I don't know why but keeps telling me error 400 when it tries to fetch data from open weather map
even i tried to change the api key and tried to change the code it self but it didn't work
so i want to know why this happening and i want to know the solution for this problem
import 'package:clima/services/location.dart';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
const apiKey = '*****53a8**************';
class LoadingScreen extends StatefulWidget {
#override
_LoadingScreenState createState() => _LoadingScreenState();
}
class _LoadingScreenState extends State<LoadingScreen> {
double lontitude;
double latitude;
#override
void initState() {
getLocation();
getData();
super.initState();
}
Future getLocation() async {
Location location = Location();
await location.getCurrentLocation();
latitude = location.latitude;
lontitude = location.lontitude;
}
Future getData() async {
http.Response response = await http.get(
Uri.parse(
'https://api.openweathermap.org/data/2.5/weather?lat=$latitude&lon=$lontitude&appid=$apiKey'),
);
if (response.statusCode == 200) {
String data = response.body;
var temperature = jsonDecode(data)['main']['temp'];
print(temperature);
var condition = jsonDecode(data)['weather'][0]['id'];
print(condition);
var city = jsonDecode(data)['name'];
print(city);
} else {
print(response.statusCode);
}
}
#override
Widget build(BuildContext context) {
return Scaffold();
}
}
Just typing in that URL in a browser and substituting longitude, latitude, and apiKey with values works just fine for me.
https://api.openweathermap.org/data/2.5/weather?lat=50,123123&lon=13.123123&appid=************** // add private key
OUTPUT:
{"coord":{"lon":13.1231,"lat":50.1231},"weather":[{"id":800,"main":"Clear","description":"clear sky","icon":"01n"}],"base":"stations","main":{"temp":281.16,"feels_like":279.56,"temp_min":279.08,"temp_max":283.95,"pressure":1023,"humidity":79},"visibility":10000,"wind":{"speed":2.57,"deg":250},"clouds":{"all":0},"dt":1632954450,"sys":{"type":2,"id":47765,"country":"CZ","sunrise":1632978356,"sunset":1633020533},"timezone":7200,"id":3061350,"name":"Žlutice","cod":200}
You should check the format of the things that get substituted by your code.
Related
On Flutter 3.7 platform channels can run on any isolate. So I tried this sample,
import ‘package:flutter/services.dart’;
import ‘package:shared_preferences/shared_preferences.dart’;
void main() {
// Identify the root isolate to pass to the background isolate.
// (API introduced in Flutter 3.7)
RootIsolateToken rootIsolateToken = RootIsolateToken.instance!;
Isolate.spawn(_isolateMain, rootIsolateToken);
}
void _isolateMain(RootIsolateToken rootIsolateToken) async {
// Register the background isolate with the root isolate.
BackgroundIsolateBinaryMessenger
.ensureInitialized(rootIsolateToken);
// You can now use the shared_preferences plugin.
SharedPreferences sharedPreferences =
await SharedPreferences.getInstance();
print(sharedPreferences.getBool(‘isDebug’));
}
I can read from data on shared_preferences in this sample okey. But how can I use this feature anywhere in my app? How can I set or read data using this isolate on initState for example?
Basically you need to implement communication between isolates. You can read more about it here
Here is an example, you can change flutter_secure_storage that i used with shared_preferences package
import 'dart:async';
import 'dart:isolate';
import 'package:flutter/services.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
class CreationEvent {
final RootIsolateToken isolateToken;
final SendPort sendPort;
CreationEvent(this.isolateToken, this.sendPort);
}
class DeletetionEvent {}
class ReadEvent {
final String key;
const ReadEvent(this.key);
}
class ReadResult {
final String key;
final String? content;
const ReadResult(this.key, this.content);
}
class IsolateIO {
IsolateIO._();
final _toBgPort = Completer();
final Map<Object, Completer> _completerMap = {};
Isolate? _isolate;
StreamSubscription? _fromBgListener;
void start() async {
RootIsolateToken rootIsolateToken = RootIsolateToken.instance!;
ReceivePort fromBG = ReceivePort();
_fromBgListener = fromBG.listen((message) {
// setup process
if (message is SendPort) {
_toBgPort.complete(message);
return;
}
if (message is ReadResult) {
_completerMap['read:${message.key}']?.complete(message.content);
_completerMap.remove('read:${message.key}');
}
});
_isolate = await Isolate.spawn(
(CreationEvent data) {
final worker = IsolateWorker(data.isolateToken, data.sendPort);
worker.listen();
},
CreationEvent(rootIsolateToken, fromBG.sendPort),
);
}
Future<String?> readFromStorage(String key) async {
// make sure isolate created with ports
final port = await _toBgPort.future;
// store completer
final completer = Completer<String?>();
_completerMap['read:$key'] = completer;
// send key to be read
port.send(ReadEvent(key));
// return result
return completer.future;
}
void stop() async {
if (_toBgPort.isCompleted) {
final port = await _toBgPort.future;
port.send(DeletetionEvent());
}
_fromBgListener?.cancel();
_isolate?.kill(priority: Isolate.immediate);
}
static final i = IsolateIO._();
}
class IsolateWorker {
final RootIsolateToken rootIsolateToken;
final SendPort toMain;
final FlutterSecureStorage storage;
StreamSubscription? subs;
IsolateWorker(
this.rootIsolateToken,
this.toMain, {
this.storage = const FlutterSecureStorage(
aOptions: AndroidOptions(
encryptedSharedPreferences: true,
),
),
}) {
// Register the background isolate with the root isolate.
BackgroundIsolateBinaryMessenger.ensureInitialized(rootIsolateToken);
}
void listen() {
ReceivePort fromMain = ReceivePort();
toMain.send(fromMain.sendPort);
subs = fromMain.listen((message) => onMessage(message));
}
void onMessage(dynamic message) async {
if (message is DeletetionEvent) {
subs?.cancel();
return;
}
if (message is ReadEvent) {
final rawJson = await storage.read(key: message.key);
toMain.send(ReadResult(message.key, rawJson));
}
}
}
class View extends StatefulWidget {
const View({super.key});
#override
State<View> createState() => _ViewState();
}
class _ViewState extends State<View> {
String username = '';
#override
void initState() {
super.initState();
IsolateIO.i.start();
WidgetsBinding.instance.addPostFrameCallback((_) async {
final name = await IsolateIO.i.readFromStorage('username');
setState(() {
username = name ?? '';
});
});
}
#override
void dispose() {
IsolateIO.i.stop();
super.dispose();
}
#override
Widget build(BuildContext context) {
return SizedBox(
child: Text(username),
);
}
}
I fatch this issue during use Local Storage(shared_preferences: ^2.0.6) in my code....but i cant store the api model object in local storage...How can i do?
storeModelInPrefs() async {
http.Response response =
await http.get(Uri.parse('http://18.191.193.64/api/view_categories'));
String encodeData = jsonEncode(response.body);
///Write Data in local Storage
GetStorageUtility.prefs!.write('key', encodeData);
///Read Data from local Storage
String data = GetStorageUtility.prefs!.read('key');
if (data == null) {
print('no data in GetStorage');
} else {
Map<String, dynamic> map = jsonDecode(data);
print(map);
}
}
This is the sample example that i have created from the code that you have provided.
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:flutter_app/utilities.dart';
import 'package:http/http.dart' as http;
void main() {
runApp(MaterialApp(
home: MyApp(),
));
}
class MyApp extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
#override
void initState() {
GetStorageUtility.init();
super.initState();
getRemoteData();
}
getRemoteData() async {
/// This is where the api is fetching the data
var response =
await http.get(Uri.parse('http://18.191.193.64/api/view_categories'));
/// This is where the string getting
String encodeData = jsonEncode(response.body);
GetStorageUtility.write("key", encodeData);
/// this is where you fetch the data
String data = GetStorageUtility.read("key");
if (data == null) {
print('no data in GetStorage');
} else {
Map<String, dynamic> jsonData = json.decode(data);
jsonData.forEach((key, value) {
print("$key : $value\n");
});
}
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Text(" Page"),
),
);
}
}
SharadPrefs Singleton,
import 'dart:async';
import 'package:shared_preferences/shared_preferences.dart';
class GetStorageUtility {
static Future<SharedPreferences> get _instance async =>
_prefsInstance ??= await SharedPreferences.getInstance();
static SharedPreferences _prefsInstance;
static Future<SharedPreferences> init() async {
_prefsInstance = await _instance;
return _prefsInstance;
}
static String read(String key, [String defValue]) {
return _prefsInstance.getString(key) ?? defValue ?? "";
}
static Future<bool> write(String key, String value) async {
var prefs = await _instance;
return prefs?.setString(key, value) ?? Future.value(false);
}
}
Now there is on thing that you have see that you have added in you android manifest file
<application android:usesCleartextTraffic="true" />
This one should be there and the internet permission should be there in the debug and the main folders manifestfile.
This will work but this is not the best practice to store the data as string in the sharedprefs. Shared Prefs has only the job to manage the small data like bool or string. For your use case you can use a sqlite as a local data base. where you can fetch the data based on the condititions.
Let me know if it works.
Happy Coding.
I am struggling to figure out why this is not working (as opposed to the documentation which states it should be working).
I have a provider something like this
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:putin_flutter_client/api/client.dart';
import 'package:putin_flutter_client/api/storage.dart';
final userProvider = StateNotifierProvider((_) => UserNotifier());
class UserNotifier extends StateNotifier<UserState> {
UserNotifier() : super(UserState());
set username(String username) {
state = UserState(username: username, password: state.password, jwt: state.jwt);
secureStorageWrite('username', username);
}
set password(String password) {
state = UserState(username: state.username, password: password, jwt: state.jwt);
secureStorageWrite('password', password);
}
set jwt(String jwt) {
state = UserState(username: state.username, password: state.password, jwt: jwt);
Client.jwt = jwt;
secureStorageWrite('jwt', jwt);
}
String get jwt {
return state.jwt;
}
Future<void> initState() async {
final user = await UserState.load();
state.username = user.username;
state.password = user.password;
state.jwt = user.jwt;
}
}
class UserState {
String username;
String password;
String jwt;
UserState({
this.username,
this.password,
this.jwt,
});
static Future<UserState> load() async {
return UserState(
username: await secureStorageRead('username'),
password: await secureStorageRead('password'),
jwt: await secureStorageRead('jwt'),
);
}
}
eventually deep in some widget something like this will update the state
// usilizing the setter on the provider to update the state...
user.jwt = data['token'];
now in some other part of the code I manage the http client. This obviously has no access to BuildContext etc. so I do the following to retrieve the jwt value from the stored state.
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:http/http.dart' as http;
import 'package:putin_flutter_client/state/user.dart';
class Client extends http.BaseClient {
final http.Client _client = http.Client();
Future<http.StreamedResponse> send(http.BaseRequest request) {
// Get the container as per riverpod documentation
final container = ProviderContainer();
// Access the value through the getter on the provider
final jwt = container.read(userProvider).jwt;
request.headers['user-agent'] = 'myclient::v1.0.0';
request.headers['Content-Type'] = 'application/json';
if (jwt != null) {
request.headers['X-Auth-Token'] = jwt;
}
return _client.send(request);
}
}
This is always null and the UserState is pretty much empty (all members are null).
In the riverpod documentation it says that this should be working
test('counter starts at 0', () {
final container = ProviderContainer();
StateController<int> counter = container.read(counterProvider);
expect(counter.state, 0);
});
Can someone please help me out figure out what is wrong in my example above?
ProviderContainer() create a new instance of your providers it won't get the actual state.
You need to make your client dependent of the user state like this :
final clientProvider = Provider<Client>((ref){
return Client(ref.watch(userProvider.state))
});
class Client extends http.BaseClient {
Client(this._userState);
final UserState _userState;
final http.Client _client = http.Client();
Future<http.StreamedResponse> send(http.BaseRequest request) {
final jwt = _userState.jwt;
request.headers['user-agent'] = 'myclient::v1.0.0';
request.headers['Content-Type'] = 'application/json';
if (jwt != null) {
request.headers['X-Auth-Token'] = jwt;
}
return _client.send(request);
}
}
when your user state will change the client will be re-instancied with new values
If you don't want to re-instancie each time pass the read method instead :
final clientProvider = Provider<Client>((ref){
return Client(ref.read)
});
class Client extends http.BaseClient {
Client(this._reader);
final Reader _reader;
final http.Client _client = http.Client();
Future<http.StreamedResponse> send(http.BaseRequest request) {
final jwt = _reader(userProvider.state).jwt;
request.headers['user-agent'] = 'myclient::v1.0.0';
request.headers['Content-Type'] = 'application/json';
if (jwt != null) {
request.headers['X-Auth-Token'] = jwt;
}
return _client.send(request);
}
}
As #moulte pointed out (really thanks) can access the providers as global variables and independent of context by instantiating outside and injecting it to the widget scope via UncontrolledProviderScope. The important part is to remember to dispose the global provider before the app terminates or it will never really terminate.
Here's an example code
/// file /state/container.dart
import 'package:hooks_riverpod/hooks_riverpod.dart';
final container = ProviderContainer();
/// file /main.dart
void main() async {
runApp(MyApp());
}
class MyApp extends StatefulWidget {
#override
_MyApp createState() => _MyApp();
}
class _MyApp extends State<MyApp> {
#override
void dispose() {
super.dispose();
// disposing the globally self managed container.
container.dispose();
}
#override
Widget build(BuildContext context) {
return UncontrolledProviderScope(container: container,
child: MaterialApp(
// The usual widget tree
);
}
}
/// Somewhere in a file that is not aware of the BuildContext
/// here's how client.dart accesses the provider
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:http/http.dart' as http;
import 'package:putin_flutter_client/state/container.dart';
import 'package:putin_flutter_client/state/user.dart';
class Client extends http.BaseClient {
final http.Client _client = http.Client();
Future<http.StreamedResponse> send(http.BaseRequest request) {
// Simply accessing the global container and calling the .read function
var jwt = container.read(userProvider.state).jwt;
request.headers['user-agent'] = 'putin_flutter::v1.0.0';
request.headers['Content-Type'] = 'application/json';
if (jwt != null) {
request.headers['X-Auth-Token'] = jwt;
}
return _client.send(request);
}
}
ProviderContainer() is meant for using RiverPod in Dart. The equivalent in Flutter is ProviderScope(), but that requires access by the widget context chain, similar to the provider package.
I'm learning to use APIs with Flutter and I'm trying to use the Open Weather Map to this but, my code is inserting this %7B and %7D in every variable that I use in URL.
actual URL:
https://api.openweathermap.org/data/2.5/weather?lat=%7B-15.783783783783784%7D&lon=%7B-47.93345625648786%7D&appid=%7Bf0060b47028a54500c466c7288e41d31%7D
This is what i want:
https://api.openweathermap.org/data/2.5/weather?lat=-15.783783783783784&lon=-47.93345625648786&appid=f0060b47028a54500c466c7288e41d31
What's wrong with my code ?
My code:
import 'package:flutter/material.dart';
import 'package:clima/services/location.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
const apiKey = 'f0060b47028a54500c466c7288e41d31';
class LoadingScreen extends StatefulWidget {
#override
_LoadingScreenState createState() => _LoadingScreenState();
}
class _LoadingScreenState extends State<LoadingScreen> {
double latitude;
double longitude;
void getLocation() async {
Location location = Location();
await location.getCurrentLocation();
latitude = location.latitude;
longitude = location.longitude;
getData();
}
void getData() async {
var url = Uri.https('api.openweathermap.org', '/data/2.5/weather', {
'lat': '{$latitude}',
'lon': '{$longitude}',
'appid': '{$apiKey}',
});
var response = await http.get(url);
if (response.statusCode == 200) {
String data = response.body;
var temperature = jsonDecode(data)['main']['temp'];
print(temperature);
} else {
print(response.statusCode);
print(url);
}
}
#override
void initState() {
getLocation();
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold();
}
#override
void deactivate() {
super.deactivate();
}
}
In your getData() function, try removing the curly braces around the url parameters, like this:
var url = Uri.https('api.openweathermap.org', '/data/2.5/weather', {
'lat': '$latitude',
'lon': '$longitude',
'appid': '$apiKey',
});
Alternatively, you can concatenate the URL tring yourself like this.
var baseUrl = 'https://api.openweathermap.org/data/2.5/weather?';
var appid = 'f0060b47028a54500c466c7288e41d31';
var latString = '-15.783783783783784';
var lonString = '-47.93345625648786';
var urlString =
baseUrl + 'lat=$latString' + '&' + 'lon=$lonString' + '&' + 'appid=$appid';
Location class is the responsible for getting the longitude and latitude.
getData() method from the Loading_screen class is the responsible for calling the api to get weather data. The problem is when I pass the longitude and latitude values to the url of api, it returned error 400.
Workaround is to hardcode the longitude and latitude and it successfully retrieved api data. I can't figure why passing longitude and latitude values to api call doesn't work
Location
import 'package:geolocator/geolocator.dart';
import 'package:http/http.dart' as http;
class Location{
double longitude;
double latitude;
Future<void> getCurrentLocation() async{
try{
Position position = await Geolocator().getCurrentPosition(desiredAccuracy: LocationAccuracy.low);
longitude = position.longitude;
latitude = position.latitude;
print('Longitude: $longitude \n' +
'Latitude: $latitude');
}catch(e){
print(e);
}
}
}
Loading_screen class
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:clima/location.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
class LoadingScreen extends StatefulWidget {
#override
_LoadingScreenState createState() => _LoadingScreenState();
}
class _LoadingScreenState extends State<LoadingScreen> {
var apiKey = 'secret';
double lat, lon;
#override
void initState() {
getLocation();
}
void getData() async{
var url = 'http://api.openweathermap.org/data/2.5/weather?lat=${lat}&${lon}&appid=$apiKey';
//var url = 'http://api.openweathermap.org/data/2.5/weather?lat=14.6102473&121.0043158&appid=secret';
//var url = 'http://api.openweathermap.org/data/2.5/weather?lat=14.6102473&lon=121.0043158&appid=secret';
var request = await http.get(url);
if(request.statusCode == 200){
String data = request.body.toString();
var city = jsonDecode(data)['name'];
var description = jsonDecode(data)['weather'][0]['description'];
print('Welcome to $city city!');
print('Weather: $description');
}else{
print(request.statusCode);
print('Latitude is: $lat *** Longitude is: $lon'); // this prints longitude and latitude values
print('request $url'); // when I entered the url in postman, I'm getting the same error 400
}
}
void getLocation() async{
Location location = new Location();
await location.getCurrentLocation();
lat = location.latitude;
lon = location.longitude;
getData();
}
#override
Widget build(BuildContext context) {
return Scaffold();
}
}
You are missing the parameter name lon in your url.
Instead of:
var url = 'http://api.openweathermap.org/data/2.5/weather?lat=${lat}&${lon}&appid=$apiKey';
Write:
var url = 'http://api.openweathermap.org/data/2.5/weather?lat=${lat}&lon=${lon}&appid=$apiKey';
Change that;
var url = 'http://api.openweathermap.org/data/2.5/weather?lat=${lat}&${lon}&appid=$apiKey';
with this;
var url = 'http://api.openweathermap.org/data/2.5/weather?lat=${lat}&lon=${lon}&appid=$apiKey';