dio Documentation

Future<Response<T>> get<T>(
   String path, {
+  Object? data,
   Map<String, dynamic>? queryParameters,
   Options? options,
   CancelToken? cancelToken,
   ProgressCallback? onReceiveProgress,
 });

Future<Response<T>> getUri<T>(
   Uri uri, {
+  Object? data,
   Map<String, dynamic>? queryParameters,
   Options? options,
   CancelToken? cancelToken,
   ProgressCallback? onReceiveProgress,
 });

void initAdapter() {
  final dio = Dio();
  // For natives.
  dio.httpClientAdapter = DefaultHttpClientAdapter();
  // For web.
  dio.httpClientAdapter = BrowserHttpClientAdapter();
}

void initAdapter() {
  final dio = Dio();
  // Universal adapter that create the adapter for the corresponding platform.
  dio.httpClientAdapter = HttpClientAdapter();
  // For natives.
  dio.httpClientAdapter = IOHttpClientAdapter();
  // For web.
  dio.httpClientAdapter = BrowserHttpClientAdapter();
}

class ExampleAdapter extends HttpClientAdapter { /* ... */ }

class ExampleAdapter implements HttpClientAdapter { /* ... */ }

Never throwDioError() {
  final error = DioError(request: requestOptions, error: e);
  error.message = 'Custom message.';
  error.stackTrace = StackTrace.current;
  throw error;
}

Never throwDioError() {
  DioError error = DioError(
    request: requestOptions,
    error: e,
    stackTrace: StackTrace.current
  );
  error = error.copyWith(message: 'Custom message.');
  throw error;
}

void request() {
  final dio = Dio(
    BaseOptions(
      connectTimeout: 5000,
      sendTimeout: 5000,
      receiveTimeout: 10000,
    ),
  );
}

void request() {
  final dio = Dio(
    BaseOptions(
      connectTimeout: const Duration(seconds: 5),
      sendTimeout: const Duration(seconds: 5),
      receiveTimeout: const Duration(seconds: 10),
    ),
  );
}

import 'package:dio/dio.dart';

final dio = Dio();

void getHttp() async {
  final response = await dio.get('https://dart.dev');
  print(response);
}

import 'package:dio/dio.dart';

final dio = Dio();

void request() async {
  Response response;
  response = await dio.get('/test?id=12&name=dio');
  print(response.data.toString());
  // The below request is the same as above.
  response = await dio.get(
    '/test',
    queryParameters: {'id': 12, 'name': 'dio'},
  );
  print(response.data.toString());
}

response = await dio.post('/test', data: {'id': 12, 'name': 'dio'});

response = await dio.query('/search', data: {'filter': {'name': 'dio'}});

List<Response> responses = await Future.wait([dio.post('/info'), dio.get('/token')]);

response = await dio.download(
  'https://pub.dev/',
  (await getTemporaryDirectory()).path + 'pub.html',
);

final rs = await dio.get(
  url,
  options: Options(responseType: ResponseType.stream), // Set the response type to `stream`.
);
print(rs.data.stream); // Response stream.

final rs = await Dio().get<List>(
  url,
  options: Options(responseType: ResponseType.bytes), // Set the response type to `bytes`.
);
print(rs.data); // Type: List.

final formData = FormData.fromMap({
  'name': 'dio',
  'date': DateTime.now().toIso8601String(),
});
final response = await dio.post('/info', data: formData);

final formData = FormData.fromMap({
  'name': 'dio',
  'date': DateTime.now().toIso8601String(),
  'file': await MultipartFile.fromFile('./text.txt', filename: 'upload.txt'),
  'files': [
    await MultipartFile.fromFile('./text1.txt', filename: 'text1.txt'),
    await MultipartFile.fromFile('./text2.txt', filename: 'text2.txt'),
  ]
});
final response = await dio.post('/info', data: formData);

final response = await dio.post(
  'https://www.dtworkroom.com/doris/1/2.0.0/test',
  data: {'aa': 'bb' * 22},
  onSendProgress: (int sent, int total) {
    print('$sent $total');
  },
);

// Binary data
final postData = [0, 1, 2];
await dio.post(
  url,
  data: Stream.fromIterable(postData.map((e) => [e])), // Creates a Stream<List>.
  options: Options(
    headers: {
      Headers.contentLengthHeader: postData.length, // Set the content-length.
    },
  ),
);

final dio = Dio(); // With default `Options`.

void configureDio() {
  // Set default configs
  dio.options.baseUrl = 'https://api.pub.dev';
  dio.options.connectTimeout = Duration(seconds: 5);
  dio.options.receiveTimeout = Duration(seconds: 3);

  // Or create `Dio` with a `BaseOptions` instance.
  final options = BaseOptions(
    baseUrl: 'https://api.pub.dev',
    connectTimeout: Duration(seconds: 5),
    receiveTimeout: Duration(seconds: 3),
  );
  final anotherDio = Dio(options);

  // Or clone the existing `Dio` instance with all fields.
  final clonedDio = dio.clone();
}

Future<Response<T>> request<T>(
  String path, {
  Object? data,
  Map<String, dynamic>? queryParameters,
  CancelToken? cancelToken,
  Options? options,
  ProgressCallback? onSendProgress,
  ProgressCallback? onReceiveProgress,
});

final response = await dio.request(
  '/test',
  data: {'id': 12, 'name': 'dio'},
  options: Options(method: 'GET'),
);

/* Detailed source-code truncated for AI context efficiency. */

/// Response body. may have been transformed, please refer to [ResponseType].
T? data;

/// The corresponding request info.
RequestOptions requestOptions;

/// HTTP status code.
int? statusCode;

/// Returns the reason phrase associated with the status code.
/// The reason phrase must be set before the body is written
/// to. Setting the reason phrase after writing to the body.
String? statusMessage;

/// Whether this response is a redirect.
/// ** Attention **: Whether this field is available depends on whether the
/// implementation of the adapter supports it or not.
bool isRedirect;

/// The series of redirects this connection has been through. The list will be
/// empty if no redirects were followed. [redirects] will be updated both
/// in the case of an automatic and a manual redirect.
///
/// ** Attention **: Whether this field is available depends on whether the
/// implementation of the adapter supports it or not.
List<RedirectRecord> redirects;

/// Custom fields that only for the [Response].
Map<String, dynamic> extra;

/// Response headers.
Headers headers;

final response = await dio.get('https://pub.dev');
print(response.data);
print(response.headers);
print(response.requestOptions);
print(response.statusCode);

dio.interceptors.add(
  InterceptorsWrapper(
    onRequest: (RequestOptions options, RequestInterceptorHandler handler) {
      // Do something before request is sent.
      // If you want to resolve the request with custom data,
      // you can resolve a `Response` using `handler.resolve(response)`.
      // If you want to reject the request with a error message,
      // you can reject with a `DioException` using `handler.reject(dioError)`.
      return handler.next(options);
    },
    onResponse: (Response response, ResponseInterceptorHandler handler) {
      // Do something with response data.
      // If you want to reject the request with a error message,
      // you can reject a `DioException` object using `handler.reject(dioError)`.
      return handler.next(response);
    },
    onError: (DioException error, ErrorInterceptorHandler handler) {
      // Do something with response error.
      // If you want to resolve the request with some custom data,
      // you can resolve a `Response` object using `handler.resolve(response)`.
      return handler.next(error);
    },
  ),
);

import 'package:dio/dio.dart';
class CustomInterceptors extends Interceptor {
  @override
  void onRequest(RequestOptions options, RequestInterceptorHandler handler) {
    print('REQUEST[${options.method}] => PATH: ${options.path}');
    super.onRequest(options, handler);
  }

  @override
  void onResponse(Response response, ResponseInterceptorHandler handler) {
    print('RESPONSE[${response.statusCode}] => PATH: ${response.requestOptions.path}');
    super.onResponse(response, handler);
  }

  @override
  Future onError(DioException err, ErrorInterceptorHandler handler) async {
    print('ERROR[${err.response?.statusCode}] => PATH: ${err.requestOptions.path}');
    super.onError(err, handler);
  }
}

dio.interceptors.add(
  InterceptorsWrapper(
    onRequest: (options, handler) {
      return handler.resolve(
        Response(requestOptions: options, data: 'fake data'),
      );
    },
  ),
);
final response = await dio.get('/test');
print(response.data); // 'fake data'

dio.interceptors.add(LogInterceptor(responseBody: false)); // Do not output responses body.

dio.interceptors.add(
  LogInterceptor(
    logPrint: (o) => debugPrint(o.toString()),
  ),
);

try {
  // 404
  await dio.get('https://api.pub.dev/not-exist');
} on DioException catch (e) {
  // The request was made and the server responded with a status code
  // that falls out of the range of 2xx and is also not 304.
  if (e.response != null) {
    print(e.response.data)
    print(e.response.headers)
    print(e.response.requestOptions)
  } else {
    // Something happened in setting up or sending the request that triggered an Error
    print(e.requestOptions)
    print(e.message)
  }
}

/// The request info for the request that throws exception.
RequestOptions requestOptions;

/// Response info, it may be `null` if the request can't reach to the
/// HTTP server, for example, occurring a DNS error, network is not available.
Response? response;

/// The type of the current [DioException].
DioExceptionType type;

/// The original error/exception object;
/// It's usually not null when `type` is [DioExceptionType.unknown].
Object? error;

/// The stacktrace of the original error/exception object;
/// It's usually not null when `type` is [DioExceptionType.unknown].
StackTrace? stackTrace;

/// The error message that throws a [DioException].
String? message;

// Instance level
dio.options.contentType = Headers.formUrlEncodedContentType;
// or only works once
dio.post(
  '/info',
  data: {'id': 5},
  options: Options(contentType: Headers.formUrlEncodedContentType),
);

final formData = FormData.fromMap({
  'name': 'dio',
  'date': DateTime.now().toIso8601String(),
  'file': await MultipartFile.fromFile('./text.txt', filename: 'upload.txt'),
});
final response = await dio.post('/info', data: formData);

final formDataWithBoundaryName = FormData(
  boundaryName: 'my-boundary-name',
);

final formData = FormData.fromMap({
  'files': [
    MultipartFile.fromFileSync('path/to/upload1.txt', filename: 'upload1.txt'),
    MultipartFile.fromFileSync('path/to/upload2.txt', filename: 'upload2.txt'),
  ],
});

final formData = FormData();
formData.files.addAll([
  MapEntry(
   'files',
    MultipartFile.fromFileSync('./example/upload.txt',filename: 'upload.txt'),
  ),
  MapEntry(
    'files',
    MultipartFile.fromFileSync('./example/upload.txt',filename: 'upload.txt'),
  ),
]);

Future<void> _repeatedlyRequest() async {
  Future<FormData> createFormData() async {
    return FormData.fromMap({
      'name': 'dio',
      'date': DateTime.now().toIso8601String(),
      'file': await MultipartFile.fromFile('./text.txt',filename: 'upload.txt'),
    });
  }
  
  await dio.post('some-url', data: await createFormData());
}

dio.httpClientAdapter = HttpClientAdapter();

import 'package:dio/io.dart';

void initAdapter() {
  dio.httpClientAdapter = IOHttpClientAdapter(
    createHttpClient: () {
      final client = HttpClient();
      // Config the client.
      client.findProxy = (uri) {
        // Forward all request to proxy "localhost:8888".
        // Be aware, the proxy should went through you running device,
        // not the host platform.
        return 'PROXY localhost:8888';
      };
      // You can also create a new HttpClient for Dio instead of returning,
      // but a client must being returned here.
      return client;
    },
  );
}

void initAdapter() {
  const String fingerprint = 'ee5ce1dfa7a53657c545c62b65802e4272878dabd65c0aadcf85783ebb0b4d5c';
  dio.httpClientAdapter = IOHttpClientAdapter(
    createHttpClient: () {
      // Don't trust any certificate just because their root cert is trusted.
      final HttpClient client = HttpClient(context: SecurityContext(withTrustedRoots: false));
      // You can test the intermediate / root cert here. We just ignore it.
      client.badCertificateCallback = (cert, host, port) => true;
      return client;
    },
    validateCertificate: (cert, host, port) {
      // Check that the cert fingerprint matches the one we expect.
      // We definitely require _some_ certificate.
      if (cert == null) {
        return false;
      }
      // Validate it any way you want. Here we only check that
      // the fingerprint matches the OpenSSL SHA256.
      return fingerprint == sha256.convert(cert.der).toString();
    },
  );
}

openssl s_client -servername pinning-test.badssl.com -connect pinning-test.badssl.com:443 < /dev/null 2>/dev/null \
  | openssl x509 -noout -fingerprint -sha256

# SHA256 Fingerprint=EE:5C:E1:DF:A7:A5:36:57:C5:45:C6:2B:65:80:2E:42:72:87:8D:AB:D6:5C:0A:AD:CF:85:78:3E:BB:0B:4D:5C
# (remove the formatting, keep only lower case hex characters to match the `sha256` above)

void initAdapter() {
  String PEM = 'XXXXX'; // root certificate content
  dio.httpClientAdapter = IOHttpClientAdapter(
    createHttpClient: () {
      final client = HttpClient();
      client.badCertificateCallback = (X509Certificate cert, String host, int port) {
        return cert.pem == PEM; // Verify the certificate.
      };
      return client;
    },
  );
}

void initAdapter() {
  String PEM = 'XXXXX'; // root certificate content
  dio.httpClientAdapter = IOHttpClientAdapter(
    onHttpClientCreate: (_) {
      final SecurityContext sc = SecurityContext();
      sc.setTrustedCertificates(File(pathToTheCertificate));
      final HttpClient client = HttpClient(context: sc);
      return client;
    },
  );
}

final cancelToken = CancelToken();
dio.get(url, cancelToken: cancelToken).catchError((DioException error) {
  if (CancelToken.isCancel(error)) {
    print('Request canceled: ${error.message}');
  } else {
    // handle error.
  }
});
// Cancel the requests with "cancelled" message.
token.cancel('cancelled');

import 'package:dio/dio.dart';
import 'package:dio/io.dart';
// If in browser, import 'package:dio/browser.dart'.

class Http extends DioForNative {
  Http([BaseOptions options]) : super(options) {
    // do something
  }
}

class MyDio with DioMixin implements Dio {
  // ...
}

import 'package:dio/dio.dart';

final dio = Dio();

void getHttp() async {
  final response = await dio.get('https://dart.dev');
  print(response);
}

import 'package:dio/dio.dart';

final dio = Dio();

void request() async {
  Response response;
  response = await dio.get('/test?id=12&name=dio');
  print(response.data.toString());
  // The below request is the same as above.
  response = await dio.get(
    '/test',
    queryParameters: {'id': 12, 'name': 'dio'},
  );
  print(response.data.toString());
}

response = await dio.post('/test', data: {'id': 12, 'name': 'dio'});

response = await dio.query('/search', data: {'filter': {'name': 'dio'}});

List<Response> responses = await Future.wait([dio.post('/info'), dio.get('/token')]);

response = await dio.download(
  'https://www.google.com/',
  '${(await getTemporaryDirectory()).path}google.html',
);

final rs = await dio.get(
  url,
  options: Options(responseType: ResponseType.stream), // 设置接收类型为 `stream`
);
print(rs.data.stream); // 响应流

final rs = await dio.get(
  url,
  options: Options(responseType: ResponseType.bytes), // 设置接收类型为 `bytes`
);
print(rs.data); // 类型: List

final formData = FormData.fromMap({
  'name': 'dio',
  'date': DateTime.now().toIso8601String(),
});
final response = await dio.post('/info', data: formData);

final formData = FormData.fromMap({
  'name': 'dio',
  'date': DateTime.now().toIso8601String(),
  'file': await MultipartFile.fromFile('./text.txt', filename: 'upload.txt'),
  'files': [
    await MultipartFile.fromFile('./text1.txt', filename: 'text1.txt'),
    await MultipartFile.fromFile('./text2.txt', filename: 'text2.txt'),
  ]
});
final response = await dio.post('/info', data: formData);

final response = await dio.post(
  'https://www.dtworkroom.com/doris/1/2.0.0/test',
  data: {'aa': 'bb' * 22},
  onSendProgress: (int sent, int total) {
    print('$sent $total');
  },
);

// Binary data
final postData = [0, 1, 2];
await dio.post(
  url,
  data: Stream.fromIterable(postData.map((e) => [e])), // 构建 Stream<List>
  options: Options(
    headers: {
      Headers.contentLengthHeader: postData.length, // 设置 content-length.
    },
  ),
);

final dio = Dio(); // With default `Options`.

void configureDio() {
  // Update default configs.
  dio.options.baseUrl = 'https://api.pub.dev';
  dio.options.connectTimeout = Duration(seconds: 5);
  dio.options.receiveTimeout = Duration(seconds: 3);

  // Or create `Dio` with a `BaseOptions` instance.
  final options = BaseOptions(
    baseUrl: 'https://api.pub.dev',
    connectTimeout: Duration(seconds: 5),
    receiveTimeout: Duration(seconds: 3),
  );
  final anotherDio = Dio(options);

  // Or clone the existing `Dio` instance with all fields.
  final clonedDio = dio.clone();
}

Future<Response<T>> request<T>(
  String path, {
  Object? data,
  Map<String, dynamic>? queryParameters,
  CancelToken? cancelToken,
  Options? options,
  ProgressCallback? onSendProgress,
  ProgressCallback? onReceiveProgress,
});

final response = await dio.request(
  '/test',
  data: {'id': 12, 'name': 'dio'},
  options: Options(method: 'GET'),
);

/* Detailed source-code truncated for AI context efficiency. */

/// 响应数据。可能已经被转换了类型, 详情请参考 [ResponseType]。
T? data;

/// 响应对应的请求配置。
RequestOptions requestOptions;

/// 响应的 HTTP 状态码。
int? statusCode;

/// 响应对应状态码的详情信息。
String? statusMessage;

/// 响应是否被重定向
bool isRedirect;

/// 请求连接经过的重定向列表。如果请求未经过重定向，则列表为空。
List<RedirectRecord> redirects;

/// 在 [RequestOptions] 中构造的自定义字段。
Map<String, dynamic> extra;

/// 响应对应的头数据。
Headers headers;

final response = await dio.get('https://pub.dev');
print(response.data);
print(response.headers);
print(response.requestOptions);
print(response.statusCode);

dio.interceptors.add(
  InterceptorsWrapper(
    onRequest: (RequestOptions options, RequestInterceptorHandler handler) {
      // 如果你想完成请求并返回一些自定义数据，你可以使用 `handler.resolve(response)`。
      // 如果你想终止请求并触发一个错误，你可以使用 `handler.reject(error)`。
      return handler.next(options);
    },
    onResponse: (Response response, ResponseInterceptorHandler handler) {
      // 如果你想终止请求并触发一个错误，你可以使用 `handler.reject(error)`。
      return handler.next(response);
    },
    onError: (DioException error, ErrorInterceptorHandler handler) {
      // 如果你想完成请求并返回一些自定义数据，你可以使用 `handler.resolve(response)`。
      return handler.next(error);
    },
  ),
);

import 'package:dio/dio.dart';
class CustomInterceptors extends Interceptor {
  @override
  void onRequest(RequestOptions options, RequestInterceptorHandler handler) {
    print('REQUEST[${options.method}] => PATH: ${options.path}');
    super.onRequest(options, handler);
  }

  @override
  void onResponse(Response response, ResponseInterceptorHandler handler) {
    print('RESPONSE[${response.statusCode}] => PATH: ${response.requestOptions.path}');
    super.onResponse(response, handler);
  }

  @override
  Future onError(DioException err, ErrorInterceptorHandler handler) async {
    print('ERROR[${err.response?.statusCode}] => PATH: ${err.requestOptions.path}');
    super.onError(err, handler);
  }
}

dio.interceptors.add(
  InterceptorsWrapper(
    onRequest: (options, handler) {
      return handler.resolve(
        Response(requestOptions: options, data: 'fake data'),
      );
    },
  ),
);
final response = await dio.get('/test');
print(response.data); // 'fake data'

dio.interceptors.add(LogInterceptor(responseBody: false)); // 不输出响应内容体

dio.interceptors.add(
  LogInterceptor(
    logPrint: (o) => debugPrint(o.toString()),
  ),
);

try {
  // 404
  await dio.get('https://api.pub.dev/not-exist');
} on DioException catch (e) {
  // The request was made and the server responded with a status code
  // that falls out of the range of 2xx and is also not 304.
  if (e.response != null) {
    print(e.response.data)
    print(e.response.headers)
    print(e.response.requestOptions)
  } else {
    // Something happened in setting up or sending the request that triggered an Error
    print(e.requestOptions)
    print(e.message)
  }
}

/// 错误的请求对应的配置。
RequestOptions requestOptions;

/// 错误的请求对应的响应内容。如果请求未完成，响应内容可能为空。
Response? response;

/// 错误的类型。
DioExceptionType type;

/// 实际错误的内容。
Object? error;

/// 实际错误的堆栈。
StackTrace? stackTrace;

/// 错误信息。
String? message;

// Instance level
dio.options.contentType = Headers.formUrlEncodedContentType;
// or only works once
dio.post(
  '/info',
  data: {'id': 5},
  options: Options(contentType: Headers.formUrlEncodedContentType),
);

final formData = FormData.fromMap({
  'name': 'dio',
  'date': DateTime.now().toIso8601String(),
  'file': await MultipartFile.fromFile('./text.txt',filename: 'upload.txt')
});
final response = await dio.post('/info', data: formData);

final formDataWithBoundaryName = FormData(
  boundaryName: 'my-boundary-name',
);

final formData = FormData.fromMap({
  'files': [
    MultipartFile.fromFileSync('path/to/upload1.txt', filename: 'upload1.txt'),
    MultipartFile.fromFileSync('path/to/upload2.txt', filename: 'upload2.txt'),
  ],
});

final formData = FormData();
formData.files.addAll([
  MapEntry(
   'files',
    MultipartFile.fromFileSync('./example/upload.txt',filename: 'upload.txt'),
  ),
  MapEntry(
    'files',
    MultipartFile.fromFileSync('./example/upload.txt',filename: 'upload.txt'),
  ),
]);

Future<void> _repeatedlyRequest() async {
  Future<FormData> createFormData() async {
    return FormData.fromMap({
      'name': 'dio',
      'date': DateTime.now().toIso8601String(),
      'file': await MultipartFile.fromFile('./text.txt',filename: 'upload.txt'),
    });
  }
  
  await dio.post('some-url', data: await createFormData());
}

/// 
Map<String, dynamic> _parseAndDecode(String response) {
  return jsonDecode(response) as Map<String, dynamic>;
}

Future<Map<String, dynamic>> parseJson(String text) {
  return compute(_parseAndDecode, text);
}

void main() {
  // 自定义 `jsonDecodeCallback`
  dio.transformer = DefaultTransformer()..jsonDecodeCallback = parseJson;
  runApp(MyApp());
}

dio.httpClientAdapter = HttpClientAdapter();

import 'package:dio/io.dart';

void initAdapter() {
  dio.httpClientAdapter = IOHttpClientAdapter(
    createHttpClient: () {
      final client = HttpClient();
      client.findProxy = (uri) {
        // 将请求代理至 localhost:8888。
        // 请注意，代理会在你正在运行应用的设备上生效，而不是在宿主平台生效。
        return 'PROXY localhost:8888';
      };
      return client;
    },
  );
}

void initAdapter() {
  const String fingerprint = 'ee5ce1dfa7a53657c545c62b65802e4272878dabd65c0aadcf85783ebb0b4d5c';
  dio.httpClientAdapter = IOHttpClientAdapter(
    createHttpClient: () {
      // Don't trust any certificate just because their root cert is trusted.
      final HttpClient client = HttpClient(context: SecurityContext(withTrustedRoots: false));
      // You can test the intermediate / root cert here. We just ignore it.
      client.badCertificateCallback = (cert, host, port) => true;
      return client;
    },
    validateCertificate: (cert, host, port) {
      // Check that the cert fingerprint matches the one we expect.
      // We definitely require _some_ certificate.
      if (cert == null) {
        return false;
      }
      // Validate it any way you want. Here we only check that
      // the fingerprint matches the OpenSSL SHA256.
      return fingerprint == sha256.convert(cert.der).toString();
    },
  );
}

openssl s_client -servername pinning-test.badssl.com -connect pinning-test.badssl.com:443 < /dev/null 2>/dev/null \
  | openssl x509 -noout -fingerprint -sha256

# SHA256 Fingerprint=EE:5C:E1:DF:A7:A5:36:57:C5:45:C6:2B:65:80:2E:42:72:87:8D:AB:D6:5C:0A:AD:CF:85:78:3E:BB:0B:4D:5C
# (remove the formatting, keep only lower case hex characters to match the `sha256` above)

void initAdapter() {
  String PEM = 'XXXXX'; // root certificate content
  dio.httpClientAdapter = IOHttpClientAdapter(
    createHttpClient: () {
      final client = HttpClient();
      client.badCertificateCallback = (X509Certificate cert, String host, int port) {
        return cert.pem == PEM; // Verify the certificate.
      };
      return client;
    },
  );
}

void initAdapter() {
  String PEM = 'XXXXX'; // root certificate content
  dio.httpClientAdapter = IOHttpClientAdapter(
    onHttpClientCreate: (_) {
      final SecurityContext sc = SecurityContext();
      sc.setTrustedCertificates(File(pathToTheCertificate));
      final HttpClient client = HttpClient(context: sc);
      return client;
    },
  );
}

final cancelToken = CancelToken();
dio.get(url, cancelToken: cancelToken).catchError((DioException error) {
  if (CancelToken.isCancel(error)) {
    print('Request canceled: ${error.message}');
  } else {
    // handle error.
  }
});
// Cancel the requests with "cancelled" message.
token.cancel('cancelled');

import 'package:dio/dio.dart';
import 'package:dio/io.dart';
// 在浏览器中，导入 'package:dio/browser.dart'。

class Http extends DioForNative {
  Http([BaseOptions options]) : super(options) {
    // 构造函数执行
  }
}

class MyDio with DioMixin implements Dio {
  // ...
}

dev_dependencies:
  # Shared test package.
  dio_test:
    git:
      url: https://github.com/cfug/dio
      path: dio_test

import 'package:dio/dio.dart';
// The import is not required and could produce lints.
// import 'package:dio_web_adapter/dio_web_adapter.dart';

void main() async {
  final dio = Dio();
  dio.httpClientAdapter = BrowserHttpClientAdapter(withCredentials: true);

  // Make a request.
  final response = await dio.get('https://dart.dev');
  print(response);
}