feat: implement responsibility chain pattern with middlewares

Author: LeadcodeDev

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## 1.3.0
+- Migrate filters to responsibility chain pattern
+
 ## 1.2.0
 - Implement `debounce` delay
 - Ignore `.dart_tool` and IDE directories by default

README.md

@@ -89,8 +89,13 @@ void main() {
     ));
 
   final watcher = Watcher(
-    includes: [Glob("**.dart")],
     onStart: () => print('Watching for changes...'),
+    middlewares: [
+      IgnoreMiddleware(['~', '.dart_tool', '.git', '.idea', '.vscode']),
+      ExcludeMiddleware(config?.excludes ?? []),
+      DebounceMiddleware(5, dateTime),
+      IncludeMiddleware([Glob("**.dart")]),
+    ],
     onFileChange: (int eventType, File file) async {
       final action = switch (eventType) {
         FileSystemEvent.create => 'created',

bin/hmr.dart

@@ -2,6 +2,10 @@ import 'dart:io';
 
 import 'package:glob/glob.dart';
 import 'package:hmr/hmr.dart';
+import 'package:hmr/src/middlewares/debounce.dart';
+import 'package:hmr/src/middlewares/exclude.dart';
+import 'package:hmr/src/middlewares/ignore.dart';
+import 'package:hmr/src/middlewares/include.dart';
 import 'package:mansion/mansion.dart';
 import 'package:path/path.dart' as path;
 
@@ -41,10 +45,14 @@ void main(List<String> arguments) async {
 
   (File, int)? lastFileChanged;
 
+  final dateTime = DateTime.now();
   final watcher = Watcher(
-      includes: config?.includes ?? [Glob("**.dart")],
-      excludes: config?.excludes ?? [],
-      debounce: config?.debounce ?? 5,
+      middlewares: [
+        IgnoreMiddleware(['~', '.dart_tool', '.git', '.idea', '.vscode']),
+        ExcludeMiddleware(config?.excludes ?? []),
+        DebounceMiddleware(Duration(milliseconds: config?.debounce ?? 5), dateTime),
+        IncludeMiddleware(config?.includes ?? [Glob("**.dart")]),
+      ],
       onStart: () {
         final List<Sequence> sequences = [
           const CursorPosition.moveTo(0, 0),

lib/src/contracts/hmr.dart

@@ -1,8 +1,6 @@
 import 'dart:async';
 import 'dart:io';
 
-import 'package:glob/glob.dart';
-
 abstract interface class RunnerContract {
   /// The entrypoint file to run.
   File get entrypoint;
@@ -18,14 +16,8 @@ abstract interface class RunnerContract {
 }
 
 abstract interface class WatcherContract {
-  /// The list of files to exclude.
-  List<Glob> get includes;
-
-  /// The list of files to exclude.
-  List<Glob> get excludes;
-
-  /// The debounce time to wait before trigger the event.
-  int get debounce;
+  /// The list of executed middlewares before trigger the watcher emitter.
+  List<MiddlewareWatcher> get middlewares;
 
   /// Emitted when the watcher is started.
   FutureOr Function()? get onStart;
@@ -48,3 +40,10 @@ abstract interface class WatcherContract {
   /// Emitted when the watcher is started.
   void watch();
 }
+
+/// The next function to execute the next middleware.
+typedef NextFn = Function();
+abstract interface class MiddlewareWatcher {
+  /// Handle the [FileSystemEvent] and execute the next middleware.
+  void handle(FileSystemEvent event, NextFn next);
+}

lib/src/entities/watcher.dart

@@ -1,22 +1,13 @@
 import 'dart:async';
 import 'dart:io';
 
-import 'package:glob/glob.dart';
 import 'package:hmr/src/contracts/hmr.dart';
 
 final class Watcher implements WatcherContract {
   StreamSubscription<FileSystemEvent>? _subscription;
 
-  DateTime? _dateTime = DateTime.now();
-
-  @override
-  final List<Glob> includes;
-
   @override
-  final List<Glob> excludes;
-
-  @override
-  final int debounce;
+  late final List<MiddlewareWatcher> middlewares;
 
   @override
   final FutureOr Function()? onStart;
@@ -37,59 +28,46 @@ final class Watcher implements WatcherContract {
   final FutureOr Function(int type, File)? onFileChange;
 
   Watcher({
-    this.excludes = const [],
-    this.includes = const [],
-    this.debounce = 5,
+    List<MiddlewareWatcher>? middlewares,
     this.onStart,
     this.onFileChange,
     this.onFileCreate,
     this.onFileDelete,
     this.onFileMove,
     this.onFileModify,
-  });
+  }) : middlewares = middlewares ?? [];
 
   @override
   void watch() {
     onStart?.call();
 
     _subscription = Directory.current.watch(recursive: true).listen((event) {
-      if (_dateTime case DateTime value
-          when DateTime.now().difference(value) < Duration(milliseconds: debounce)) {
-        return;
-      }
-
-      final ignoredFiles = event.path.endsWith('~') ||
-          event.path.contains('.idea') ||
-          event.path.contains('.git') ||
-          event.path.contains('.dart_tool');
-
-      if (ignoredFiles) {
-        return;
-      }
-
-      final hasExclude = excludes.any((glob) => glob.matches(event.path));
-      if (hasExclude) {
-        return;
-      }
-
-      final hasMatch = includes.any((glob) => glob.matches(event.path));
-      if (hasMatch) {
-        switch (event.type) {
-          case FileSystemEvent.modify:
-            onFileModify?.call(File(event.path));
-          case FileSystemEvent.create:
-            onFileCreate?.call(File(event.path));
-          case FileSystemEvent.delete:
-            onFileDelete?.call(File(event.path));
-          case FileSystemEvent.move:
-            onFileMove?.call(File(event.path));
-          default:
-            () => throw 'Unknown event type: ${event.type}';
+      int currentMiddleware = 0;
+
+      void executeNext() {
+        if (currentMiddleware < middlewares.length) {
+          final middleware = middlewares[currentMiddleware];
+          currentMiddleware++;
+          middleware.handle(event, executeNext);
+        } else {
+          switch (event.type) {
+            case FileSystemEvent.modify:
+              onFileModify?.call(File(event.path));
+            case FileSystemEvent.create:
+              onFileCreate?.call(File(event.path));
+            case FileSystemEvent.delete:
+              onFileDelete?.call(File(event.path));
+            case FileSystemEvent.move:
+              onFileMove?.call(File(event.path));
+            default:
+              () => throw 'Unknown event type: ${event.type}';
+          }
+
+          onFileChange?.call(event.type, File(event.path));
         }
-
-        onFileChange?.call(event.type, File(event.path));
-        _dateTime = DateTime.now();
       }
+
+      executeNext();
     });
   }
 

lib/src/middlewares/debounce.dart

@@ -0,0 +1,18 @@
+import 'dart:io';
+
+import 'package:hmr/hmr.dart';
+
+final class DebounceMiddleware implements MiddlewareWatcher {
+  final Duration _debounce;
+  DateTime _dateTime;
+
+  DebounceMiddleware(this._debounce, this._dateTime);
+
+  @override
+  void handle(FileSystemEvent event, NextFn next) {
+    if (!(DateTime.now().difference(_dateTime) < _debounce)) {
+      next();
+      _dateTime = DateTime.now();
+    }
+  }
+}

lib/src/middlewares/exclude.dart

@@ -0,0 +1,18 @@
+import 'dart:io';
+
+import 'package:glob/glob.dart';
+import 'package:hmr/hmr.dart';
+
+final class ExcludeMiddleware implements MiddlewareWatcher {
+  final List<Glob> _globs;
+
+  ExcludeMiddleware(this._globs);
+
+  @override
+  void handle(FileSystemEvent event, NextFn next) {
+    final hasExclude = _globs.any((glob) => glob.matches(event.path));
+    if (!hasExclude) {
+      next();
+    }
+  }
+}

lib/src/middlewares/ignore.dart

@@ -0,0 +1,17 @@
+import 'dart:io';
+
+import 'package:hmr/hmr.dart';
+
+final class IgnoreMiddleware implements MiddlewareWatcher {
+  final List<String> _matches;
+
+  IgnoreMiddleware(this._matches);
+
+  @override
+  void handle(FileSystemEvent event, NextFn next) {
+    final ignoredFiles = _matches.any((match) => event.path.contains(match));
+    if (!ignoredFiles) {
+      next();
+    }
+  }
+}

lib/src/middlewares/include.dart

@@ -0,0 +1,18 @@
+import 'dart:io';
+
+import 'package:glob/glob.dart';
+import 'package:hmr/hmr.dart';
+
+final class IncludeMiddleware implements MiddlewareWatcher {
+  final List<Glob> _globs;
+
+  IncludeMiddleware(this._globs);
+
+  @override
+  void handle(FileSystemEvent event, NextFn next) {
+    final hasMatch = _globs.any((glob) => glob.matches(event.path));
+    if (hasMatch) {
+      next();
+    }
+  }
+}

pubspec.yaml

@@ -1,6 +1,6 @@
 name: hmr
 description: Hot Module Replacement system specially designed for command-line Dart applications.
-version: 1.2.0
+version: 1.3.0
 repository: https://github.com/LeadcodeDev/hmr
 executables:
   hmr: hmr