Add RequestHeader to PoolConfig; default User-Agent header

pool.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
+	"net/http"
 
 	"git.wisehodl.dev/jay/go-honeybee/transport"
 	"git.wisehodl.dev/jay/go-honeybee/types"
@@ -82,16 +83,20 @@ type PoolConfig struct {
 	InboxBufferSize  int
 	EventsBufferSize int
 	WorkerConfig     WorkerConfig
+	RequestHeader    http.Header
 }
 
 type PoolOption func(*PoolConfig)
 
 func NewPoolConfig(opts ...PoolOption) (*PoolConfig, error) {
 	workerCfg, _ := NewWorkerConfig()
+	defaultHeader := http.Header{}
+	defaultHeader.Set("User-Agent", "honeybee/0.1.0")
 	cfg := &PoolConfig{
 		InboxBufferSize:  256,
 		EventsBufferSize: 10,
 		WorkerConfig:     *workerCfg,
+		RequestHeader:    defaultHeader,
 	}
 	for _, o := range opts {
 		o(cfg)
@@ -120,6 +125,16 @@ func WithWorkerConfig(wc WorkerConfig) PoolOption {
 	}
 }
 
+func WithRequestHeader(h http.Header) PoolOption {
+	return func(c *PoolConfig) {
+		if h == nil {
+			c.RequestHeader = nil
+		} else {
+			c.RequestHeader = h.Clone()
+		}
+	}
+}
+
 func ValidatePoolConfig(c *PoolConfig) error {
 	if c.InboxBufferSize < 1 {
 		return fmt.Errorf("invalid inbox buffer size: %d", c.InboxBufferSize)
@@ -328,9 +343,12 @@ func (p *Pool) Connect(id string, opts ...ConnectOption) error {
 		opt(o)
 	}
 
-	// TODO: pass headers
+	var hdr http.Header
+	if p.config.RequestHeader != nil {
+		hdr = p.config.RequestHeader.Clone()
+	}
 	dialFn := func(ctx context.Context) (types.Socket, error) {
-		socket, _, err := p.dialer.DialContext(ctx, id, nil)
+		socket, _, err := p.dialer.DialContext(ctx, id, hdr)
 		return socket, err
 	}
 

pool_test.go

@@ -302,6 +302,85 @@ func TestPoolRetire(t *testing.T) {
 	})
 }
 
+func TestPoolRequestHeader(t *testing.T) {
+	t.Run("default pool passes User-Agent header to DialContext", func(t *testing.T) {
+		config, _ := NewPoolConfig()
+		pool, _ := NewPool(context.Background(), config, nil)
+
+		var capturedHeader http.Header
+		pool.dialer = &honeybeetest.MockDialer{
+			DialContextFunc: func(
+				_ context.Context, _ string, h http.Header,
+			) (types.Socket, *http.Response, error) {
+				capturedHeader = h
+				return honeybeetest.NewMockSocket(), nil, nil
+			},
+		}
+
+		pool.Connect("wss://test")
+		expectEvent(t, pool.events, "wss://test", EventConnected)
+
+		assert.Equal(t, "honeybee/0.1.0", capturedHeader.Get("User-Agent"))
+		pool.Close()
+	})
+
+	t.Run("WithRequestHeader passes header to DialContext", func(t *testing.T) {
+		h := http.Header{}
+		h.Set("X-Custom", "value")
+		config, _ := NewPoolConfig(WithRequestHeader(h))
+		pool, _ := NewPool(context.Background(), config, nil)
+
+		var capturedHeader http.Header
+		pool.dialer = &honeybeetest.MockDialer{
+			DialContextFunc: func(
+				_ context.Context, _ string, h http.Header,
+			) (types.Socket, *http.Response, error) {
+				capturedHeader = h
+				return honeybeetest.NewMockSocket(), nil, nil
+			},
+		}
+
+		pool.Connect("wss://test")
+		expectEvent(t, pool.events, "wss://test", EventConnected)
+
+		assert.Equal(t, "value", capturedHeader.Get("X-Custom"))
+		pool.Close()
+	})
+
+	t.Run("pool stores a clone - external mutation does not affect dial calls", func(t *testing.T) {
+		h := http.Header{}
+		h.Set("X-Custom", "original")
+		config, _ := NewPoolConfig(WithRequestHeader(h))
+
+		// mutate original after config is built
+		h.Set("X-Custom", "mutated")
+
+		pool, _ := NewPool(context.Background(), config, nil)
+
+		var capturedHeader http.Header
+		pool.dialer = &honeybeetest.MockDialer{
+			DialContextFunc: func(
+				_ context.Context, _ string, h http.Header,
+			) (types.Socket, *http.Response, error) {
+				capturedHeader = h
+				return honeybeetest.NewMockSocket(), nil, nil
+			},
+		}
+
+		pool.Connect("wss://test")
+		expectEvent(t, pool.events, "wss://test", EventConnected)
+
+		assert.Equal(t, "original", capturedHeader.Get("X-Custom"))
+		pool.Close()
+	})
+
+	t.Run("WithRequestHeader(nil) stores nil cleanly", func(t *testing.T) {
+		cfg, err := NewPoolConfig(WithRequestHeader(nil))
+		assert.NoError(t, err)
+		assert.Nil(t, cfg.RequestHeader)
+	})
+}
+
 func TestPoolSend(t *testing.T) {
 	mockSocket := honeybeetest.NewMockSocket()
 	outgoingData := make(chan honeybeetest.MockOutgoingData, 10)