How can I remove ref after my function is finished running? Is it necessary? I want my function to run as quickly as possible, and don't want "things" piling up.
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);
exports.myFunction = functions.database.ref('/path/{uid}').onWrite(event => {
const ref = event.data.adminRef.root.child('something').child(event.params.uid);
return ref.transaction(current => {
if (event.data.exists() && !event.data.previous.exists()) {
return _.toInteger(current) + _.toInteger(_.get(data, 'value', 0));
}
}).then(() => {
return null; // Avoid "Error serializing return value: TypeError: Converting circular structure to JSON"
});
});
A DatabaseReference is nothing you can "remove". It is just a pointer to a location in your database. The documentation has a page for it:
https://firebase.google.com/docs/reference/admin/node/admin.database.Reference
The only thing you can remove/detach is a callback you set with ref.on(...), with ref.off(...), but there is no callback in your code and I think that ref.once() should get the job done most of the time in Functions.
To be clear: ref.transactions()'s do not have to be detached, they just run once, i.e. there is no callback. Same for ref.set() and ref.once().
Related
I'm using Firebase as backend to my iOS app and can't figure out how to construct a batch write through their Cloud Functions.
I have two collections in my Firestore, drinks and customers. Each new drink and each new customer is assigned a userId property that corresponds to the uid of the currently logged in user. This userId is used with a query to the Firestore to fetch only the drinks and customers connected to the logged in user, like so: Firestore.firestore().collection("customers").whereField("userId", isEqualTo: Auth.auth().currentUser.uid)
Users are able to log in anonymously and also subscribe while anonymous. The problem is if they log out there's no way to log back in to the same anonymous uid. The uid is also stored as an appUserID with the RevenueCat SDK so I can still access it, but since I can't log the user back in to their anonymous account using the uid the only way to help a user access their data in case of a restoring of purchases is to update the userId field of their data from the old uid to the new uid. This is where the need for a batch write comes in.
I'm relatively new to programming in general but I'm super fresh when it comes to Cloud Functions, JavaScript and Node.js. I dove around the web though and thought I found a solution where I make a callable Cloud Function and send both old and new userID with the data object, query the collections for documents with the old userID and update their userId fields to the new. Unfortunately it's not working and I can't figure out why.
Here's what my code looks like:
// Cloud Function
exports.transferData = functions.https.onCall((data, context) => {
const firestore = admin.firestore();
const customerQuery = firestore.collection('customers').where('userId', '==', `${data.oldUser}`);
const drinkQuery = firestore.collection('drinks').where('userId', '==', `${data.oldUser}`);
const customerSnapshot = customerQuery.get();
const drinkSnapshot = drinkQuery.get();
const batch = firestore.batch();
for (const documentSnapshot of customerSnapshot.docs) {
batch.update(documentSnapshot.ref, { 'userId': `${data.newUser}` });
};
for (const documentSnapshot of drinkSnapshot.docs) {
batch.update(documentSnapshot.ref, { 'userId': `${data.newUser}` });
};
return batch.commit();
});
// Call from app
func transferData(from oldUser: String, to newUser: String) {
let functions = Functions.functions()
functions.httpsCallable("transferData").call(["oldUser": oldUser, "newUser": newUser]) { _, error in
if let error = error as NSError? {
if error.domain == FunctionsErrorDomain {
let code = FunctionsErrorCode(rawValue: error.code)
let message = error.localizedDescription
let details = error.userInfo[FunctionsErrorDetailsKey]
print(code)
print(message)
print(details)
}
}
}
}
This is the error message from the Cloud Functions log:
Unhandled error TypeError: customerSnapshot.docs is not iterable
at /workspace/index.js:22:51
at fixedLen (/workspace/node_modules/firebase-functions/lib/providers/https.js:66:41)
at /workspace/node_modules/firebase-functions/lib/common/providers/https.js:385:32
at processTicksAndRejections (internal/process/task_queues.js:95:5)
From what I understand customerSnapshot is something called a Promise which I'm guessing is why I can't iterate over it. By now I'm in way too deep for my sparse knowledge and don't know how to handle these Promises returned by the queries.
I guess I could just force users to create a login before they subscribe but that feels like a cowards way out now that I've come this far. I'd rather have both options available and make a decision instead of going down a forced path. Plus, I'll learn some more JavaScript if I figure this out!
Any and all help is greatly appreciated!
EDIT:
Solution:
// Cloud Function
exports.transferData = functions.https.onCall(async(data, context) => {
const firestore = admin.firestore();
const customerQuery = firestore.collection('customers').where('userId', '==', `${data.oldUser}`);
const drinkQuery = firestore.collection('drinks').where('userId', '==', `${data.oldUser}`);
const customerSnapshot = await customerQuery.get();
const drinkSnapshot = await drinkQuery.get();
const batch = firestore.batch();
for (const documentSnapshot of customerSnapshot.docs.concat(drinkSnapshot.docs)) {
batch.update(documentSnapshot.ref, { 'userId': `${data.newUser}` });
};
return batch.commit();
});
As you already guessed, the call customerQuery.get() returns a promise.
In order to understand what you need, you should first get familiar with the concept of promises here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise
For your use case, you will probably end up with either using the then callback:
customerQuery.get().then((result) => {
// now you can access the result
}
or by making the method call synchronous, by using the await statement:
const result = await customerQuery.get()
// now you can access the result
I have a function that's doing calls for firebase database and return those data. I'm trying to implement a listener to this function so when the database updates, the content in my web site also updates without refresh.
My function is as follows
export const loadBookings = async () => {
const providersSnapshot = await firebase.database().ref('products').once('value');
const providers = providersSnapshot && providersSnapshot.val();
if (!providers) {
return undefined;
}
return providers;
};
After going through some documentation i have tried changing itto something like this
const providersSnapshot = await firebase.database().ref('products').once('value');
let providers = "";
providersSnapshot.on('value', function(snapshot) {
providers = snapshot.val();
});
But the code doesn't work like that. How can i listen in real time for my firebase call?
Use on('value') instead of once('value'). once() just queries a single time (as its name suggests). on() adds a listener that will get invoked repeatedly with changes as they occur.
I suggest reading over the documentation to find an example of using on(). It shows:
var starCountRef = firebase.database().ref('posts/' + postId + '/starCount');
starCountRef.on('value', function(snapshot) {
updateStarCount(postElement, snapshot.val());
});
I have three Firebase database trigger function to push notifications to users. However, I have noticed that .onCreate() gets triggered on database update and delete. Is this expected? Is there a way to prevent this?
const functions = require('firebase-functions')
exports.onNoteCreate = functions
.region('europe-west1')
.database
.ref('/notes/{noteId}')
.onCreate((snapshot, context) => {
...
//Push notification to affected users
//Compose notification object
const notificationObject = { "test": true }
membersToAlert.forEach((memberId, index) => {
let isAlreadyPresent = false
//Do not write if already present! - This code should not be needed?
const ref = snapshot.ref.root.child(`/notes/${personId}/noteAdditions`)
ref.orderByChild('originId')
.equalTo(noteId)
.on("value", (removeSnapshot) => {
isAlreadyPresent = true
})
//Write notification to all affected users
if(!isAlreadyPresent) {
snapshot.ref.root.child(`/notifications/${personId}/noteAdditions`).push(notificationObject)
}
})
return true
})
My .onUpdate() and .onDelete() triggers are also listening to .ref('/notes/{noteId}'). Is that a problem?
How can I make sure .onCreate() only gets triggered when a new object is inserted?
EDIT:
My testing workflow is as follows:
Create a new node in /notes using .push() -> works as expected
Update the same node using .update() -> works as expected
Delete the node in /notes/{noteId} directly from the Firebase Console
Step 3 triggers both .onCreate() and .onUpdate(). See log below:
I 2019-08-12T17:17:25.867Z onNoteCreate 670055884755913 onNoteCreate ... onNoteCreate 670055884755913
I 2019-08-12T17:17:26.053Z onNoteUpdate 670048941917608 onNoteUpdate ... onNoteUpdate 670048941917608
D 2019-08-12T17:17:26.843878505Z onNoteDelete 670054292162841 Function execution started onNoteDelete 670054292162841
D 2019-08-12T17:17:26.849773576Z onNoteDelete 670054292162841 Function execution took 7 ms, finished with status: 'ok' onNoteDelete 670054292162841
Database before delete
-notifications
-userId
-noteAdditions
-guid01
-notificationData
-noteUpdates
-guid03
-notificationData
Database after delete
//guid01 gets deleted by .onDelete() as expected
//guid03 gets deleted by .onDelete() as expected
-notifications
-userId
-noteAdditions
-guid02
-notificationData //Inserted by .onCreate() upon delete
-noteUpdates
-guid04
-notificationData //Inserted by .onUpdate() upon delete
The listeners are attached to /notes/{noteId} and updates are being made at /notifications/{userId}/...
onNoteCreate
exports.onNoteCreate = functions
.region('europe-west1')
.database
.ref('/notes/{noteId}')
.onCreate((snapshot, context) => {
...
snapshot.ref.root.child(`/notifications/${personId}/noteAdditions`).push(notificationObject)
...
console.log('onNoteCreate', '...')
...
})
onNoteUpdate
exports.onNoteUpdate = functions
.region('europe-west1')
.database
.ref('/notes/{noteId}')
.onUpdate((change, context) => {
...
change.after.ref.root.child(`/notifications/${personId}/noteUpdates`).push(notificationObject)
...
console.log('onNoteUpdate', '...')
...
})
Does it matter that I import the functions like so?
const create = require('./src/db-functions/notes').onNoteCreate
const update = require('./src/db-functions/notes').onNoteUpdate
const delete = require('./src/db-functions/notes').onNoteDelete
exports.onNoteCreate = create
exports.onNoteUpdate = update
exports.onNoteDelete = delete
I failed to include the code in my example where I call
//Get user data - also updated by onNoteCreate, onNoteUpdate , onNoteDelete
dbRoot.child(`users/${userId}`)
.on('value', (snapshot) => {
.on() attached a listener that was being triggered each time the value was updated, thus triggering "onNoteCreate", "onNoteUpdate" and "onNoteDelete" when not expected. I should have used .once() if I did not wish to attach a listener which I did not.
All credits to #doug for pointing this out to me in this post:
Firebase database trigger - how to wait for calls
I have been trying to use Firebase Functions to write a simple method, but I am unfamiliar with JS.
Below is the structure of my Realtime Database
-spots
---is_hidden: false
---likes
------like_id_1: true
---dislikes
------dislike_id_1: true
I am trying to write a simple method that does the following: Whenever an entry is added to dislikes, count the likes and the dislikes.
If the number of dislikes is larger than the number of ( likes + 5 ),
change the value of is_hidden to true
This is my attempt to solving the problem
exports.checkHiddenStatus = functions.database.ref('/spots/{spotid}').onWrite(
(change, context) => {
const collectionRef = change.after.ref;
const isHiddenRef = collectionRef.child('is_hidden');
const likesRef = collectionRef.child('likes');
const dislikesRef = collectionRef.child('dislikes');
if(isHiddenRef.before.val()) return;
let likeCount = likesRef.numChildren();
let dislikeCount = dislikesRef.numChildren();
let isHidden = false;
if( dislikeCount >= (likeCount + 5))
isHidden = true;
if(!isHidden) return;
// Return the promise from countRef.transaction() so our function
// waits for this async event to complete before it exits.
return isHiddenRef.transaction((current) => {
return isHidden;
}).then(() => {
return console.log('Counter updated.');
});
});
Sadly, because I have no experience with JS I keep getting stuck with error messages I don't understand. The most recent being
TypeError: Cannot read property 'val' of undefined
at exports.checkHiddenStatus.functions.database.ref.onWrite (/user_code/index.js:28:28)
Can somebody please help me write this function? Thank you!
It looks like you're trying to treat a database Reference object like a Change object. Change has before and after properties, but a reference does not.
If you have a database reference object, and you want the value of the database at that location, you need to query it with its once() method.
Read more about reading and writing data using the Admin SDK.
I have a firebase database and I am currently trying to use cloud functions to perform an operation when a value in my database changes. So far, it successfully triggers code to run when the value in my database changes. However, when the database value changes, I now need to check another value to determine it's status, and then perform an action after that. The problem is that I have ~0 experience with JS and I have no way of debugging my code other than deploying, changing the value in my database, and looking at the console log.
Is there any way to look up another value in the database and read it? How about look up a value and then set a value for it? Here is the code:
exports.determineCompletion =
functions.database.ref('/Jobs/{pushId}/client_job_complete')
.onWrite(event => {
const status = event.data.val();
const other = functions.database.ref('/Jobs/' + event.params.pushId + '/other_job_complete');
console.log('Status', status, other);
if(status == true && **other.getValueSomehow** == true) {
return **setAnotherValue**;
}
});
This code partially works, it successfully gets the value associated with client_job_complete and stores it in status. But how do I get the other value?
Additionally, if anyone has any JS or firebase documentation that they think would help me, please share! I have read a bunch on firebase here : https://firebase.google.com/docs/functions/database-events but it only talks about events and is very brief
Thank you for your help!
When writing a database trigger function, the event contains two properties that are references to the location of the data that changed:
event.data.ref
event.data.adminRef
ref is limited to the permissions of the user who triggered the function. adminRef has full access to the database.
Each of those Reference objects has a root property which gives you a reference to the root of your database. You can use that reference to build a path to a reference in another part of your database, and read it with the once() method.
You can also use the Firebase admin SDK.
There are lots of code samples that you should probably look at as well.
I'm maybe a bit late, but I hope my solution can help some people:
exports.processJob = functions.database.ref('/Jobs/{pushId}/client_job_complete').onWrite(event => {
const status = event.data.val();
return admin.database().ref('Jobs/' + event.params.pushId + '/other_job_complete').once('value').then((snap) => {
const other = snap.val();
console.log('Status', status, other);
/** do something with your data here, for example increase its value by 5 */
other = (other + 5);
/** when finished with processing your data, return the value to the {{ admin.database().ref(); }} request */
return snap.ref.set(other).catch((error) => {
return console.error(error);
});
});
});
But take notice of your firebase database rules.
If no user should have access to write Jobs/pushId/other_job_complete, except Your cloud function admin, You need to initialize Your cloud function admin with a recognizable, unique uid.
For example:
const functions = require('firebase-functions');
const admin = require('firebase-admin');
const adminCredentials = require('path/to/admin/credentials.json');
admin.initializeApp({
credential: admin.credential.cert(adminCredentials),
databaseURL: "https://your-database-url-com",
databaseAuthVariableOverride: {
uid: 'super-special-unique-firebase-admin-uid'
}
});
Then Your firebase database rule should look something like this:
"client_job_complete": {
".read": "auth !== null",
".write": "auth.uid === 'super-special-unique-firebase-admin-uid'"
}
Hope it helps!
You have to wait on the promise from a once() on the new ref, something like:
exports.processJob = functions.database.ref('/Jobs/{pushId}/client_job_complete')
.onWrite(event => {
const status = event.data.val();
const ref = event.data.adminRef.root.child('Jobs/'+event.params.pushId+'/other_job_complete');
ref.once('value').then(function(snap){
const other = snap.val();
console.log('Status', status, other);
if(status && other) {
return other;
}
});
});
Edit to fix the error that #Doug Stevenson noticed (I did say "something like")