Flutter http headers

Question

The post request is throwing an error while setting the header map.

Here is my code

Future<GenericResponse> makePostCall(   GenericRequest genericRequest) {String URL = "$BASE_URL/api/";  Map data = {   "name": "name",   "email": "email",   "mobile": "mobile",   "transportationRequired": false,   "userId": 5, };  Map userHeader = {"Content-type": "application/json", "Accept": "application/json"};   return _netUtil.post(URL, body: data, headers:userHeader).then((dynamic res) {   print(res);   if (res["code"] != 200) throw new Exception(res["message"][0]);   return GenericResponse.fromJson(res); });  } 

but I'm getting this exception with headers.

══╡ EXCEPTION CAUGHT BY GESTURE ╞═ flutter: The following assertion was thrown while handling a gesture: flutter: type '_InternalLinkedHashMap<dynamic, dynamic>' is not a subtype of type 'Map<String, String>' flutter: flutter: Either the assertion indicates an error in the framework itself, or we should provide substantially flutter: more information in this error message to help you determine and fix the underlying cause. flutter: In either case, please report this assertion by filing a bug on GitHub: flutter:   https://github.com/flutter/flutter/issues/new?template=BUG.md flutter: flutter: When the exception was thrown, this was the stack: flutter: #0      NetworkUtil.post1 (package:saranam/network/network_util.dart:50:41) flutter: #1      RestDatasource.bookPandit (package:saranam/network/rest_data_source.dart:204:21) 

Anybody facing this issue? I didn't find any clue with the above log.

Answer 1

Try

 Map<String, String> requestHeaders = {        'Content-type': 'application/json',        'Accept': 'application/json',        'Authorization': '<Your token>'      }; 

Answer 2

You can try this:

Map<String, String> get headers => {         "Content-Type": "application/json",         "Accept": "application/json",         "Authorization": "Bearer $_token",       }; 

and then along with your http request for header just pass header as header

example:

Future<AvatarResponse> getAvatar() async {     var url = "$urlPrefix/api/v1/a/me/avatar";     print("fetching $url");     var response = await http.get(url, headers: headers);     if (response.statusCode != 200) {       throw Exception(           "Request to $url failed with status ${response.statusCode}: ${response.body}");     }      var avatar = AvatarResponse()       ..mergeFromProto3Json(json.decode(response.body),           ignoreUnknownFields: true);     print(avatar);     return avatar;   }