Response.ContentEncoding(): store as field and avoid using Header.SetCanonical() (#1311)

* Response.ContentEncoding(): store as field

The CE is not so often used for plain APIs responses and even not so often used for static files and on the fly compression.
But still it should be checked each time.
Also having a dedicated field getter and setter simplifies code

* header.go Use shorter Response.setNonSpecial() and Request.setNonSpecial() methods instead of SetCanonical()

The change should improve performance because the setSpecialHeader() call is omitted.
As a downside on adding a new basic header field all putHeader() must be replaced with a direct getter and setter.

1 files changed, 57 insertions, 9 deletions

diff --git a/header_test.go b/header_test.go
index c958dbd..ac8b5eb 100644
--- a/header_test.go
+++ b/header_test.go
@@ -33,6 +33,26 @@ func TestResponseHeaderAddContentType(t *testing.T) {
 	}
 }
 
+func TestResponseHeaderAddContentEncoding(t *testing.T) {
+	t.Parallel()
+
+	var h ResponseHeader
+	h.Add("Content-Encoding", "test")
+
+	got := string(h.Peek("Content-Encoding"))
+	expected := "test"
+	if got != expected {
+		t.Errorf("expected %q got %q", expected, got)
+	}
+
+	var buf bytes.Buffer
+	h.WriteTo(&buf) //nolint:errcheck
+
+	if n := strings.Count(buf.String(), "Content-Encoding: "); n != 1 {
+		t.Errorf("Content-Encoding occurred %d times", n)
+	}
+}
+
 func TestResponseHeaderMultiLineValue(t *testing.T) {
 	t.Parallel()
 
@@ -600,6 +620,7 @@ func TestResponseHeaderDel(t *testing.T) {
 	h.Set("aaa", "bbb")
 	h.Set(HeaderConnection, "keep-alive")
 	h.Set(HeaderContentType, "aaa")
+	h.Set(HeaderContentEncoding, "gzip")
 	h.Set(HeaderServer, "aaabbb")
 	h.Set(HeaderContentLength, "1123")
 	h.Set(HeaderTrailer, "foo, bar")
@@ -633,6 +654,10 @@ func TestResponseHeaderDel(t *testing.T) {
 	if string(hv) != string(defaultContentType) {
 		t.Fatalf("unexpected content-type: %q. Expecting %q", hv, defaultContentType)
 	}
+	hv = h.Peek(HeaderContentEncoding)
+	if string(hv) != ("gzip") {
+		t.Fatalf("unexpected content-encoding: %q. Expecting %q", hv, "gzip")
+	}
 	hv = h.Peek(HeaderServer)
 	if len(hv) > 0 {
 		t.Fatalf("non-zero value: %q", hv)
@@ -1274,6 +1299,7 @@ func TestResponseHeaderCopyTo(t *testing.T) {
 
 	h.Set(HeaderSetCookie, "foo=bar")
 	h.Set(HeaderContentType, "foobar")
+	h.Set(HeaderContentEncoding, "gzip")
 	h.Set("AAA-BBB", "aaaa")
 	h.Set(HeaderTrailer, "foo, bar")
 
@@ -1285,6 +1311,9 @@ func TestResponseHeaderCopyTo(t *testing.T) {
 	if !bytes.Equal(h1.Peek(HeaderContentType), h.Peek(HeaderContentType)) {
 		t.Fatalf("unexpected content-type %q. Expected %q", h1.Peek("content-type"), h.Peek("content-type"))
 	}
+	if !bytes.Equal(h1.Peek(HeaderContentEncoding), h.Peek(HeaderContentEncoding)) {
+		t.Fatalf("unexpected content-encoding %q. Expected %q", h1.Peek("content-encoding"), h.Peek("content-encoding"))
+	}
 	if !bytes.Equal(h1.Peek("aaa-bbb"), h.Peek("AAA-BBB")) {
 		t.Fatalf("unexpected aaa-bbb %q. Expected %q", h1.Peek("aaa-bbb"), h.Peek("aaa-bbb"))
 	}
@@ -1308,6 +1337,7 @@ func TestRequestHeaderCopyTo(t *testing.T) {
 
 	h.Set(HeaderCookie, "aa=bb; cc=dd")
 	h.Set(HeaderContentType, "foobar")
+	h.Set(HeaderContentEncoding, "gzip")
 	h.Set(HeaderHost, "aaaa")
 	h.Set("aaaxxx", "123")
 	h.Set(HeaderTrailer, "foo, bar")
@@ -1320,6 +1350,9 @@ func TestRequestHeaderCopyTo(t *testing.T) {
 	if !bytes.Equal(h1.Peek("content-type"), h.Peek(HeaderContentType)) {
 		t.Fatalf("unexpected content-type %q. Expected %q", h1.Peek("content-type"), h.Peek("content-type"))
 	}
+	if !bytes.Equal(h1.Peek("content-encoding"), h.Peek(HeaderContentEncoding)) {
+		t.Fatalf("unexpected content-encoding %q. Expected %q", h1.Peek("content-encoding"), h.Peek("content-encoding"))
+	}
 	if !bytes.Equal(h1.Peek("host"), h.Peek("host")) {
 		t.Fatalf("unexpected host %q. Expected %q", h1.Peek("host"), h.Peek("host"))
 	}
@@ -1513,17 +1546,18 @@ func TestResponseHeaderVisitAll(t *testing.T) {
 
 	var h ResponseHeader
 
-	r := bytes.NewBufferString("HTTP/1.1 200 OK\r\nContent-Type: aa\r\nContent-Length: 123\r\nSet-Cookie: aa=bb; path=/foo/bar\r\nSet-Cookie: ccc\r\nTrailer: Foo, Bar\r\n\r\n")
+	r := bytes.NewBufferString("HTTP/1.1 200 OK\r\nContent-Type: text/plain\r\nContent-Encoding: gzip\r\nContent-Length: 123\r\nSet-Cookie: aa=bb; path=/foo/bar\r\nSet-Cookie: ccc\r\nTrailer: Foo, Bar\r\n\r\n")
 	br := bufio.NewReader(r)
 	if err := h.Read(br); err != nil {
 		t.Fatalf("Unexpected error: %v", err)
 	}
 
-	if h.Len() != 5 {
-		t.Fatalf("Unexpected number of headers: %d. Expected 5", h.Len())
+	if h.Len() != 6 {
+		t.Fatalf("Unexpected number of headers: %d. Expected 6", h.Len())
 	}
 	contentLengthCount := 0
 	contentTypeCount := 0
+	contentEncodingCount := 0
 	cookieCount := 0
 	h.VisitAll(func(key, value []byte) {
 		k := string(key)
@@ -1539,6 +1573,11 @@ func TestResponseHeaderVisitAll(t *testing.T) {
 				t.Fatalf("Unexpected content-type: %q. Expected %q", v, h.Peek(k))
 			}
 			contentTypeCount++
+		case HeaderContentEncoding:
+			if v != string(h.Peek(k)) {
+				t.Fatalf("Unexpected content-encoding: %q. Expected %q", v, h.Peek(k))
+			}
+			contentEncodingCount++
 		case HeaderSetCookie:
 			if cookieCount == 0 && v != "aa=bb; path=/foo/bar" {
 				t.Fatalf("unexpected cookie header: %q. Expected %q", v, "aa=bb; path=/foo/bar")
@@ -1561,6 +1600,9 @@ func TestResponseHeaderVisitAll(t *testing.T) {
 	if contentTypeCount != 1 {
 		t.Fatalf("unexpected number of content-type headers: %d. Expected 1", contentTypeCount)
 	}
+	if contentEncodingCount != 1 {
+		t.Fatalf("unexpected number of content-encoding headers: %d. Expected 1", contentEncodingCount)
+	}
 	if cookieCount != 2 {
 		t.Fatalf("unexpected number of cookie header: %d. Expected 2", cookieCount)
 	}
@@ -2081,6 +2123,7 @@ func TestResponseHeaderSetGet(t *testing.T) {
 	h := &ResponseHeader{}
 	h.Set("foo", "bar")
 	h.Set("content-type", "aaa/bbb")
+	h.Set("content-encoding", "gzip")
 	h.Set("connection", "close")
 	h.Set("content-length", "1234")
 	h.Set(HeaderServer, "aaaa")
@@ -2089,6 +2132,7 @@ func TestResponseHeaderSetGet(t *testing.T) {
 
 	expectResponseHeaderGet(t, h, "Foo", "bar")
 	expectResponseHeaderGet(t, h, HeaderContentType, "aaa/bbb")
+	expectResponseHeaderGet(t, h, HeaderContentEncoding, "gzip")
 	expectResponseHeaderGet(t, h, HeaderConnection, "close")
 	expectResponseHeaderGet(t, h, HeaderContentLength, "1234")
 	expectResponseHeaderGet(t, h, "seRVer", "aaaa")
@@ -2127,6 +2171,7 @@ func TestResponseHeaderSetGet(t *testing.T) {
 
 	expectResponseHeaderGet(t, &h1, "Foo", "bar")
 	expectResponseHeaderGet(t, &h1, HeaderContentType, "aaa/bbb")
+	expectResponseHeaderGet(t, &h1, HeaderContentEncoding, "gzip")
 	expectResponseHeaderGet(t, &h1, HeaderConnection, "close")
 	expectResponseHeaderGet(t, &h1, "seRVer", "aaaa")
 	expectResponseHeaderGet(t, &h1, "baz", "xxxxx")
@@ -2244,14 +2289,14 @@ func TestResponseHeaderBufioPeek(t *testing.T) {
 	t.Parallel()
 
 	r := &bufioPeekReader{
-		s: "HTTP/1.1 200 OK\r\nContent-Length: 10\r\nContent-Type: aaa\r\n" + getHeaders(10) + "\r\n0123456789",
+		s: "HTTP/1.1 200 OK\r\nContent-Length: 10\r\nContent-Type: text/plain\r\nContent-Encoding: gzip\r\n" + getHeaders(10) + "\r\n0123456789",
 	}
 	br := bufio.NewReaderSize(r, 4096)
 	h := &ResponseHeader{}
 	if err := h.Read(br); err != nil {
 		t.Fatalf("Unexpected error when reading response: %v", err)
 	}
-	verifyResponseHeader(t, h, 200, 10, "aaa")
+	verifyResponseHeader(t, h, 200, 10, "text/plain", "gzip")
 }
 
 func getHeaders(n int) string {
@@ -2720,7 +2765,7 @@ func testResponseHeaderReadSuccess(t *testing.T, h *ResponseHeader, headers stri
 	if err != nil {
 		t.Fatalf("Unexpected error when parsing response headers: %v. headers=%q", err, headers)
 	}
-	verifyResponseHeader(t, h, expectedStatusCode, expectedContentLength, expectedContentType)
+	verifyResponseHeader(t, h, expectedStatusCode, expectedContentLength, expectedContentType, "")
 }
 
 func testRequestHeaderReadSuccess(t *testing.T, h *RequestHeader, headers string, expectedContentLength int,
@@ -2734,15 +2779,18 @@ func testRequestHeaderReadSuccess(t *testing.T, h *RequestHeader, headers string
 	verifyRequestHeader(t, h, expectedContentLength, expectedRequestURI, expectedHost, expectedReferer, expectedContentType)
 }
 
-func verifyResponseHeader(t *testing.T, h *ResponseHeader, expectedStatusCode, expectedContentLength int, expectedContentType string) {
+func verifyResponseHeader(t *testing.T, h *ResponseHeader, expectedStatusCode, expectedContentLength int, expectedContentType, expectedContentEncoding string) {
 	if h.StatusCode() != expectedStatusCode {
 		t.Fatalf("Unexpected status code %d. Expected %d", h.StatusCode(), expectedStatusCode)
 	}
 	if h.ContentLength() != expectedContentLength {
 		t.Fatalf("Unexpected content length %d. Expected %d", h.ContentLength(), expectedContentLength)
 	}
-	if string(h.Peek(HeaderContentType)) != expectedContentType {
-		t.Fatalf("Unexpected content type %q. Expected %q", h.Peek(HeaderContentType), expectedContentType)
+	if string(h.ContentType()) != expectedContentType {
+		t.Fatalf("Unexpected content type %q. Expected %q", h.ContentType(), expectedContentType)
+	}
+	if string(h.ContentEncoding()) != expectedContentEncoding {
+		t.Fatalf("Unexpected content encoding %q. Expected %q", h.ContentEncoding(), expectedContentEncoding)
 	}
 }