http request in dart is not behaving the same as in postman-CodePudding

I am trying the write a program that uses the public API for the online investment broker Questrade.

You manually generate a refresh token on the website, and then pass it to a request to get an access token.

Use the token you copied to redeem it for an access token and the server or practice server URL using the following command:

https://login.questrade.com/oauth2/token?grant_type=refresh_token&refresh_token=

or

https://practicelogin.questrade.com/oauth2/token?grant_type=refresh_token&refresh_token=

I structured the GET request in postman as follows, and it succeeds and receives a valid json body.

https://login.questrade.com/oauth2/token?grant_type=refresh_token&refresh_token=MT1men5gBhSXyv15e6j7gC4CrD8msq3P0

In dart I structure the request as follows...

static Future<AccessToken> getAccessToken(String refreshToken) async {
      var uri = Uri.https("login.questrade.com", "/oauth2/token?grant_type=refresh_token&refresh_token=$refreshToken");
      var response = await http.get(uri);
      print(response);
      var json = jsonDecode(response.body);
      return AccessToken.fromJson(json);
    }

But all it give me is an actually html response that looks like it is a login page(too big to post).

So it seems like the endpoint is treating these requests differently, but I can not figure out what is different about these two requests...

CodePudding user response：

You are creating the Uri wrong since you are using the path as a way to encode data which does not work since it will try encode &. You can see the problem if you print your uri object:

https://login.questrade.com/oauth2/token?grant_type=refresh_token&refresh_token=MT1men5gBhSXyv15e6j7gC4CrD8msq3P0

Instead, do something like this where you provide the data to the Uri.https constructor:

void main() {
  var refreshToken = 'MT1men5gBhSXyv15e6j7gC4CrD8msq3P0';
  var uri = Uri.https(
    'login.questrade.com',
    '/oauth2/token',
    <String, String>{
      'grant_type': 'refresh_token',
      'refresh_token': refreshToken,
    },
  );
  print(uri);
  // https://login.questrade.com/oauth2/token?grant_type=refresh_token&refresh_token=MT1men5gBhSXyv15e6j7gC4CrD8msq3P0
}

CodePudding user response：

The solution was not to use Uri.https but rather Uri.parse

var uri = Uri.parse("https://login.questrade.com/oauth2/token?grant_type=refresh_token&refresh_token=$refreshToken");