Why is my data storing twice in my Firebase Database? - javascript

I am new at using Firebase so all advice is welcome.
What i'm trying to achieve?
I want to create a player only if the user has not exceeded their team size ("numberOfplayersLimit").
So currently I am using a firebase transaction which first checks that the team has not exceeded their limit "numberOfPlayers", if the team has not exceeded their limit, increment the "numberOfplayersLimit" counter and then add the player to the database as shown below.
Whats my issue
I am currently using .push() to add the players however it is creating the player twice as shown below as you can see the full name is the same in other records but they have different uids.
Below is a screenshot from my Firebase real-time database JSON structure
var myUserId = firebase.auth().currentUser.uid;
const playerData = {
fullName:this.state.fullName,
};
//This is where the players are stored
const teamplayersref = firebase.database().ref('/teams').child(myUserId).child('/players')
//Transaction - Team reference path for the TeamPlayers Limit
const getTeamPlayersLimit = firebase.database().ref('/teams').child(myUserId).child('numberOfplayersLimit');
getTeamPlayersLimit.transaction(function(numberOfplayersLimit){
if (numberOfplayersLimit == 11) {
alert('You have exceed your team size limit, Delete a player from your team or contact us to upgrade your package');
}
else
{
//increment teamplayers limit
numberOfplayersLimit = numberOfplayersLimit + 1;
teamplayersref.push(playerData);
return numberOfplayersLimit;
}
});

The teamplayersref.push(playerData) call in your transaction handler is not part of the transaction itself. So if the transaction is retried, you end up calling teamplayersref.push(playerData) multiple times, creating a child node for each try.
To generate a new child with unique push ID, use push without an argument to get a new key, and then use that in the return value of your transaction. This means that your transaction will have to run on the entire firebase.database().ref('/teams') node, since you're modifying both the counter and the players.
const teamRef = firebase.database().ref('/teams').child(myUserId);
teamRef.transaction(function(team){
team = team || { numberOfplayersLimit: 0, players: {} };
if (team.numberOfplayersLimit == 11) {
console.error('You have exceed your team size limit, Delete a player from your team or contact us to upgrade your package');
}
else {
team.numberOfplayersLimit = team.numberOfplayersLimit + 1;
const newPlayerKey = teamRef.push().key; // this line does not write to the database
team.players[newPlayerKey] = playerData;
return team;
}
});

Related

Allowing only one like per item. JS + Firebase Realtime Database

I am new to programming and I am trying to implement a picture gallery in which you can like/vote your favorite pictures. Each picture displays a counter of the number of likes/votes.
The caveat is that while you can vote for different pictures, you can only vote once for each one.
Any ideas on how to achieve this?
const dCounters = document.querySelectorAll('.CountLike');
[].forEach.call(dCounters, function(dCounter) {
const el = dCounter.querySelector('button');
const cId = dCounter.id;
const dDatabase = firebase.database().ref('Like Number Counter').child(cId);
// get firebase data
dDatabase.on('value', function(snap) {
let data = snap.val() || 0;
dCounter.querySelector('span').innerHTML = data;
});
// set firebase data
el.addEventListener('click', function() {
dDatabase.transaction(function(dCount) {
return (dCount || 0) + 1;
});
});
});
I have tried using local storage to check if user has voted already =
localStorage.getItem('iHaveVoted', 'yes')
but this doesnt get into account until browser is refreshed. Therefore, user is still allowed to increase the votes multiple times.

Firestore listen only to root component [duplicate]

Is it possible to count how many items a collection has using the new Firebase database, Cloud Firestore?
If so, how do I do that?
2023 Update
Firestore now supports aggregation queries.
Node SDK
const collectionRef = db.collection('cities');
const snapshot = await collectionRef.count().get();
console.log(snapshot.data().count);
Web v9 SDK
const coll = collection(db, "cities");
const snapshot = await getCountFromServer(coll);
console.log('count: ', snapshot.data().count);
Notable Limitation - You cannot currently use count() queries with real-time listeners and offline queries. (See below for alternatives)
Pricing - Pricing depends on the number of matched index entries rather than the number of documents. One index entry contains multiple documents making this cheaper than counting documents individually.
Old Answer
As with many questions, the answer is - It depends.
You should be very careful when handling large amounts of data on the front end. On top of making your front end feel sluggish, Firestore also charges you $0.60 per million reads you make.
Small collection (less than 100 documents)
Use with care - Frontend user experience may take a hit
Handling this on the front end should be fine as long as you are not doing too much logic with this returned array.
db.collection('...').get().then(snap => {
size = snap.size // will return the collection size
});
Medium collection (100 to 1000 documents)
Use with care - Firestore read invocations may cost a lot
Handling this on the front end is not feasible as it has too much potential to slow down the users system. We should handle this logic server side and only return the size.
The drawback to this method is you are still invoking Firestore reads (equal to the size of your collection), which in the long run may end up costing you more than expected.
Cloud Function:
db.collection('...').get().then(snap => {
res.status(200).send({length: snap.size});
});
Front End:
yourHttpClient.post(yourCloudFunctionUrl).toPromise().then(snap => {
size = snap.length // will return the collection size
})
Large collection (1000+ documents)
Most scalable solution
FieldValue.increment()
As of April 2019 Firestore now allows incrementing counters, completely atomically, and without reading the data prior. This ensures we have correct counter values even when updating from multiple sources simultaneously (previously solved using transactions), while also reducing the number of database reads we perform.
By listening to any document deletes or creates we can add to or remove from a count field that is sitting in the database.
See the firestore docs - Distributed Counters
Or have a look at Data Aggregation by Jeff Delaney. His guides are truly fantastic for anyone using AngularFire but his lessons should carry over to other frameworks as well.
Cloud Function:
export const documentWriteListener = functions.firestore
.document('collection/{documentUid}')
.onWrite((change, context) => {
if (!change.before.exists) {
// New document Created : add one to count
db.doc(docRef).update({ numberOfDocs: FieldValue.increment(1) });
} else if (change.before.exists && change.after.exists) {
// Updating existing document : Do nothing
} else if (!change.after.exists) {
// Deleting document : subtract one from count
db.doc(docRef).update({ numberOfDocs: FieldValue.increment(-1) });
}
return;
});
Now on the frontend you can just query this numberOfDocs field to get the size of the collection.
Simplest way to do so is to read the size of a "querySnapshot".
db.collection("cities").get().then(function(querySnapshot) {
console.log(querySnapshot.size);
});
You can also read the length of the docs array inside "querySnapshot".
querySnapshot.docs.length;
Or if a "querySnapshot" is empty by reading the empty value, which will return a boolean value.
querySnapshot.empty;
As far as I know there is no build-in solution for this and it is only possible in the node sdk right now.
If you have a
db.collection('someCollection')
you can use
.select([fields])
to define which field you want to select. If you do an empty select() you will just get an array of document references.
example:
db.collection('someCollection').select().get().then(
(snapshot) => console.log(snapshot.docs.length)
);
This solution is only a optimization for the worst case of downloading all documents and does not scale on large collections!
Also have a look at this:
How to get a count of number of documents in a collection with Cloud Firestore
Aggregate count query just landed as a preview in Firestore.
Announced at the 2022 Firebase Summit: https://firebase.blog/posts/2022/10/whats-new-at-Firebase-Sumit-2022
Excerpt:
[Developer Preview] Count() function: With the new count function in
Firstore [sic], you can now get the count of the matching documents when you
run a query or read from a collection, without loading the actual
documents, which saves you a lot of time.
Code sample they showed at the summit:
During the Q&A, someone asked about pricing for aggregated queries, and the answer the Firebase team provided was that it'll cost 1 / 1000th of the price of a read (rounded up to the nearest read, see comments below for more details), but will count all records that are part of the aggregate.
Be careful counting number of documents for large collections. It is a little bit complex with firestore database if you want to have a precalculated counter for every collection.
Code like this doesn't work in this case:
export const customerCounterListener =
functions.firestore.document('customers/{customerId}')
.onWrite((change, context) => {
// on create
if (!change.before.exists && change.after.exists) {
return firestore
.collection('metadatas')
.doc('customers')
.get()
.then(docSnap =>
docSnap.ref.set({
count: docSnap.data().count + 1
}))
// on delete
} else if (change.before.exists && !change.after.exists) {
return firestore
.collection('metadatas')
.doc('customers')
.get()
.then(docSnap =>
docSnap.ref.set({
count: docSnap.data().count - 1
}))
}
return null;
});
The reason is because every cloud firestore trigger has to be idempotent, as firestore documentation say: https://firebase.google.com/docs/functions/firestore-events#limitations_and_guarantees
Solution
So, in order to prevent multiple executions of your code, you need to manage with events and transactions. This is my particular way to handle large collection counters:
const executeOnce = (change, context, task) => {
const eventRef = firestore.collection('events').doc(context.eventId);
return firestore.runTransaction(t =>
t
.get(eventRef)
.then(docSnap => (docSnap.exists ? null : task(t)))
.then(() => t.set(eventRef, { processed: true }))
);
};
const documentCounter = collectionName => (change, context) =>
executeOnce(change, context, t => {
// on create
if (!change.before.exists && change.after.exists) {
return t
.get(firestore.collection('metadatas')
.doc(collectionName))
.then(docSnap =>
t.set(docSnap.ref, {
count: ((docSnap.data() && docSnap.data().count) || 0) + 1
}));
// on delete
} else if (change.before.exists && !change.after.exists) {
return t
.get(firestore.collection('metadatas')
.doc(collectionName))
.then(docSnap =>
t.set(docSnap.ref, {
count: docSnap.data().count - 1
}));
}
return null;
});
Use cases here:
/**
* Count documents in articles collection.
*/
exports.articlesCounter = functions.firestore
.document('articles/{id}')
.onWrite(documentCounter('articles'));
/**
* Count documents in customers collection.
*/
exports.customersCounter = functions.firestore
.document('customers/{id}')
.onWrite(documentCounter('customers'));
As you can see, the key to prevent multiple execution is the property called eventId in the context object. If the function has been handled many times for the same event, the event id will be the same in all cases. Unfortunately, you must have "events" collection in your database.
In 2020 this is still not available in the Firebase SDK however it is available in Firebase Extensions (Beta) however it's pretty complex to setup and use...
A reasonable approach
Helpers... (create/delete seems redundant but is cheaper than onUpdate)
export const onCreateCounter = () => async (
change,
context
) => {
const collectionPath = change.ref.parent.path;
const statsDoc = db.doc("counters/" + collectionPath);
const countDoc = {};
countDoc["count"] = admin.firestore.FieldValue.increment(1);
await statsDoc.set(countDoc, { merge: true });
};
export const onDeleteCounter = () => async (
change,
context
) => {
const collectionPath = change.ref.parent.path;
const statsDoc = db.doc("counters/" + collectionPath);
const countDoc = {};
countDoc["count"] = admin.firestore.FieldValue.increment(-1);
await statsDoc.set(countDoc, { merge: true });
};
export interface CounterPath {
watch: string;
name: string;
}
Exported Firestore hooks
export const Counters: CounterPath[] = [
{
name: "count_buildings",
watch: "buildings/{id2}"
},
{
name: "count_buildings_subcollections",
watch: "buildings/{id2}/{id3}/{id4}"
}
];
Counters.forEach(item => {
exports[item.name + '_create'] = functions.firestore
.document(item.watch)
.onCreate(onCreateCounter());
exports[item.name + '_delete'] = functions.firestore
.document(item.watch)
.onDelete(onDeleteCounter());
});
In action
The building root collection and all sub collections will be tracked.
Here under the /counters/ root path
Now collection counts will update automatically and eventually! If you need a count, just use the collection path and prefix it with counters.
const collectionPath = 'buildings/138faicnjasjoa89/buildingContacts';
const collectionCount = await db
.doc('counters/' + collectionPath)
.get()
.then(snap => snap.get('count'));
Limitations
As this approach uses a single database and document, it is limited to the Firestore constraint of 1 Update per Second for each counter. It will be eventually consistent, but in cases where large amounts of documents are added/removed the counter will lag behind the actual collection count.
I agree with #Matthew, it will cost a lot if you perform such query.
[ADVICE FOR DEVELOPERS BEFORE STARTING THEIR PROJECTS]
Since we have foreseen this situation at the beginning, we can actually make a collection namely counters with a document to store all the counters in a field with type number.
For example:
For each CRUD operation on the collection, update the counter document:
When you create a new collection/subcollection: (+1 in the counter) [1 write operation]
When you delete a collection/subcollection: (-1 in the counter) [1 write operation]
When you update an existing collection/subcollection, do nothing on the counter document: (0)
When you read an existing collection/subcollection, do nothing on the counter document: (0)
Next time, when you want to get the number of collection, you just need to query/point to the document field. [1 read operation]
In addition, you can store the collections name in an array, but this will be tricky, the condition of array in firebase is shown as below:
// we send this
['a', 'b', 'c', 'd', 'e']
// Firebase stores this
{0: 'a', 1: 'b', 2: 'c', 3: 'd', 4: 'e'}
// since the keys are numeric and sequential,
// if we query the data, we get this
['a', 'b', 'c', 'd', 'e']
// however, if we then delete a, b, and d,
// they are no longer mostly sequential, so
// we do not get back an array
{2: 'c', 4: 'e'}
So, if you are not going to delete the collection , you can actually use array to store list of collections name instead of querying all the collection every time.
Hope it helps!
As of October 2022, Firestore has introduced a count() method on the client SDKs. Now you can count for a query without downloads.
For 1000 documents, it will charge you for 1 document read.
Web (v9)
Introduced in Firebase 9.11.0:
const collectionRef = collection(db, "cities");
const snapshot = await getCountFromServer(collectionRef);
console.log('count: ', snapshot.data().count);
Web V8
Not Available.
Node (Admin)
const collectionRef = db.collection('cities');
const snapshot = await collectionRef.count().get();
console.log(snapshot.data().count);
Android (Kotlin)
Introduced in firestore v24.4.0 (BoM 31.0.0):
val query = db.collection("cities")
val countQuery = query.count()
countQuery.get(AggregateSource.SERVER).addOnCompleteListener { task ->
if (task.isSuccessful) {
val snapshot = task.result
Log.d(TAG, "Count: ${snapshot.count}")
} else {
Log.d(TAG, "Count failed: ", task.getException())
}
}
Apple Platforms (Swift)
Introduced in Firestore v10.0.0:
do {
let query = db.collection("cities")
let countQuery = query.countAggregateQuery
let snapshot = try await countQuery.aggregation(source: AggregateSource.server)
print(snapshot.count)
} catch {
print(error)
}
Increment a counter using admin.firestore.FieldValue.increment:
exports.onInstanceCreate = functions.firestore.document('projects/{projectId}/instances/{instanceId}')
.onCreate((snap, context) =>
db.collection('projects').doc(context.params.projectId).update({
instanceCount: admin.firestore.FieldValue.increment(1),
})
);
exports.onInstanceDelete = functions.firestore.document('projects/{projectId}/instances/{instanceId}')
.onDelete((snap, context) =>
db.collection('projects').doc(context.params.projectId).update({
instanceCount: admin.firestore.FieldValue.increment(-1),
})
);
In this example we increment an instanceCount field in the project each time a document is added to the instances sub collection. If the field doesn't exist yet it will be created and incremented to 1.
The incrementation is transactional internally but you should use a distributed counter if you need to increment more frequently than every 1 second.
It's often preferable to implement onCreate and onDelete rather than onWrite as you will call onWrite for updates which means you are spending more money on unnecessary function invocations (if you update the docs in your collection).
No, there is no built-in support for aggregation queries right now. However there are a few things you could do.
The first is documented here. You can use transactions or cloud functions to maintain aggregate information:
This example shows how to use a function to keep track of the number of ratings in a subcollection, as well as the average rating.
exports.aggregateRatings = firestore
.document('restaurants/{restId}/ratings/{ratingId}')
.onWrite(event => {
// Get value of the newly added rating
var ratingVal = event.data.get('rating');
// Get a reference to the restaurant
var restRef = db.collection('restaurants').document(event.params.restId);
// Update aggregations in a transaction
return db.transaction(transaction => {
return transaction.get(restRef).then(restDoc => {
// Compute new number of ratings
var newNumRatings = restDoc.data('numRatings') + 1;
// Compute new average rating
var oldRatingTotal = restDoc.data('avgRating') * restDoc.data('numRatings');
var newAvgRating = (oldRatingTotal + ratingVal) / newNumRatings;
// Update restaurant info
return transaction.update(restRef, {
avgRating: newAvgRating,
numRatings: newNumRatings
});
});
});
});
The solution that jbb mentioned is also useful if you only want to count documents infrequently. Make sure to use the select() statement to avoid downloading all of each document (that's a lot of bandwidth when you only need a count). select() is only available in the server SDKs for now so that solution won't work in a mobile app.
UPDATE 11/20
I created an npm package for easy access to a counter function: https://code.build/p/9DicAmrnRoK4uk62Hw1bEV/firestore-counters
I created a universal function using all these ideas to handle all counter situations (except queries).
The only exception would be when doing so many writes a second, it
slows you down. An example would be likes on a trending post. It is
overkill on a blog post, for example, and will cost you more. I
suggest creating a separate function in that case using shards:
https://firebase.google.com/docs/firestore/solutions/counters
// trigger collections
exports.myFunction = functions.firestore
.document('{colId}/{docId}')
.onWrite(async (change: any, context: any) => {
return runCounter(change, context);
});
// trigger sub-collections
exports.mySubFunction = functions.firestore
.document('{colId}/{docId}/{subColId}/{subDocId}')
.onWrite(async (change: any, context: any) => {
return runCounter(change, context);
});
// add change the count
const runCounter = async function (change: any, context: any) {
const col = context.params.colId;
const eventsDoc = '_events';
const countersDoc = '_counters';
// ignore helper collections
if (col.startsWith('_')) {
return null;
}
// simplify event types
const createDoc = change.after.exists && !change.before.exists;
const updateDoc = change.before.exists && change.after.exists;
if (updateDoc) {
return null;
}
// check for sub collection
const isSubCol = context.params.subDocId;
const parentDoc = `${countersDoc}/${context.params.colId}`;
const countDoc = isSubCol
? `${parentDoc}/${context.params.docId}/${context.params.subColId}`
: `${parentDoc}`;
// collection references
const countRef = db.doc(countDoc);
const countSnap = await countRef.get();
// increment size if doc exists
if (countSnap.exists) {
// createDoc or deleteDoc
const n = createDoc ? 1 : -1;
const i = admin.firestore.FieldValue.increment(n);
// create event for accurate increment
const eventRef = db.doc(`${eventsDoc}/${context.eventId}`);
return db.runTransaction(async (t: any): Promise<any> => {
const eventSnap = await t.get(eventRef);
// do nothing if event exists
if (eventSnap.exists) {
return null;
}
// add event and update size
await t.update(countRef, { count: i });
return t.set(eventRef, {
completed: admin.firestore.FieldValue.serverTimestamp()
});
}).catch((e: any) => {
console.log(e);
});
// otherwise count all docs in the collection and add size
} else {
const colRef = db.collection(change.after.ref.parent.path);
return db.runTransaction(async (t: any): Promise<any> => {
// update size
const colSnap = await t.get(colRef);
return t.set(countRef, { count: colSnap.size });
}).catch((e: any) => {
console.log(e);
});;
}
}
This handles events, increments, and transactions. The beauty in this, is that if you are not sure about the accuracy of a document (probably while still in beta), you can delete the counter to have it automatically add them up on the next trigger. Yes, this costs, so don't delete it otherwise.
Same kind of thing to get the count:
const collectionPath = 'buildings/138faicnjasjoa89/buildingContacts';
const colSnap = await db.doc('_counters/' + collectionPath).get();
const count = colSnap.get('count');
Also, you may want to create a cron job (scheduled function) to remove old events to save money on database storage. You need at least a blaze plan, and there may be some more configuration. You could run it every sunday at 11pm, for example.
https://firebase.google.com/docs/functions/schedule-functions
This is untested, but should work with a few tweaks:
exports.scheduledFunctionCrontab = functions.pubsub.schedule('5 11 * * *')
.timeZone('America/New_York')
.onRun(async (context) => {
// get yesterday
const yesterday = new Date();
yesterday.setDate(yesterday.getDate() - 1);
const eventFilter = db.collection('_events').where('completed', '<=', yesterday);
const eventFilterSnap = await eventFilter.get();
eventFilterSnap.forEach(async (doc: any) => {
await doc.ref.delete();
});
return null;
});
And last, don't forget to protect the collections in firestore.rules:
match /_counters/{document} {
allow read;
allow write: if false;
}
match /_events/{document} {
allow read, write: if false;
}
Update: Queries
Adding to my other answer if you want to automate query counts as well, you can use this modified code in your cloud function:
if (col === 'posts') {
// counter reference - user doc ref
const userRef = after ? after.userDoc : before.userDoc;
// query reference
const postsQuery = db.collection('posts').where('userDoc', "==", userRef);
// add the count - postsCount on userDoc
await addCount(change, context, postsQuery, userRef, 'postsCount');
}
return delEvents();
Which will automatically update the postsCount in the userDocument. You could easily add other one to many counts this way. This just gives you ideas of how you can automate things. I also gave you another way to delete the events. You have to read each date to delete it, so it won't really save you to delete them later, just makes the function slower.
/**
* Adds a counter to a doc
* #param change - change ref
* #param context - context ref
* #param queryRef - the query ref to count
* #param countRef - the counter document ref
* #param countName - the name of the counter on the counter document
*/
const addCount = async function (change: any, context: any,
queryRef: any, countRef: any, countName: string) {
// events collection
const eventsDoc = '_events';
// simplify event type
const createDoc = change.after.exists && !change.before.exists;
// doc references
const countSnap = await countRef.get();
// increment size if field exists
if (countSnap.get(countName)) {
// createDoc or deleteDoc
const n = createDoc ? 1 : -1;
const i = admin.firestore.FieldValue.increment(n);
// create event for accurate increment
const eventRef = db.doc(`${eventsDoc}/${context.eventId}`);
return db.runTransaction(async (t: any): Promise<any> => {
const eventSnap = await t.get(eventRef);
// do nothing if event exists
if (eventSnap.exists) {
return null;
}
// add event and update size
await t.set(countRef, { [countName]: i }, { merge: true });
return t.set(eventRef, {
completed: admin.firestore.FieldValue.serverTimestamp()
});
}).catch((e: any) => {
console.log(e);
});
// otherwise count all docs in the collection and add size
} else {
return db.runTransaction(async (t: any): Promise<any> => {
// update size
const colSnap = await t.get(queryRef);
return t.set(countRef, { [countName]: colSnap.size }, { merge: true });
}).catch((e: any) => {
console.log(e);
});;
}
}
/**
* Deletes events over a day old
*/
const delEvents = async function () {
// get yesterday
const yesterday = new Date();
yesterday.setDate(yesterday.getDate() - 1);
const eventFilter = db.collection('_events').where('completed', '<=', yesterday);
const eventFilterSnap = await eventFilter.get();
eventFilterSnap.forEach(async (doc: any) => {
await doc.ref.delete();
});
return null;
}
I should also warn you that universal functions will run on every
onWrite call period. It may be cheaper to only run the function on
onCreate and on onDelete instances of your specific collections. Like
the noSQL database we are using, repeated code and data can save you
money.
There is no direct option available. You cant't do db.collection("CollectionName").count().
Below are the two ways by which you can find the count of number of documents within a collection.
1 :- Get all the documents in the collection and then get it's size.(Not the best Solution)
db.collection("CollectionName").get().subscribe(doc=>{
console.log(doc.size)
})
By using above code your document reads will be equal to the size of documents within a collection and that is the reason why one must avoid using above solution.
2:- Create a separate document with in your collection which will store the count of number of documents in the collection.(Best Solution)
db.collection("CollectionName").doc("counts")get().subscribe(doc=>{
console.log(doc.count)
})
Above we created a document with name counts to store all the count information.You can update the count document in the following way:-
Create a firestore triggers on the document counts
Increment the count property of counts document when a new document is created.
Decrement the count property of counts document when a document is deleted.
w.r.t price (Document Read = 1) and fast data retrieval the above solution is good.
A workaround is to:
write a counter in a firebase doc, which you increment within a transaction everytime you create a new entry
You store the count in a field of your new entry (i.e: position: 4).
Then you create an index on that field (position DESC).
You can do a skip+limit with a query.Where("position", "<" x).OrderBy("position", DESC)
Hope this helps!
I have try a lot with different approaches.
And finally, I improve one of the methods.
First you need to create a separate collection and save there all events.
Second you need to create a new lambda to be triggered by time. This lambda will Count events in event collection and clear event documents.
Code details in article.
https://medium.com/#ihor.malaniuk/how-to-count-documents-in-google-cloud-firestore-b0e65863aeca
one of the fast + money saver trick is that:-
make a doc and store a 'count' variable in firestore, when user add new doc in the collection, increase that variable, and when user delete a doc, decrease variable. e.g.
updateDoc(doc(db, "Count_collection", "Count_Doc"), {count: increment(1)});
note: use (-1) for decreasing, (1) for increasing count
How it save money and time:-
you(firebase) don't need to loop through the collection, nor browser needs to load whole collection to count number of docs.
all the counts are save in a doc of only one variable named "count" or whatever, so less than 1kb data is used, and it use only 1 reads in firebase firestore.
Solution using pagination with offset & limit:
public int collectionCount(String collection) {
Integer page = 0;
List<QueryDocumentSnapshot> snaps = new ArrayList<>();
findDocsByPage(collection, page, snaps);
return snaps.size();
}
public void findDocsByPage(String collection, Integer page,
List<QueryDocumentSnapshot> snaps) {
try {
Integer limit = 26000;
FieldPath[] selectedFields = new FieldPath[] { FieldPath.of("id") };
List<QueryDocumentSnapshot> snapshotPage;
snapshotPage = fireStore()
.collection(collection)
.select(selectedFields)
.offset(page * limit)
.limit(limit)
.get().get().getDocuments();
if (snapshotPage.size() > 0) {
snaps.addAll(snapshotPage);
page++;
findDocsByPage(collection, page, snaps);
}
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
}
findDocsPage it's a recursive method to find all pages of collection
selectedFields for otimize query and get only id field instead full body of document
limit max size of each query page
page define inicial page for pagination
From the tests I did it worked well for collections with up to approximately 120k records!
Firestore is introducing a new Query.count() that fetches the count of a query without fetching the docs.
This would allow to simply query all collection items and get the count of that query.
Ref:
Firebase 10 iOS SDK
[JS SDK PR] (https://github.com/firebase/firebase-js-sdk/pull/6608)
There's a new build in function since version 9.11.0 called getCountFromServer(), which fetches the number of documents in the result set without actually downloading the documents.
https://firebase.google.com/docs/reference/js/firestore_#getcountfromserver
Took me a while to get this working based on some of the answers above, so I thought I'd share it for others to use. I hope it's useful.
'use strict';
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
const db = admin.firestore();
exports.countDocumentsChange = functions.firestore.document('library/{categoryId}/documents/{documentId}').onWrite((change, context) => {
const categoryId = context.params.categoryId;
const categoryRef = db.collection('library').doc(categoryId)
let FieldValue = require('firebase-admin').firestore.FieldValue;
if (!change.before.exists) {
// new document created : add one to count
categoryRef.update({numberOfDocs: FieldValue.increment(1)});
console.log("%s numberOfDocs incremented by 1", categoryId);
} else if (change.before.exists && change.after.exists) {
// updating existing document : Do nothing
} else if (!change.after.exists) {
// deleting document : subtract one from count
categoryRef.update({numberOfDocs: FieldValue.increment(-1)});
console.log("%s numberOfDocs decremented by 1", categoryId);
}
return 0;
});
This uses counting to create numeric unique ID. In my use, I will not be decrementing ever, even when the document that the ID is needed for is deleted.
Upon a collection creation that needs unique numeric value
Designate a collection appData with one document, set with .doc id only
Set uniqueNumericIDAmount to 0 in the firebase firestore console
Use doc.data().uniqueNumericIDAmount + 1 as the unique numeric id
Update appData collection uniqueNumericIDAmount with firebase.firestore.FieldValue.increment(1)
firebase
.firestore()
.collection("appData")
.doc("only")
.get()
.then(doc => {
var foo = doc.data();
foo.id = doc.id;
// your collection that needs a unique ID
firebase
.firestore()
.collection("uniqueNumericIDs")
.doc(user.uid)// user id in my case
.set({// I use this in login, so this document doesn't
// exist yet, otherwise use update instead of set
phone: this.state.phone,// whatever else you need
uniqueNumericID: foo.uniqueNumericIDAmount + 1
})
.then(() => {
// upon success of new ID, increment uniqueNumericIDAmount
firebase
.firestore()
.collection("appData")
.doc("only")
.update({
uniqueNumericIDAmount: firebase.firestore.FieldValue.increment(
1
)
})
.catch(err => {
console.log(err);
});
})
.catch(err => {
console.log(err);
});
});
var variable=0
variable=variable+querySnapshot.count
then if you are to use it on a String variable then
let stringVariable= String(variable)
Along with my npm package adv-firestore-functions above, you can also just use firestore rules to force a good counter:
Firestore Rules
function counter() {
let docPath = /databases/$(database)/documents/_counters/$(request.path[3]);
let afterCount = getAfter(docPath).data.count;
let beforeCount = get(docPath).data.count;
let addCount = afterCount == beforeCount + 1;
let subCount = afterCount == beforeCount - 1;
let newId = getAfter(docPath).data.docId == request.path[4];
let deleteDoc = request.method == 'delete';
let createDoc = request.method == 'create';
return (newId && subCount && deleteDoc) || (newId && addCount && createDoc);
}
function counterDoc() {
let doc = request.path[4];
let docId = request.resource.data.docId;
let afterCount = request.resource.data.count;
let beforeCount = resource.data.count;
let docPath = /databases/$(database)/documents/$(doc)/$(docId);
let createIdDoc = existsAfter(docPath) && !exists(docPath);
let deleteIdDoc = !existsAfter(docPath) && exists(docPath);
let addCount = afterCount == beforeCount + 1;
let subCount = afterCount == beforeCount - 1;
return (createIdDoc && addCount) || (deleteIdDoc && subCount);
}
and use them like so:
match /posts/{document} {
allow read;
allow update;
allow create: if counter();
allow delete: if counter();
}
match /_counters/{document} {
allow read;
allow write: if counterDoc();
}
Frontend
Replace your set and delete functions with these:
set
async setDocWithCounter(
ref: DocumentReference<DocumentData>,
data: {
[x: string]: any;
},
options: SetOptions): Promise<void> {
// counter collection
const counterCol = '_counters';
const col = ref.path.split('/').slice(0, -1).join('/');
const countRef = doc(this.afs, counterCol, col);
const countSnap = await getDoc(countRef);
const refSnap = await getDoc(ref);
// don't increase count if edit
if (refSnap.exists()) {
await setDoc(ref, data, options);
// increase count
} else {
const batch = writeBatch(this.afs);
batch.set(ref, data, options);
// if count exists
if (countSnap.exists()) {
batch.update(countRef, {
count: increment(1),
docId: ref.id
});
// create count
} else {
// will only run once, should not use
// for mature apps
const colRef = collection(this.afs, col);
const colSnap = await getDocs(colRef);
batch.set(countRef, {
count: colSnap.size + 1,
docId: ref.id
});
}
batch.commit();
}
}
delete
async delWithCounter(
ref: DocumentReference<DocumentData>
): Promise<void> {
// counter collection
const counterCol = '_counters';
const col = ref.path.split('/').slice(0, -1).join('/');
const countRef = doc(this.afs, counterCol, col);
const countSnap = await getDoc(countRef);
const batch = writeBatch(this.afs);
// if count exists
batch.delete(ref);
if (countSnap.exists()) {
batch.update(countRef, {
count: increment(-1),
docId: ref.id
});
}
/*
if ((countSnap.data() as any).count == 1) {
batch.delete(countRef);
}*/
batch.commit();
}
see here for more info...
J
This feature is now supported in FireStore, albeit in Beta.
Here are the official Firebase docs
With the new version of Firebase, you can now run aggregated queries!
Simply write
.count().get();
after your query.
As it stands, firebase only allows server-side count, like this
const collectionRef = db.collection('cities');
const snapshot = await collectionRef.count().get();
console.log(snapshot.data().count);
Please not this is for nodeJS
New feature available in Firebase/Firestore provides a count of documents in a collection:
See this thread to see how to achieve it, with an example.
How To Count Number of Documents in a Collection in Firebase Firestore With a WHERE query in react.js
According to this documentation Cloud Firestore supports the count() aggregation query and is available in preview.
The Flutter/Dart code was missing (at the time of writing this) so I played around with it and the following function seems to work:
Future<int> getCount(String path) async {
var collection = _fireStore.collection(path);
var countQuery = collection.count();
var snapShot = await countQuery.get(source: AggregateSource.server);
return snapShot.count;
}
firebaseFirestore.collection("...").addSnapshotListener(new EventListener<QuerySnapshot>() {
#Override
public void onEvent(QuerySnapshot documentSnapshots, FirebaseFirestoreException e) {
int Counter = documentSnapshots.size();
}
});
So my solution for this problem is a bit non-technical, not super precise, but good enough for me.
Those are my documents. As I have a lot of them (100k+) there are 'laws of big numbers' happening. I can assume that there is less-or-more equal number of items having id starting with 0, 1, 2, etc.
So what I do is I scroll my list till I get into id's starting with 1, or with 01, depending on how long you have to scroll
👆 here we are.
Now, having scrolled so far, I open the inspector and see how much did I scroll and divide it by height of single element
Had to scroll 82000px to get items with id starting with 1. Height of single element is 32px.
It means I have 2500 with id starting with 0, so now I multiply it by number of possible 'starting char'. In firebase it can be A-Z, a-z, 0-9 which means it's 24 + 24 + 10 = 58.
It means I have ~~2500*58 so it gives roughly 145000 items in my collection.
Summarizing: What is wrong with you firebase?

Collect the full list of buttons to follow without having to scroll the page (DevTools Google Chrome)

DevTools Google Chrome:
On this site (https://booyah.live/users/41874362/followers), to load the complete list of followers it is necessary to keep scrolling down the page to reload more profiles, but there comes a time when the page weighs so much that the browser crashes and it ends up needing to be closed.
Is there any way to be able to collect the follow buttons without this happening?
The current script I use is:
setInterval(function(){
document.getElementById("layout-content").scrollTo(0, 50000000000000000000000000000000000000);
document.querySelectorAll('.components-button.components-button-size-mini.components-button-type-orange.desktop.components-button-inline').forEach(btn => btn.click());
}, 10)
I use setInterval to create a loop of:
1 - Scrolling the page
2 - Loading more profiles
3 - Clicking the follow buttons
My need:
For the study I'm doing for learning, the idea is that my profile follows all profiles followers of a single most famous profile in order to analyze how many people follow back on this social media.
Additional:
In this answer provided by Leftium, it is possible to follow only one profile:
https://stackoverflow.com/a/67882688/11462274
In this answer given by KCGD, it is possible to collect the entire list of followers but during this collection the profiles are not followed, it is possible to create a list and save the data, but not follow the profiles:
https://stackoverflow.com/a/67865968/11462274
I tried to contact them both, but they haven't returned yet. It was a good way but I couldn't combine the two answers so I can follow all the profiles, I thought about the possibility according to which I would collect the profiles of the KCGD response, I would follow the profiles too, but not only the first one but also the answer of the Leftium.
Would it be possible to take advantage of the loop created by the response from KCGD and from each response, already follow all profiles instead of just the first one as in Leftium's response?
I tried to create but was unsuccessful.
The browser crashes because too much memory is used. As you scroll down the page, the HTML DOM tree is extended and more avatar images are downloaded. These HTML and image resources are not necessary for your goal.
It is possible to avoid crashing by calling the (internal) Booyah API directly. This will be much faster and consume less resources since only the text is transferred. There are two API endpoints of interest:
GET /api/v3/users/[USERID]/followers?cursor=0&count=100
Gets list of followers following a certain user:
[USERID] is the ID of the user being studied (WEEDZAO's id).
cursor is where in the list of followers to start listing. When the page first loads, this is 0. As you scroll down, the following API calls increment this (101, 201, 301...)
count is how many results to return.
Since this is a GET call, you can open this URL in your browser.
POST /api/v3/users/[USERID]/followings
Follows a user (same as clicking their 'Follow' button).
Here [USERID] is ID of the user whose follower list will be updated (your own ID).
A payload must be sent that looks like this: {followee_uid: ID, source: 43}. I'm not sure what source is.
Also a CSRF header must be included.
Because this is a POST type call, it is not possible to open this type of URL directly in your browser.
DELETE /api/v3/users/[USERID]/followings
There is also an API to unfollow a user. (Just for reference).
If you call these API's from outside the browser, you probably need to send session cookies.
This script will list WEEDZAO's first 10 followers, then follow the first one from the list:
You must replace USERID and CSRF_TOKEN with your own values.
You can copy/paste this code into the browser dev console.
Alternatively, you can use this code from a web scraping framework like Puppeteer.
// Find these values in dev console "Network" tab:
var CSRF_TOKEN, USERID, USERID_TARGET, main;
USERID_TARGET = '41874362';
USERID = '12345678';
CSRF_TOKEN = 'MTYy...p8wg';
main = async function() {
var body, followers, json, options, payload, response, url;
// Get list of first 10 followers
console.log(url = `/api/v3/users/${USERID_TARGET}/followers?cursor=0&count=10`);
response = (await fetch(url));
json = (await response.json());
followers = json.follower_list;
console.table(followers);
// Follow first member from list above
console.log(url = `/api/v3/users/${USERID}/followings`);
payload = JSON.stringify({
followee_uid: followers[0].uid,
source: 43
});
response = (await fetch(url, options = {
method: 'POST',
body: payload,
headers: {
'X-CSRF-Token': CSRF_TOKEN
}
}));
body = (await response.text());
return console.log(body);
};
main();
It crashes because the interval is too fast
setInterval(function(){}, 10)
you are trying to call a scroll and click function every 10 milliseconds (that's 100 function call every 1 second). Which also interferes with the server as they fetch new users while scrolling.
Your script could work if you will adjust the interval to atleast 1000 milliseconds (1 second). Of course, it may take a while, but it will work. You should also expect that the page may become laggy specially when the page already loaded tons of users because Virtual Scrolling is not implemented in this page.
Even with slowing down the rate of the scrolling it still really bogs down the browser, the solution to this may be in the API the page contacts. To get the user's followers it contacts the site's V3 API
https://booyah.live/api/v3/users/41874362/followers?cursor=[LAST USER IN API RETURN]&count=100
to get all the users that would show up in the page. I wrote a script that can contact the api over and over again to get all the follower data, just run it in the page's console and use print() when you want to export the data
and copy/paste it into a .json file
//WARNING: THIS SCRIPT USES RECURSION, i have no clue how long the followers list goes so use at your own risk
var followers = []; //data collected from api
function getFollowers(cursor){
httpGet(`https://booyah.live/api/v3/users/41874362/followers?cursor=${cursor}&count=100`, function (data) { //returns data from API for given cursor (user at the end of last follower chunk)
console.log("got cursor: "+cursor);
var _followChunk = JSON.parse(String(data));
console.log(_followChunk)
followers.push(_followChunk.follower_list); //saves followers from chunk
var last_user = _followChunk.follower_list[_followChunk.follower_list.length - 1]; //gets last user of chunk (cursor for the next chunk)
setTimeout(function(){ //1 second timeout so that the API doesnt return "too many requests", not nessicary but you should probably leave this on
getFollowers(last_user.uid); //get next chunk
},1000)
})
}
var print = function(){console.log(JSON.stringify(followers))};
getFollowers(0); //get initial set of followers (cursor 0)
function httpGet(theUrl, callback) {
var xmlHttp = new XMLHttpRequest();
xmlHttp.open("GET", theUrl, false); // false for synchronous request
xmlHttp.setRequestHeader("Cache-Control", "no-store");
xmlHttp.send(null);
callback(xmlHttp.responseText);
};
if you really only need the button elements then the only way is to scroll all the way down for each time it loads new followers, as the page creates the elements as you scroll down
This is a fully working solution that I have tested in my own Chrome browser with a fresh account, successfully following all the follower accounts of the account you are targeting.
UPDATE (2021-06-18)
I've updated my solution to a drastically improved and faster function, rewritten with async/await. This new function reduces the estimated runtime from ~45min to ~10min. 10min is still a long while, but that's to be expected considering the large number of followers the user you are targeting has.
After a few iterations, the latest function not only improves speed, performance, and error reporting, but it also extends what is possible with the function. I provide several example below my solutions of how to use the function completely.
For the sake of de-cluttering my answer, I am removing my older function from this solution altogether, but you can still reference it in my solution's edit history if you like.
TL;DR
Here is the final, fastest, working solution. Make sure to replace PUT_YOUR_CSRF_TOKEN_HERE with your own CSRF token value. Detailed instructions on how to find your CSRF token are below.
You must run this in your console on the Booyah website in order to avoid CORS issues.
const csrf = 'PUT_YOUR_CSRF_TOKEN_HERE';
async function booyahGetAccounts(uid, type = 'followers', follow = 1) {
if (typeof uid !== 'undefined' && !isNaN(uid)) {
const loggedInUserID = window.localStorage?.loggedUID;
if (uid === 0) uid = loggedInUserID;
const unfollow = follow === -1;
if (unfollow) follow = 1;
if (loggedInUserID) {
if (csrf) {
async function getUserData(uid) {
const response = await fetch(`https://booyah.live/api/v3/users/${uid}`),
data = await response.json();
return data.user;
}
const loggedInUserData = await getUserData(loggedInUserID),
targetUserData = await getUserData(uid),
followUser = uid => fetch(`https://booyah.live/api/v3/users/${loggedInUserID}/followings`, { method: (unfollow ? 'DELETE' : 'POST'), headers: { 'X-CSRF-Token': csrf }, body: JSON.stringify({ followee_uid: uid, source: 43 }) }),
logSep = (data = '', usePad = 0) => typeof data === 'string' && usePad ? console.log((data ? data + ' ' : '').padEnd(50, '━')) : console.log('━'.repeat(50),data,'━'.repeat(50));
async function getList(uid, type, follow) {
const isLoggedInUser = uid === loggedInUserID;
if (isLoggedInUser && follow && !unfollow && type === 'followings') {
follow = 0;
console.warn('You alredy follow your followings. `follow` mode switched to `false`. Followings will be retrieved instead of followed.');
}
const userData = await getUserData(uid),
totalCount = userData[type.slice(0,-1)+'_count'] || 0,
totalCountStrLength = totalCount.toString().length;
if (totalCount) {
let userIDsLength = 0;
const userIDs = [],
nickname = userData.nickname,
nicknameStr = `${nickname ? ` of ${nickname}'s ${type}` : ''}`,
alreadyFollowedStr = uid => `User ID ${uid} already followed by ${loggedInUserData.nickname} (Account #${loggedInUserID})`;
async function followerFetch(cursor = 0) {
const fetched = [];
await fetch(`https://booyah.live/api/v3/users/${uid}/${type}?cursor=${cursor}&count=100`).then(res => res.json()).then(data => {
const list = data[type.slice(0,-1)+'_list'];
if (list?.length) fetched.push(...list.map(e => e.uid));
if (fetched.length) {
userIDs.push(...fetched);
userIDsLength += fetched.length;
if (follow) followUser(uid);
console.log(`${userIDsLength.toString().padStart(totalCountStrLength)} (${(userIDsLength / totalCount * 100).toFixed(4)}%)${nicknameStr} ${follow ? 'followed' : 'retrieved'}`);
if (fetched.length === 100) {
followerFetch(data.cursor);
} else {
console.log(`END REACHED. ${userIDsLength} accounts ${follow ? 'followed' : 'retrieved'}.`);
if (!follow) logSep(targetList);
}
}
});
}
await followerFetch();
return userIDs;
} else {
console.log(`This account has no ${type}.`);
}
}
logSep(`${follow ? 'Following' : 'Retrieving'} ${targetUserData.nickname}'s ${type}`, 1);
const targetList = await getList(uid, type, follow);
} else {
console.error('Missing CSRF token. Retrieve your CSRF token from the Network tab in your inspector by clicking into the Network tab item named "bug-report-claims" and then scrolling down in the associated details window to where you see "x-csrf-token". Copy its value and store it into a variable named "csrf" which this function will reference when you execute it.');
}
} else {
console.error('You do not appear to be logged in. Please log in and try again.');
}
} else {
console.error('UID not passed. Pass the UID of the profile you are targeting to this function.');
}
}
booyahGetAccounts(41874362);
Detailed explanation of the process
As the function runs, it logs the progress to the console, both how many users have been followed so far, and how much progress has been made percentage-wise, based on the total number of followers the profile you are targeting has.
Retrieving your CSRF token
The only manual portion of this process is retrieving your CSRF token. This is rather simple though. Once you log into Booyah, navigate to the Network tab of your Chrome console and click on the item named bug-report-claims, then scroll all the way down the details window which appears on the right. There should see x-csrf-token. Store this value as a string variable in your console as csrf, which my function will reference when it runs. This is necessary in order to use the POST method to follow users.
Here is what it will look like:
The solution
The function will loop through all users the account you are targeting follows in batches of 100 (the max amount allowed per GET request) and follow them all. When the end of each batch is met, the next batch is automatically triggered recursively.
🚀 Version 3 (Fastest and most flexible, using async/await and fetch())
My previous two solution versions (🐇 …🐢) can be referenced in this answer's edit history.
Make sure to replace PUT_YOUR_CSRF_TOKEN_HERE with your own CSRF token value. Detailed instructions on how to find your CSRF token are below.
You must run this in your console on the Booyah website in order to avoid CORS issues.
const csrf = 'PUT_YOUR_CSRF_TOKEN_HERE';
async function booyahGetAccounts(uid, type = 'followers', follow = 1) {
if (typeof uid !== 'undefined' && !isNaN(uid)) {
const loggedInUserID = window.localStorage?.loggedUID;
if (uid === 0) uid = loggedInUserID;
const unfollow = follow === -1;
if (unfollow) follow = 1;
if (loggedInUserID) {
if (csrf) {
async function getUserData(uid) {
const response = await fetch(`https://booyah.live/api/v3/users/${uid}`),
data = await response.json();
return data.user;
}
const loggedInUserData = await getUserData(loggedInUserID),
targetUserData = await getUserData(uid),
followUser = uid => fetch(`https://booyah.live/api/v3/users/${loggedInUserID}/followings`, { method: (unfollow ? 'DELETE' : 'POST'), headers: { 'X-CSRF-Token': csrf }, body: JSON.stringify({ followee_uid: uid, source: 43 }) }),
logSep = (data = '', usePad = 0) => typeof data === 'string' && usePad ? console.log((data ? data + ' ' : '').padEnd(50, '━')) : console.log('━'.repeat(50),data,'━'.repeat(50));
async function getList(uid, type, follow) {
const isLoggedInUser = uid === loggedInUserID;
if (isLoggedInUser && follow && !unfollow && type === 'followings') {
follow = 0;
console.warn('You alredy follow your followings. `follow` mode switched to `false`. Followings will be retrieved instead of followed.');
}
const userData = await getUserData(uid),
totalCount = userData[type.slice(0,-1)+'_count'] || 0,
totalCountStrLength = totalCount.toString().length;
if (totalCount) {
let userIDsLength = 0;
const userIDs = [],
nickname = userData.nickname,
nicknameStr = `${nickname ? ` of ${nickname}'s ${type}` : ''}`,
alreadyFollowedStr = uid => `User ID ${uid} already followed by ${loggedInUserData.nickname} (Account #${loggedInUserID})`;
async function followerFetch(cursor = 0) {
const fetched = [];
await fetch(`https://booyah.live/api/v3/users/${uid}/${type}?cursor=${cursor}&count=100`).then(res => res.json()).then(data => {
const list = data[type.slice(0,-1)+'_list'];
if (list?.length) fetched.push(...list.map(e => e.uid));
if (fetched.length) {
userIDs.push(...fetched);
userIDsLength += fetched.length;
if (follow) followUser(uid);
console.log(`${userIDsLength.toString().padStart(totalCountStrLength)} (${(userIDsLength / totalCount * 100).toFixed(4)}%)${nicknameStr} ${follow ? 'followed' : 'retrieved'}`);
if (fetched.length === 100) {
followerFetch(data.cursor);
} else {
console.log(`END REACHED. ${userIDsLength} accounts ${follow ? 'followed' : 'retrieved'}.`);
if (!follow) logSep(targetList);
}
}
});
}
await followerFetch();
return userIDs;
} else {
console.log(`This account has no ${type}.`);
}
}
logSep(`${follow ? 'Following' : 'Retrieving'} ${targetUserData.nickname}'s ${type}`, 1);
const targetList = await getList(uid, type, follow);
} else {
console.error('Missing CSRF token. Retrieve your CSRF token from the Network tab in your inspector by clicking into the Network tab item named "bug-report-claims" and then scrolling down in the associated details window to where you see "x-csrf-token". Copy its value and store it into a variable named "csrf" which this function will reference when you execute it.');
}
} else {
console.error('You do not appear to be logged in. Please log in and try again.');
}
} else {
console.error('UID not passed. Pass the UID of the profile you are targeting to this function.');
}
}
Usage
To run the function (for either of the above solutions), just call the function name with the desired User ID name as an argument, in your example case, 41874362. The function call would look like this:
booyahGetAccounts(41874362);
The function is quite flexible in its abilities though. booyahGetAccounts() accepts three parameters, but only the first is required.
booyahGetAccounts(
uid, // required, no default
type = 'followers', // optional, must be 'followers' or 'followings' -> default: 'followers'
follow = 1 // optional, must be 0, 1, or -1, -> default: 1 (boolean true)
)
The second parameter, type, allows you to choose whether you would like to process the targeted user's followers or followings (the users which that user follows).
The third parameter allows you to choose whether you would like to follow/unfollow the returned users or only retrieve their User IDs. This defaults to 1 (boolean true) which will follow the users returned, but if you only want to test the function and not actually follow the returned users, set this to a falsy value such as 0 or false. Using -1 will unfollow the users returned.
This function intelligently retrieves your own User ID for you from the window.localStorage object, so you don't need to retrieve that yourself. If you would like to process your own followers or followings, simply pass 0 as the main uid parameter value, and the function will default the uid to your own User ID.
Because you can't re-follow users you already follow, if you try to follow your followings, the function will produce the warning You already follow your followings. 'follow' mode switched to 'false'. Followings will be retrieved instead of followed. and instead return them as if you had set the follow parameter to false.
However, it can be very useful to process your own list. For example, if you want to follow all of your own followers back, you could do so like this:
booyahGetAccounts(0); // `type` and `follow` parameters already default to the correct values here
On the other hand, if you were strategically using a follow/unfollow technique in order to increase your number of followers and needed to unfollow all of your followers, you could do so like this:
booyahGetAccounts(0, 'followers', -1);
By setting the follow parameter value to -1, you instruct the function to run its followUser function on all returned User IDs using the DELETE method instead of the POST method, thereby unfollowing those users returned instead of following them.
Desired outcome
Function call
Follow all your own followers
booyahGetAccounts(0, 'followers');
Unfollow all your own followers
booyahGetAccounts(0, 'followers', -1);
Unfollow all your own followings
booyahGetAccounts(0, 'followings', -1);
Follow users that follow User ID #12345
booyahGetAccounts(12345, 'followers');
Follow users followed by User ID #12345
booyahGetAccounts(12345, 'followings');
Retrieve User IDs of accounts following User ID #12345
booyahGetAccounts(12345, 'followers', 0);
Retrieve User IDs of accounts followed by User ID #12345
booyahGetAccounts(12345, 'followings', 0);
Other notes
To improve the performance of this function, as it's very heavy, I've replaced all calls to userIDs.length with a dedicated userIDsLength variable which I add to using += with each iteration rather than calling length each time. Similarly, I store the length of the stringified followerCount in the variable followerCountStrLength rather than calling followerCount.toString().length with each iteration. Because this is a rather heavy function, it is possible for your browser window to crash. However, it should eventually complete.
If the page appears to crash by flickering and auto-closing the console, FIRST try to re-open the console without refreshing the page at all. In my case, the inspector occasionally closed on its own, likely due to the exhaustion from the function, but when I opened the inspector's console again, the function was still running.

Dialogflow Firebase Realtime Database Getting Error: No responses defined for platform: Undefined yet method still goes through

I've been trying for a project I'm working on to develop a function for a Food chatbot. What I'm currently working on is to perform a method for a user to make a purchase of an order that is stored in firebase realtime database.
The method is set as the method for an actionMap and the actionMap is linked to an intent for knowing when to call the method and for retrieving the parameters.
My current method uses a simple check for a user's existence and status within the database before identifying the existence of the order they're trying to make a purchase for by its id by going through the user's reference path and doing a .forEach to check every order found and look at its parent folder name to check if it matches the user's order id. My code is as follows:
const MakePurchaseACTION = 'Make Purchase';
function makePurchase(app){
let email = parameter.email;
let orderId = parameter.orderId;
var currDate = currDateGenerator();
var name = email.split(".com");
//Check if User exists first in database
var userRef = database.ref().child('user/' + name);
return userRef.once('value').then(function(snapshot) {
if (snapshot.exists()) {
let statusRetrieved = snapshot.child('Status').val();
//Check if user's status in database is signed in.
if (statusRetrieved == "Signed In") {
var orderRef = database.ref().child('order/' + name);
//Check the order table for the user.
return orderRef.once('value').then(function(orderSnapshot){
let orderVal = orderSnapshot.val();
console.log(orderVal);
//Check through every child for the matching id.
orderSnapshot.forEach(function(childSnapshot) {
let orderIdFound = childSnapshot.key;
//let cost = childSnapshot.child('Cost').val();
console.log(orderIdFound);
if(orderId == orderIdFound) {
let eateryName = childSnapshot.child('Eatery').val();
let eateryLocation = childSnapshot.child('EateryLocation').val();
let deliveryAddress = childSnapshot.child('DeliveryAddress').val();
let orderItem = childSnapshot.child('OrderItem').val();
let quantity = childSnapshot.child('Quantity').val();
let cost = childSnapshot.child('Cost').val();
var purchaseRef = database.ref().child('purchase/' + name + "/" + currDate + "/" + orderId);
purchaseRef.set({
"Eatery" : eateryName,
"EateryLocation" : eateryLocation,
"DeliveryAddress": deliveryAddress,
"OrderItem" : orderItem,
"Quantity": quantity,
"Cost": cost,
"DateCreated": currDate
});
app.add("You have successfully purchased Order " + orderId);
} else {
app.add("There is no order with that id.");
}
});
});
} else {
app.add("You need to be signed in before you can order!");
}
}
else {
app.add("Sorry pal you don't exist in the database.");
}
});
}
actionMap.set(MakePurchaseACTION, makePurchase);
After checking through some firebase logs
Firebase Logs screenshot here
Firebase Realtime Database Order Table Sample
I found that the method actually completes Purchase table sample but my dialogflow returns with the stated error of:
Error: No responses defined for platform: undefined and displays "Not Available" back to the user. My question is how do I go about resolving this error?

Firebase data gets overwritten ! sought guidance

I am building an Angular App with Firebase.
My intention is to create an object (say Rooms) at the root with 3 child objects (say Room1, Room2 & Room3) . Also, I am trying to create a logic that would check if the Rooms object is there - it wont create it again.
My code was :
var ref = new Firebase(firebaseURL);
ref.child('Rooms').once('value', function (snapshot){
if(snapshot.numChildren() == 0){
// Create Room within a loop
ref.child('Rooms').child(i).set(roomObj);
}else if(snapshot.numChildren() > 0){
// do not create
}
}
But when the code runs - it always enters into the if block !! And creates the child Rooms.
What is my mistake in the code ??
Most likely the value event will be triggered again with the value you expect.
Your solution is to run the code in a transaction.
var ref = new Firebase(firebaseURL);
ref.child('Rooms').transaction(function (data){
if(!data){
var rooms = {};
for (var roomNum=0; roomNum < 3; roomNum++) {
rooms['room'+roomNum] = { name: 'Room '+roomNum };
}
return rooms
}
}
So if the rooms don't exist yet, the above code creates them. If they already exist, the code does nothing (not returning a value, leaves the data unmodified).
Be sure to read the Firebase documentation for transaction.

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