From 68815fd4175a10b43e1debcf56118a7c4bf86069 Mon Sep 17 00:00:00 2001
From: roc <roc@imroc.cc>
Date: Mon, 31 Jul 2023 17:03:23 +0800
Subject: [PATCH] Refactor: share excluded headers between http2 and http3

---
 internal/header/header.go        | 28 ++++++++++++++++++++++++++++
 internal/http2/transport.go      | 21 +--------------------
 internal/http3/request_writer.go | 21 +--------------------
 3 files changed, 30 insertions(+), 40 deletions(-)

diff --git a/internal/header/header.go b/internal/header/header.go
index 33e779bc..4098febe 100644
--- a/internal/header/header.go
+++ b/internal/header/header.go
@@ -1,5 +1,7 @@
 package header
 
+import "strings"
+
 const (
 	DefaultUserAgent     = "req/v3 (https://github.com/imroc/req)"
 	UserAgent            = "User-Agent"
@@ -14,3 +16,29 @@ const (
 	HeaderOderKey        = "__header_order__"
 	PseudoHeaderOderKey  = "__pseudo_header_order__"
 )
+
+var reqWriteExcludeHeader = map[string]bool{
+	// Host is :authority, already sent.
+	// Content-Length is automatic.
+	"host":           true,
+	"content-length": true,
+	// Per 8.1.2.2 Connection-Specific Header
+	// Fields, don't send connection-specific
+	// fields. We have already checked if any
+	// are error-worthy so just ignore the rest.
+	"connection":        true,
+	"proxy-connection":  true,
+	"transfer-encoding": true,
+	"upgrade":           true,
+	"keep-alive":        true,
+	// Ignore header order keys which is only used internally.
+	HeaderOderKey:       true,
+	PseudoHeaderOderKey: true,
+}
+
+func IsExcluded(key string) bool {
+	if reqWriteExcludeHeader[strings.ToLower(key)] {
+		return true
+	}
+	return false
+}
diff --git a/internal/http2/transport.go b/internal/http2/transport.go
index 1208cbeb..75b100e3 100644
--- a/internal/http2/transport.go
+++ b/internal/http2/transport.go
@@ -1748,25 +1748,6 @@ func (cs *clientStream) awaitFlowControl(maxBytes int) (taken int32, err error)
 	}
 }
 
-var reqWriteExcludeHeader = map[string]bool{
-	// Host is :authority, already sent.
-	// Content-Length is automatic.
-	"host":           true,
-	"content-length": true,
-	// Per 8.1.2.2 Connection-Specific Header
-	// Fields, don't send connection-specific
-	// fields. We have already checked if any
-	// are error-worthy so just ignore the rest.
-	"connection":        true,
-	"proxy-connection":  true,
-	"transfer-encoding": true,
-	"upgrade":           true,
-	"keep-alive":        true,
-	// Ignore header order keys which is only used internally.
-	header.HeaderOderKey:       true,
-	header.PseudoHeaderOderKey: true,
-}
-
 var errNilRequestURL = errors.New("http2: Request.URI is nil")
 
 // requires cc.wmu be held.
@@ -1884,7 +1865,7 @@ func (cc *ClientConn) encodeHeaders(req *http.Request, addGzipHeader bool, trail
 
 		var didUA bool
 		for k, vv := range req.Header {
-			if reqWriteExcludeHeader[strings.ToLower(k)] {
+			if header.IsExcluded(k) {
 				continue
 			} else if ascii.EqualFold(k, "user-agent") {
 				// Match Go's http1 behavior: at most one
diff --git a/internal/http3/request_writer.go b/internal/http3/request_writer.go
index 1f6ce445..443b34c2 100644
--- a/internal/http3/request_writer.go
+++ b/internal/http3/request_writer.go
@@ -71,25 +71,6 @@ func (w *requestWriter) writeHeaders(wr io.Writer, req *http.Request, gzip bool,
 	return err
 }
 
-var reqWriteExcludeHeader = map[string]bool{
-	// Host is :authority, already sent.
-	// Content-Length is automatic.
-	"host":           true,
-	"content-length": true,
-	// Per 8.1.2.2 Connection-Specific Header
-	// Fields, don't send connection-specific
-	// fields. We have already checked if any
-	// are error-worthy so just ignore the rest.
-	"connection":        true,
-	"proxy-connection":  true,
-	"transfer-encoding": true,
-	"upgrade":           true,
-	"keep-alive":        true,
-	// Ignore header order keys which is only used internally.
-	header.HeaderOderKey:       true,
-	header.PseudoHeaderOderKey: true,
-}
-
 // copied from net/transport.go
 // Modified to support Extended CONNECT:
 // Contrary to what the godoc for the http.Request says,
@@ -207,7 +188,7 @@ func (w *requestWriter) encodeHeaders(req *http.Request, addGzipHeader bool, tra
 
 		var didUA bool
 		for k, vv := range req.Header {
-			if reqWriteExcludeHeader[strings.ToLower(k)] {
+			if header.IsExcluded(k) {
 				continue
 			} else if strings.EqualFold(k, "user-agent") {
 				// Match Go's http1 behavior: at most one