Develop Reference

Why cant i see any notifications when i send data to device over BLE?

I'm trying to make an app that sends commands to a BLE device and i cant get any feedback. I am using a library called ble.plx which has an option to monitor characteristics but it wont output anything for me.
I need to read values from notifications to use later in my code. This is my first time working with BLE in general so i have no idea what i am doing wrong. I know serviceUUID and characteristicUUID are correct. I am out of ideas.
Here is my code:
function scanAndConnect() {
BLTManager.startDeviceScan(null, null, (error, device) => {
if (error) {
// Handle error (scanning will be stopped automatically)
return
}
// Check if it is a device you are looking for based on advertisement data
// or other criteria.
if (device.name=='Audio PCM Streamer') {
console.log(device.name);
// Stop scanning as it's not necessary if you are scanning for one device.
BLTManager.stopDeviceScan();
device.connect()
.then((device) => {
return device.discoverAllServicesAndCharacteristics()
})
.then( (device) => {
device.monitorCharacteristicForService(SERVICE_UUID,CHARACTERISTIC_UUID,(err,result)=>{
if(err) {
console.log(err)
return;
}
console.log(result);
}); Subscription
device.requestMTU(251)
let data = Uint8Array(9);
data[0]=0xA5;
data[1]=0xA5;
data[2]=0xA5;
data[3]=0xA5;
var b64encoded = btoa(decoder.decode(data));
device.writeCharacteristicWithoutResponseForService(SERVICE_UUID,CHARACTERISTIC_UUID,b64encoded);
})
.catch((error) => {
// Handle errors
});
}
});
}

I did this completely wrong do not use this or try to fix this its just bad.

Shopify REST API Pagination using Node.js and Express

I'm facing an issue, using Product resource on Shopify REST Api : I need to display many products on a Node.js Express app, I've left the default limit at 50 and when I want to fetch the next page of 50 products when I click on a next or previous button (I use the nextPageUrl/prevPageUrl from the response headers) I get a 401 error if the request is made from the client-side because of CORS error
Then I tried to make the request on server-side, I've passed the link from client to server when hitting the next button for example but it still does not work
The documentation is not clear at all about the paginated request and nothing that i've done from the documentation now is correct, it just says "Make a GET request to the link headers" and voila
Anyone have done this before ?
Code below
protectedRouter.get('/inventory', async (req, res) => {
try {
const session = await Shopify.Utils.loadCurrentSession(req, res);
const client = new Shopify.Clients.Rest(session.shop, session.accessToken)
const result = await client.get({
path: 'products',
})
res.render('inventory', {
products: result,
})
} catch (error) {
throw error;
}
});
script(src="/scripts/pagination.js")
div.View
h3.title.my-4 Etat des stocks
div.row
div.col-6
span(id='previousLink') #{products.pageInfo.prevPageUrl ? products.pageInfo.prevPageUrl : '' }
button.btn.btn-outline-dark.ml-4(id="previous_btn")
i(class="bi bi-arrow-left-circle-fill") Précédent
div.col-6
span(id='nextLink') #{products.pageInfo.nextPageUrl ? products.pageInfo.nextPageUrl : '' }
a.btn.btn-outline-dark.float-right.mr-4(id="next_btn") Suivant
i(class="fa-solid fa-circle-arrow-right")
window.addEventListener('DOMContentLoaded', () => {
console.log('dom content loaded')
document.getElementById('next_btn').onclick = function (e) {
console.log('next button clicked')
const nextLink = document.getElementById('nextLink').innerHTML;
fetch(nextLink).then(response => {
console.log(response);
}).catch(error => {
console.log(error)
})
console.log(nextLink)
}
});

You're doing it wrong. If you want to display Shopify products in your own App, you use the StorefrontAPI calls. With a StorefrontAPI token, you get products, and can display them. Trying to use Admin API calls is never going to work properly. Switch to StorefrontAPI and all your problems go away.

Getting cal cancelled error in firebase cloud functions

Firebase cloud functions logs "Error: 1 CANCELLED: Call cancelled" sometimes. am trying to send the push notifications one day before the timestamp, everything works till getting the fcm tokens but not able to send notification here is my code.
const NotificationLive_dayBefore = async () => {
try {
const path = models.payments.firebasePath;
let imageURL = null;
let tokens = [];
let subscribedUsers = await getSubscribedUsers().catch(e => { console.log(e) });
if (subscribedUsers && subscribedUsers.length > 0) {
for(const subscriber of subscribedUsers){
const userDoc = db
.collection('Payments').doc('v1').collection('users')
.doc(subscriber)
.collection('subscriptions').where('deleted_at', '==', null)
.get() // <------------here is the error according to logs
.then(async (snapshot) => {
if (!snapshot.empty) {
console.log('snapshot.empty', snapshot.empty);
for(const doc of snapshot.docs ){
// let friend_doc_id = doc.data().friend_doc_id
console.log("Friend id", doc.id);
if (doc.exists) {
let oneDay = new Date().getTime() + (24 * 60 * 60 * 1000);
let oneDayMinus1 = new Date().getTime() + (23 * 60 * 60 * 1000);
console.log(oneDayMinus1);
console.log(oneDay);
try {
let liveLesson = await db
.collection('Lessons').doc('v1').collection('friends')
.doc(doc.id)
.collection('live')
.where('start_time', '>', new Date(oneDayMinus1))
.where('start_time', '<', new Date(oneDay))
.where('deleted_at', '==', null)
.get();
for( const liveSnap of liveLesson.docs){
console.log("liveSnapid", '=>', liveSnap.data());
console.log('Private lesson exists', liveSnap.exists);
if (liveSnap.exists) {
// time is equal send notification
console.log("Subscriber ID", subscriber);
const Users = db
.collection(models.notification.firebasePath)
.where('deleted_at', '==', null)
.where('__name__', '==', subscriber)
.get()
.then(async (UserSnapshot) => {
for( const userdoc of UserSnapshot.docs){
const userdocument = userdoc.data();
if (userdocument.fcm_token) {
tokens = userdocument.fcm_token;
}
console.log('tokens',tokens);
if (tokens.length>0) {
try {
let live_lessons_images = await db
.collection('Accounts').doc('v1').collection('friends')
.doc(doc.id)
.get();
if (!live_lessons_images.data().image_url) {
imageURL = null;
console.log("Image not found");
} else {
imageURL = live_lessons_images.data().image_url;
}
} catch (error) {
console.log('That did not go well.', error)
}
console.log("notification sent live lesson 24 hr before");
await sendNotificationNew(
"test",
test notification,
imageURL,
tokens
).catch(error => { console.error("promise 1", error) });; //send notification to users as a remainder for live lesson before one day
}
}
}).catch(error => { console.error("promise 1", error) });
}
}
} catch (error) {
console.log('That did not go well.', error)
}
} else {
console.log("friend_doc_id is not present");
}
}
}
}).catch(error => { console.error("promise error", error) });
} //end foreach of subscribed user
}
return Promise.all('success');
}
catch (err) {
// Handle error here
// This will return error from api
console.log("Exceptions: ", err);
}}
and my sendNotificationNew function is
const sendNotificationNew = async (title, body, image, tokens) => {
console.log("title", title);
if (tokens.length > 0) {
if(tokens.length>1){
tokens = tokens[tokens.length-1];
}
try {
let message = {
notification: {
title: title,
body: body
},
token: tokens
};
if (image) {
message.notification.image = image;
}
admin.messaging().send(message)
.then((response) => {
// Response is a message ID string.
console.log('Successfully sent message:', response);
})
.catch((error) => {
console.log('Error sending message:', error);
console.log('Error sending message:', tokens);
});
} catch (err) {
console.log(err);
}
} else {
console.log("Token not available");
}
};
i was able to see the logs printing "title" of the notification, but not "Successfully sent message" or "Error sending message:".
Error message i got
Error: 1 CANCELLED: Call cancelled
at Object.callErrorFromStatus (/workspace/node_modules/#grpc/grpc-js/build/src/call.js:31)
at Object.onReceiveStatus (/workspace/node_modules/#grpc/grpc-js/build/src/client.js:327)
at Object.onReceiveStatus (/workspace/node_modules/#grpc/grpc-js/build/src/client-interceptors.js:299)
at (/workspace/node_modules/#grpc/grpc-js/build/src/call-stream.js:145)
at processTicksAndRejections (internal/process/task_queues.js:79)
And this
Error: 9 FAILED_PRECONDITION: The requested snapshot version is too old.
at Object.callErrorFromStatus (/workspace/node_modules/#grpc/grpc-js/build/src/call.js:31)
at Object.onReceiveStatus (/workspace/node_modules/#grpc/grpc-js/build/src/client.js:327)
at Object.onReceiveStatus (/workspace/node_modules/#grpc/grpc-js/build/src/client-interceptors.js:299)
at (/workspace/node_modules/#grpc/grpc-js/build/src/call-stream.js:145)
at processTicksAndRejections (internal/process/task_queues.js:79)

3rd Edit: Finally I've found the solution to this problem. A same error occurred in 2 cloud functions and I solved both of them by following the same process.
I'm not deleting the previous wrong answers, which didn't work for me, so that you also could know what won't work.
This error occurs because the Firestore has hit a limit.
I was trying to do lots of writes and updates in Firestore in parallel.
Example: Here all the functions are called all together. This is very fast as all the tasks are done in parallel. And recommended by Firebase.
But this might hit a limit in firestore and give error.
exports.botsCompletingLectures = functions.region('asia-south1')
.database.ref('triggerCloudFunctions/botsCompletingLectures')
.onUpdate(async(change, context)=>{
const promises = [];
promises.push(doSomeTaskInFirestore());
promises.push(doAnotherTaskInFirestore());
promises.push(doSomeMoreTaskInFirestore());
function doSomeTaskInFirestore(){
//Write to lots of documents in a collection
}
async function doAnotherTaskInFirestore(){
//Update lots of documents in firestore
}
async function doSomeMoreTaskInFirestore(){
//Do more tasks in firestore
}
return Promise.all(promises);
});
Solution: Here only one task will execute at a time and so it will take little more time. But will not give any error.
exports.botsCompletingLectures = functions.region('asia-south1')
.database.ref('triggerCloudFunctions/botsCompletingLectures')
.onUpdate(async(change, context)=>{
await doSomeTaskInFirestore()
await doAnotherTaskInFirestore()
return doSomeMoreTaskInFirestore()
function doSomeTaskInFirestore(){
//Write to lots of documents in a collection
}
async function doAnotherTaskInFirestore(){
//Update lots of documents in firestore
}
async function doSomeMoreTaskInFirestore(){
//Do more tasks in firestore
}
});
2nd Edit: The Cloud Function worked well for 4-5 days and then started giving errors again.
So this time I've given up on trying to fix it and instead enabled Retry on failure in Cloud Functions.
In my case as the Cloud Function is running correctly for some days and gives error on other days, due to some temperory problems, like network issue or cold start, so I can enable it here.
We should not enable it, if the error is permanent for eg a Bug in the code, else the function will keep on retrying for 7 days.
You can learn about Enabling Retry in Cloud Functions from this video.
https://www.youtube.com/watch?v=Pwsy8XR7HNE
1st Edit: The error appeared again the next day
So after reading and searching about it, I found out this problem occurs because of Cold Starting of a function after a long time and some Network problem and memory leak and most of the people (including me), who are getting this error, are getting it in PubSub Cloud Function and while doing some tasks in Firestore.
So I used a workaround. I don't know if it is recommended or not, but I'm tired of these errors, so I just did it.
I created a PubSub Cloud Function that updates a field value in Realtime Database. And this update in the field will trigger another function, that will do the task in firestore.
exports.triggerTheMainFunction = functions.pubsub.schedule('40 11 * * *').onRun(async(context)=> {
return admin.database().ref()
.child('triggerOtherFunction')
.child('doSomeTaskInFirestore')
.set(admin.database.ServerValue.increment(1))
.catch((error)=>{
console.log('Error incrementing the value', error);
});
});
And converted the Actual Function for Firestore from PubSub to Event Triggered. And since then I'm not getting any errors.
exports.doSomeTaskInCloudFirestore = functions
.database.ref('triggerOtherFunction/doSomeTaskInFirestore')
.onUpdate(async(change, context)=>{
//Do the task that was needed to be done in firestore.
});
If I get any errors in future, then I'll update this answer.
First Answer
I also got a similar error. I don't know what was causing the problem. But I solved it by installing the latest version.
So first I saved a copy of index.js on desktop and reinstalled everything.
I was using NodeJS 14 version. So I uninstalled it from control panel and downloaded the nodeJS 16 version from the nodejs website. And installed it.
ran in terminal.
npm install -g npm
then
npm install npm#latest -g
Then
firebase init
then
npm install -g firebase-tools
And then redeployed the same cloud function, without making any changes. And test run the function. And the error disappeared.

I resolved this issue by adding indexes in the firestore and proper catch blocks to all the promises to avoid unhandled rejection errors.

Service worker offline page won't load

This used to work for me but stopped a couple of months ago and I've tinkered my way right out of being able to figure this out anymore. What am I doing wrong here?
Call the service worker template, no problem:
if(navigator.serviceWorker){
window.addEventListener('load',() => {
navigator.serviceWorker
.register('/sw.js')
.then(console.log('[ServiceWorker] Registered Successfully'))
.catch(err => console.log(`[ServiceWorker] Error: ${err}`));
});
} else {
console.log('Service Worker not supported.');
}
Setup a cache version and preloaded the cache, no problem:
const cacheName='2020.10.06-01';
var cacheFiles = ['/offline.html'];
Installed the Services Worker, no problem:
addEventListener('install', e => {
e.waitUntil(
caches.open(cacheName).then(cache => {
return cache.addAll(cacheFiles);
})
);
});
Activated the Services Worker for auto cache rollover, no problem:
addEventListener('activate', e => {
e.waitUntil(
caches.keys().then(keyList => {
return Promise.all(keyList.map(key => {
if(key !== cacheName) {
return caches.delete(key);
}
}));
})
);
});
Fetching from cache or network, no problem:
addEventListener('fetch', e => {
e.respondWith(async function() {
try {
const cache = await caches.open(cacheName);
const cachedResponse = await cache.match(e.request);
const networkResponsePromise = fetch(e.request);
e.waitUntil(async function() {
const networkResponse = await networkResponsePromise;
await cache.put(e.request, networkResponse.clone());
}());
// Returned the cached response if we have one, otherwise return the network response.
return cachedResponse || networkResponsePromise;
} catch (error) {
console.log('Fetch failed; returning offline page instead.', error);
const cache = await caches.open(cacheName);
const cachedResponse = await cache.match('/offline.html');
return cachedResponse;
}
}());
});
But if the page/resource I'm trying to request is not already in the cache AND the network is not available it refuses to display my 'offline.html' page. (Which I know IS in the cache)
Any ideas?

Here's the Fetch code I wrote in the end that works perfectly for me:
self.addEventListener('fetch', (event) => {
event.respondWith((async() => {
const cache = await caches.open(cacheName);
try {
const cachedResponse = await cache.match(event.request);
if(cachedResponse) {
console.log('cachedResponse: ', event.request.url);
return cachedResponse;
}
const fetchResponse = await fetch(event.request);
if(fetchResponse) {
console.log('fetchResponse: ', event.request.url);
await cache.put(event.request, fetchResponse.clone());
return fetchResponse;
}
} catch (error) {
console.log('Fetch failed: ', error);
const cachedResponse = await cache.match('/en/offline.html');
return cachedResponse;
}
})());
});
This does everything I need, in a very specific order. It checks the cache first, if found it's returned. It checks the network next, if found it caches it first then returns it. Or it displays a custom offline page with a big Reload button to encourage visitors to try again when they are back online.
But the most important this to realise is that doing it this way alows me to display a page and all it's resources with or without network access.
UPDATE: In order to deal with changes to CORS security requirements that where implemented in all browsers between March and August of 2020, I had to make one small change to the 'fetch' event.
Changed from:
const fetchResponse = await fetch(event.request);
To:
const fetchResponse = await fetch(event.request, {mode:'no-cors'});

Replace your fetch event code with this one. For every request your fetch event will be invoked and it will check if your request is found in the cache file list then it will serve the file from there otherwise it will make the fetch call to get the file from server.
self.addEventListener("fetch", function (event) {
event.respondWith(
caches.match(event.request)
.then(function (response) {
if (response) {
return response;
}
return fetch(event.request);
})
);
});
Also you don't need a separate "offline.html" file in your cache file list. Instead add your main application html file and your relevant css and js files in that list. That will make your application completely offline in case of no network.

Using Discord.js to get all of the messages sent since the bot went offline

So I am making a bot that will store all of the messages sent in a channel into a txt file on my computer. Since I don't have my computer on all the time and I run the bot on my computer it leaves gaps in messages stored in the .txt file. I am trying to make it so that my bot will get all the messages sent since it went offline and store all of them in my file. I created a txt file that saves the message id of every message, it will overwrite the last message so its basically just a file with one message id in it. When my bot starts a boolean variable is instantiated to false and will be set to true once the startup procedure has been completed. This is what I have so far:
var latest;
var beenRunning = false;
bot.on('message', msg => {
latest = msg.id;
if(beenRunning == false) {
msg.channel.messages.fetch(latest, {limit: 100})
.then(messages =>
//code to get messages since last online
)
.catch(console.error);
beenRunning = true;
}
else {
messageTest(msg);
}
fs.writeFile('lastMsg.txt', latest, (err) => {
if (err) throw err;
})
});
I am not sure how to get every message since going offline using the fetch() method. How would I do this?

Not sure how you are structuring your lastMsg.txt, so I just used json.
Might be a bit slow since it'll be a bigger file and its using a lot of array higher functions
let logged = require("./lastMsg.json");
let beenRunning;
bot.on('message', msg => {
if (!beenRunning) {
msg.channel.messages.fetch({ limit: 100 })
.then(messages => {
const reduced = messages
.map(e => ({ id: e.id, content: e.content }))
.filter(e => {
return logged.find(l => l.id === e.id && l.content === e.content);
});
logged = logged.concat(reduced.array());
beenRunning = true;
})
.catch(console.error);
} else {
messageTest(msg);
}
fs.writeFile('lastMsg.json', JSON.stringify(logged), (err) => {
if (err) throw err;
})
});
Initalize your ./lastMsg.json to
[]