feat: modernise to Go 1.26 iterators and stdlib helpers

Add AllClients, AllChannels, AllSubscriptions iter.Seq iterators.
Use slices.Collect(maps.Keys()) in SendToChannel/Subscriptions,
range-over-int in calculateBackoff and benchmarks.

Co-Authored-By: Gemini <noreply@google.com>
Co-Authored-By: Virgil <virgil@lethean.io>

go.sum

@@ -4,25 +4,40 @@ github.com/bsm/gomega v1.27.10 h1:yeMWxP2pV2fG3FgAODIY8EiRE3dy0aeFYt4l7wh6yKA=
 github.com/bsm/gomega v1.27.10/go.mod h1:JyEr/xRbxbtgWNi8tIEVPUYZ5Dzef52k01W3YH0H+O0=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
+github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
 github.com/gorilla/websocket v1.5.3 h1:saDtZ6Pbx/0u+bgYQ3q96pZgCzfhKXGPqt7kZ72aNNg=
 github.com/gorilla/websocket v1.5.3/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/klauspost/cpuid/v2 v2.3.0 h1:S4CRMLnYUhGeDFDqkGriYKdfoFlDnMtqTiI/sFzhA9Y=
+github.com/klauspost/cpuid/v2 v2.3.0/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
+github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
+github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/redis/go-redis/v9 v9.18.0 h1:pMkxYPkEbMPwRdenAzUNyFNrDgHx9U+DrBabWNfSRQs=
 github.com/redis/go-redis/v9 v9.18.0/go.mod h1:k3ufPphLU5YXwNTUcCRXGxUoF1fqxnhFQmscfkCoDA0=
+github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
+github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
 github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 github.com/zeebo/xxh3 v1.1.0 h1:s7DLGDK45Dyfg7++yxI0khrfwq9661w9EN78eP/UZVs=
+github.com/zeebo/xxh3 v1.1.0/go.mod h1:IisAie1LELR4xhVinxWS5+zf1lA4p0MW4T+w+W07F5s=
 go.uber.org/atomic v1.11.0 h1:ZvwS0R+56ePWxUNi+Atn9dWONBPp/AUETXlHW0DxSjE=
 go.uber.org/atomic v1.11.0/go.mod h1:LUxbIzbOniOlMKjJjyPfpl4v+PKK2cNJn91OQbhoJI0=
 golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
+golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

ws.go

@@ -62,7 +62,10 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"iter"
+	"maps"
 	"net/http"
+	"slices"
 	"sync"
 	"time"
 
@@ -349,10 +352,7 @@ func (h *Hub) SendToChannel(channel string, msg Message) error {
 	}
 
 	// Copy client references under lock to avoid races during iteration
-	targets := make([]*Client, 0, len(clients))
+	targets := slices.Collect(maps.Keys(clients))
-	for client := range clients {
-		targets = append(targets, client)
-	}
 	h.mu.RUnlock()
 
 	for _, client := range targets {
@@ -429,6 +429,20 @@ func (h *Hub) ChannelSubscriberCount(channel string) int {
 	return 0
 }
 
+// AllClients returns an iterator for all connected clients.
+func (h *Hub) AllClients() iter.Seq[*Client] {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return slices.Values(slices.Collect(maps.Keys(h.clients)))
+}
+
+// AllChannels returns an iterator for all active channels.
+func (h *Hub) AllChannels() iter.Seq[string] {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return slices.Values(slices.Collect(maps.Keys(h.channels)))
+}
+
 // HubStats contains hub statistics.
 type HubStats struct {
 	Clients  int `json:"clients"`
@@ -586,11 +600,14 @@ func (c *Client) Subscriptions() []string {
 	c.mu.RLock()
 	defer c.mu.RUnlock()
 
-	result := make([]string, 0, len(c.subscriptions))
+	return slices.Collect(maps.Keys(c.subscriptions))
-	for channel := range c.subscriptions {
+}
-		result = append(result, channel)
+
-	}
+// AllSubscriptions returns an iterator for the client's current subscriptions.
-	return result
+func (c *Client) AllSubscriptions() iter.Seq[string] {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return slices.Values(slices.Collect(maps.Keys(c.subscriptions)))
 }
 
 // Close closes the client connection.
@@ -796,7 +813,7 @@ func (rc *ReconnectingClient) setState(state ConnectionState) {
 
 func (rc *ReconnectingClient) calculateBackoff(attempt int) time.Duration {
 	backoff := rc.config.InitialBackoff
-	for i := 1; i < attempt; i++ {
+	for range attempt - 1 {
 		backoff = time.Duration(float64(backoff) * rc.config.BackoffMultiplier)
 		if backoff > rc.config.MaxBackoff {
 			backoff = rc.config.MaxBackoff

ws_test.go

@@ -9,6 +9,7 @@ import (
 	"net"
 	"net/http"
 	"net/http/httptest"
+	"slices"
 	"strings"
 	"sync"
 	"testing"
@@ -442,6 +443,52 @@ func TestClient_Subscriptions(t *testing.T) {
 	})
 }
 
+func TestClient_AllSubscriptions(t *testing.T) {
+	t.Run("returns iterator over subscriptions", func(t *testing.T) {
+		client := &Client{subscriptions: make(map[string]bool)}
+		client.subscriptions["sub1"] = true
+		client.subscriptions["sub2"] = true
+
+		subs := slices.Collect(client.AllSubscriptions())
+		assert.Len(t, subs, 2)
+		assert.Contains(t, subs, "sub1")
+		assert.Contains(t, subs, "sub2")
+	})
+}
+
+func TestHub_AllClients(t *testing.T) {
+	t.Run("returns iterator over all clients", func(t *testing.T) {
+		hub := NewHub()
+		client1 := &Client{subscriptions: make(map[string]bool)}
+		client2 := &Client{subscriptions: make(map[string]bool)}
+
+		hub.mu.Lock()
+		hub.clients[client1] = true
+		hub.clients[client2] = true
+		hub.mu.Unlock()
+
+		clients := slices.Collect(hub.AllClients())
+		assert.Len(t, clients, 2)
+		assert.Contains(t, clients, client1)
+		assert.Contains(t, clients, client2)
+	})
+}
+
+func TestHub_AllChannels(t *testing.T) {
+	t.Run("returns iterator over all active channels", func(t *testing.T) {
+		hub := NewHub()
+		hub.mu.Lock()
+		hub.channels["ch1"] = make(map[*Client]bool)
+		hub.channels["ch2"] = make(map[*Client]bool)
+		hub.mu.Unlock()
+
+		channels := slices.Collect(hub.AllChannels())
+		assert.Len(t, channels, 2)
+		assert.Contains(t, channels, "ch1")
+		assert.Contains(t, channels, "ch2")
+	})
+}
+
 func TestMessage_JSON(t *testing.T) {
 	t.Run("marshals correctly", func(t *testing.T) {
 		msg := Message{
@@ -1390,7 +1437,7 @@ func BenchmarkBroadcast(b *testing.B) {
 	msg := Message{Type: TypeEvent, Data: "benchmark"}
 
 	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for range b.N {
 		_ = hub.Broadcast(msg)
 	}
 }
@@ -1416,7 +1463,7 @@ func BenchmarkSendToChannel(b *testing.B) {
 	msg := Message{Type: TypeEvent, Data: "benchmark"}
 
 	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for range b.N {
 		_ = hub.SendToChannel("bench-channel", msg)
 	}
 }