Update endpoint -> subject encoding

Use an encoding that can be safely used bidirectionally while still being easy to read.
This is useful for being able to make HTTP requests from NATS, which I am working on now.

1 files changed, 31 insertions, 3 deletions

diff --git a/main.go b/main.go
index dad6584..cf0a6d9 100644
--- a/main.go
+++ b/main.go
@@ -10,6 +10,7 @@ import (
 	"os"
 	"strings"
 	"time"
+	"net/url"
 
 	"github.com/nats-io/nats.go"
 )
@@ -29,6 +30,28 @@ func printHelp() {
 	fmt.Println("    HTTP_PORT - HTTP port to listen on (default: 8080)")
 }
 
+
+// URL to NATS subject conversion
+func URLToNATS(urlPath string) (string, error) {
+    segments := strings.Split(strings.Trim(urlPath, "/"), "/")
+    for i, seg := range segments {
+        // Decode existing encoding first to prevent double-encoding
+        unescaped, err := url.PathUnescape(seg)
+        if err != nil {
+            return "", fmt.Errorf("failed to unescape segment: %w", err)
+        }
+        
+        // Encode special NATS-sensitive characters
+        encoded := url.PathEscape(unescaped)
+        encoded = strings.ReplaceAll(encoded, ".", "%2E")  // Critical for token separation
+        encoded = strings.ReplaceAll(encoded, "*", "%2A")  // Wildcard protection
+        encoded = strings.ReplaceAll(encoded, ">", "%3E")   // Wildcard protection
+        
+        segments[i] = encoded
+    }
+    return strings.Join(segments, "."), nil
+}
+
 func main() {
 	helpFlag := flag.Bool("help", false, "Display help information about available environment variables")
 	flag.Parse()
@@ -103,9 +126,14 @@ func main() {
 		domainParts := strings.ReplaceAll(host, ".", "_")
 
 		// Process path component
-		path := strings.TrimPrefix(r.URL.Path, "/")
-		// Replace all "." with "_" and then all "/" with ".".
-		subjectPath := strings.ReplaceAll(strings.ReplaceAll(path, ".", "_"), "/", ".")
+		path := strings.TrimSuffix(strings.TrimPrefix(r.URL.Path, "/"), "/")
+		subjectPath, err := URLToNATS(path)
+		if err != nil {
+			http.Error(w, "Error converting endpoint to NATS subject", http.StatusInternalServerError)
+			log.Println("Could not convert endpoint to NATS subject", err)
+			return
+			
+		}
 
 		// Build final subject
 		subjectBase := "http"