Add StringID call option (#44)

Fixes #43

call_opt.go

@@ -28,3 +28,12 @@ func PickID(id ID) CallOption {
 		return nil
 	})
 }
+
+// StringID returns a call option that instructs the request ID to be set as a
+// string.
+func StringID() CallOption {
+	return callOptionFunc(func(r *Request) error {
+		r.ID.IsString = true
+		return nil
+	})
+}

call_opt_test.go

@@ -0,0 +1,92 @@
+package jsonrpc2_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/sourcegraph/jsonrpc2"
+)
+
+func TestPickID(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	a, b := inMemoryPeerConns()
+	defer a.Close()
+	defer b.Close()
+
+	handler := handlerFunc(func(ctx context.Context, conn *jsonrpc2.Conn, req *jsonrpc2.Request) {
+		if err := conn.Reply(ctx, req.ID, fmt.Sprintf("hello, #%s: %s", req.ID, *req.Params)); err != nil {
+			t.Error(err)
+		}
+	})
+	connA := jsonrpc2.NewConn(ctx, jsonrpc2.NewBufferedStream(a, jsonrpc2.VSCodeObjectCodec{}), handler)
+	connB := jsonrpc2.NewConn(ctx, jsonrpc2.NewBufferedStream(b, jsonrpc2.VSCodeObjectCodec{}), noopHandler{})
+	defer connA.Close()
+	defer connB.Close()
+
+	const n = 100
+	for i := 0; i < n; i++ {
+		var opts []jsonrpc2.CallOption
+		id := jsonrpc2.ID{Num: uint64(i)}
+
+		// This is the actual test, every 3rd request we specify the
+		// ID and ensure we get a response with the correct ID echoed
+		// back
+		if i%3 == 0 {
+			id = jsonrpc2.ID{
+				Str:      fmt.Sprintf("helloworld-%d", i/3),
+				IsString: true,
+			}
+			opts = append(opts, jsonrpc2.PickID(id))
+		}
+
+		var got string
+		if err := connB.Call(ctx, "f", []int32{1, 2, 3}, &got, opts...); err != nil {
+			t.Fatal(err)
+		}
+		if want := fmt.Sprintf("hello, #%s: [1,2,3]", id); got != want {
+			t.Errorf("got result %q, want %q", got, want)
+		}
+	}
+}
+
+func TestStringID(t *testing.T) {
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	a, b := inMemoryPeerConns()
+	defer a.Close()
+	defer b.Close()
+
+	handler := handlerFunc(func(ctx context.Context, conn *jsonrpc2.Conn, req *jsonrpc2.Request) {
+		replyWithError := func(msg string) {
+			respErr := &jsonrpc2.Error{Code: jsonrpc2.CodeInvalidRequest, Message: msg}
+			if err := conn.ReplyWithError(ctx, req.ID, respErr); err != nil {
+				t.Error(err)
+			}
+		}
+		if !req.ID.IsString {
+			replyWithError("ID.IsString should be true")
+			return
+		}
+		if len(req.ID.Str) == 0 {
+			replyWithError("ID.Str should be populated but is empty")
+			return
+		}
+		if err := conn.Reply(ctx, req.ID, "ok"); err != nil {
+			t.Error(err)
+		}
+	})
+	connA := jsonrpc2.NewConn(ctx, jsonrpc2.NewBufferedStream(a, jsonrpc2.VSCodeObjectCodec{}), handler)
+	connB := jsonrpc2.NewConn(ctx, jsonrpc2.NewBufferedStream(b, jsonrpc2.VSCodeObjectCodec{}), noopHandler{})
+	defer connA.Close()
+	defer connB.Close()
+
+	var res string
+	if err := connB.Call(ctx, "f", nil, &res, jsonrpc2.StringID()); err != nil {
+		t.Fatal(err)
+	}
+}

jsonrpc2.go

@@ -366,9 +366,14 @@ func (c *Conn) send(_ context.Context, m *anyMessage, wait bool) (cc *call, err
 	// responses.
 	if m.request != nil && wait {
 		cc = &call{request: m.request, seq: c.seq, done: make(chan error, 1)}
-		if !m.request.ID.IsString && m.request.ID.Num == 0 {
-			// unset, use next seq as call ID
-			m.request.ID.Num = c.seq
+
+		isIDUnset := len(m.request.ID.Str) == 0 && m.request.ID.Num == 0
+		if isIDUnset {
+			if m.request.ID.IsString {
+				m.request.ID.Str = strconv.FormatUint(c.seq, 10)
+			} else {
+				m.request.ID.Num = c.seq
+			}
 		}
 		id = m.request.ID
 		c.pending[id] = cc

jsonrpc2_test.go

@@ -243,50 +243,6 @@ func (h handlerFunc) Handle(ctx context.Context, conn *jsonrpc2.Conn, req *jsonr
 	h(ctx, conn, req)
 }
 
-func TestPickID(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	a, b := inMemoryPeerConns()
-	defer a.Close()
-	defer b.Close()
-
-	handler := handlerFunc(func(ctx context.Context, conn *jsonrpc2.Conn, req *jsonrpc2.Request) {
-		if err := conn.Reply(ctx, req.ID, fmt.Sprintf("hello, #%s: %s", req.ID, *req.Params)); err != nil {
-			t.Error(err)
-		}
-	})
-	connA := jsonrpc2.NewConn(ctx, jsonrpc2.NewBufferedStream(a, jsonrpc2.VSCodeObjectCodec{}), handler)
-	connB := jsonrpc2.NewConn(ctx, jsonrpc2.NewBufferedStream(b, jsonrpc2.VSCodeObjectCodec{}), noopHandler{})
-	defer connA.Close()
-	defer connB.Close()
-
-	const n = 100
-	for i := 0; i < n; i++ {
-		var opts []jsonrpc2.CallOption
-		id := jsonrpc2.ID{Num: uint64(i)}
-
-		// This is the actual test, every 3rd request we specify the
-		// ID and ensure we get a response with the correct ID echoed
-		// back
-		if i%3 == 0 {
-			id = jsonrpc2.ID{
-				Str:      fmt.Sprintf("helloworld-%d", i/3),
-				IsString: true,
-			}
-			opts = append(opts, jsonrpc2.PickID(id))
-		}
-
-		var got string
-		if err := connB.Call(ctx, "f", []int32{1, 2, 3}, &got, opts...); err != nil {
-			t.Fatal(err)
-		}
-		if want := fmt.Sprintf("hello, #%s: [1,2,3]", id); got != want {
-			t.Errorf("got result %q, want %q", got, want)
-		}
-	}
-}
-
 func TestHandlerBlocking(t *testing.T) {
 	// We send N notifications with an increasing parameter. Since the
 	// handler is blocking, we expect to process the notifications in the