How to check the internet reachability in React-native? - react-native

I've tried #react-native-community/netinfo to check the internet reachability. But the scenario I want to implement is, suppose if my device is connected to a wifi hotspot from another device and if that device's mobile data is turned off I want to show an offline toast.
componentDidMount() {
NetInfo.addEventListener(status => {
this.props.checkOnlineStatus(
status.isConnected,
status.isInternetReachable
);
this.setState({
isConnected: status.isConnected,
isInternetReachable: status.isInternetReachable
});
});
}
render() {
if (!this.state.isInternetReachable && this.props.isOfflineNoticeVisible) {
return <MiniOfflineSign />;
}
return null;
}
But in this case, when the mobile data of the other device is turned off, it doesn't handle the change.

The non-deprecated way (using functional components) with the #react-native-community/netinfo package is now:
import React, { useEffect } from "react";
import NetInfo from "#react-native-community/netinfo";
useEffect(() => {
return NetInfo.addEventListener(state => {
// use state.isInternetReachable or some other field
// I used a useState hook to store the result for use elsewhere
});
}, []);
This will run the callback whenever the state changes, and unsubscribe when the component unmounts.

These connection types could help: https://github.com/react-native-community/react-native-netinfo#netinfostatetype
Otherwise:
Then to be sure, you are online just implement a fetch with timeout:
export default function(url, options, timeout = 5000) {
return Promise.race([
fetch(url, options),
new Promise((_, reject) => setTimeout(() => reject("timeout"), timeout)),
]);
}
Then use it like this:
fetchWithTimeout(url, options)
.then(resp => {
if (resp.status === 200) {
let json = resp.json().then(j => {
return j;
});
})
.catch(ex => {
// HANDLE offline usage
if (ex === "timeout") return true;
//ANY OTHER CASE RETURN FALSE
return false;
}

async function InternetCheck() {
const connectionInfo = await NetInfo.getConnectionInfo();
if (connectionInfo.type === 'none') {
alert('PLEASE CONNECT TO INTERNET');
} else {
//navigate to page or Call API
}
}

Related

wait for onSnapshot fetching data

I'm currently learning React Native (Expo).
I want to use redux and react-native-firebase.
When I subscribe to firebase (onSnapshot) at startup of my app, it returns the data from firebase. But since onSnapchot doesn't return a promise, I can't use it for my app-loading component.
Therefore, I also need to fetch the data from firebase to prevent the app from flicker.
The result is that at startup of my app I fetch the data twice.
So my question is:
How can I wait for onSnapshot loading my data from firebase?
Thanks
const Manager = (props) => {
//STATE
const [init, setInit] = useState(false);
//HOOKS
const fetchData = useFetchData();
useInitFirebaseSubscriptions();
//FUNCTIONS
async function onInit() {
console.log('[MANAGER]: loading app...');
await Promise.all([fetchData()]);
}
function onFinishedInit() {
console.log('[MANAGER]: ...app loading successfull!');
setInit(true);
}
//RETURN
if (!init) {
return <AppLoading startAsync={onInit} onFinish={onFinishedInit} onError={console.warn} />;
} else {
return props.children;
}
};
export default Manager;
//INITIAL FETCH BEFORE RENDERING
export function useFetchData() {
const dispatch = useDispatch();
return async function () {
try {
await firestore()
.collection('users')
.get()
.then((querySnapshot) => dispatch(actions.fetch(querySnapshot)));
} catch (err) {
console.log(err.message);
}
};
}
//INIT SUBSCRIPTIONS TO FIREBASE
export function useInitFirebaseSubscriptions() {
const dispatch = useDispatch();
useEffect(() => {
console.log('[CONTROLLER]: subscribed to Firebase');
const unsubscribe = firestore()
.collection('users')
.onSnapshot(
(querySnapshot) => dispatch(action.fetch(querySnapshot)),
(error) => console.log(error)
);
return () => {
unsubscribe();
console.log('[CONTROLLER]: unsubscribed from Firebase');
};
}, []);
}
[MANAGER]: loading app...
[MANAGER]: subscribed to Firebase
[USER_REDUCER]: fetched data
[USER_REDUCER]: fetched data
[MANAGER]: ...app loading successfull!
I think you can accomplish your goal by adding some "loading" state in redux for when you are actively fetching data from firebase. Add the state and reducer cases specific to this data fetching/loading.
Example code:
export function useInitFirebaseSubscriptions() {
const dispatch = useDispatch();
useEffect(() => {
console.log('[CONTROLLER]: subscribed to Firebase');
dispatch(action.startFetch()); // <-- dispatch starting data fetch
const unsubscribe = firestore()
.collection('users')
.onSnapshot(
(querySnapshot) => {
dispatch(action.fetch(querySnapshot));
dispatch(action.completedFetch()); // <-- done fetching
},
(error) => {
console.log(error);
dispatch(action.completedFetch()); // <-- done fetching
},
);
return () => {
unsubscribe();
console.log('[CONTROLLER]: unsubscribed from Firebase');
};
}, []);
};
Select the loading state from the redux store and conditionally render the loading UI, otherwise render the passed children.
const Manager = (props) => {
const isFetchingData = useSelector(state => state.isFetchingData);
if (isFetchingData) {
return <AppLoadingIndicator />;
}
return props.children; // *
};
* Generally you may use some additional conditional rendering here depending on if data was actually fetched/returned and is just empty, or if there was an error, etc... basically provide a bit of a result status.

Detect coming back from app settings/background with React Native

My app asks permission to use location services.
If a user denies permission, they can click a button to go to the settings page and grant permissions.
On ios, they are given the option to return directly to the app. on Android, I think they can do something similar.
Is there a way to detect arriving back at the app so I can check their permissions again?
I've tried with React Navigation's useFocusEffect hook:
useFocusEffect(
React.useCallback(() => {
console.log("navigated")
return () => getPosition()
}, [])
)
But unfortunately, that only works when navigating between screens/routes in the app.
Is there a way to detect the app transitioning from background to foreground?
You can track app state with https://reactnative.dev/docs/appstate
in pseudo-code: if previously 'background' and now 'active' then run your effects
Ciao, when I want to manage permission, I use react-native-permissions. In this way you can manage all permissions directly in your app without exit from it.
Works well for iOs and Android. In your case, you could something like:
import {check, PERMISSIONS, RESULTS} from 'react-native-permissions';
check(<permission you need>)
.then((result) => {
switch (result) {
case RESULTS.UNAVAILABLE:
console.log(
'This feature is not available (on this device / in this context)',
);
break;
case RESULTS.DENIED:
console.log(
'The permission has not been requested / is denied but requestable',
);
break;
case RESULTS.GRANTED:
console.log('The permission is granted');
break;
case RESULTS.BLOCKED:
console.log('The permission is denied and not requestable anymore');
break;
}
})
.catch((error) => {
// …
});
Use this hook:
// hooks/useAppIsActive.ts
import { useCallback, useEffect, useRef } from "react";
import { AppState } from "react-native";
export default (callback: Function) => {
const appStateRef = useRef(AppState.currentState);
const handleAppStateChange = useCallback((nextAppState) => {
if (
appStateRef.current.match(/inactive|background/) &&
nextAppState === "active"
) {
callback();
}
appStateRef.current = nextAppState;
}, []);
useEffect(() => {
AppState.addEventListener("change", handleAppStateChange);
return () => {
AppState.removeEventListener("change", handleAppStateChange);
};
}, []);
};
And from the component you want to detect "the come back", pass by parameter the callback you want to run:
const MyView = () => {
const requestLocationAccess = useCallback(() => {
// request permissions...
}, [])
useAppIsActive(() => requestLocationAccess());
}

Deep links in react-native-firebase notifications

I am using react-native-firebase with messaging to deliver notifications to my app with cloud functions, with admin.messaging().send(message), very similar to here: https://medium.com/the-modern-development-stack/react-native-push-notifications-with-firebase-cloud-functions-74b832d45386 .
I receive notifications when the app is in the background. Right now I am sending a text in the body of the notification, like 'a new location has been added to the map'. I want to be able to add some sort of deep link, so that when I swipe View on the notification (on iOS for example), it will take me to a specific screen inside the app. How do I pass data from the notification to the app?
I am using react-native-navigation in the app. I can only find code about deep links from inside the app (https://wix.github.io/react-native-navigation/#/deep-links?id=deep-links).
My solution was to use add what information I need in the data object of the notification message object:
in functions/index.js:
let message = {
notification: {
body: `new notification `
},
token: pushToken,
data: {
type: 'NEW_TRAINING',
title: locationTitle
}
};
and process as follows in the app for navigation:
this.notificationOpenedListener =
firebase.notifications().onNotificationOpened((notificationOpen: NotificationOpen) => {
if (notification.data.type === 'NEW_TRAINING') {
this.props.navigator.push({
screen: 'newtrainingscreen',
title: notification.data.title,
animated: true
});
}
I think you are fine with the "how firebase notification work"... cause of this, here is only an description of the Logic how you can Deeplinking into your App.
If you send a notification, add a data-field. Let's say your app has a Tab-Navigator and the sections "News","Service" and "Review".
In your Push-Notification - Datafield (let's name it "jumpToScreen" you define your value:
jumpToScreen = Service
I assume you still have the Handling to recieve Notifications from Firebase implemented.
So create an /lib/MessageHandler.js Class and put your business-logic inside.
import firebase from 'react-native-firebase';
/*
* Get a string from Firebase-Messages and return the Screen to jump to
*/
const getJumpPoint = (pointer) => {
switch (pointer) {
case 'News':
return 'NAV_NewsList'; // <= this are the names of your Screens
case 'Service':
return 'NAV_ServiceList';
case 'Review':
return 'NAV_ReviewDetail';
default: return false;
}
};
const MessageHandler = {
/**
* initPushNotification initialize Firebase Messaging
* #return fcmToken String
*/
initPushNotification: async () => {
try {
const notificationPermission = await firebase.messaging().hasPermission();
MessageHandler.setNotificationChannels();
if (notificationPermission) {
try {
return await MessageHandler.getNotificationToken();
} catch (error) {
console.log(`Error: failed to get Notification-Token \n ${error}`);
}
}
} catch (error) {
console.log(`Error while checking Notification-Permission\n ${error}`);
}
return false;
},
clearBadges: () => {
firebase.notifications().setBadge(0);
},
getNotificationToken: () => firebase.messaging().getToken(),
setNotificationChannels() {
try {
/* Notification-Channels is a must-have for Android >= 8 */
const channel = new firebase.notifications.Android.Channel(
'app-infos',
'App Infos',
firebase.notifications.Android.Importance.Max,
).setDescription('General Information');
firebase.notifications().android.createChannel(channel);
} catch (error) {
console.log('Error while creating Push_Notification-Channel');
}
},
requestPermission: () => {
try {
firebase.messaging().requestPermission();
firebase.analytics().logEvent('pushNotification_permission', { decision: 'denied' });
} catch (error) {
// User has rejected permissions
firebase.analytics().logEvent('pushNotification_permission', { decision: 'allowed' });
}
},
foregroundNotificationListener: (navigation) => {
// In-App Messages if App in Foreground
firebase.notifications().onNotification((notification) => {
MessageHandler.setNotificationChannels();
navigation.navigate(getJumpPoint(notification.data.screen));
});
},
backgroundNotificationListener: (navigation) => {
// In-App Messages if App in Background
firebase.notifications().onNotificationOpened((notificationOpen) => {
const { notification } = notificationOpen;
notification.android.setChannelId('app-infos');
if (notification.data.screen !== undefined) {
navigation.navigate(getJumpPoint(notification.data.screen));
}
});
},
appInitNotificationListener: () => {
// In-App Messages if App in Background
firebase.notifications().onNotificationOpend((notification) => {
notification.android.setChannelId('app-infos');
console.log('App-Init: Da kommt ne Message rein', notification);
firebase.notifications().displayNotification(notification);
});
},
};
export default MessageHandler;
In your index.js you can connect it like this:
import MessageHandler from './lib/MessageHandler';
export default class App extends Component {
state = {
loading: null,
connection: null,
settings: null,
};
async componentDidMount() {
const { navigation } = this.props;
await MessageHandler.initPushNotification();
this.notificationForegroundListener = MessageHandler.foregroundNotificationListener(navigation);
this.notificationBackgroundListener = MessageHandler.backgroundNotificationListener(navigation);
this.setState({ loading: false, data });
}
componentWillUnmount() {
this.notificationForegroundListener();
this.notificationBackgroundListener();
}
async componentDidMount() {
MessageHandler.requestPermission();
AppState.addEventListener('change', this.handleAppStateChange);
MessageHandler.clearBadges();
}
componentWillUnmount() {
AppState.removeEventListener('change', this.handleAppStateChange);
}
handleAppStateChange = (nextAppState) => {
if (nextAppState.match(/inactive|background/)) {
MessageHandler.clearBadges();
}
....
I hope this give you an Idea how to implement it for your needs.
I think you don't need to use deep links nor dynamic links but just use Firebase/Notifications properly. If I were you I would add the following logic in the componentDidMount method of your parent container:
async componentDidMount() {
// 1. Check notification permission
const notificationsEnabled = await firebase.messaging().hasPermission();
if (!notificationsEnabled) {
try {
await firebase.messaging().requestPermission(); // Request notification permission
// At this point the user has authorized the notifications
} catch (error) {
// The user has NOT authorized the notifications
}
}
// 2. Get the registration token for firebase notifications
const fcmToken = await firebase.messaging().getToken();
// Save the token
// 3. Listen for notifications. To do that, react-native-firebase offer you some methods:
firebase.messaging().onMessage(message => { /* */ })
firebase.notifications().onNotificationDisplayed(notification => { /* */ })
firebase.messaging().onNotification(notification => { /* */ })
firebase.messaging().onNotificationOpened(notification => {
/* For instance, you could use it and do the NAVIGATION at this point
this.props.navigation.navigate('SomeScreen');
// Note that you can send whatever you want in the *notification* object, so you can add to the notification the route name of the screen you want to navigate to.
*/
})
}
You can find the documentation here: https://rnfirebase.io/docs/v4.3.x/notifications/receiving-notifications

How to check internet connection every http request in react native and display alert message?

I'm just trying to check internet connection when app launches and also check internet connectivity before calling HTTP Request.I have seen some example but it's confusing for me.Please guide me.
You can use the NetInfo API from react native.
Here is the example:
componentDidMount() {
NetInfo.isConnected.addEventListener(
'change',
this._handleConnectivityChange
);
NetInfo.isConnected.fetch().done(
(isConnected) => { this.setState({isConnected}); }
);
}
componentWillUnmount() {
NetInfo.isConnected.removeEventListener(
'change',
this._handleConnectivityChange
);
}
_handleConnectivityChange = (isConnected) => {
this.setState({
isConnected,
});
};
render() {
return (
<View style={styles.container}>
<Text>{this.state.isConnected ? 'Online' : 'Offline'}</Text>
</View>
);
}
}
Thereby the above code lets you know if you are having internet before making any api call in your app.
You can refer https://facebook.github.io/react-native/docs/netinfo.html for more.
Here is the example:
import { NetInfo,Alert } from 'react-native';
const netStatus = await NetInfo.fetch()
if (netStatus === 'none' || netStatus === 'NONE') {
Alert.alert("Internet not connected ")
return []
}
There probably is a better way to do this, but you could do a console.log() before the HTTP request and pass in parameters of the API, if you get a result of the title in your console, then you're connected to the internet, otherwise you're not.
You should hook this into your api calls before making them. In such case a higher order function would be useful.
import NetInfo from "#react-native-community/netinfo";
import api from "./MyApi"
//higher order function for api calls
const connectionWrapper = async (errorHandler, apiRequest) => () => {
NetInfo.fetch().then(state => {
return state.isConnected
? errorHandler(state)
: apiRequest()
})
}
//use connection wrapper to build your resource calls
const apiCall = connectionWrapper(
state => ...handleError,
api.resource({ myParams : "myParams"})
)
//now you can reuse api call which should return a promise or anything else that you want
var firstCall = apiCall()
var secondCall = apiCall()
var thirdCall = apiCall()

Promise isn't working in react component when testing component using jest

Good day. I have the following problem:
I have an item editor.
How it works: I push 'Add' button, fill some information, click 'Save' button.
_onSaveClicked function in my react component handles click event and call function from service, which sends params from edit form to server and return promise.
_onSaveClicked implements
.then(response => {
console.log('I\'m in then() block.');
console.log('response', response.data);
})
function and waits for promise result. It works in real situation.
I created fake service and placed it instead of real service.
Service's function contains:
return Promise.resolve({data: 'test response'});
As you can see fake service return resolved promise and .then() block should work immediatly. But .then() block never works.
Jest test:
jest.autoMockOff();
const React = require('react');
const ReactDOM = require('react-dom');
const TestUtils = require('react-addons-test-utils');
const expect = require('expect');
const TestService = require('./service/TestService ').default;
let testService = new TestService ();
describe('TestComponent', () => {
it('correct test component', () => {
//... some initial code here
let saveButton = TestUtils.findRenderedDOMComponentWithClass(editForm, 'btn-primary');
TestUtils.Simulate.click(saveButton);
// here I should see response in my console, but I don't
});
});
React component save function:
_onSaveClicked = (data) => {
this.context.testService.saveData(data)
.then(response => {
console.log('I\'m in then() block.');
console.log('response', response.data);
});
};
Service:
export default class TestService {
saveData = (data) => {
console.log('I\'m in services saveData function');
return Promise.resolve({data: data});
};
}
I see only "I'm in services saveData function" in my console.
How to make it works? I need to immitate server response.
Thank you for your time.
You can wrap your testing component in another one like:
class ContextInitContainer extends React.Component {
static childContextTypes = {
testService: React.PropTypes.object
};
getChildContext = () => {
return {
testService: {
saveData: (data) => {
return {
then: function(callback) {
return callback({
// here should be your response body object
})
}
}
}
}
};
};
render() {
return this.props.children;
}
}
then:
<ContextInitContainer>
<YourTestingComponent />
</ContextInitContainer>
So your promise will be executed immediately.