// Session contains session-related methods.
+type Session interface {
+	// CreateSession creates session using provided expiration time.
+	CreateSession(context.Context, uint64, ...CallOption) (*session.Token, error)
+}
+
+var errMalformedResponseBody = errors.New("malformed response body")
+
+func (c *clientImpl) CreateSession(ctx context.Context, expiration uint64, opts ...CallOption) (*session.Token, error) {
+	// apply all available options
+	callOptions := c.defaultCallOptions()
+
+	for i := range opts {
+		opts[i](callOptions)
+	}
+
+	w, err := owner.NEO3WalletFromPublicKey(&callOptions.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(callOptions.key, req)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := rpcapi.CreateSession(c.Raw(), req, client.WithContext(ctx))
+	if err != nil {
+		return nil, fmt.Errorf("transport error: %w", err)
+	}
+
+	// handle response meta info
+	if err := c.handleResponseInfoV2(callOptions, resp); err != nil {
+		return nil, err
+	}
+
+	err = v2signature.VerifyServiceMessage(resp)
+	if err != nil {
+		return nil, fmt.Errorf("can't verify response message: %w", err)
+	}
+
+	body := resp.GetBody()
+	if body == nil {
+		return nil, errMalformedResponseBody
+	}
+
+	sessionToken := session.NewToken()
+	sessionToken.SetID(body.GetID())
+	sessionToken.SetSessionKey(body.GetSessionKey())
+	sessionToken.SetOwnerID(ownerID)
+
+	return sessionToken, nil
+}