How to send custom header in flutter http post request

Question

There is http package in my flutter project. I want to send a post request with custom header. Here is my code snippet. it will make clear my problem using http for custom header. It always runs else statement means the response type is not 200 and it gives me the error provided Invalid token. but on a post man, it works fine

Map data = {
    'user_fullname': _name,
    'user_address': _address,
    'user_mobile': _phone,
  };
  var tokenData = {
    'User_token': token,
    'Content-Type': 'application/x-www-form-urlencoded'
  };

  final response = await http.post(url, body: data, headers: tokenData);
  if (response.statusCode == 200) {
    print(response.body);
  } else {
    print(response.body);
  }

Postman Testing

My bet is that your server is incorrectly requiring that the User_token header have an upper case U. (Dart will lower case it as it sends it.) Try your postman request again, but with a lowercase user_token and see what happens. — Richard Heap
– Richard Heap, Commented Oct 1, 2019 at 14:39
@RichardHeap good point, but wouldn't that affect Postman request as well? — Fernando Rocha
– Fernando Rocha, Commented Oct 1, 2019 at 15:00

Fernando Rocha · Accepted Answer · 2019-10-01 17:02:27Z

4

I'm guessing you're passing invalid types to the post request. (headers must be Map<String, String> (i'm not sure what is dart inferring from tokenData at runtime), body can be dynamic, etc.)

  final String url = 'YOUR_API_URL';
  final Map<String, String> tokenData = {
   "Content-type": "application/x-www-form-urlencoded",
   "user_token": token
  };
  final Map<String, String> data = { //is _phone a String?
    'user_fullname': _name,
    'user_address': _address,
    'user_mobile': _phone,
  };

  final Response response = await post(url, headers: tokenData, body: data);

  if (response.statusCode == 200) {
    print(response.body);
  } else {
    print(response.body);
  }
}

the body can only be a String, a List<int> or a Map<String, String>

as descibed at https://pub.dev/documentation/http/latest/http/Client/post.html

edited Oct 1, 2019 at 17:02

answered Oct 1, 2019 at 13:53

Fernando Rocha

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Comments

Solly · Accepted Answer · 2020-03-29 23:25:31Z

1

A little late to this but just got the same issue. What I realised on my side is that Headers for flutter HTTP clients are case insensitive. They automatically lowercase it https://github.com/flutter/flutter/issues/16665. Some servers receive case sensitive headers.

Postman sends a case sensitive header thats why User_token is properly received.

Solution wise try :https://pub.dev/packages/alt_http

answered Mar 29, 2020 at 23:25

Solly

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Comments

Dhaval Solanki · Accepted Answer · 2019-10-01 14:35:02Z

0

In your case must use try... catch exception.

And you can refer the below one.

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

And http request is...

  var client = new http.Client();
    try{
       var response = await client.post(
         "Your Url", 
         headers: {"User_token" : token /*, ...etc*/},
         body : {
           'user_fullname': _name,
           'user_address': _address,
           'user_mobile': _phone,
         }
       );
      if(response.statusCode == 200 || response.statusCode == 201){
          //enter your code
      }
    } on Exception catch (err){
       print("Error : $err");
    }

I hope help you.

Authorization image

edited Oct 1, 2019 at 14:35

Dhaval Solanki

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answered Oct 1, 2019 at 13:33

Akio Alex

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4 Comments

Code Land Over a year ago

Thanks for your response but still i am getting the same error :(

Code Land Over a year ago

yes of course I/flutter ( 7261): {"result":{"status":false,"message":"Provided invalid token"}}

Code Land Over a year ago

please see in the authorization link in the question section

Akio Alex Over a year ago

Hmm... Thanks for you reply. I have one ask. Can you share your postman request. If it not security, please send me the postman request file. I will test in here. And I will try my self. After complete, i will provide the code.

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