fix #175

pkgs/http/lib/src/multipart_file.dart

@@ -73,7 +73,7 @@ class MultipartFile {
   factory MultipartFile.fromString(String field, String value,
       {String? filename, MediaType? contentType}) {
     contentType ??= MediaType('text', 'plain');
-    var encoding = encodingForCharset(contentType.parameters['charset'], utf8);
+    var encoding = encodingForContentTypeHeader(contentType, utf8);
     contentType = contentType.change(parameters: {'charset': encoding.name});
 
     return MultipartFile.fromBytes(field, encoding.encode(value),

pkgs/http/lib/src/response.dart

@@ -21,10 +21,10 @@ class Response extends BaseResponse {
   ///
   /// This is converted from [bodyBytes] using the `charset` parameter of the
   /// `Content-Type` header field, if available. If it's unavailable or if the
-  /// encoding name is unknown, [latin1] is used by default, as per
-  /// [RFC 2616][].
+  /// encoding name is unknown, [utf8] is used by default, as per
+  /// [RFC3629][].
   ///
-  /// [RFC 2616]: http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html
+  /// [RFC3629]:https://www.rfc-editor.org/rfc/rfc3629.
   String get body => _encodingForHeaders(headers).decode(bodyBytes);
 
   /// Creates a new HTTP response with a string body.
@@ -43,11 +43,7 @@ class Response extends BaseResponse {
 
   /// Create a new HTTP response with a byte array body.
   Response.bytes(List<int> bodyBytes, super.statusCode,
-      {super.request,
-      super.headers,
-      super.isRedirect,
-      super.persistentConnection,
-      super.reasonPhrase})
+      {super.request, super.headers, super.isRedirect, super.persistentConnection, super.reasonPhrase})
       : bodyBytes = toUint8List(bodyBytes),
         super(contentLength: bodyBytes.length);
 
@@ -66,10 +62,12 @@ class Response extends BaseResponse {
 
 /// Returns the encoding to use for a response with the given headers.
 ///
-/// Defaults to [latin1] if the headers don't specify a charset or if that
-/// charset is unknown.
+/// If the `Content-Type` header specifies a charset, it will use that charset.
+/// If no charset is provided or the charset is unknown:
+/// - Defaults to [utf8] if the `Content-Type` is `application/json` (since JSON is defined to use UTF-8 by default).
+/// - Otherwise, defaults to [latin1] for compatibility.
 Encoding _encodingForHeaders(Map<String, String> headers) =>
-    encodingForCharset(_contentTypeForHeaders(headers).parameters['charset']);
+    encodingForContentTypeHeader(_contentTypeForHeaders(headers));
 
 /// Returns the [MediaType] object for the given headers' content-type.
 ///

pkgs/http/lib/src/utils.dart

@@ -6,34 +6,42 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:typed_data';
 
+import 'package:http_parser/http_parser.dart';
+
 import 'byte_stream.dart';
 
 /// Converts a [Map] from parameter names to values to a URL query string.
 ///
 ///     mapToQuery({"foo": "bar", "baz": "bang"});
 ///     //=> "foo=bar&baz=bang"
-String mapToQuery(Map<String, String> map, {required Encoding encoding}) =>
-    map.entries
-        .map((e) => '${Uri.encodeQueryComponent(e.key, encoding: encoding)}'
-            '=${Uri.encodeQueryComponent(e.value, encoding: encoding)}')
-        .join('&');
+String mapToQuery(Map<String, String> map, {required Encoding encoding}) => map.entries
+    .map((e) => '${Uri.encodeQueryComponent(e.key, encoding: encoding)}'
+        '=${Uri.encodeQueryComponent(e.value, encoding: encoding)}')
+    .join('&');
 
-/// Returns the [Encoding] that corresponds to [charset].
+/// Determines the appropriate [Encoding] based on the given [contentTypeHeader].
 ///
-/// Returns [fallback] if [charset] is null or if no [Encoding] was found that
-/// corresponds to [charset].
-Encoding encodingForCharset(String? charset, [Encoding fallback = latin1]) {
-  if (charset == null) return fallback;
-  return Encoding.getByName(charset) ?? fallback;
+/// - If the `Content-Type` is `application/json` and no charset is specified, it defaults to [utf8].
+/// - If a charset is specified in the parameters, it attempts to find a matching [Encoding].
+/// - If no charset is specified or the charset is unknown, it falls back to the provided [fallback], which defaults to [latin1].
+Encoding encodingForContentTypeHeader(MediaType contentTypeHeader, [Encoding fallback = latin1]) {
+  final charset = contentTypeHeader.parameters['charset'];
+
+  // Default to utf8 for application/json when charset is unspecified.
+  if (contentTypeHeader.type == 'application' && contentTypeHeader.subtype == 'json' && charset == null) {
+    return utf8;
+  }
+
+  // Attempt to find the encoding or fall back to the default.
+  return charset != null ? Encoding.getByName(charset) ?? fallback : fallback;
 }
 
 /// Returns the [Encoding] that corresponds to [charset].
 ///
 /// Throws a [FormatException] if no [Encoding] was found that corresponds to
 /// [charset].
 Encoding requiredEncodingForCharset(String charset) =>
-    Encoding.getByName(charset) ??
-    (throw FormatException('Unsupported encoding "$charset".'));
+    Encoding.getByName(charset) ?? (throw FormatException('Unsupported encoding "$charset".'));
 
 /// A regular expression that matches strings that are composed entirely of
 /// ASCII-compatible characters.

pkgs/http/test/response_test.dart

@@ -16,17 +16,18 @@ void main() {
 
     test('sets bodyBytes', () {
       var response = http.Response('Hello, world!', 200);
-      expect(
-          response.bodyBytes,
-          equals(
-              [72, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 100, 33]));
+      expect(response.bodyBytes, equals([72, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 100, 33]));
     });
 
     test('respects the inferred encoding', () {
-      var response = http.Response('föøbãr', 200,
-          headers: {'content-type': 'text/plain; charset=iso-8859-1'});
+      var response = http.Response('föøbãr', 200, headers: {'content-type': 'text/plain; charset=iso-8859-1'});
       expect(response.bodyBytes, equals([102, 246, 248, 98, 227, 114]));
     });
+
+    test('test empty charset', () {
+      var response = http.Response('{"foo":"Привет, мир!"}', 200, headers: {'content-type': 'application/json'});
+      expect(response.body, equals('{"foo":"Привет, мир!"}'));
+    });
   });
 
   group('.bytes()', () {
@@ -50,8 +51,7 @@ void main() {
   group('.fromStream()', () {
     test('sets body', () async {
       var controller = StreamController<List<int>>(sync: true);
-      var streamResponse =
-          http.StreamedResponse(controller.stream, 200, contentLength: 13);
+      var streamResponse = http.StreamedResponse(controller.stream, 200, contentLength: 13);
       controller
         ..add([72, 101, 108, 108, 111, 44, 32])
         ..add([119, 111, 114, 108, 100, 33]);
@@ -62,8 +62,7 @@ void main() {
 
     test('sets bodyBytes', () async {
       var controller = StreamController<List<int>>(sync: true);
-      var streamResponse =
-          http.StreamedResponse(controller.stream, 200, contentLength: 5);
+      var streamResponse = http.StreamedResponse(controller.stream, 200, contentLength: 5);
       controller.add([104, 101, 108, 108, 111]);
       unawaited(controller.close());
       var response = await http.Response.fromStream(streamResponse);
@@ -78,33 +77,29 @@ void main() {
     });
 
     test('one header', () async {
-      var response =
-          http.Response('Hello, world!', 200, headers: {'fruit': 'apple'});
+      var response = http.Response('Hello, world!', 200, headers: {'fruit': 'apple'});
       expect(response.headersSplitValues, const {
         'fruit': ['apple']
       });
     });
 
     test('two headers', () async {
-      var response = http.Response('Hello, world!', 200,
-          headers: {'fruit': 'apple,banana'});
+      var response = http.Response('Hello, world!', 200, headers: {'fruit': 'apple,banana'});
       expect(response.headersSplitValues, const {
         'fruit': ['apple', 'banana']
       });
     });
 
     test('two headers with lots of spaces', () async {
-      var response = http.Response('Hello, world!', 200,
-          headers: {'fruit': 'apple   \t   ,  \tbanana'});
+      var response = http.Response('Hello, world!', 200, headers: {'fruit': 'apple   \t   ,  \tbanana'});
       expect(response.headersSplitValues, const {
         'fruit': ['apple', 'banana']
       });
     });
 
     test('one set-cookie', () async {
-      var response = http.Response('Hello, world!', 200, headers: {
-        'set-cookie': 'id=a3fWa; Expires=Wed, 21 Oct 2015 07:28:00 GMT'
-      });
+      var response = http.Response('Hello, world!', 200,
+          headers: {'set-cookie': 'id=a3fWa; Expires=Wed, 21 Oct 2015 07:28:00 GMT'});
       expect(response.headersSplitValues, const {
         'set-cookie': ['id=a3fWa; Expires=Wed, 21 Oct 2015 07:28:00 GMT']
       });