feat(dart_frog_gen): detect custom init method (#564)

Co-authored-by: Renan <6718144+renancaraujo@users.noreply.github.com>

Author: Jochum van der Ploeg

packages/dart_frog_gen/lib/src/build_route_configuration.dart

@@ -45,6 +45,16 @@ RouteConfiguration buildRouteConfiguration(Directory directory) {
   );
   final publicDirectory = Directory(path.join(directory.path, 'public'));
   final mainDartFile = File(path.join(directory.path, 'main.dart'));
+
+  final customInitRegex = RegExp(
+    r'^Future(?:Or)?<void>\s*init\(InternetAddress .*?,\s*int .*?\)\s*(?:async)?\s*{',
+    multiLine: true,
+  );
+
+  final mainDartFileExists = mainDartFile.existsSync();
+  final hasCustomInit = mainDartFileExists &&
+      customInitRegex.hasMatch(mainDartFile.readAsStringSync());
+
   return RouteConfiguration(
     globalMiddleware: globalMiddleware,
     middleware: middleware,
@@ -53,7 +63,8 @@ RouteConfiguration buildRouteConfiguration(Directory directory) {
     rogueRoutes: rogueRoutes,
     endpoints: endpoints,
     serveStaticFiles: publicDirectory.existsSync(),
-    invokeCustomEntrypoint: mainDartFile.existsSync(),
+    invokeCustomEntrypoint: mainDartFileExists,
+    invokeCustomInit: hasCustomInit,
   );
 }
 
@@ -252,11 +263,15 @@ class RouteConfiguration {
     this.globalMiddleware,
     this.serveStaticFiles = false,
     this.invokeCustomEntrypoint = false,
+    this.invokeCustomInit = false,
   });
 
   /// Whether to invoke a custom entrypoint script (`main.dart`).
   final bool invokeCustomEntrypoint;
 
+  /// Whether to invoke a custom init method (`init` in `main.dart`).
+  final bool invokeCustomInit;
+
   /// Whether to serve static files. Defaults to false.
   final bool serveStaticFiles;
 

packages/dart_frog_gen/test/src/build_route_configuration_test.dart

@@ -50,6 +50,74 @@ void main() {
       expect(configuration.invokeCustomEntrypoint, isFalse);
     });
 
+    test('invokeCustomInit is true when init exists in main.dart', () {
+      final tempDirectory = createTempDir(
+        directories: ['routes'],
+        files: ['main.dart'],
+      );
+
+      File(path.join(tempDirectory.path, 'main.dart')).writeAsStringSync('''
+Future<void> init(InternetAddress ip, int port) async {}
+''');
+
+      final configuration = buildRouteConfiguration(tempDirectory);
+      expect(configuration.invokeCustomEntrypoint, isTrue);
+    });
+
+    test('invokeCustomInit is true when init with FutureOr exists in main.dart',
+        () {
+      final tempDirectory = createTempDir(
+        directories: ['routes'],
+        files: ['main.dart'],
+      );
+
+      File(path.join(tempDirectory.path, 'main.dart')).writeAsStringSync('''
+FutureOr<void> init(InternetAddress ip, int port) async {}
+''');
+
+      final configuration = buildRouteConfiguration(tempDirectory);
+      expect(configuration.invokeCustomEntrypoint, isTrue);
+    });
+
+    test(
+        '''invokeCustomInit is true when init with different parameter names exists in main.dart''',
+        () {
+      final tempDirectory = createTempDir(
+        directories: ['routes'],
+        files: ['main.dart'],
+      );
+
+      File(path.join(tempDirectory.path, 'main.dart')).writeAsStringSync('''
+Future<void> init(InternetAddress hello, int world) async {}
+''');
+
+      final configuration = buildRouteConfiguration(tempDirectory);
+      expect(configuration.invokeCustomEntrypoint, isTrue);
+    });
+
+    test(
+        '''invokeCustomInit is true when init with bad spacing exists in main.dart''',
+        () {
+      final tempDirectory = createTempDir(
+        directories: ['routes'],
+        files: ['main.dart'],
+      );
+
+      File(path.join(tempDirectory.path, 'main.dart')).writeAsStringSync('''
+Future<void>init(InternetAddress ip,int port)async{}
+''');
+
+      final configuration = buildRouteConfiguration(tempDirectory);
+      expect(configuration.invokeCustomEntrypoint, isTrue);
+    });
+
+    test('invokeCustomEntrypoint is false when main.dart does not exist', () {
+      final configuration = buildRouteConfiguration(
+        createTempDir(directories: ['routes']),
+      );
+      expect(configuration.invokeCustomInit, isFalse);
+    });
+
     test('includes global middleware when it exists', () {
       final configuration = buildRouteConfiguration(
         createTempDir(files: ['routes/_middleware.dart']),