dio
A powerful Http client for Dart, which supports Interceptors, Global configuration, FormData, Request Cancellation, File downloading, Timeout etc.
Get started
Add dependency
dependencies:
dio: 3.x #latest version
In order to support Flutter Web, v3.x was heavily refactored, so it was not compatible with version 3.x See here for a detailed list of updates.
Super simple to use
import 'package:dio/dio.dart';
void getHttp() async {
try {
Response response = await Dio().get("http://www.google.com");
print(response);
} catch (e) {
print(e);
}
}
awesome-dio
Plugins
Plugins | Status | Description |
---|---|---|
dio_cookie_manager | A cookie manager for Dio | |
dio_http2_adapter | A Dio HttpClientAdapter which support Http/2.0 | |
dio_flutter_transformer | A Dio transformer especially for flutter, by which the json decoding will be in background with compute function. |
|
dio_http_cache | A cache library for Dio, like Rxcache in Android. dio-http-cache uses sqflite as disk cache, and LRU strategy as memory cache. | |
retrofit | retrofit.dart is an dio client generator using source_gen and inspired by Chopper and Retrofit. |
Related Projects
Welcome to submit Dio's third-party plugins and related libraries here .
Table of contents
Examples
Performing a GET
request:
Response response;
Dio dio = new Dio();
response = await dio.get("/test?id=12&name=wendu");
print(response.data.toString());
// Optionally the request above could also be done as
response = await dio.get("/test", queryParameters: {"id": 12, "name": "wendu"});
print(response.data.toString());
Performing a POST
request:
response = await dio.post("/test", data: {"id": 12, "name": "wendu"});
Performing multiple concurrent requests:
response = await Future.wait([dio.post("/info"), dio.get("/token")]);
Downloading a file:
response = await dio.download("https://www.google.com/", "./xx.html");
Get response stream:
Response<ResponseBody> rs = await Dio().get<ResponseBody>(url,
options: Options(responseType: ResponseType.stream), // set responseType to `stream`
);
print(rs.data.stream); //response stream
Get response with bytes:
Response<List<int>> rs = await Dio().get<List<int>>(url,
options: Options(responseType: ResponseType.bytes), // // set responseType to `bytes`
);
print(rs.data); // List<int>
Sending FormData:
FormData formData = new FormData.fromMap({
"name": "wendux",
"age": 25,
});
response = await dio.post("/info", data: formData);
Uploading multiple files to server by FormData:
FormData.fromMap({
"name": "wendux",
"age": 25,
"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"),
]
});
response = await dio.post("/info", data: formData);
Listening the uploading progress:
response = await dio.post(
"http://www.dtworkroom.com/doris/1/2.0.0/test",
data: {"aa": "bb" * 22},
onSendProgress: (int sent, int total) {
print("$sent $total");
},
);
Post binary data by Stream:
// Binary data
List<int> postData = <int>[...];
await dio.post(
url,
data: Stream.fromIterable(postData.map((e) => [e])), //create a Stream<List<int>>
options: Options(
headers: {
Headers.contentLengthHeader: postData.length, // set content-length
},
),
);
…you can find all examples code here.
Dio APIs
Creating an instance and set default configs.
You can create instance of Dio with an optional BaseOptions
object:
Dio dio = new Dio(); // with default Options
// Set default configs
dio.options.baseUrl = "https://www.xx.com/api";
dio.options.connectTimeout = 5000; //5s
dio.options.receiveTimeout = 3000;
// or new Dio with a BaseOptions instance.
BaseOptions options = new BaseOptions(
baseUrl: "https://www.xx.com/api",
connectTimeout: 5000,
receiveTimeout: 3000,
);
Dio dio = new Dio(options);
The core API in Dio instance is:
Future request(String path, {data,Map queryParameters, Options options,CancelToken cancelToken, ProgressCallback onSendProgress, ProgressCallback onReceiveProgress)
response=await request(
"/test",
data: {"id":12,"name":"xx"},
options: Options(method:"GET"),
);
Request method aliases
For convenience aliases have been provided for all supported request methods.
Future get(...)
Future post(...)
Future put(...)
Future delete(...)
Future head(...)
Future put(...)
Future path(...)
Future download(...)
Request Options
The Options class describes the http request information and configuration. Each Dio instance has a base config for all requests maked by itself, and we can override the base config with [Options] when make a single request. The [BaseOptions] declaration as follows:
{
/// Http method.
String method;
/// Request base url, it can contain sub path, like: "https://www.google.com/api/".
String baseUrl;
/// Http request headers.
Map<String, dynamic> headers;
/// Timeout in milliseconds for opening url.
int connectTimeout;
/// Whenever more than [receiveTimeout] (in milliseconds) passes between two events from response stream,
/// [Dio] will throw the [DioError] with [DioErrorType.RECEIVE_TIMEOUT].
/// Note: This is not the receiving time limitation.
int receiveTimeout;
/// Request data, can be any type.
T data;
/// If the `path` starts with "http(s)", the `baseURL` will be ignored, otherwise,
/// it will be combined and then resolved with the baseUrl.
String path="";
/// The request Content-Type. The default value is "application/json; charset=utf-8".
/// If you want to encode request body with "application/x-www-form-urlencoded",
/// you can set [Headers.formUrlEncodedContentType], and [Dio]
/// will automatically encode the request body.
String contentType;
/// [responseType] indicates the type of data that the server will respond with
/// options which defined in [ResponseType] are `JSON`, `STREAM`, `PLAIN`.
///
/// The default value is `JSON`, dio will parse response string to json object automatically
/// when the content-type of response is "application/json".
///
/// If you want to receive response data with binary bytes, for example,
/// downloading a image, use `STREAM`.
///
/// If you want to receive the response data with String, use `PLAIN`.
ResponseType responseType;
/// `validateStatus` defines whether the request is successful for a given
/// HTTP response status code. If `validateStatus` returns `true` ,
/// the request will be perceived as successful; otherwise, considered as failed.
ValidateStatus validateStatus;
/// Custom field that you can retrieve it later in [Interceptor]、[Transformer] and the [Response] object.
Map<String, dynamic> extra;
/// Common query parameters
Map<String, dynamic /*String|Iterable<String>*/ > queryParameters;
}
There is a complete example here.
Response Schema
The response for a request contains the following information.
{
/// Response body. may have been transformed, please refer to [ResponseType].
T data;
/// Response headers.
Headers headers;
/// The corresponding request info.
Options request;
/// Http status code.
int statusCode;
/// Whether redirect
bool isRedirect;
/// redirect info
List<RedirectInfo> redirects ;
/// Returns the final real request uri (maybe redirect).
Uri realUri;
/// Custom field that you can retrieve it later in `then`.
Map<String, dynamic> extra;
}
When request is succeed, you will receive the response as follows:
Response response = await dio.get("https://www.google.com");
print(response.data);
print(response.headers);
print(response.request);
print(response.statusCode);
Interceptors
For each dio instance, We can add one or more interceptors, by which we can intercept requests or responses before they are handled by then
or catchError
.
dio.interceptors.add(InterceptorsWrapper(
onRequest:(RequestOptions options) async {
// Do something before request is sent
return options; //continue
// If you want to resolve the request with some custom data,
// you can return a `Response` object or return `dio.resolve(data)`.
// If you want to reject the request with a error message,
// you can return a `DioError` object or return `dio.reject(errMsg)`
},
onResponse:(Response response) async {
// Do something with response data
return response; // continue
},
onError: (DioError e) async {
// Do something with response error
return e;//continue
}
));
Simple interceptor example:
import 'package:dio/dio.dart';
class CustomInterceptors extends InterceptorsWrapper {
@override
Future onRequest(RequestOptions options) {
print("REQUEST[${options?.method}] => PATH: ${options?.path}");
return super.onRequest(options);
}
@override
Future onResponse(Response response) {
print("RESPONSE[${response?.statusCode}] => PATH: ${response?.request?.path}");
return super.onResponse(response);
}
@override
Future onError(DioError err) {
print("ERROR[${err?.response?.statusCode}] => PATH: ${err?.request?.path}");
return super.onError(err);
}
}
Resolve and reject the request
In all interceptors, you can interfere with their execution flow. If you want to resolve the request/response with some custom data,you can return a Response
object or return dio.resolve(data)
. If you want to reject the request/response with a error message, you can return a DioError
object or return dio.reject(errMsg)
.
dio.interceptors.add(InterceptorsWrapper(
onRequest:(RequestOptions options) {
return dio.resolve("fake data")
},
));
Response response = await dio.get("/test");
print(response.data);//"fake data"
Lock/unlock the interceptors
You can lock/unlock the interceptors by calling their lock()
/unlock
method. Once the request/response interceptor is locked, the incoming request/response will be added to a queue before they enter the interceptor, they will not be continued until the interceptor is unlocked.
tokenDio = new Dio(); //Create a new instance to request the token.
tokenDio.options = dio;
dio.interceptors.add(InterceptorsWrapper(
onRequest:(Options options) async {
// If no token, request token firstly and lock this interceptor
// to prevent other request enter this interceptor.
dio.interceptors.requestLock.lock();
// We use a new Dio(to avoid dead lock) instance to request token.
Response response = await tokenDio.get("/token");
//Set the token to headers
options.headers["token"] = response.data["data"]["token"];
dio.interceptors.requestLock.unlock();
return options; //continue
}
));
You can clean the waiting queue by calling clear()
;
aliases
When the request interceptor is locked, the incoming request will pause, this is equivalent to we locked the current dio instance, Therefore, Dio provied the two aliases for the lock/unlock
of request interceptors.
dio.lock() == dio.interceptors.requestLock.lock()
dio.unlock() == dio.interceptors.requestLock.unlock()
dio.clear() == dio.interceptors.requestLock.clear()
Example
Because of security reasons, we need all the requests to set up a csrfToken in the header, if csrfToken does not exist, we need to request a csrfToken first, and then perform the network request, because the request csrfToken progress is asynchronous, so we need to execute this async request in request interceptor. The code is as follows:
dio.interceptors.add(InterceptorsWrapper(
onRequest: (Options options) async {
print('send request:path:${options.path},baseURL:${options.baseUrl}');
if (csrfToken == null) {
print("no token,request token firstly...");
//lock the dio.
dio.lock();
return tokenDio.get("/token").then((d) {
options.headers["csrfToken"] = csrfToken = d.data['data']['token'];
print("request token succeed, value: " + d.data['data']['token']);
print(
'continue to perform request:path:${options.path},baseURL:${options.path}');
return options;
}).whenComplete(() => dio.unlock()); // unlock the dio
} else {
options.headers["csrfToken"] = csrfToken;
return options;
}
}
));
For complete codes click here.
Log
You can set LogInterceptor
to print request/response log automaticlly, for example:
dio.interceptors.add(LogInterceptor(responseBody: false)); //开启请求日志
Custom Interceptor
You can custom interceptor by extending the Interceptor
class. There is an example that implementing a simple cache policy: custom cache interceptor.
Cookie Manager
dio_cookie_manager package is a cookie manager for Dio.
Handling Errors
When a error occurs, Dio will wrap the Error/Exception
to a DioError
:
try {
//404
await dio.get("https://wendux.github.io/xsddddd");
} on DioError 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) {
print(e.response.data)
print(e.response.headers)
print(e.response.request)
} else{
// Something happened in setting up or sending the request that triggered an Error
print(e.request)
print(e.message)
}
}
DioError scheme
{
/// 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;
/// Error descriptions.
String message;
DioErrorType type;
/// The original error/exception object; It's usually not null when `type`
/// is DioErrorType.DEFAULT
dynamic error;
}
DioErrorType
enum DioErrorType {
/// When opening url timeout, it occurs.
CONNECT_TIMEOUT,
///It occurs when receiving timeout.
RECEIVE_TIMEOUT,
/// When the server response, but with a incorrect status, such as 404, 503...
RESPONSE,
/// When the request is cancelled, dio will throw a error with this type.
CANCEL,
/// Default error type, Some other Error. In this case, you can
/// read the DioError.error if it is not null.
DEFAULT,
}
Using application/x-www-form-urlencoded format
By default, Dio serializes request data(except String type) to JSON
. To send data in the application/x-www-form-urlencoded
format instead, you can :
//Instance level
dio.options.contentType= Headers.formUrlEncodedContentType;
//or works once
dio.post("/info", data:{"id":5},
options: Options(contentType:Headers.formUrlEncodedContentType ));
Sending FormData
You can also send FormData with Dio, which will send data in the multipart/form-data
, and it supports uploading files.
FormData formData = FormData.fromMap({
"name": "wendux",
"age": 25,
"file": await MultipartFile.fromFile("./text.txt",filename: "upload.txt")
});
response = await dio.post("/info", data: formData);
There is a complete example here.
Multiple files upload
There are two ways to add multiple files to FormData
, the only difference is that upload keys are different for array types。
FormData.fromMap({
"files": [
MultipartFile.fromFileSync("./example/upload.txt",
filename: "upload.txt"),
MultipartFile.fromFileSync("./example/upload.txt",
filename: "upload.txt"),
]
});
The upload key eventually becomes "files[]",This is because many back-end services add a middle bracket to key when they get an array of files. If you don't want “[]”,you should create FormData as follows(Don't use FormData.fromMap
):
var 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"),
),
]);
Transformer
Transformer
allows changes to the request/response data before it is sent/received to/from the server. This is only applicable for request methods 'PUT', 'POST', and 'PATCH'. Dio has already implemented a DefaultTransformer
, and as the default Transformer
. If you want to customize the transformation of request/response data, you can provide a Transformer
by your self, and replace the DefaultTransformer
by setting the dio.transformer
.
In flutter
If you use dio in flutter development, you'd better to decode json in background with [compute] function.
// Must be top-level function
_parseAndDecode(String response) {
return jsonDecode(response);
}
parseJson(String text) {
return compute(_parseAndDecode, text);
}
void main() {
...
//Custom jsonDecodeCallback
(dio.transformer as DefaultTransformer).jsonDecodeCallback = parseJson;
runApp(MyApp());
}
Other Example
There is an example for customizing Transformer.
HttpClientAdapter
HttpClientAdapter is a bridge between Dio and HttpClient.
Dio implements standard and friendly API for developer.
HttpClient: It is the real object that makes Http requests.
We can use any HttpClient not just dart:io:HttpClient
to make the Http request. And all we need is providing a HttpClientAdapter
. The default HttpClientAdapter for Dio is DefaultHttpClientAdapter
.
dio.httpClientAdapter = new DefaultHttpClientAdapter();
Here is a simple example to custom adapter.
Using proxy
DefaultHttpClientAdapter
provide a callback to set proxy to dart:io:HttpClient
, for example:
import 'package:dio/dio.dart';
import 'package:dio/adapter.dart';
...
(dio.httpClientAdapter as DefaultHttpClientAdapter).onHttpClientCreate = (client) {
// config the http client
client.findProxy = (uri) {
//proxy all request to localhost:8888
return "PROXY localhost:8888";
};
// you can also create a new HttpClient to dio
// return new HttpClient();
};
There is a complete example here.
Https certificate verification
There are two ways to verify the https certificate. Suppose the certificate format is PEM, the code like:
String PEM="XXXXX"; // certificate content
(dio.httpClientAdapter as DefaultHttpClientAdapter).onHttpClientCreate = (client) {
client.badCertificateCallback=(X509Certificate cert, String host, int port){
if(cert.pem==PEM){ // Verify the certificate
return true;
}
return false;
};
};
Another way is creating a SecurityContext
when create the HttpClient
:
(dio.httpClientAdapter as DefaultHttpClientAdapter).onHttpClientCreate = (client) {
SecurityContext sc = new SecurityContext();
//file is the path of certificate
sc.setTrustedCertificates(file);
HttpClient httpClient = new HttpClient(context: sc);
return httpClient;
};
In this way, the format of certificate must be PEM or PKCS12.
Http2 support
dio_http2_adapter package is a Dio HttpClientAdapter which support Http/2.0 .
Cancellation
You can cancel a request using a cancel token. One token can be shared with multiple requests. When a token's cancel
method invoked, all requests with this token will be cancelled.
CancelToken token = CancelToken();
dio.get(url1, cancelToken: token);
dio.get(url2, cancelToken: token);
// cancel the requests with "cancelled" message.
token.cancel("cancelled");
There is a complete example here.
Extends Dio class
Dio
is a abstract class with factory constructor,so we don't extend Dio
class directy. For this purpose, we can extend DioForNative
or DioForBrowser
instead, for example:
import 'package:dio/dio.dart';
import 'package:dio/native_imp.dart'; //If in browser, import 'package:dio/browser_imp.dart'
class Http extends DioForNative {
Http([BaseOptions options]):super(options){
// do something
}
}
We can also implement our Dio client:
class MyDio with DioMixin implements Dio{
// ...
}
Copyright & License
This open source project authorized by https://flutterchina.club , and the license is MIT.
Features and bugs
Please file feature requests and bugs at the issue tracker.
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