refactor and organize code

internal/net/gphttp/httpheaders/sse.go

@@ -0,0 +1,7 @@
+package httpheaders
+
+import "net/http"
+
+func IsSSE(h http.Header) bool {
+	return h.Get("Content-Type") == "text/event-stream"
+}

internal/net/gphttp/httpheaders/utils.go

@@ -0,0 +1,119 @@
+package httpheaders
+
+import (
+	"net/http"
+	"net/textproto"
+
+	"github.com/yusing/go-proxy/internal/utils/strutils"
+	"golang.org/x/net/http/httpguts"
+)
+
+const (
+	HeaderXForwardedMethod = "X-Forwarded-Method"
+	HeaderXForwardedFor    = "X-Forwarded-For"
+	HeaderXForwardedProto  = "X-Forwarded-Proto"
+	HeaderXForwardedHost   = "X-Forwarded-Host"
+	HeaderXForwardedPort   = "X-Forwarded-Port"
+	HeaderXForwardedURI    = "X-Forwarded-Uri"
+	HeaderXRealIP          = "X-Real-IP"
+
+	HeaderContentType   = "Content-Type"
+	HeaderContentLength = "Content-Length"
+
+	HeaderUpstreamName   = "X-Godoxy-Upstream-Name"
+	HeaderUpstreamScheme = "X-Godoxy-Upstream-Scheme"
+	HeaderUpstreamHost   = "X-Godoxy-Upstream-Host"
+	HeaderUpstreamPort   = "X-Godoxy-Upstream-Port"
+
+	HeaderGoDoxyCheckRedirect = "X-Godoxy-Check-Redirect"
+)
+
+// Hop-by-hop headers. These are removed when sent to the backend.
+// As of RFC 7230, hop-by-hop headers are required to appear in the
+// Connection header field. These are the headers defined by the
+// obsoleted RFC 2616 (section 13.5.1) and are used for backward
+// compatibility.
+var hopHeaders = []string{
+	"Connection",
+	"Proxy-Connection", // non-standard but still sent by libcurl and rejected by e.g. google
+	"Keep-Alive",
+	"Proxy-Authenticate",
+	"Proxy-Authorization",
+	"Te",      // canonicalized version of "TE"
+	"Trailer", // not Trailers per URL above; https://www.rfc-editor.org/errata_search.php?eid=4522
+	"Transfer-Encoding",
+	"Upgrade",
+}
+
+func UpgradeType(h http.Header) string {
+	if !httpguts.HeaderValuesContainsToken(h["Connection"], "Upgrade") {
+		return ""
+	}
+	return h.Get("Upgrade")
+}
+
+// RemoveHopByHopHeaders removes hop-by-hop headers.
+func RemoveHopByHopHeaders(h http.Header) {
+	// RFC 7230, section 6.1: Remove headers listed in the "Connection" header.
+	for _, f := range h["Connection"] {
+		for _, sf := range strutils.SplitComma(f) {
+			if sf = textproto.TrimString(sf); sf != "" {
+				h.Del(sf)
+			}
+		}
+	}
+	// RFC 2616, section 13.5.1: Remove a set of known hop-by-hop headers.
+	// This behavior is superseded by the RFC 7230 Connection header, but
+	// preserve it for backwards compatibility.
+	for _, f := range hopHeaders {
+		h.Del(f)
+	}
+}
+
+func RemoveHop(h http.Header) {
+	reqUpType := UpgradeType(h)
+	RemoveHopByHopHeaders(h)
+
+	if reqUpType != "" {
+		h.Set("Connection", "Upgrade")
+		h.Set("Upgrade", reqUpType)
+	} else {
+		h.Del("Connection")
+	}
+}
+
+func CopyHeader(dst, src http.Header) {
+	for k, vv := range src {
+		for _, v := range vv {
+			dst.Add(k, v)
+		}
+	}
+}
+
+func FilterHeaders(h http.Header, allowed []string) http.Header {
+	if len(allowed) == 0 {
+		return h
+	}
+
+	filtered := make(http.Header)
+
+	for i, header := range allowed {
+		values := h.Values(header)
+		if len(values) == 0 {
+			continue
+		}
+		filtered[http.CanonicalHeaderKey(allowed[i])] = append([]string(nil), values...)
+	}
+
+	return filtered
+}
+
+func HeaderToMap(h http.Header) map[string]string {
+	result := make(map[string]string)
+	for k, v := range h {
+		if len(v) > 0 {
+			result[k] = v[0] // Take the first value
+		}
+	}
+	return result
+}

internal/net/gphttp/httpheaders/websocket.go

@@ -0,0 +1,21 @@
+package httpheaders
+
+import (
+	"net/http"
+)
+
+const (
+	HeaderXGoDoxyWebsocketAllowedDomains = "X-GoDoxy-Websocket-Allowed-Domains"
+)
+
+func WebsocketAllowedDomains(h http.Header) []string {
+	return h[HeaderXGoDoxyWebsocketAllowedDomains]
+}
+
+func SetWebsocketAllowedDomains(h http.Header, domains []string) {
+	h[HeaderXGoDoxyWebsocketAllowedDomains] = domains
+}
+
+func IsWebsocket(h http.Header) bool {
+	return UpgradeType(h) == "websocket"
+}