我使用网络服务进行图像处理,它在Postman中运行良好:
现在我想用Dart:
来制作http请求import 'package:http/http.dart' as http;
static ocr(File image) async {
var url = '${API_URL}ocr';
var bytes = image.readAsBytesSync();
var response = await http.post(
url,
headers:{ "Content-Type":"multipart/form-data" } ,
body: { "lang":"fas" , "image":bytes},
encoding: Encoding.getByName("utf-8")
);
return response.body;
}
但我不知道如何上传图片文件,在上面的代码中我得到例外:Bad state: Cannot set the body fields of a Request with content-type "multipart/form-data".
我该如何撰写请求正文?
答案 0 :(得分:14)
你的解决方法应该有效;许多服务器将接受application / x-www-form-urlencoded作为替代方案(尽管数据编码效率适中,效率不高)。
但是,可以使用dart:http来执行此操作。您不想使用http.post
,而是想要使用http.MultipartFile
对象。
var request = new http.MultipartRequest("POST", url);
request.fields['user'] = 'someone@somewhere.com';
request.files.add(http.MultipartFile.fromPath(
'package',
'build/package.tar.gz',
contentType: new MediaType('application', 'x-tar'),
));
request.send().then((response) {
if (response.statusCode == 200) print("Uploaded!");
});
答案 1 :(得分:10)
我想向您推荐dio包,dio是Dart / Flutter的强大Http客户端,它支持拦截器,FormData,请求取消,文件下载,超时等。
dio非常易于使用,在这种情况下,您可以:
发送FormData:
FormData formData = new FormData.from({
"name": "wendux",
"file1": new UploadFileInfo(new File("./upload.jpg"), "upload1.jpg")
});
response = await dio.post("/info", data: formData)
更多详情请参阅dio。
答案 2 :(得分:6)
我找到了一个不使用任何外部插件的有效示例,仅使用
import 'package:http/http.dart' as http;
import 'dart:io';
import 'package:path/path.dart';
import 'package:async/async.dart';
import 'dart:convert';
代码
var stream =
new http.ByteStream(DelegatingStream.typed(imageFile.openRead()));
// get file length
var length = await imageFile.length(); //imageFile is your image file
Map<String, String> headers = {
"Accept": "application/json",
"Authorization": "Bearer " + token
}; // ignore this headers if there is no authentication
// string to uri
var uri = Uri.parse(Constants.BASE_URL + "api endpoint here");
// create multipart request
var request = new http.MultipartRequest("POST", uri);
// multipart that takes file
var multipartFileSign = new http.MultipartFile('profile_pic', stream, length,
filename: basename(imageFile.path));
// add file to multipart
request.files.add(multipartFileSign);
//add headers
request.headers.addAll(headers);
//adding params
request.fields['loginId'] = '12';
request.fields['firstName'] = 'abc';
// request.fields['lastName'] = 'efg';
// send
var response = await request.send();
print(response.statusCode);
// listen for response
response.stream.transform(utf8.decoder).listen((value) {
print(value);
});
答案 3 :(得分:4)
使用MultipartRequest类。 如何在flutter / dart中使用restAPI上传图像文件
void uploadImage1(File _image) async {
// open a byteStream
var stream = new http.ByteStream(DelegatingStream.typed(_image.openRead()));
// get file length
var length = await _image.length();
// string to uri
var uri = Uri.parse("enter here upload URL");
// create multipart request
var request = new http.MultipartRequest("POST", uri);
// if you need more parameters to parse, add those like this. i added "user_id". here this "user_id" is a key of the API request
request.fields["user_id"] = "text";
// multipart that takes file.. here this "image_file" is a key of the API request
var multipartFile = new http.MultipartFile('image_file', stream, length, filename: basename(_image.path));
// add file to multipart
request.files.add(multipartFile);
// send request to upload image
await request.send().then((response) async {
// listen for response
response.stream.transform(utf8.decoder).listen((value) {
print(value);
});
}).catchError((e) {
print(e);
});
}
名称空间:
import 'package:path/path.dart';
import 'package:async/async.dart';
import 'dart:io';
import 'package:http/http.dart' as http;
答案 4 :(得分:2)
使用表单数据将图像上传到服务器
要将图像上传到服务器,您需要一个dio库。
功能:
代码示例:
import 'package:dio/dio.dart' as dio;
import 'dart:convert';
try {
///[1] CREATING INSTANCE
var dioRequest = dio.Dio();
dioRequest.options.baseUrl = '<YOUR-URL>';
//[2] ADDING TOKEN
dioRequest.options.headers = {
'Authorization': '<IF-YOU-NEED-ADD-TOKEN-HERE>',
'Content-Type': 'application/x-www-form-urlencoded'
};
//[3] ADDING EXTRA INFO
var formData =
new dio.FormData.fromMap({'<SOME-EXTRA-FIELD>': 'username-forexample'});
//[4] ADD IMAGE TO UPLOAD
var file = await dio.MultipartFile.fromFile(image.path,
filename: basename(image.path),
contentType: MediaType("image", basename(image.path)));
formData.files.add(MapEntry('photo', file));
//[5] SEND TO SERVER
var response = await dioRequest.post(
url,
data: formData,
);
final result = json.decode(response.toString())['result'];
} catch (err) {
print('ERROR $err');
}
答案 5 :(得分:2)
如何在flutter / dart中使用restAPI上传图像文件。
这对我有用。
var postUri = Uri.parse("apiUrl");
http.MultipartRequest request = new http.MultipartRequest("POST", postUri);
http.MultipartFile multipartFile = await http.MultipartFile.fromPath(
'file', filePath);
request.files.add(multipartFile);
http.StreamedResponse response = await request.send();
print(response.statusCode);
答案 6 :(得分:2)
如果有人尝试使用 MultipartRequest
方法上传 pdf 或任何其他文档,请留在这里。
只需将内容类型添加为 -
contentType: new MediaType('application', 'pdf')
答案 7 :(得分:1)
这可以使用MultipartRequest类(https://docs.flutter.io/flutter/package-http_http/MultipartRequest-class.html)
实现根据需要更改媒体类型和uri。
uploadFile() async {
var postUri = Uri.parse("<pathToFile>");
var request = new http.MultipartRequest("POST", postUri);
request.fields['user'] = 'blah';
request.files.add(new http.MultipartFile.fromBytes('file', await File.fromUri("<path/to/file").readAsBytes(), contentType: new MediaType('image', 'jpeg')))
request.send().then((response) {
if (response.statusCode == 200) print("Uploaded!");
});
}
答案 8 :(得分:1)
要添加标头并将 http multipart 与 https://pub.dev/packages/multi_image_picker 插件一起使用,
这是代码。
var request = http.MultipartRequest(
'POST', Uri.parse(myurl)
);
//Header....
request.headers['Authorization'] ='bearer $authorizationToken';
request.fields['PropertyName'] = propertyName;
request.fields['Country'] = country.toString();
request.fields['Description'] = des;
request.fields['State'] = state.toString();
request.files.add(http.MultipartFile.fromBytes(
'ImagePaths',
learnImage,
filename: 'some-file-name.jpg',
contentType: MediaType("image", "jpg"),
)
);
var response = await request.send();
print(response.stream);
print(response.statusCode);
final res = await http.Response.fromStream(response);
print(res.body);
使用 HTTP 和 https://pub.dev/packages/image_picker 插件
这是代码
var request = http.MultipartRequest(
'POST', Uri.parse(myurl)
);
request.headers['Authorization'] ='bearer $authorizationToken';
request.fields['PropertyName'] = propertyName;
request.fields['Country'] = country.toString();
request.fields['Description'] = des;
request.fields['State'] = state.toString();
request.files.add(await http.MultipartFile.fromPath(
'ImagePaths',
file.path
)
);
var response = await request.send();
print(response.stream);
print(response.statusCode);
final res = await http.Response.fromStream(response);
print(res.body);
答案 9 :(得分:0)
带听到者 上传图片
Future uploadImageMedia(File fileImage, String token) async {
final mimeTypeData =
lookupMimeType(fileImage.path, headerBytes: [0xFF, 0xD8]).split('/');
final imageUploadRequest =
http.MultipartRequest('POST', Uri.parse(mainUrlSite + "wp-json/wp/v2/media"));
final file = await http.MultipartFile.fromPath('file', fileImage.path,
contentType: MediaType(mimeTypeData[0], mimeTypeData[1]));
imageUploadRequest.files.add(file);
imageUploadRequest.headers.addAll({
"Authorization": "Bearer " + token
});
try {
final streamedResponse = await imageUploadRequest.send();
streamedResponse.stream.transform(utf8.decoder).listen((value) {
print(value);
return Future.value(value);
});
} catch (e) {
print(e);
}
}
答案 10 :(得分:0)
对于dio,我喜欢这样:
Future<void> _uploadFileAsFormData(String path) async {
try {
final dio = Dio();
dio.options.headers = {
'Content-Type': 'application/x-www-form-urlencoded'
};
final file =
await MultipartFile.fromFile(path, filename: 'test_file');
final formData = FormData.fromMap({'file': file}); // 'file' - this is an api key, can be different
final response = await dio.put( // or dio.post
uploadFileUrlAsString,
data: formData,
);
} catch (err) {
print('uploading error: $err');
}
}
答案 11 :(得分:0)
我通过 put 方法使用 Dio 库:
var formData = FormData.fromMap({
'simpleParam': 'example',
'file': await MultipartFile.fromFile(filePath, filename: 'file.jpg')
});
var dio = Dio();
dio.options.headers[HttpHeaders.authorizationHeader] = myToken;
var response = new Response(); //Response from Dio
response = await dio.put(myUrl + "/myApi", data: formData);
结果在response.data
答案 12 :(得分:0)
2021 年更新方式:
import 'package:mime/mime.dart';
import 'package:http/http.dart' as http;
import 'package:http_parser/http_parser.dart';
import 'dart:io';
Future<dynamic> multipartImageUpload(String baseUrl, String api, File image) async {
var uri = Uri.parse(baseUrl + api);
final mimeTypeData =
lookupMimeType(image.path, headerBytes: [0xFF, 0xD8]).split('/');
// Intilize the multipart request
final imageUploadRequest = http.MultipartRequest('PUT', uri);
// Attach the file in the request
final file = await http.MultipartFile.fromPath('image', image.path,
contentType: MediaType(mimeTypeData[0], mimeTypeData[1]));
imageUploadRequest.files.add(file);
// add headers if needed
//imageUploadRequest.headers.addAll(<some-headers>);
try {
final streamedResponse = await imageUploadRequest.send();
final response = await http.Response.fromStream(streamedResponse);
return response;
} catch (e) {
print(e);
return null;
}
}
答案 13 :(得分:-1)
MultipartFile
类中有一个静态方法,称为fromPath
,它将返回Future。您可以使用request.files.add()
方法在请求正文中添加文件。
final postUri = Uri.parse(kAPIUrl);
http.MultipartRequest request = http.MultipartRequest('POST', postUri);
http.MultipartFile multipartFile =
await http.MultipartFile.fromPath('image_file', filePath); //returns a Future<MultipartFile>
request.files.add(multipartFile);
http.StreamedResponse response = await request.send();