Develop Reference

What is going wrong with my express call? I need an array of ID's but its returning an empty array

Im guessing this problem is because I don't know how to use async await effectively. I still dont get it and I've been trying to understand for ages. sigh.
Anyway, heres my function:
app.post("/declineTrades", async (request, response) => {
//---------------------------------------------
const batch = db.batch();
const listingID = request.body.listingID;
const tradeOfferQuery = db
//---------------------------------------------
//Get trade offers that contain the item that just sold
//(therefore it cannot be traded anymore, I need to cancel all existing trade offers that contain the item because this item isn't available anymore)
//---------------------------------------------
.collection("tradeOffers")
.where("status", "==", "pending")
.where("itemIds", "array-contains", listingID);
//---------------------------------------------
//Function that gets all trade offers that contain the ID of the item.
async function getIdsToDecline() {
let tempArray = [];
tradeOfferQuery.get().then((querySnapshot) => {
querySnapshot.forEach((doc) => {
//For each trade offer found
let offerRef = db.collection("tradeOffers").doc(doc.id);
//Change the status to declined
batch.update(offerRef, { status: "declined" });
//Get the data from the trade offer because I want to send an email
//to the who just got their trade offer declined.
const offerGet = offerRef.get().then((offer) => {
const offerData = offer.data();
//Check the items that the receiving person had in this trade offer
const receiverItemIds = Array.from(
offerData.receiversItems
.reduce((set, { itemID }) => set.add(itemID), new Set())
.values()
);
//if the receiver item id's array includes this item that just sold, I know that
//I can get the sender ID (users can be sender or receiver, so i need to check which person is which)
if (receiverItemIds.includes(listingID)) {
tempArray.push(offerData.senderID);
}
});
});
});
//With the ID's now pushed, return the tempArray
return tempArray;
}
//---------------------------------------------
//Call the above function to get the ID's of people that got declined
//due to the item no longer being available
const peopleToDeclineArray = await getIdsToDecline();
//Update the trade offer objects to declined
const result = await batch.commit();
//END
response.status(201).send({
success: true,
result: result,
idArray: peopleToDeclineArray,
});
});
Im guessing that my return tempArray is in the wrong place? But I have tried putting it in other places and it still returns an empty array. Is my logic correct here? I need to run the forEach loop and add to the array before the batch.commit happens and before the response is sent.
TIA Guys!

As #jabaa pointed out in their comment, there are problems with an incorrectly chained Promise in your getIdsToDecline function.
Currently the function initializes an array called tempArray, starts executing the trade offer query and then returns the array (which is currently still empty) because the query hasn't finished yet.
While you could throw in await before tradeOfferQuery.get(), this won't solve your problem as it will only wait for the tradeOfferQuery to execute and the batch to be filled with entries, while still not waiting for any of the offerRef.get() calls to be completed to fill the tempArray.
To fix this, we need to make sure that all of the offerRef.get() calls finish first. To get all of these documents, you would use the following code to fetch each document, wait for all of them to complete and then pull out the snapshots:
const itemsToFetch = [ /* ... */ ];
const getAllItemsPromise = Promise.all(
itemsToFetch.map(item => item.get())
);
const fetchedItemSnapshots = await getAllItemsPromise;
For documents based on a query, you'd tweak this to be:
const querySnapshot = /* ... */;
const getSenderDocPromises = [];
querySnapshot.forEach((doc) => {
const senderID = doc.get("senderID");
const senderRef = db.collection("users").doc(senderID);
getSenderDocPromises.push(senderRef.get());
}
const getAllSenderDocPromise = Promise.all(getSenderDocPromises);
const fetchedSenderDataSnapshots = await getAllSenderDocPromise;
However neither of these approaches are necessary, as the document you are requesting using these offerRef.get() calls are already returned in your query so we don't even need to use get() here!
(doc) => {
let offerRef = db.collection("tradeOffers").doc(doc.id);
//Change the status to declined
batch.update(offerRef, { status: "declined" });
//Get the data from the trade offer because I want to send an email
//to the who just got their trade offer declined.
const offerGet = offerRef.get().then((offer) => {
const offerData = offer.data();
//Check the items that the receiving person had in this trade offer
const receiverItemIds = Array.from(
offerData.receiversItems
.reduce((set, { itemID }) => set.add(itemID), new Set())
.values()
);
//if the receiver item id's array includes this item that just sold, I know that
//I can get the sender ID (users can be sender or receiver, so i need to check which person is which)
if (receiverItemIds.includes(listingID)) {
tempArray.push(offerData.senderID);
}
});
}
could be replaced with just
(doc) => {
// Change the status to declined
batch.update(doc.ref, { status: "declined" });
// Fetch the IDs of items that the receiving person had in this trade offer
const receiverItemIds = Array.from(
doc.get("receiversItems") // <-- this is the efficient form of doc.data().receiversItems
.reduce((set, { itemID }) => set.add(itemID), new Set())
.values()
);
// If the received item IDs includes the listed item, add the
// sender's ID to the array
if (receiverItemIds.includes(listingID)) {
tempArray.push(doc.get("senderID"));
}
}
which could be simplified to just
(doc) => {
//Change the status to declined
batch.update(doc.ref, { status: "declined" });
// Check if any items that the receiving person had in this trade offer
// include the listing ID.
const receiversItemsHasListingID = doc.get("receiversItems")
.some(item => item.itemID === listingID);
// If the listing ID was found, add the sender's ID to the array
if (receiversItemsHasListingID) {
tempArray.push(doc.get("senderID"));
}
}
Based on this, getIdsToDecline actually queues declining the invalid trades and returns the IDs of those senders affected. Instead of using the batch and tradeOfferQuery objects that are outside of the function that make this even more unclear, you should roll them into the function and pull it out of the express handler. I'll also rename it to declineInvalidTradesAndReturnAffectedSenders.
async function declineInvalidTradesAndReturnAffectedSenders(listingID) {
const tradeOfferQuery = db
.collection("tradeOffers")
.where("status", "==", "pending")
.where("itemIds", "array-contains", listingID);
const batch = db.batch();
const affectedSenderIDs = [];
const querySnapshot = await tradeOfferQuery.get();
querySnapshot.forEach((offerDoc) => {
batch.update(offerDoc.ref, { status: "declined" });
const receiversItemsHasListingID = offerDoc.get("receiversItems")
.some(item => item.itemID === listingID);
if (receiversItemsHasListingID) {
affectedSenderIDs.push(offerDoc.get("senderID"));
}
}
await batch.commit(); // generally, the return value of this isn't useful
return affectedSenderIDs;
}
This then would change your route handler to:
app.post("/declineTrades", async (request, response) => {
const listingID = request.body.listingID;
const peopleToDeclineArray = await declineInvalidTradesAndReturnAffectedSenders(listingID);
response.status(201).send({
success: true,
result: result,
idArray: peopleToDeclineArray,
});
});
Then adding the appropriate error handling, swapping out the incorrect use of HTTP 201 Created for HTTP 200 OK, and using json() instead of send(); you now get:
app.post("/declineTrades", async (request, response) => {
try {
const listingID = request.body.listingID;
const affectedSenderIDs = await declineInvalidTradesAndReturnAffectedSenders(listingID);
response.status(200).json({
success: true,
idArray: affectedSenderIDs, // consider renaming to affectedSenderIDs
});
} catch (error) {
console.error(`Failed to decline invalid trades for listing ${listingID}`, error);
if (!response.headersSent) {
response.status(500).json({
success: false,
errorCode: error.code || "unknown"
});
} else {
response.end(); // forcefully end corrupt response
}
}
});
Note: Even after all these changes, you are still missing any form of authentication. Consider swapping the HTTPS Event Function out for a Callable Function where this is handled for you but requires using a Firebase Client SDK.

Send a notification every 15 minutes during the day

I want to send a notification within 1 hour of the data I added to Firebase and I want to cancel the notification 1 day after adding the data. Because I don't know JavaScript, and I'm new to the software world yet, I couldn't quite figure out its algorithm, and I wrote something like that. The addedNewCard method works, but I couldn't adjust the time.
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().functions);
var newData;
exports.addedNewCard =
functions.firestore.document('Users/{userID}/Cards/{cardID}').onCreate(async
(snapshot, context) => {
const cardID = context.params.cardID;
if (snapshot.empty) {
console.log('No Devices');
return;
}
newData = snapshot.data();
const cardAddedDate = newData.cardAddedDate;
const deviceIdTokens = await admin
.firestore()
.collection('DeviceToken')
.get();
var tokens = [];
for (var token of deviceIdTokens.docs) {
tokens.push(token.data().deviceToken);
}
var payload = {
notification: {
title: 'Tekrar vakti',
body: 'Tekrar etmen gereken kelimeler var!!!',
sound: 'default',
},
data: {
click_action: 'FLUTTER_NOTIFICATIoN_CLICK',
sendCardID: cardID,
}
};
const options = {
priority: "high",
};
try {
await admin.messaging().sendToDevice(tokens, payload, options);
console.log('Notification sent successfully');
} catch (err) {
console.log(err);
}
})
exports.timeSettings = functions.pubsub.schedule('every 1 mins').onRun(async
(context) => {
console.log(context.timestamp);
let now = new Date();
const finishWorking = now.setDate(now.getDate + 1);
const finishWorkingStamp = admin.firestore.Timestamp.fromDate(finishWorking);
db.collection('Users/{userID}/Cards').where('cardAddedDate', '<',
finishWorkingStamp).get().then((snap) => {
if (snap.exist) {
snap.forEach(() => {
return addedNewCard();
}).catch((e) => {
return console.log(e);
});
}
});
})

Thanks to your comment, I would recommend you to use Cloud Task. With Cloud Task you can delay an execution in the futur.
When a user send a data, you can plan the 24H notification in advance (with 1 notification every 15 minutes, for 1 day -> create 96 tasks, the next one with 15 minutes more in the delay than the previous one).
You have code sample here. Have a look on this part, to change the delay
if (inSeconds) {
// The time when the task is scheduled to be attempted.
task.scheduleTime = {
seconds: inSeconds + Date.now() / 1000,
};
}

I wouldn't do the schedule notification in client side, instead, config and send schedule by server side. Try to create thread for client for processing the notifications.

You have to create a firebase cloud function where you need to upgrade your firebase account subscription and use pub-sub.
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
exports.scheduledFunctionCrontab = functions.pubsub.schedule('*/15 * * * *').timeZone('Asia/Kolkata').onRun(async (context) => {
console.log('This will be run every 15 minutes');
return null});

How do I make multiple fetch calls without getting 429 error?

I came across a problem in a book which I can't seem to figure out. Unfortunately, I don't have a live link for it, so if anyone could help me with my approach to this theoretically, I'd really appreciate it.
The process:
I get from a fetch call an array of string codes (["abcde", "fghij", "klmno", "pqrst"]).
I want to make a call to a link with each string code.
example:
fetch('http://my-url/abcde').then(res => res.json()).then(res => res).catch(error => new Error(`Error: ${error}`)); // result: 12345
fetch('http://my-url/fghij').then(res => res.json()).then(res => res).catch(error => new Error(`Error: ${error}`)); // result: 67891
...etc
Each of the calls is going to give me a number code, as shown.
I need to get the highest number of the 5 and get its afferent string code and make another call with that.
"abcde" => 1234
"fghij" => 5314
"klmno" => 3465
"pqrst" => 7234 <--- winner
fetch('http://my-url/pqrst').then(res => res.json()).then(res => res).catch(error => new Error(`Error: ${error}`));
What I tried:
let codesArr = []; // array of string codes
let promiseArr = []; // array of fetch using each string code in `codesArr`, meant to be used in Promise.all()
let codesObj = {}; // object with string code and its afferent number code gotten from the Promise.all()
fetch('http://my-url/some-code')
.then(res => res.json())
.then(res => codesArr = res) // now `codesArr` is ["abcde", "fghij", "klmno", "pqrst"]
.catch(error => new Error(`Error: ${error}`);
for(let i = 0; i < codesArr.length; i++) {
promiseArr.push(
fetch(`http://my-url/${codesArr[i]}`)
.then(res => res.text())
.then(res => {
codesObj[codesArr[i]] = res;
// This is to get an object from which I can later get the highest number and its string code. Like this:
// codesObj = {
// "abcde": 12345,
// "fghij": 67891
// }
})
.catch(error => new Error(`Error: ${error}`));
// I am trying to make an array with fetch, so that I can use it later in Promise.all()
}
Promise.all(promiseArray) // I wanted this to go through all the fetches inside the `promiseArr` and return all of the results at once.
.then(res => {
for(let i = 0; i < res.length; i++) {
console.log(res[i]);
// this should output the code number for each call (`12345`, `67891`...etc)
// this is where I get lost
}
})
One of the problems with my approach so far seems to be that it makes too many requests and I get 429 error. I sometimes get the number codes all right, but not too often.

Like you already found out the 429 means that you send too many requests:
429 Too Many Requests
The user has sent too many requests in a given amount of time ("rate
limiting").
The response representations SHOULD include details explaining the
condition, and MAY include a Retry-After header indicating how long to
wait before making a new request.
For example:
HTTP/1.1 429 Too Many Requests
Content-Type: text/html
Retry-After: 3600
<html>
<head>
<title>Too Many Requests</title>
</head>
<body>
<h1>Too Many Requests</h1>
<p>I only allow 50 requests per hour to this Web site per
logged in user. Try again soon.</p>
</body>
</html>
Note that this specification does not define how the origin server
identifies the user, nor how it counts requests. For example, an
origin server that is limiting request rates can do so based upon
counts of requests on a per-resource basis, across the entire server,
or even among a set of servers. Likewise, it might identify the user
by its authentication credentials, or a stateful cookie.
Responses with the 429 status code MUST NOT be stored by a cache.
To handle this issue you should reduce the amount of requests made in a set amount of time. You should iterate your codes with a delay, spacing out the request by a few seconds. If not specified in the API documentation or the 429 response, you have to use trial and error approach to find a delay that works. In the example below I've spaced them out 2 seconds (2000 milliseconds).
The can be done by using the setTimeout() to execute some piece of code later, combine this with a Promise to create a sleep function. When iterating the initially returned array, make sure to await sleep(2000) to create a 2 second delay between each iteration.
An example could be:
const fetch = createFetchMock({
"/some-code": ["abcde", "fghij", "klmno", "pqrst"],
"/abcde": 12345,
"/fghij": 67891,
"/klmno": 23456,
"/pqrst": 78912,
});
const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
(async function () {
try {
const url = "https://my-url/some-code";
console.log("fetching url", url);
const response = await fetch(url);
const codes = await response.json();
console.log("got", codes);
const codesObj = {};
for (const code of codes) {
await sleep(2000);
const url = `https://my-url/${code}`;
console.log("fetching url", url);
const response = await fetch(url);
const value = await response.json();
console.log("got", value);
codesObj[code] = value;
}
console.log("codesObj =", codesObj);
} catch (error) {
console.error(error);
}
})();
// fetch mocker factory
function createFetchMock(dataByPath = {}) {
const empty = new Blob([], {type: "text/plain"});
const status = {
ok: { status: 200, statusText: "OK" },
notFound: { status: 404, statusText: "Not Found" },
};
const blobByPath = Object.create(null);
for (const path in dataByPath) {
const json = JSON.stringify(dataByPath[path]);
blobByPath[path] = new Blob([json], { type: "application/json" });
}
return function (url) {
const path = new URL(url).pathname;
const response = (path in blobByPath)
? new Response(blobByPath[path], status.ok)
: new Response(empty, status.notFound);
return Promise.resolve(response);
};
}

In this case... You should run and wait each fetch run finish before run new fetch by using async/await
runFetch = async (codesArr) => {
for(let i = 0; i < codesArr.length; i++){
const rawResponse = await fetch(`http://my-url/${codesArr[i]}`);
const codeResponse = rawResponse.json();
console.log(rawResponse);
codesObj[codesArr[i]] = codeResponse;
}
}
hope that help you.

How to append to an array in IndexedDB filtered by ID?

Init code:
let dbPormise = null;
const OBJECT_STORE_NAME = 'pages';
const DB_NAME = 'tracking-log';
To initiate an ObjectStore:
dbPromise = idb.open(DB_NAME, 3, upgradeDB => {
upgradeDB.createObjectStore(OBJECT_STORE_NAME, {
autoIncrement: true,
keypath: 'id'
});
});
This is how I generate a blank record in the IndexedDB:
const tx = db.transaction(OBJECT_STORE_NAME, 'readwrite');
tx.objectStore(OBJECT_STORE_NAME).put(
{ id: newBucketID, data: [] });
Now, at a later point, I have some elements that I want to append to the data array for a particular id.
This is how I tried doing it:
const tx = db.transaction(OBJECT_STORE_NAME, 'readwrite');
tx.objectStore(OBJECT_STORE_NAME).put(
{ id: localStorage.getItem("currentBucket"), data: item }
);
Schema
{
data: Array
}
Every item has a unique key generated and provided by me.
However, this doesn't work and returns an error: "Key already exists in the object store."
So, how can I append a value to a field inside a IDB objectt?

Not sure about the error, but regardless of that, the basic way of adding an item would be something like this:
function addItem(db, bucketId, item) {
return new Promise(addItemExecutor.bind(null, db, bucketId, item));
}
function addItemExecutor(db, bucketId, item, resolve, reject) {
// Start a single writable transaction that we will use for two requests. One to
// find the corresponding bucket, and one to update it.
const tx = db.transaction(OBJECT_STORE_NAME, 'readwrite');
// If all requests completed without error, we are done
tx.oncomplete = resolve;
// If any request fails, the operation fails
tx.onerror = event => reject(event.target.error);
const store = tx.objectStore(OBJECT_STORE_NAME);
// Go find the corresponding bucket object to update
const findRequest = store.get(bucketId);
findRequest.onsuccess = findRequestOnsuccess.bind(findRequest, bucketId, item, reject);
}
// React to the resolution of the get request
function findRequestOnsuccess(bucketId, item, reject, event) {
const bucket = event.target.result;
// If no bucket exists for that id then fail
if(!bucket) {
const error = new Error('No bucket found for id ' + bucketId);
reject(error);
return;
}
// Lazily init the data array property
if(!bucket.data) {
bucket.data = [];
}
// Add our item to the data array
bucket.data.push(item);
// Save the bucket object back into the bucket object store, completely replacing
// the bucket that was there before.
const bucketStore = event.target.source;
bucketStore.put(bucket);
}
async function someCallingCodeExampleAvoidingTopLevelAwait() {
const bucketId = localStorage.currentBucket;
const item = {foo:bar};
const db = evilUnreliableGlobalDbVariableFromSomewhereMagicalForeverOpenAssumeInitialized;
try {
await addItem(db, bucketId, item);
} catch(error) {
console.debug(error);
}
// Leave the database connection open for page lifetime
}

Without a reduced example it's difficult to figure out what's going on. The best way to get help is to create a reduced example of the problem, as in, the smallest amount of code needed to recreate the issue you're seeing, then put it on something like jsbin.com or glitch.com so folks only have to click a link to see the error you're seeing.
I wasn't able to recreate the error you're seeing. You have keypath when it should be keyPath, but I don't think that creates the error you're seeing.
Anyway, here's how to modify a record in IDB:
async function main() {
// Set up the database.
const OBJECT_STORE_NAME = 'pages';
const DB_NAME = 'tracking-log';
const db = await idb.open(DB_NAME, 1, upgradeDB => {
upgradeDB.createObjectStore(OBJECT_STORE_NAME, {
autoIncrement: true,
keyPath: 'id'
});
});
// The OP didn't make it clear what this value was, so I'll guess.
const newBucketID = 1;
{
// Create the record.
const tx = db.transaction(OBJECT_STORE_NAME, 'readwrite');
tx.objectStore(OBJECT_STORE_NAME).put({ id: newBucketID, data: ['first value'] });
}
{
const tx = db.transaction(OBJECT_STORE_NAME, 'readwrite');
// Get the record.
const record = await tx.objectStore(OBJECT_STORE_NAME).get(newBucketID);
// Modify it.
record.data.push('second value');
// Put the modified record back.
tx.objectStore(OBJECT_STORE_NAME).put(record);
}
{
// Read the value to confirm everything worked.
const tx = db.transaction(OBJECT_STORE_NAME);
const value = await tx.objectStore(OBJECT_STORE_NAME).get(newBucketID);
console.log(value);
}
}
main();
And here's that example running: https://jsbin.com/dineguq/edit?js,console

Firebase Functions: Cannot read property 'val' of undefined

I'm trying to add a Function in my Firebase Database, that creates/updates a combined property of two others, whenever they change.
The model is like this:
database/
sessions/
id/
day = "1"
room = "A100"
day_room = "1_A100"
And my function so far:
exports.combineOnDayChange = functions.database
.ref('/sessions/{sessionId}/day')
.onWrite(event => {
if (!event.data.exists()) {
return;
}
const day = event.data.val();
const room = event.data.ref.parent.child('room').data.val();
console.log(`Day: ${day}, Room: ${room}`)
return event.data.ref.parent.child("day_room").set(`${day}_${room}`)
});
exports.combineOnRoomChange = functions.database
.ref('/sessions/{sessionId}/room')
.onWrite(event => {
if (!event.data.exists()) {
return;
}
const room = event.data.val();
const day = event.data.ref.parent.child('day').data.val();
console.log(`Day: ${day}, Room: ${room}`)
return event.data.ref.parent.child("day_room").set(`${day}_${room}`)
});
But it's throwing this error:
TypeError: Cannot read property 'val' of undefined
I'm following the very first example in the Firebase Functions Get Started (Add the makeUppercase() function) and this is what it does in order to reach the entity reference:
event.data.ref.parent
Am I using the child() function wrongly? Any ideas?

When Cloud Functions triggers your code, it passes in a snapshot of the data that triggered the change.
In your code:
exports.combineOnDayChange = functions.database
.ref('/sessions/{sessionId}/day')
This means you event.data has the data for /sessions/{sessionId}/day. It does not contain any data from higher in the tree.
So when you call event.data.ref.parent, this points to a location in the database for which the data hasn't been loaded yet. If you want to load the additional data, you'll have to load it explicitly in your code:
exports.combineOnDayChange = functions.database
.ref('/sessions/{sessionId}/day')
.onWrite(event => {
if (!event.data.exists()) {
return;
}
const day = event.data.val();
const roomRef = event.data.ref.parent.child('room');
return roomRef.once("value").then(function(snapshot) {
const room = snapshot.val();
console.log(`Day: ${day}, Room: ${room}`)
return event.data.ref.parent.child("day_room").set(`${day}_${room}`)
});
});
Alternatively, consider triggering higher in your tree /sessions/{sessionId}. Doing so means that you get all the necessary data in event.data already, and also means you only need a single function:
exports.updateSyntheticSessionProperties = functions.database
.ref('/sessions/{sessionId}')
.onWrite(event => {
if (!event.data.exists()) {
return; // the session was deleted
}
const session = event.data.val();
const day_room = `${session.day}_${session.room}`;
if (day_room !== session.day_room) {
return event.data.ref.parent.child("day_room").set(`${day}_${room}`)
});
});