Add fabric session websocket client smoke API

agents/rap-node-agent/internal/mesh/client.go

@@ -6,7 +6,12 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"net/url"
+	"strings"
 	"time"
+
+	"github.com/example/remote-access-platform/agents/rap-node-agent/internal/fabricproto"
+	"github.com/gorilla/websocket"
 )
 
 type Client struct {
@@ -14,6 +19,13 @@ type Client struct {
 	HTTPClient *http.Client
 }
 
+type FabricSessionDialOptions struct {
+	Token   string
+	Header  http.Header
+	Dialer  *websocket.Dialer
+	Timeout time.Duration
+}
+
 func NewClient(baseURL string) Client {
 	return Client{
 		BaseURL: baseURL,
@@ -109,3 +121,88 @@ func (c Client) SendProduction(ctx context.Context, envelope ProductionEnvelope)
 	}
 	return result, nil
 }
+
+func (c Client) DialFabricSession(ctx context.Context, opts FabricSessionDialOptions) (*websocket.Conn, *http.Response, error) {
+	target, err := c.fabricSessionWebSocketURL()
+	if err != nil {
+		return nil, nil, err
+	}
+	header := cloneHeader(opts.Header)
+	if strings.TrimSpace(opts.Token) != "" {
+		header.Set("X-RAP-Fabric-Session-Token", strings.TrimSpace(opts.Token))
+	}
+	dialer := opts.Dialer
+	if dialer == nil {
+		base := *websocket.DefaultDialer
+		if opts.Timeout > 0 {
+			base.HandshakeTimeout = opts.Timeout
+		}
+		dialer = &base
+	}
+	return dialer.DialContext(ctx, target, header)
+}
+
+func (c Client) SendFabricSessionFrame(ctx context.Context, opts FabricSessionDialOptions, frame fabricproto.Frame) (fabricproto.Frame, error) {
+	conn, resp, err := c.DialFabricSession(ctx, opts)
+	if err != nil {
+		if resp != nil {
+			return fabricproto.Frame{}, fmt.Errorf("fabric session websocket rejected with status %d: %w", resp.StatusCode, err)
+		}
+		return fabricproto.Frame{}, err
+	}
+	defer conn.Close()
+	payload, err := fabricproto.MarshalFrame(frame)
+	if err != nil {
+		return fabricproto.Frame{}, err
+	}
+	if err := conn.WriteMessage(websocket.BinaryMessage, payload); err != nil {
+		return fabricproto.Frame{}, err
+	}
+	if deadline, ok := ctx.Deadline(); ok {
+		_ = conn.SetReadDeadline(deadline)
+	} else if opts.Timeout > 0 {
+		_ = conn.SetReadDeadline(time.Now().Add(opts.Timeout))
+	}
+	messageType, responsePayload, err := conn.ReadMessage()
+	if err != nil {
+		return fabricproto.Frame{}, err
+	}
+	if messageType != websocket.BinaryMessage {
+		return fabricproto.Frame{}, fmt.Errorf("fabric session websocket returned non-binary message type %d", messageType)
+	}
+	return fabricproto.UnmarshalFrame(responsePayload, fabricproto.DefaultMaxPayload)
+}
+
+func (c Client) fabricSessionWebSocketURL() (string, error) {
+	base := strings.TrimSpace(c.BaseURL)
+	if base == "" {
+		return "", fmt.Errorf("mesh base url is required")
+	}
+	parsed, err := url.Parse(base)
+	if err != nil {
+		return "", err
+	}
+	switch parsed.Scheme {
+	case "http":
+		parsed.Scheme = "ws"
+	case "https":
+		parsed.Scheme = "wss"
+	case "ws", "wss":
+	default:
+		return "", fmt.Errorf("unsupported mesh base url scheme %q", parsed.Scheme)
+	}
+	parsed.Path = strings.TrimRight(parsed.Path, "/") + "/mesh/v1/fabric/session/ws"
+	parsed.RawQuery = ""
+	parsed.Fragment = ""
+	return parsed.String(), nil
+}
+
+func cloneHeader(header http.Header) http.Header {
+	out := http.Header{}
+	for key, values := range header {
+		for _, value := range values {
+			out.Add(key, value)
+		}
+	}
+	return out
+}