🩹 fix: Cache middleware hasDirective misses directives with trailing space/tab/=

middleware/cache/cache.go

@@ -905,7 +905,11 @@ func New(config ...Config) fiber.Handler {
 	}
 }
 
-// hasDirective checks if a cache-control header contains a directive (case-insensitive)
+// hasDirective checks if a cache-control header contains a directive (case-insensitive).
+// A directive is considered matched when it appears as a standalone token, meaning
+// it must be preceded by the start of string, a comma, or whitespace, and followed
+// by the end of string, a comma, whitespace, or '=' (for directives with arguments
+// like no-cache="field").
 func hasDirective(cc, directive string) bool {
 	ccLen := len(cc)
 	dirLen := len(directive)
@@ -919,7 +923,8 @@ func hasDirective(cc, directive string) bool {
 				continue
 			}
 		}
-		if i+dirLen == ccLen || cc[i+dirLen] == ',' {
+		end := i + dirLen
+		if end == ccLen || cc[end] == ',' || cc[end] == ' ' || cc[end] == '=' || cc[end] == '\t' {
 			return true
 		}
 	}

middleware/cache/cache_test.go

@@ -5091,3 +5091,56 @@ func Test_Cache_ConfigurationAndResponseHandling(t *testing.T) {
 		require.Equal(t, cacheMiss, rsp2.Header.Get("X-Cache"))
 	})
 }
+
+// go test -run Test_hasDirective
+func Test_hasDirective(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name      string
+		cc        string
+		directive string
+		expected  bool
+	}{
+		// Basic matching
+		{name: "exact match", cc: "no-cache", directive: "no-cache", expected: true},
+		{name: "not found", cc: "public", directive: "no-cache", expected: false},
+		{name: "empty header", cc: "", directive: "no-cache", expected: false},
+
+		// Comma-separated directives
+		{name: "first in list", cc: "no-cache, no-store", directive: "no-cache", expected: true},
+		{name: "last in list", cc: "public, no-cache", directive: "no-cache", expected: true},
+		{name: "middle in list", cc: "public, no-cache, no-store", directive: "no-cache", expected: true},
+		{name: "no spaces", cc: "public,no-cache,no-store", directive: "no-cache", expected: true},
+
+		// Trailing/leading whitespace
+		{name: "trailing space", cc: "no-cache ", directive: "no-cache", expected: true},
+		{name: "trailing tab", cc: "no-cache\t", directive: "no-cache", expected: true},
+		{name: "space before comma", cc: "no-cache , public", directive: "no-cache", expected: true},
+
+		// Directives with arguments (=)
+		{name: "directive with value", cc: "no-cache=\"Set-Cookie\"", directive: "no-cache", expected: true},
+		{name: "directive with value in list", cc: "public, no-cache=\"Set-Cookie\", no-store", directive: "no-cache", expected: true},
+
+		// Partial matches should not match
+		{name: "prefix match only", cc: "no-cache-extended", directive: "no-cache", expected: false},
+		{name: "suffix match only", cc: "xno-cache", directive: "no-cache", expected: false},
+
+		// Case insensitivity
+		{name: "uppercase", cc: "NO-CACHE", directive: "no-cache", expected: true},
+		{name: "mixed case", cc: "No-Cache", directive: "no-cache", expected: true},
+
+		// Private directive
+		{name: "private standalone", cc: "private", directive: "private", expected: true},
+		{name: "private with trailing space", cc: "private ", directive: "private", expected: true},
+		{name: "private in list with spaces", cc: "max-age=3600, private ", directive: "private", expected: true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			result := hasDirective(tt.cc, tt.directive)
+			require.Equal(t, tt.expected, result)
+		})
+	}
+}