feat: rpc auth in path

README.md

@@ -109,6 +109,10 @@ Each JSON configuration file for the gateways can specify detailed settings for
 ## Authentication
 Authentication can be enabled using the `--auth` flag. The auth token should be set through environment variables `GATEWAY_PASSWORD`.
 
+Auth token needs to be the last entry in the RPC gateway URL. Example:
+
+`https://sample/rpc-gateway/sepolia/a1b2c3d4e5f7`
+
 ### Running the Application
 To run the application with authentication:
 

internal/auth/auth.go

@@ -2,17 +2,20 @@ package auth
 
 import (
 	"net/http"
+	"strings"
 )
 
 func URLTokenAuth(token string) func(next http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			authToken := r.URL.Query().Get("auth_token")
-			if authToken == "" || authToken != token {
+			pathParts := strings.Split(r.URL.Path, "/")
+			if len(pathParts) < 2 || pathParts[len(pathParts)-1] != token {
 				w.WriteHeader(http.StatusUnauthorized)
 
 				return
 			}
+			// Remove the token part from the path to forward the request to the next handler
+			r.URL.Path = strings.Join(pathParts[:len(pathParts)-1], "/")
 			next.ServeHTTP(w, r)
 		})
 	}

internal/auth/auth_test.go

@@ -6,7 +6,7 @@ import (
 	"testing"
 )
 
-func TestUrlTokenAuth(t *testing.T) {
+func TestURLTokenAuth(t *testing.T) {
 	validToken := "valid_token"
 	middleware := URLTokenAuth(validToken)
 
@@ -17,17 +17,22 @@ func TestUrlTokenAuth(t *testing.T) {
 	}{
 		{
 			name:           "Valid token",
-			url:            "/?auth_token=valid_token",
+			url:            "/some/path/valid_token",
+			expectedStatus: http.StatusOK,
+		},
+		{
+			name:           "Valid token",
+			url:            "/some/really/long/path/valid_token",
 			expectedStatus: http.StatusOK,
 		},
 		{
 			name:           "Invalid token",
-			url:            "/?auth_token=invalid_token",
+			url:            "/some/path/invalid_token",
 			expectedStatus: http.StatusUnauthorized,
 		},
 		{
 			name:           "Missing token",
-			url:            "/",
+			url:            "/some/path/",
 			expectedStatus: http.StatusUnauthorized,
 		},
 	}