Converting my Postman Call to Dart/Flutter API Call

Question

I hope to use nutritionix api to get food information for the users of my application, I manage to get the call to work in Postman, however I cannot convert it to dart code. I am getting this error: '{message: Unexpected token " in JSON at position 0}'

Here is my (POST) postman call:

Here is my attempt at converting that to dart code:

  Future<void> fetchNutritionix() async {
    String url = 'https://trackapi.nutritionix.com/v2/natural/nutrients';
    Map<String, String> headers = {
      "Content-Type": "application/json",
      "x-app-id": "5bf----",
      "x-app-key": "c3c528f3a0c68-------------",
      "x-remote-user-id": "0",
    };
    String query = 'query: chicken noodle soup';

    http.Response response =
        await http.post(url, headers: headers, body: query);

    int statusCode = response.statusCode;
    print('This is the statuscode: $statusCode');
    final responseJson = json.decode(response.body);
    print(responseJson);

    //print('This is the API response: $responseJson');
  }

Any help would be appreciated! And, again thank you!

score 3 · Accepted Answer · answered Nov 07 '19 at 15:57

Your postman screenshot shows x-www-form-urlencoded as the content-type, so why are you changing that to application/json in your headers? Remove the content type header (the package will add it for you) and simply pass a map to the body parameter:

  var response = await http.post(
    url,
    headers: headers,
    body: {
      'query': 'chicken soup',
      'brand': 'acme',
    },
  );

score 1 · Answer 2 · answered Dec 18 '20 at 08:00

1

Also you can now generate Dart code (and many other languages) for your Postman request by clicking the Code button just below the Save button.

answered Dec 18 '20 at 08:00

JtheSaw

109
4

score 1 · Answer 3 · edited Jul 06 '21 at 13:49

1

click the three dotes button in request tab and select code option then select your language that you want convert code to

edited Jul 06 '21 at 13:49

Slava Rozhnev

9,510
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answered Jul 06 '21 at 10:25

Abdullah Alamodi

129
1
7

Thanks for the simple but valuable answer – user2244131 Sep 28 '22 at 08:44

score 0 · Answer 4 · answered Nov 07 '19 at 11:08

0

review the query you're posting

your Postman input is x-www-form-urlencoded instead of plain text

String query = 'query: chicken noodle soup';

why don't you try JSON better

String query = '{ "query" : "chicken noodle soup" }';

answered Nov 07 '19 at 11:08

arhak

2,488
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Woah! After being stuck at this problem for 2 days you fixed it! Thank you so much! I hope you have a great day/evening! – Allen Andre Indefenzo Nov 07 '19 at 11:13
Hello again @arhak, how do I add another body parameter such as "num_servings" : "1"? I tried creating a map but i'm getting an error: 'Unhandled Exception: Bad state: Cannot set the body fields of a Request with content-type "application/json"' – Allen Andre Indefenzo Nov 07 '19 at 13:44
@AllenAndreIndefenzo although the `headers` is taking in a map, the `body` is not, so you'd need to make it JSON yourself, e.g. https://stackoverflow.com/a/44740579/1681985 – arhak Nov 08 '19 at 08:12

Converting my Postman Call to Dart/Flutter API Call

4 Answers4