React-Native async-storage putting functions in common js file? - react-native

In React-native (to which I'm relatively new), I use async storage to store a list of favourites between sessions.
eg
const StoreFavourites = async (sFavourites) => {
try {
await AsyncStorage.setItem(storageKeyFavourites, sFavourites);
} catch (e) {
// saving error
Alert.alert('Unable to store favourites')
}
}
const getFavourites = async () => {
try {
const value = await AsyncStorage.getItem(storageKeyFavourites)
if (value !== null) {
checkPageIsFavourite(value, false)
}
} catch (e) {
// err
}
}
As this will be used on multiple pages, I thought it would be good to store the code once in an external file, so I moved it to
PersistenStorage.js
and in the page, added
import * as pStorage from './PersistentStorage.js'
From my main component, I can then call
pStorage.StoreFavourites('somevalue')
and
pStorage.getFavourites()
which work, but I can't find a way for the getFavourites to call functions in the main component (ie which imports the external code)
checkPageIsFavourite(value, false)
can't run as it can't access this function from the external file.
Hope this is clear and is there a way around this? in other words, once the async get has completed, call functions in the main file.

Related

react-native (Expo) upload file on background

In my Expo (react-native) application, I want to do the upload task even if the application is in the background or killed.
the upload should be done to firebase storage, so we don't have a REST API.
checked out the Expo task manager library, but I could not figure out how it should be done. is it even possible to achieve this goal with Expo? is the TaskManager the correct package for this task?
there are only some Expo packages that could be registered as a task (e.g. backgroundFetch), and it is not possible to register a custom function (in this case uploadFile method).
I even got more confused as we should enable add UIBackgroundModes key for iOS but it only has audio,location,voip,external-accessory,bluetooth-central,bluetooth-peripheral,fetch,remote-notification,processing as possible values.
I would appreciate it if you can at least guide me on where to start or what to search for, to be able to upload the file even if the app is in the background is killed/terminated.
import { getStorage, ref, uploadBytes } from "firebase/storage";
const storage = getStorage();
const storageRef = ref(storage, 'videos');
const uploadFile = async (file)=>{
// the file is Blob object
await uploadBytes(storageRef, file);
}
I have already reviewed react-native-background-fetch, react-native-background-upload, react-native-background-job . upload should eject Expo, job does not support iOS, and fetch is a fetching task designed for doing task in intervals.
if there is a way to use mentioned libraries for my purpose, please guide me :)
to my understanding, the Firebase Cloud JSON API does not accept files, does it ? if so please give me an example. If I can make storage json API work with file upload, then I can use Expo asyncUpload probably without ejecting.
I have done something similar like you want, you can use expo-task-manager and expo-background-fetch. Here is the code as I used it. I Hope this would be useful for you.
import * as BackgroundFetch from 'expo-background-fetch';
import * as TaskManager from 'expo-task-manager';
const BACKGROUND_FETCH_TASK = 'background-fetch';
const [isRegistered, setIsRegistered] = useState(false);
const [status, setStatus] = useState(null);
//Valor para que se ejecute en IOS
BackgroundFetch.setMinimumIntervalAsync(60 * 15);
// Define the task to execute
TaskManager.defineTask(BACKGROUND_FETCH_TASK, async () => {
const now = Date.now();
console.log(`Got background fetch call at date: ${new Date(now).toISOString()}`);
// Your function or instructions you want
return BackgroundFetch.Result.NewData;
});
// Register the task in BACKGROUND_FETCH_TASK
async function registerBackgroundFetchAsync() {
return BackgroundFetch.registerTaskAsync(BACKGROUND_FETCH_TASK, {
minimumInterval: 60 * 15, // 1 minutes
stopOnTerminate: false, // android only,
startOnBoot: true, // android only
});
}
// Task Status
const checkStatusAsync = async () => {
const status = await BackgroundFetch.getStatusAsync();
const isRegistered = await TaskManager.isTaskRegisteredAsync(
BACKGROUND_FETCH_TASK
);
setStatus(status);
setIsRegistered(isRegistered);
};
// Check if the task is already register
const toggleFetchTask = async () => {
if (isRegistered) {
console.log('Task ready');
} else {
await registerBackgroundFetchAsync();
console.log('Task registered');
}
checkStatusAsync();
};
useEffect(() => {
toggleFetchTask();
}, []);
Hope this isn't too late to be helpful.
I've been dealing with a variety of expo <-> firebase storage integrations recently, and here's some info that might be helpful.
First, I'd recommend not using the uploadBytes / uploadBytesResumable methods from Firebase. This Thread has a long ongoing discussion about it, but basically it's broken in v9. Maybe in the future the Firebase team will solve the issues, but it's pretty broken with Expo right now.
Instead, I'd recommend either going down the route of writing a small Firebase function that either gives a signed-upload-url or handles the upload itself.
Basically, if you can get storage uploads to work via an http endpoint, you can get any kind of upload mechanism working. (e.g. the FileSystem.uploadAsync() method you're probably looking for here, like #brentvatne pointed out, or fetch, or axios. I'll show a basic wiring at the end).
Server Side
Option 1: Signed URL Upload.
Basically, have a small firebase function that returns a signed url. Your app calls a cloud function like /get-signed-upload-url , which returns the url, which you then use. Check out: https://cloud.google.com/storage/docs/access-control/signed-urls for how you'd go about this.
This might work well for your use case. It can be configured just like any httpsCallable function, so it's not much work to set up, compared to option 2.
However, this doesn't work for the firebase storage / functions emulator! For this reason, I don't use this method, because I like to intensively use the emulators, and they only offer a subset of all the functionalities.
Option 2: Upload the file entirely through a function
This is a little hairier, but gives you a lot more fidelity over your uploads, and will work on an emulator! I like this too because it allows doing upload process within the endpoint execution, instead of as a side effect.
For example, you can have a photo-upload endpoint generate thumbnails, and if the endpoint 201's, then you're good! Rather than the traditional Firebase approach of having a listener to cloud storage which would generate thumbnails as a side effect, which then has all kinds of bad race conditions (checking for processing completion via exponentiational backoff? Gross!)
Here are three resources I'd recommend to go about this approach:
https://cloud.google.com/functions/docs/writing/http#multipart_data
https://github.com/firebase/firebase-js-sdk/issues/5848
https://github.com/mscdex/busboy
Basically, if you can make a Firebase cloud endpoint that accepts a File within formdata, you can have busboy parse it, and then you can do anything you want with it... like upload it to Cloud Storage!
an outline of this:
import * as functions from "firebase-functions";
import * as busboy from "busboy";
import * as os from "os";
import * as path from "path";
import * as fs from "fs";
type FieldMap = {
[fieldKey: string]: string;
};
type Upload = {
filepath: string;
mimeType: string;
};
type UploadMap = {
[fileName: string]: Upload;
};
const MAX_FILE_SIZE = 2 * 1024 * 1024; // 2MB
export const uploadPhoto = functions.https.onRequest(async (req, res) => {
verifyRequest(req); // Verify parameters, auth, etc. Better yet, use a middleware system for this like express.
// This object will accumulate all the fields, keyed by their name
const fields: FieldMap = {};
// This object will accumulate all the uploaded files, keyed by their name.
const uploads: UploadMap = {};
// This will accumulator errors during the busboy process, allowing us to end early.
const errors: string[] = [];
const tmpdir = os.tmpdir();
const fileWrites: Promise<unknown>[] = [];
function cleanup() {
Object.entries(uploads).forEach(([filename, { filepath }]) => {
console.log(`unlinking: ${filename} from ${path}`);
fs.unlinkSync(filepath);
});
}
const bb = busboy({
headers: req.headers,
limits: {
files: 1,
fields: 1,
fileSize: MAX_FILE_SIZE,
},
});
bb.on("file", (name, file, info) => {
verifyFile(name, file, info); // Verify your mimeType / filename, etc.
file.on("limit", () => {
console.log("too big of file!");
});
const { filename, mimeType } = info;
// Note: os.tmpdir() points to an in-memory file system on GCF
// Thus, any files in it must fit in the instance's memory.
console.log(`Processed file ${filename}`);
const filepath = path.join(tmpdir, filename);
uploads[filename] = {
filepath,
mimeType,
};
const writeStream = fs.createWriteStream(filepath);
file.pipe(writeStream);
// File was processed by Busboy; wait for it to be written.
// Note: GCF may not persist saved files across invocations.
// Persistent files must be kept in other locations
// (such as Cloud Storage buckets).
const promise = new Promise((resolve, reject) => {
file.on("end", () => {
writeStream.end();
});
writeStream.on("finish", resolve);
writeStream.on("error", reject);
});
fileWrites.push(promise);
});
bb.on("close", async () => {
await Promise.all(fileWrites);
// Fail if errors:
if (errors.length > 0) {
functions.logger.error("Upload failed", errors);
res.status(400).send(errors.join());
} else {
try {
const upload = Object.values(uploads)[0];
if (!upload) {
functions.logger.debug("No upload found");
res.status(400).send("No file uploaded");
return;
}
const { uploadId } = await processUpload(upload, userId);
cleanup();
res.status(201).send({
uploadId,
});
} catch (error) {
cleanup();
functions.logger.error("Error processing file", error);
res.status(500).send("Error processing file");
}
}
});
bb.end(req.rawBody);
});
Then, that processUpload function can do anything you want with the file, like upload it to cloud storage:
async function processUpload({ filepath, mimeType }: Upload, userId: string) {
const fileId = uuidv4();
const bucket = admin.storage().bucket();
await bucket.upload(filepath, {
destination: `users/${userId}/${fileId}`,
{
contentType: mimeType,
},
});
return { fileId };
}
Mobile Side
Then, on the mobile side, you can interact with it like this:
async function uploadFile(uri: string) {
function getFunctionsUrl(): string {
if (USE_EMULATOR) {
const origin =
Constants?.manifest?.debuggerHost?.split(":").shift() || "localhost";
const functionsPort = 5001;
const functionsHost = `http://${origin}:${functionsPort}/{PROJECT_NAME}/${PROJECT_LOCATION}`;
return functionsHost;
} else {
return `https://{PROJECT_LOCATION}-{PROJECT_NAME}.cloudfunctions.net`;
}
}
// The url of your endpoint. Make this as smart as you want.
const url = `${getFunctionsUrl()}/uploadPhoto`;
await FileSystem.uploadAsync(uploadUrl, uri, {
httpMethod: "POST",
uploadType: FileSystem.FileSystemUploadType.MULTIPART,
fieldName: "file", // Important! make sure this matches however you want bussboy to validate the "name" field on file.
mimeType,
headers: {
"content-type": "multipart/form-data",
Authorization: `${idToken}`,
},
});
});
TLDR
Wrap Cloud Storage in your own endpoint, treat it like a normal http upload, everything plays nice.

null is not an object (using async storage)

I'm trying to implement secure store (like async storage) into my testproject and it works. The only thing that doesn't work appears to be my load() useEffect that runs every time I start a new session.
So every time I start the session "null is not an object" appears and throws errors at every part where I'm looking for my list on my home-screen (my state is called goals).
but if I temporarily turn it off, add a goal to my list, and then turn it on - it works fine every time I restart the app
I feel like I need to write a condition in my load() statement but I can't figure out what, I think the app runs the load() and gets stuck at the statements where I use goals before I've added any. Can someone help me here? I've tried if (goals !== null) but it doesn't work.
const [goals, setGoals] = useState([])
const load = async() => {
if (goals !== null) {
try {
const goalsValue = await SecureStore.getItemAsync('Goals');
setGoals(JSON.parse(goalsValue))
} catch (err) {
alert(err)
}
}
}
useEffect(()=> {
load()
},[])
So what is happening is that there's nothing inside goalsValue so when you try parsing it you get an error. To avoid that you should add an if statement that checks if it's empty or not
const [goals, setGoals] = useState([])
const load = async() => {
if (goals !== null) {
try {
const goalsValue = await SecureStore.getItemAsync('Goals');
if(goalsValue) setGoals(JSON.parse(goalsValue))
}catch (err) {alert(err)}
}}
useEffect(()=> {
load()
},[])
Try this and let me know if it works ☺️

Async Storage / Secure Store help for React Native

I'm doing a test app to learn react native, and I'm trying to use secure store (a bit like async storage) to store my individual goals and save them. So far it's working, however when I refresh the app only the last goal I entered gets loaded.
Where am I going wrong here? In my console log the full array is shown with both the old and the new ones I add, then I refresh and I only have one left.
const [goals, setGoals] = useState([])
const addGoal = async (goal) => {
try{
const goalJson = JSON.stringify({text: goal, id:`${Math.random()}`, todos:[], date: Date.now(), percentage:0})
await SecureStore.setItemAsync("Goal", goalJson)
load()
}
catch (err) {alert(err)}
}
const load = async() => {
try {
const goalValue = await SecureStore.getItemAsync("Goal")
const parsed = JSON.parse(goalValue)
if(goals !== null) {
setGoals([...goals, parsed])
console.log(goals)
}
}catch (err) {alert(err)}
}
useEffect(()=> {
load()
},[])
SecureStore is like a key-value database, so currently you're always writing to the same key Goal and your addGoal function is erasing the previous value with goalJson content.
Instead, load once the goals from storage, then update the goals state when a new goal is added, and write them all to on storage each time goals value is updated.
This how effects works, by "reacting" to a change of value. This is just a little bit more complicated because of SecureStorage async functions.
Here is my (untested) improved code. I renamed the storage key from Goal to Goals.
const [goals, setGoals] = useState([])
const [loaded, setLoaded] = useState(false)
useEffect(()=> {
async function load() {
try {
const goalsValue = await SecureStore.getItemAsync("Goals")
const goalsParsed = JSON.parse(goalsValue)
if (goalsParsed !== null) {
setGoals(goalsParsed)
}
setLoaded(true)
} catch (err) { alert(err) }
}
load()
}, []) // load only when component mount
const addGoal = (text) => {
const goal = { text, id:`${Math.random()}`, todos:[],
date: Date.now(), percentage:0 }
setGoals([...goals, goal])
})
useEffect(() => {
async function saveGoals() {
try {
// save all goals to storage
const goalsJson = JSON.stringify(goals)
await SecureStore.setItemAsync("Goals", goalsJson)
}
catch (err) {alert(err)}
}
if (loaded) { // don't save before saved goals were loaded
saveGoals();
}
}, [goals, loaded]) // run the effect each time goals is changed

In which file do I set a key in react native async storage for the first time the app starts?

I am developing a react native app and I would like data persistence. Async storage is working fine as I expect it to, however the problem is that I initialize a key 'servers' in a component and and call the setItem function in componentDidMount function. Now because of this every time I terminate the app and run it again all the data from the previous session is removed as the 'servers' key is reset when the component is mounted. I understand why this is causing the problem so I want to know where should I set the key in my code that it will not reset on every time my component mounts.
This is the function that I call in componentDidMount. This is the only way to declare a key in Async storage correct? because without it I would not be able to call getItem.
const save = async () => {
try {
server_list = await AsyncStorage.setItem('server_list', JSON.stringify({servers: []}));
}
catch (e){
console.log("Failed to load")
}
}
You can achieve this by filling the AsyncStorage only as long as there is no data under the server_list key.
This would look like this:
setServerList = async (value) => {
try {
const serverList = await AsyncStorage.getItem('server_list');
if(serverList === null) {
await AsyncStorage.setItem('server_list', value)
}
} catch(e) {
// save error
}
console.log('Done.')
}
You can still call this in the componentDidMount and your server list will no longer be overwritten

Vue.js component not loading/rendering data when called via URL or F5

I have a Vue.js SPA with some pages that display data from a backend. When I navigate the pages via the navbar, everything works fine, components and data are loaded.
When I'm on the page, e.g. localhost:8080/#/mypage and press F5, the data doesn't get loaded / rendered. Same goes for when I directly navigate to the page via the address bar.
The data gets loaded in this function:
async beforeMount() {
await this.initializeData();
}
I've tried to call the method in every lifecycle hook, i.e. created, beforeCreated, mounted etc...
In the mounted lifecycle hook I'm setting a boolean property to true, so that the table is only rendered when the component is loaded (done with v-if).
mounted() {
this.componentLoaded = true;
}
Not sure if this is important, but I've tried it with or without and it doesn't work.
I would really appreciate it if somebody knew whats happening here.
EDIT:
this.applications is a prop and contains multiple applications which contain instances. I want to add some variables from the backend to each application.
console.log(1) gets printed
console.log(2) does not
initializeData: function () {
let warn = 0;
console.log("1");
this.applications.forEach(async application => {
const instance = application.instances[0];
console.log("2");
let myData = null;
try {
const response = await instance.axios.get('url/myData');
myData = response.data;
} catch (err) {
}
let tmpCount = 0;
let tmpFulfilled = 0;
myData.forEach(ba => {
if(!ba.fulfilled){
warn++;
application.baAllFulfilled = false;
}else {
tmpFulfilled++;
}
tmpCount++;
})
console.log("3");
// Assign values
this.baTotalWarnings = warn;
application.baAnzahl = tmpCount;
application.baFulfilled = tmpFulfilled;
this.componentLoaded = true;
}
Try removing the async and await keywords from your beforeMount, and remove this.componentLoaded from mounted. Set it instead in the then block (or after await) in your initializeData method. I'm not sure Vue supports the async keyword in its lifecycle methods.
Something like this:
beforeMount() {
this.initializeData(); // start processing the method
}
methods: {
initializeData() {
callToBackend().then(() => {
this.componentLoaded = true // backend call ready, can now show the table
})
}
}