How to get response body with request.send() in dart

I'm doing an api request uploading an image with

var request = new http.MultipartRequest("POST", uri);
var response = await request.send()

in dart using flutter. I can then check the response code with for instance

if (response.statusCode == 200) {
   print('ok');
}

with other calls I can also get the response body with

var result = response.body;

however when using request.send() I can't seem to find out how to get the response body result.

Any help or input is very much appreciated, thanks!

I checked the docs for request.send I returns Future<StreamedResponse> instead of Future<Response>

Digging more for StreamedResponse I found that it response.stream which is a ByteStream

Here is what you can do to get response in String

final response = await request.send();
final respStr = await response.stream.bytesToString();

In my opinoin you should only use request.send if you want streamed response instead of "collected" response. More about streams in dart here

Just use http.Response.fromStream()

import 'package:http/http.dart' as http;

var streamedResponse = await request.send()
var response = await http.Response.fromStream(streamedResponse);

You can cast after first response, look :

var postUri = Uri.parse("http://my-api.com/updatePhoto");
var request = new http.MultipartRequest("POST", postUri);

request.fields['user_id'] = user_id

request.files.add(await http.MultipartFile.fromPath(
  'photo',
  myPhoto.absolute.path,
  contentType: new MediaType('application', 'x-tar'),
));

request.send().then((result) async {

  http.Response.fromStream(result)
      .then((response) {

    if (response.statusCode == 200)
    {
      print("Uploaded! ");
      print('response.body '+response.body);
    }

    return response.body;

  });
}).catchError((err) => print('error : '+err.toString()))
    .whenComplete(()
{});

So this is my expected json object:

 {"hasErrors":true,"errorMessage":"Some Error Message","done":false}

On the basis of 'hasErrors' property I want to perform some action.

This is how I get it from Http Post Request:

  var request = http.Request('POST', url);
  request.body = json.encode(data);
  request.headers.addAll(headers);

  var streamedResponse = await request.send();
  var response = await http.Response.fromStream(streamedResponse);
  final result = jsonDecode(response.body) as Map<String, dynamic>;
  return !result['hasErrors'];

Your MultipartRequest returns a Streamed Response since you used request.send. You will need to extract the string value from the response like below:

import 'package:http/http.dart'

var request = new MultipartRequest("POST", uri);
var response = await request.send()

// Extract String from Streamed Response
var responseString = await response.stream.bytesToString();

In this case the responseString will be just like response.body of

final response = await post(URL, body : map);

    import 'package:http/http.dart'
    import 'dart:convert';
    
    var request = new MultipartRequest("POST", uri);
    var response = await request.send()
    
    // Extract String from Streamed Response
    var responseString = await response.stream.bytesToString();
    final decodedMap = json.decode(responseString);
    print(decodedMap['id']);
    print(decodedMap['name']);

What worked for me was,

await res.stream.transform(utf8.decoder).transform(json.decoder).first;