go fix updates

Author: kevinmcconnell

internal/cacheable_response.go

@@ -5,6 +5,7 @@ import (
 	"encoding/gob"
 	"io"
 	"log/slog"
+	"maps"
 	"net/http"
 	"regexp"
 	"strconv"
@@ -149,9 +150,7 @@ func (c *CacheableResponse) wasNotModified(r *http.Request) bool {
 }
 
 func (c *CacheableResponse) copyHeaders(w http.ResponseWriter, wasHit bool, statusCode int) {
-	for k, v := range c.HttpHeader {
-		w.Header()[k] = v
-	}
+	maps.Copy(w.Header(), c.HttpHeader)
 
 	if wasHit {
 		w.Header().Set("X-Cache", "hit")

internal/compression_guard_handler.go

@@ -60,7 +60,7 @@ func hasUserSpecificResponseHeaders(h http.Header) bool {
 	}
 
 	cacheControl := strings.ToLower(h.Get("Cache-Control"))
-	for _, directive := range strings.Split(cacheControl, ",") {
+	for directive := range strings.SplitSeq(cacheControl, ",") {
 		dir := strings.TrimSpace(directive)
 		// Strip any value (e.g. private="Set-Cookie") before comparison.
 		dirName := strings.SplitN(dir, "=", 2)[0]
@@ -70,7 +70,7 @@ func hasUserSpecificResponseHeaders(h http.Header) bool {
 	}
 
 	vary := h.Get("Vary")
-	for _, token := range strings.Split(vary, ",") {
+	for token := range strings.SplitSeq(vary, ",") {
 		if strings.EqualFold(strings.TrimSpace(token), "cookie") {
 			return true
 		}

internal/memory_cache.go

@@ -101,7 +101,7 @@ func (c *MemoryCache) evictOldestItem() {
 	//
 	// If we find an expired item while looking, that's a better choice to evict,
 	// so we can choose it immediately.
-	for i := 0; i < 5; i++ {
+	for range 5 {
 		index := rand.Intn(len(c.keys))
 		key := c.keys[index]
 		v := c.items[key]

internal/memory_cache_test.go

@@ -76,7 +76,7 @@ func TestMemoryCache_items_are_evicted_to_make_space(t *testing.T) {
 	maxCacheSize := 10 * KB
 	c := NewMemoryCache(maxCacheSize, 1*KB)
 
-	for i := CacheKey(0); i < 20; i++ {
+	for i := range CacheKey(20) {
 		payload := bytes.Repeat([]byte{byte(i)}, 1*KB)
 		c.Set(i, payload, time.Now().Add(1*time.Hour))