How to upload image in Flutter?

问题:

I would like to upload a image, I am using http.Client() for making requests,

static uploadImage(String id, File file) {
  var httpClient = createHttpClient();

  Map<String, String> headers = new Map<String, String>();
  headers.putIfAbsent("Authorization", () => "---");
  headers.putIfAbsent("Content-Type", () => "application/json");

  var body=new List();
  body.add(id.)
  httpClient.post(URL_UPLOADIMAGE,headers: headers,body: ,encoding: )
}

What should be the body and encoding part for the request ?

回答1:

Use MultipartRequest class

Upload(File imageFile) async {    
    var stream = new http.ByteStream(DelegatingStream.typed(imageFile.openRead()));
      var length = await imageFile.length();

      var uri = Uri.parse(uploadURL);

     var request = new http.MultipartRequest("POST", uri);
      var multipartFile = new http.MultipartFile('file', stream, length,
          filename: basename(imageFile.path));
          //contentType: new MediaType('image', 'png'));

      request.files.add(multipartFile);
      var response = await request.send();
      print(response.statusCode);
      response.stream.transform(utf8.decoder).listen((value) {
        print(value);
      });
    }

name spaces:

import 'package:path/path.dart';
import 'package:async/async.dart';
import 'dart:io';
import 'package:http/http.dart' as http;

回答2:

Checkout the body in submitForm() method.

File _image;

Future cameraImage() async {
  var image = await ImagePicker.pickImage(
    source: ImageSource.camera,
    maxHeight: 240.0,
    maxWidth: 240.0,
  );

  setState(() {
    _image = image;
  });
}

submitForm() async {
  final response = await http.post(
    uri,
    headers: {
      AuthUtils.AUTH_HEADER: _authToken
    },
    body: {
      'user_id': userId
      'photo': _image != null ? 'data:image/png;base64,' +
          base64Encode(_image.readAsBytesSync()) : '',
    },
  );

  final responseJson = json.decode(response.body);

  print(responseJson);
}

回答3:

Consider using Flutter's Firebase Storage plugin -- it has features that could be useful for uploading large image files on a mobile connection.

I wrote the plugin, contributions and feedback are welcome!

回答4:

I had try above all but non of above work for me for upload file in server.

After deep search, I got a plugin for same as Dio.

The following code use for upload file in server

uploadFileFromDio(UserProfile userProfile, File photoFile) async {
    var dio = new Dio();
    dio.options.baseUrl = url;
    dio.options.connectTimeout = 5000; //5s
    dio.options.receiveTimeout = 5000;
    dio.options.headers = <Header Json>;
    FormData formData = new FormData();
    formData.add("user_id", userProfile.userId);
    formData.add("name", userProfile.name);
    formData.add("email", userProfile.email);

    if (photoFile != null &&
        photoFile.path != null &&
        photoFile.path.isNotEmpty) {
      // Create a FormData
      String fileName = basename(photoFile.path);
      print("File Name : $fileName");
      print("File Size : ${photoFile.lengthSync()}");
      formData.add("user_picture", new UploadFileInfo(photoFile, fileName));
    }
    var response = await dio.post("user/manage_profile",
        data: formData,
        options: Options(
            method: 'POST',
            responseType: ResponseType.PLAIN // or ResponseType.JSON
            ));
    print("Response status: ${response.statusCode}");
    print("Response data: ${response.data}");
  }