Infobip SMS bulk messages API with flutter/dart - flutter

Question

My post request doesn't work
I've tried running this but i end up with :
{"requestError":{"serviceException":{"messageId":"UNAUTHORIZED","text":"Invalid logindetails"}}}
This is my code :
data() async {
final client = HttpClient();
final request = await client .postUrl(Uri.parse("https://....api.infobip.com/sms/2/text/advanced")); request.headers.set(HttpHeaders.contentTypeHeader, "{'Authorization':'App ...KEY','Content-Type': 'application/json','Accept': 'application/json'}");
request.write({ '"messages": [{"from": "sms","destinations": [{"to": "..."}],"text": "ABC"}]' });
final response = await request.close();
response.transform(utf8.decoder).listen((contents) {
print(contents);
});
}

Answer 1

I just figured out an answer for this POST request in flutter
makePostRequest(int number) async {
final uri = Uri.parse('https://....api.infobip.com/sms/2/text/advanced');
final headers = {
'Authorization':
'App API-KEY',
'Content-Type': 'application/json'
};
Map<String, dynamic> body = {
"messages": [
{
"from": "SenderID",
"destinations": [
{"to": number}
],
"text": "TEST!"
}
]
};
String jsonBody = json.encode(body);
final encoding = Encoding.getByName('utf-8');
Response response = await post(
uri,
headers: headers,
body: jsonBody,
encoding: encoding,
);
int statusCode = response.statusCode;
String responseBody = response.body;
print(responseBody);
}