Add regex for path matching

Author: fabian4

internal/controller/nginx/config/servers.go

@@ -414,7 +414,7 @@ func initializeExternalLocations(
 		}
 		if !exactPathExists {
 			externalLocExact := http.Location{
-				Path: exactPath(externalLocPath),
+				Path: exactPath(rule.Path),
 				Type: locType,
 			}
 			extLocations = append(extLocations, externalLocExact)
@@ -977,19 +977,31 @@ func exactPath(path string) string {
 	return fmt.Sprintf("= %s", path)
 }
 
+func prefixPath(path string) string {
+	return fmt.Sprintf("^~ %s", path)
+}
+
+func regularExpressionPath(path string) string {
+	return fmt.Sprintf("~ %s", path)
+}
+
 // createPath builds the location path depending on the path type.
 func createPath(rule dataplane.PathRule) string {
 	switch rule.PathType {
 	case dataplane.PathTypeExact:
 		return exactPath(rule.Path)
+	case dataplane.PathTypePrefix:
+		return prefixPath(rule.Path)
+	case dataplane.PathTypeRegularExpression:
+		return regularExpressionPath(rule.Path)
 	default:
-		return rule.Path
+		return "" // should never happen because path type is validated earlier
 	}
 }
 
 func createDefaultRootLocation() http.Location {
 	return http.Location{
-		Path:   "/",
+		Path:   "= /",
 		Return: &http.Return{Code: http.StatusNotFound},
 	}
 }