Add host to subject

main.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
+	"net"
 	"net/http"
 	"os"
 	"strings"
@@ -90,10 +91,28 @@ func main() {
 
 		// Create the NATS subject.
 		// Remove the leading slash from the path and replace remaining slashes with dots.
-		// The subject is prefixed with "http.<method>.", where <method> is lower-case.
+		// The subject is prefixed with "http.<host>.<method>.", where <method> is lower-case.
+
+		// Extract host and reverse domain components
+		host := r.Host
+		// Remove port if present
+		if h, _, err := net.SplitHostPort(host); err == nil {
+			host = h
+		}
+		// Use "-" instead of "." in the domain to make it a single token.
+		domainParts := strings.ReplaceAll(host, ".", "-")
+
+		// Process path component
 		path := strings.TrimPrefix(r.URL.Path, "/")
 		subjectPath := strings.ReplaceAll(path, "/", ".")
-		subject := fmt.Sprintf("http.%s.%s", strings.ToLower(r.Method), subjectPath)
+
+		// Build final subject
+		subjectBase := "http"
+		subjectParts := []string{subjectBase, domainParts, strings.ToLower(r.Method)}
+		if subjectPath != "" {
+			subjectParts = append(subjectParts, subjectPath)
+		}
+		subject := strings.Join(subjectParts, ".")
 
 		log.Println("Forwarding HTTP", r.Method, "request on", r.URL.Path, "to NATS subject:", subject)
 
@@ -115,6 +134,7 @@ func main() {
 		msg.Header.Set("X-HTTP-Method", r.Method)
 		msg.Header.Set("X-HTTP-Path", r.URL.Path)
 		msg.Header.Set("X-HTTP-Query", r.URL.RawQuery)
+		msg.Header.Set("X-HTTP-Host", r.Host)
 		msg.Header.Set("X-Remote-Addr", r.RemoteAddr)
 
 		// Send the NATS request and wait synchronously for a reply (timeout: 30 seconds)