HTTP POST with Json on Body - Flutter/Dart

OK, finally we have an answer...

You are correctly specifying headers: {"Content-Type": "application/json"}, to set your content type. Under the hood either the package http or the lower level dart:io HttpClient is changing this to application/json; charset=utf-8. However, your server web application obviously isn't expecting the suffix.

To prove this I tried it in Java, with the two versions

conn.setRequestProperty("content-type", "application/json; charset=utf-8"); // fails
conn.setRequestProperty("content-type", "application/json"); // works

Are you able to contact the web application owner to explain their bug? I can't see where Dart is adding the suffix, but I'll look later.

EDIT Later investigation shows that it's the http package that, while doing a lot of the grunt work for you, is adding the suffix that your server dislikes. If you can't get them to fix the server then you can by-pass http and use the dart:io HttpClient directly. You end up with a bit of boilerplate which is normally handled for you by http.

Working example below:

import 'dart:convert';
import 'dart:io';
import 'dart:async';

main() async {
  String url =
      'https://pae.ipportalegre.pt/testes2/wsjson/api/app/ws-authenticate';
  Map map = {
    'data': {'apikey': '12345678901234567890'},
  };

  print(await apiRequest(url, map));
}

Future<String> apiRequest(String url, Map jsonMap) async {
  HttpClient httpClient = new HttpClient();
  HttpClientRequest request = await httpClient.postUrl(Uri.parse(url));
  request.headers.set('content-type', 'application/json');
  request.add(utf8.encode(json.encode(jsonMap)));
  HttpClientResponse response = await request.close();
  // todo - you should check the response.statusCode
  String reply = await response.transform(utf8.decoder).join();
  httpClient.close();
  return reply;
}

Depending on your use case, it may be more efficient to re-use the HttpClient, rather than keep creating a new one for each request. Todo - add some error handling ;-)

This works!

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

Future<http.Response> postRequest () async {
  var url ='https://pae.ipportalegre.pt/testes2/wsjson/api/app/ws-authenticate';

  Map data = {
    'apikey': '12345678901234567890'
  }
  //encode Map to JSON
  var body = json.encode(data);

  var response = await http.post(url,
      headers: {"Content-Type": "application/json"},
      body: body
  );
  print("${response.statusCode}");
  print("${response.body}");
  return response;
}

This would also work :

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

  sendRequest() async {

    Map data = {
       'apikey': '12345678901234567890'
    };

    var url = 'https://pae.ipportalegre.pt/testes2/wsjson/api/app/ws-authenticate';
    http.post(url, body: data)
        .then((response) {
      print("Response status: ${response.statusCode}");
      print("Response body: ${response.body}");
    });  
  }

I think many people have problems with Post 'Content-type': 'application / json' The problem here is parse data Map <String, dynamic> to json:

Hope the code below can help someone

Model:

class ConversationReq {
  String name = '';
  String description = '';
  String privacy = '';
  String type = '';
  String status = '';

  String role;
  List<String> members;
  String conversationType = '';

  ConversationReq({this.type, this.name, this.status, this.description, this.privacy, this.conversationType, this.role, this.members});

  Map<String, dynamic> toJson() {

    final Map<String, dynamic> data = new Map<String, dynamic>();

    data['name'] = this.name;
    data['description'] = this.description;
    data['privacy'] = this.privacy;
    data['type'] = this.type;

    data['conversations'] = [
      {
        "members": members,
        "conversationType": conversationType,
      }
    ];

    return data;
  }
}

Request:

createNewConversation(ConversationReq param) async {
    HeaderRequestAuth headerAuth = await getAuthHeader();
    var headerRequest = headerAuth.toJson();
/*
{
            'Content-type': 'application/json',
            'x-credential-session-token': xSectionToken,
            'x-user-org-uuid': xOrg,
          }
*/

    var bodyValue = param.toJson();

    var bodydata = json.encode(bodyValue);// important
    print(bodydata);

    final response = await http.post(env.BASE_API_URL + "xxx", headers: headerRequest, body: bodydata);

    print(json.decode(response.body));
    if (response.statusCode == 200) {
      // TODO
    } else {
      // If that response was not OK, throw an error.
      throw Exception('Failed to load ConversationRepo');
    }
  }