TUN-3467: Serialize cf-cloudflared-response-meta during package initialization using jsoniter

connection/header.go

@@ -0,0 +1,33 @@
+package connection
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/cloudflare/cloudflared/h2mux"
+)
+
+const (
+	responseMetaHeaderField   = "cf-cloudflared-response-meta"
+	responseSourceCloudflared = "cloudflared"
+	responseSourceOrigin      = "origin"
+)
+
+var (
+	canonicalResponseUserHeadersField = http.CanonicalHeaderKey(h2mux.ResponseUserHeadersField)
+	canonicalResponseMetaHeaderField  = http.CanonicalHeaderKey(responseMetaHeaderField)
+	responseMetaHeaderCfd             = mustInitRespMetaHeader(responseSourceCloudflared)
+	responseMetaHeaderOrigin          = mustInitRespMetaHeader(responseSourceOrigin)
+)
+
+type responseMetaHeader struct {
+	Source string `json:"src"`
+}
+
+func mustInitRespMetaHeader(src string) string {
+	header, err := json.Marshal(responseMetaHeader{Source: src})
+	if err != nil {
+		panic(fmt.Sprintf("Failed to serialize response meta header = %s, err: %v", responseSourceCloudflared, err))
+	}
+	return string(header)
+}