How to post x-www-form-urlencoded in Flutter - flutter

Question

I am trying to send a POST request to an API to create an account.
The request is working well, it should look like this :
Bulk Edit Mode :
Key-Value Edit mode :
There are also 9 headers that are auto-generated, so I did not show them, but I can take another screen if you need to.
My request looks like this :
import 'dart:convert' as convert ;
import 'package:my_project/requests/utils.dart';
import 'package:http/http.dart' as http;
Future<String> createUser(String firstName, String name, String mail,
String password, String confirmPassword, String birthDate,
String phone) async {
String url = BASE_URL + "createUser" ; // Don't worry about BASE_URL, the final url is correct
Map<String, dynamic> formMap = {
"name": name,
"surname": firstName,
"mail": mail,
"password": password,
"birth": birthDate,
"phone": phone,
"confirmPassword": confirmPassword
} ;
http.Response response = await http.post(
url,
body: convert.jsonEncode(formMap),
headers: {
"Content-Type": "application/x-www-form-urlencoded"
},
encoding: convert.Encoding.getByName("utf-8"),
);
print("RESPONSE ${response.statusCode} ; BODY = ${response.body}");
return (response.body) ;
}
Here is my print result :
I/flutter ( 6942): RESPONSE 307 ; BODY =
As you can see, I am getting a 307 error, and the problem does not come from the server, as it worked with Postman.
Am I sending this form-urlencoded POST request correctly ?
I also tried :
http.Response response = await http.post(
url,
body: "name=$name&surname=$firstName&mail=$mail&password=$password&birth=$birthDate&phone=$phone&confirmPassword=$confirmPassword",
headers: {
"Content-Type": "application/x-www-form-urlencoded"
},
encoding: convert.Encoding.getByName("utf-8"),
);
but with the same results. I tried too :
http.Response response = await http.post(
url,
body: formMap,
headers: {
"Content-Type": "application/x-www-form-urlencoded"
},
encoding: convert.Encoding.getByName("utf-8"),
);
with same result again.
What am I doing wrong ?
EDIT :
I tried FoggyDay answer, here is my request now :
final client = HttpClient() ;
final request = await client.postUrl(Uri.parse(url));
request.headers.set(HttpHeaders.contentTypeHeader, "application/x-www_form-urlencoded");
request.followRedirects = true ;
request.write(formMap);
final response = await request.close();
print("STATUS CODE = ${response.statusCode}");
However I still have a 307 error. Did I create the right request ?
EDIT 2 :
As asked, I printed location as follow :
final client = HttpClient() ;
final request = await client.postUrl(Uri.parse(url));
request.headers.set(HttpHeaders.contentTypeHeader, "application/x-www_form-urlencoded");
request.followRedirects = true ;
request.write(formMap);
final response = await request.close();
print("STATUS CODE = ${response.statusCode}");
print("Response headers = ${response.headers}");
And I get :
I/flutter ( 7671): STATUS CODE = 307
I/flutter ( 7671): Response headers = location: /app/createUser/
I/flutter ( 7671): date: Tue, 26 May 2020 09:00:29 GMT
I/flutter ( 7671): content-length: 0
I/flutter ( 7671): server: Apache/2.4.41 (Amazon) OpenSSL/1.0.2k-fips
The thing is I am already making a call on /app/createUser... ('/app/' is in BASE_URL)

Answer 1

For x-www-form-urlencoded parameters, just use this:
Future<String> login(user, pass) async {
final response = await http.post(
Uri.parse('https:youraddress.com/api'),
headers: {
"Content-Type": "application/x-www-form-urlencoded",
},
encoding: Encoding.getByName('utf-8'),
body: {"title": "title"},
);
if (response.statusCode == 200) {
// If the server did return a 200 OK response,
// then parse the JSON.
} else {
// If the server did not return a 200 OK response,
// then throw an exception.
}
}

Answer 2

official http package from flutter is buggy with urlencoded type, you can use Dio package instead.
final dio = Dio();
final res = dio.post(
'/info',
data: {'id': 5},
options: Options(contentType: Headers.formUrlEncodedContentType),
);

Answer 3

As you can see, I am getting a 307 error, and the problem does not come from the server, as it worked with Postman.
No, that's NOT necessarily the case. Look here:
MDN: 307 Temporary Redirect
In other words, Postman is following the redirect ... and your Flutter app isn't.
SUGGESTION: Try setting followRedirects to true:
https://api.flutter.dev/flutter/dart-io/HttpClientRequest/followRedirects.html
ADDITIONAL INFO:
The default value for request.followRedirects happens to be "true" anyway. It doesn't hurt to explicitly set it ... but it explains why the behavior didn't change.
Per this post:
The Dart HTTP client won't follow
redirects
for POSTs unless the response code is 303. It follows 302 redirects
for GET or HEAD.
Per this post
The correct way to handle redirects on POST requests is to manually
implement an appropriate strategy for your use case:
var response = await client.post(...);
if (response.statusCode == 301 || response.statusCode == 302) {
// send post request again if appropriate
}

Answer 4

let try with this code, it works well for me.
var headers = {
'Content-Type': 'application/x-www-form-urlencoded'
};
var request = http.Request('POST', Uri.parse('https://oauth2.googleapis.com/token'));
request.bodyFields = {
'client_id': '',
'client_secret': '',
'code': '',
'grant_type': 'authorization_code',
'redirect_uri': ''
};
request.headers.addAll(headers);
http.StreamedResponse response = await request.send();
if (response.statusCode == 200) {
print(await response.stream.bytesToString());
}
else {
print(response.reasonPhrase);
}

Answer 5

If you are using http, you should add the below lines
Android -
android/app/src/main/AndroidManifest.xml
<uses-permission android:name="android.permission.INTERNET" />
<application
android:label="first_app"
android:usesCleartextTraffic="true" //this line
android:icon="#mipmap/ic_launcher">
iOS -
ios/Runner/info.plist
<key>NSAppTransportSecurity</key>
<dict>
<key>NSAllowsArbitraryLoads</key>
<true/>
</dict>
Be warned that you will need to have an explanation for Apple's review team when enabling this, otherwise, your app will get rejected on submission.
Uninstall the app and Reinstall again if you have the app already in the emulator when you add those lines to avoid confusions.
If you send HTTP GET request, you can use query parameters as follows:
QueryParameters
http://example.com/path/to/page?name=ferret&color=purple
The contents are encoded as query parameters in the URL
application/x-www-form- urlencoded
The contents are encoded as query parameters in the body of the
request instead of the URL.
The data is sent as a long query string. The query string contains
name-value pairs separated by & character
POST example
flutter http package version - http: ^0.13.1
import 'package:http/http.dart' as httpClient;
Future<dynamic> postData() async {
//Uri.https("192.168.1.30:5000", "/api/data")
//Uri.parse("your url");
final Uri uri = Uri.http("192.168.1.30:5000", "/api/data");
final response = await httpClient.post(
uri,
body: {
"name": "yourName",
"age": "yourAge"
},
headers: {
"Content-Type": "application/x-www-form-urlencoded",
},
encoding: Encoding.getByName('utf-8'),
);
return response.body;
}