HTTP POST 与 Json 在身体上 - 颤振/飞镖

Question

This is my code to make a request to an API:

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';
  var body = jsonEncode({ 'data': { 'apikey': '12345678901234567890' } });

  print("Body: " + body);

  http.post(url,
      headers: {"Content-Type": "application/json"},
      body: body
  ).then((http.Response response) {
    print("Response status: ${response.statusCode}");
    print("Response body: ${response.contentLength}");
    print(response.headers);
    print(response.request);

  });
  }

I have a problem with the response from the request, where its suppose to have a body with json, but something went wrong and i think is with the json that i send on the body request, because it is a nested json object, and the value of the key is a json object. i would love to know how i can parse the json right and insert into body of the request.

this is the header response:

 {set-cookie: JSESSIONID=DA65FBCBA2796D173F8C8D78AD87F9AD;path=/testes2/;HttpOnly, last-modified: Thu, 10 May 2018 17:15:13 GMT, cache-control: no-store, no-cache, must-revalidate, max-age=0, post-check=0, pre-check=0, date: Thu, 10 May 2018 17:15:13 GMT, content-length: 0, pragma: no-cache, content-type: text/html, server: Apache-Coyote/1.1, expires: Tue, 03 Jul 2001 06:00:00 GMT}

and this is how is suppose to be:

Server: Apache-Coyote/1.1
Expires: Tue, 03 Jul 2001 06:00:00 GMT
Last-Modified: Thu, 10 May 2018 17:17:07 GMT
Cache-Control: no-store, no-cache, must-revalidate, max-age=0, post-check=0, pre-check=0
Pragma: no-cache
Content-Type: application/json;charset=UTF-8
Vary: Accept-Encoding
Set-Cookie: JSESSIONID=84813CC68E0E8EA6021CB0B4C2F245BC;path=/testes2/;HttpOnly
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Transfer-Encoding: chunked

the body response came empty and i think its because the body i sent on the request, can anyone help me with the nested json object in value??

SCREENSHOT OF POSTMAN:

Answer 1

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;
}

Answer 2

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 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 ;-)

Answer 3

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}");
    });  
  }

Answer 4

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');
    }
  }

Answer 5

this works for me

String body = json.encode(parameters);

http.Response response = await http.post(
  url: 'https://example.com',
  headers: {"Content-Type": "application/json"},
  body: body,
);

Answer 6

I implement like this:

static createUserWithEmail(String username, String email, String password) async{
    var url = 'http://www.yourbackend.com/'+ "users";
    var body = {
        'user' : {
          'username': username,
          'address': email,
          'password': password
       }
    };

    return http.post(
      url, 
      body: json.encode(body),
      headers: {
        "Content-Type": "application/json"
      },
      encoding: Encoding.getByName("utf-8")
    );
  }

Answer 7

This one is for using HTTPClient class

 request.headers.add("body", json.encode(map));

I attached the encoded json body data to the header and added to it. It works for me.

Answer 8

In my case POST in the Flutter App is working on the Web, but not on Android devices or the emulator.

Flutter->Server->API

To fix it, I:

1. changed HTTP HEADER on server with:

    $curlArr[CURLOPT_HTTPHEADER] = str_replace("application/x-www-form-urlencoded; charset=utf-8", "application/x-www-form-urlencoded",$curlArr[CURLOPT_HTTPHEADER]);

2. copied most of the Headers to my App from postman.

Answer 9

String body = json.encode(parameters);

http.Response response = await http.post(
  url: Uri.parse('https://example.com'),
  headers: {"Content-Type": "application/json"},
  body: body,
);

This worked for me!

Answer 10

This code works for me:

static Future<LoginAPI> connectToAPI(String email, String password) async {
    String apiURL = "domain/login";

    Map<String, String> headers = {
      "Content-Type": "application/json",
      "Accept": "application/json",
    };

    var body = json.encode({"email": email, "password": password});

    var apiResult = await http.post(
      Uri.parse(apiURL),
      headers: headers,
      body: body,
    );

    var jsonObject = json.decode(apiResult.body);
    if (apiResult.statusCode >= 300) {
      return jsonObject // you can mapping json object also here
    } else {
      return jsonObject // you can mapping json object also here
    }
  }

Answer 11

If your using freeze dont forget to encode it first. Which is probably easy to forget.

String body = json.encode(parameters.toJson()); //dont skip this one
http.Response response = await http.post(
  Uri.parse(apiURL),
  headers: {"Content-Type": "application/json"},
  body: body,
);

Answer 12

In my case I forgot to enable

app.use(express.json());

in my NodeJs server.