Clean code (#34)

* 🚨 Fix linter rules

* ⚡️ Add missing type infer

* 🚀 Move around `download` and `downloadUri`

* ⚡️ Improve fields' definition with multiple classes

* ⚡️ Improve docs and comments

* ⚡️ Improve interceptor's internal classes

* 🎨 Reorg tests

* 🎨 ++

* 📝 Fix broken links

* 🎨 `Object` -> `dynamic` in `download()`

* 🥅 Improve type checks

dio/CHANGELOG.md

@@ -149,8 +149,8 @@ the subsequent interceptors processing logic more finely (whether to skip them o
 ### New features
 
 - Support Flutter Web.
-- Extract [CookieManager](/plugins/cookie_manager) into a separate package（No need for Flutter Web）.
-- Provides [HTTP/2.0 HttpClientAdapter](/plugins/http2_adapter).
+- Extract [CookieManager](../plugins/cookie_manager) into a separate package（No need for Flutter Web）.
+- Provides [HTTP/2.0 HttpClientAdapter](../plugins/http2_adapter).
 
 ### Change List
 

dio/analysis_options.yaml

@@ -4,9 +4,10 @@ analyzer:
   errors:
     deprecated_member_use_from_same_package: ignore
     todo: ignore
+
 linter:
   rules:
-    - prefer_final_fields: true
-    - prefer_final_locals: true
-    - prefer_final_in_for_each: true
-    - unnecessary_parenthesis: true
+    - prefer_final_fields
+    - prefer_final_locals
+    - prefer_final_in_for_each
+    - unnecessary_parenthesis

dio/lib/src/adapter.dart

@@ -63,13 +63,13 @@ class ResponseBody {
     this.redirects,
   });
 
-  /// The response stream
+  /// The response stream.
   Stream<Uint8List> stream;
 
-  /// the response headers
-  late Map<String, List<String>> headers;
+  /// The response headers.
+  Map<String, List<String>> headers;
 
-  /// Http status code
+  /// HTTP status code.
   int statusCode;
 
   /// Returns the reason phrase associated with the status code.

dio/lib/src/adapters/browser_adapter.dart

@@ -10,6 +10,7 @@ import '../options.dart';
 
 HttpClientAdapter createAdapter() => BrowserHttpClientAdapter();
 
+/// The default [HttpClientAdapter] for Web platforms.
 class BrowserHttpClientAdapter implements HttpClientAdapter {
   /// These are aborted if the client is closed.
   final _xhrs = <HttpRequest>{};
@@ -55,7 +56,7 @@ class BrowserHttpClientAdapter implements HttpClientAdapter {
     final completer = Completer<ResponseBody>();
 
     xhr.onLoad.first.then((_) {
-      Uint8List body = (xhr.response as ByteBuffer).asUint8List();
+      final Uint8List body = (xhr.response as ByteBuffer).asUint8List();
       completer.complete(
         ResponseBody.fromBytes(
           body,
@@ -117,10 +118,7 @@ class BrowserHttpClientAdapter implements HttpClientAdapter {
         if (duration > sendTimeout) {
           uploadStopwatch.stop();
           completer.completeError(
-            DioError.sendTimeout(
-              timeout: sendTimeout,
-              requestOptions: options,
-            ),
+            DioError.sendTimeout(timeout: sendTimeout, requestOptions: options),
             StackTrace.current,
           );
           xhr.abort();
@@ -186,10 +184,7 @@ class BrowserHttpClientAdapter implements HttpClientAdapter {
         connectTimeoutTimer?.cancel();
         try {
           xhr.abort();
-        } catch (e) {
-          // ignore
-        }
-
+        } catch (_) {}
         // xhr.onError will not triggered when xhr.abort() called.
         // so need to manual throw the cancel error to avoid Future hang ups.
         // or added xhr.onAbort like axios did https://github.com/axios/axios/blob/master/lib/adapters/xhr.js#L102-L111

dio/lib/src/adapters/io_adapter.dart

@@ -1,21 +1,25 @@
 import 'dart:async';
 import 'dart:io';
 import 'dart:typed_data';
+
 import '../adapter.dart';
-import '../options.dart';
 import '../dio_error.dart';
+import '../options.dart';
 import '../redirect_record.dart';
 
 @Deprecated('Use IOHttpClientAdapter instead. This will be removed in 6.0.0')
 typedef DefaultHttpClientAdapter = IOHttpClientAdapter;
 
 typedef OnHttpClientCreate = HttpClient? Function(HttpClient client);
 typedef ValidateCertificate = bool Function(
-    X509Certificate? certificate, String host, int port);
+  X509Certificate? certificate,
+  String host,
+  int port,
+);
 
 HttpClientAdapter createAdapter() => IOHttpClientAdapter();
 
-/// The default HttpClientAdapter for Dio.
+/// The default [HttpClientAdapter] for native platforms.
 class IOHttpClientAdapter implements HttpClientAdapter {
   /// [Dio] will create HttpClient when it is needed.
   /// If [onHttpClientCreate] is provided, [Dio] will call
@@ -41,8 +45,9 @@ class IOHttpClientAdapter implements HttpClientAdapter {
     Future<void>? cancelFuture,
   ) async {
     if (_closed) {
-      throw Exception(
-          "Can't establish connection after [HttpClientAdapter] closed!");
+      throw StateError(
+        "Can't establish connection after the adapter was closed!",
+      );
     }
     final httpClient = _configHttpClient(cancelFuture, options.connectTimeout);
     final reqFuture = httpClient.openUrl(options.method, options.uri);
@@ -64,7 +69,7 @@ class IOHttpClientAdapter implements HttpClientAdapter {
         request = await reqFuture;
       }
 
-      //Set Headers
+      // Set Headers
       options.headers.forEach((k, v) {
         if (v != null) request.headers.set(k, v);
       });
@@ -102,7 +107,6 @@ class IOHttpClientAdapter implements HttpClientAdapter {
           },
         );
       }
-
       await future;
     }
 
@@ -126,8 +130,11 @@ class IOHttpClientAdapter implements HttpClientAdapter {
     if (validateCertificate != null) {
       final host = options.uri.host;
       final port = options.uri.port;
-      final isCertApproved =
-          validateCertificate!(responseStream.certificate, host, port);
+      final bool isCertApproved = validateCertificate!(
+        responseStream.certificate,
+        host,
+        port,
+      );
       if (!isCertApproved) {
         throw DioError(
           requestOptions: options,
@@ -138,9 +145,8 @@ class IOHttpClientAdapter implements HttpClientAdapter {
       }
     }
 
-    final stream =
-        responseStream.transform<Uint8List>(StreamTransformer.fromHandlers(
-      handleData: (data, sink) {
+    final stream = responseStream.transform<Uint8List>(
+      StreamTransformer.fromHandlers(handleData: (data, sink) {
         stopwatch.stop();
         final duration = stopwatch.elapsed;
         final receiveTimeout = options.receiveTimeout;
@@ -155,8 +161,8 @@ class IOHttpClientAdapter implements HttpClientAdapter {
         } else {
           sink.add(Uint8List.fromList(data));
         }
-      },
-    ));
+      }),
+    );
 
     final headers = <String, List<String>>{};
     responseStream.headers.forEach((key, values) {

dio/lib/src/cancel_token.dart

@@ -1,45 +1,41 @@
 import 'dart:async';
+
 import 'dio_error.dart';
 import 'options.dart';
 
-/// You can cancel a request by using a cancel token.
+/// An instance which controls cancellation of [Dio]'s requests,
+/// build from [Completer].
+///
+/// You can cancel requests by using a [CancelToken].
 /// One token can be shared with different requests.
-/// when a token's [cancel] method invoked, all requests
-/// with this token will be cancelled.
+/// When [cancel] is invoked, all requests using this token will be cancelled.
 class CancelToken {
-  CancelToken() {
-    _completer = Completer<DioError>();
-  }
+  CancelToken();
 
-  /// Whether is throw by [cancel]
-  static bool isCancel(DioError e) {
-    return e.type == DioErrorType.cancel;
-  }
+  final Completer<DioError> _completer = Completer<DioError>();
 
-  /// If request have been canceled, save the cancel Error.
-  DioError? _cancelError;
+  /// Whether the [error] is thrown by [cancel].
+  static bool isCancel(DioError error) => error.type == DioErrorType.cancel;
 
-  /// If request have been canceled, save the cancel Error.
+  /// If request have been canceled, save the cancel error.
   DioError? get cancelError => _cancelError;
-
-  late Completer<DioError> _completer;
+  DioError? _cancelError;
 
   RequestOptions? requestOptions;
 
-  /// whether cancelled
+  /// Whether the token is cancelled.
   bool get isCancelled => _cancelError != null;
 
   /// When cancelled, this future will be resolved.
   Future<DioError> get whenCancel => _completer.future;
 
-  /// Cancel the request
+  /// Cancel the request with the given [reason].
   void cancel([Object? reason]) {
     _cancelError = DioError.requestCancelled(
-      requestOptions: requestOptions ?? RequestOptions(path: ''),
+      requestOptions: requestOptions ?? RequestOptions(),
       reason: reason,
       stackTrace: StackTrace.current,
     );
-
     if (!_completer.isCompleted) {
       _completer.complete(_cancelError);
     }