Flutter: Send JSON body for Http GET request

Question

I need to make a GET request to an API from my Flutter app which requires request body as JSON (raw).

I tested the API with JSON request body in Postman and it seems to be working fine.

Now on my Flutter application I am trying to do the same thing:

_fetchDoctorAvailability() async {
    var params = {
      "doctor_id": "DOC000506",
      "date_range": "25/03/2019-25/03/2019" ,
      "clinic_id":"LAD000404"
    };

    Uri uri = Uri.parse("http://theapiiamcalling:8000");
    uri.replace(queryParameters: params);

    var response = await http.get(uri, headers: {
      "Authorization": Constants.APPOINTMENT_TEST_AUTHORIZATION_KEY,
      HttpHeaders.contentTypeHeader: "application/json",
      "callMethod" : "DOCTOR_AVAILABILITY"
    });

    print('---- status code: ${response.statusCode}');
    var jsonData = json.decode(response.body);

    print('---- slot: ${jsonData}');
}

However the API gives me an error saying

{message: Missing input json., status: false}

How do I send a raw (or rather JSON) request body for Http GET request in Flutter?

Suragch · Answer 1 · 2021-01-26T23:44:31.643

GET

GET requests are not intended for sending data to the server (but see this). That's why the http.dart get method doesn't have a body parameter. However, when you want to specify what you are getting from the server, sometimes you need to include query parameters, which is a form of data. The query parameters are key-value pairs, so you can include them as a map like this:

final queryParameters = {
  'name': 'Bob',
  'age': '87',
};
final uri = Uri.http('www.example.com', '/path', queryParameters);
final headers = {HttpHeaders.contentTypeHeader: 'application/json'};
final response = await http.get(uri, headers: headers);

POST

Unlike GET requests, POST requests are intended for sending data in the body. You can do it like this:

final body = {
  'name': 'Bob',
  'age': '87',
};
final jsonString = json.encode(body);
final uri = Uri.http('www.example.com', '/path');
final headers = {HttpHeaders.contentTypeHeader: 'application/json'};
final response = await http.post(uri, headers: headers, body: jsonString);

Note that the parameters were a Map on the Dart side. Then they were converted to a JSON string by the json.encode() function from the dart:convert library. That string is the POST body.

So if the server is asking you to pass it data in a GET request body, check again. While it is possible to design a server in this way, it isn't standard.

diegoveloper · Accepted Answer · 2019-03-25T06:05:44.783

9

uri.replace... returns a new Uri, so you have to assign it into a new variable or use directly into the get function.

final newURI = uri.replace(queryParameters: params);

var response = await http.get(newURI, headers: {
  "Authorization": Constants.APPOINTMENT_TEST_AUTHORIZATION_KEY,
  HttpHeaders.contentTypeHeader: "application/json",
  "callMethod" : "DOCTOR_AVAILABILITY"
});

using post:

      var params = {
        "doctor_id": "DOC000506",
        "date_range": "25/03/2019-25/03/2019" ,
        "clinic_id":"LAD000404"
      };

      var response = await http.post("http://theapiiamcalling:8000", 
      body: json.encode(params)
      ,headers: {
        "Authorization": Constants.APPOINTMENT_TEST_AUTHORIZATION_KEY,
        HttpHeaders.contentTypeHeader: "application/json",
        "callMethod" : "DOCTOR_AVAILABILITY"
      });

edited Mar 25 '19 at 06:05

answered Mar 25 '19 at 05:52

diegoveloper

79,114
19
208
182

Thanks, now I no longer get that error message but the response body comes back as empty. – codeinprogress Mar 25 '19 at 06:01
1

maybe you should use post instead of get to send raw data. – diegoveloper Mar 25 '19 at 06:04
@diegoveloper can we use the body tag use in post request in get request, if we want to submit some data. When I'm sending data in same manner, I'm receiving parameters as query string on the server like: http://someUrl.com/method?param=1 and so on... – Jennis Vaishnav May 08 '20 at 09:16
@diegoveloper: Every where i see the params , If i have to send bool, int as well. how can i do that? – Abhishek Thapliyal Aug 24 '20 at 10:42
final uriL = Uri.http('http://10.130.34.165:4002/masterRequest','/Get_IFSCDetail' ,queryParameters); in my code i am passing this but tis giving error of FormatException: Invalid radix-10 number – s.j Feb 12 '21 at 06:19
Invalid radix-10 number – Johan Ordenes Galleguillos Jan 19 '22 at 14:05

score -1 · Answer 3 · answered Aug 26 '21 at 09:51

if you want to send complex/nested data through a GET request like the sample below, you can use a simple class i created on github https://github.com/opatajoshua/SimplifiedUri

final params = {
  'name': 'John',
  'columns': ['firstName', 'lastName'],
  'ageRange': {
    'from': 12,
    'to': 60,
  },
  'someInnerArray': [1,2,3,5]
};
final Uri uri = SimplifiedUri.uri('http://api.mysite.com/users', params);
final headers = {HttpHeaders.contentTypeHeader: 'application/json'};
final response = await http.get(uri, headers: headers);

output

http://api.mysite.com/users?name=John&columns%5B%5D=firstName&columns%5B%5D=lastName&ageRange%5Bfrom%5D=12&ageRange%5Bto%5D=60&someInnerArray%5B%5D=1&someInnerArray%5B%5D=2&someInnerArray%5B%5D=3&someInnerArray%5B%5D=5

Flutter: Send JSON body for Http GET request

3 Answers3

GET

POST

Linked