I`m studying cloud function right now and I saw this sample code
'use strict';
const functions = require('firebase-functions');
// Max number of lines of the chat history.
const MAX_LOG_COUNT = 5;
// Removes siblings of the node that element that triggered the function
if there are more than MAX_LOG_COUNT.
// In this example we'll keep the max number of chat message history to
MAX_LOG_COUNT.
exports.truncate =
functions.database.ref('/chat/{messageid}').onWrite(async (change) => {
const parentRef = change.after.ref.parent;
const snapshot = await parentRef.once('value');
if (snapshot.numChildren() >= MAX_LOG_COUNT) {
let childCount = 0;
const updates = {};
snapshot.forEach((child) => {
if (++childCount <= snapshot.numChildren() - MAX_LOG_COUNT) {
updates[child.key] = null;
}
});
// Update the parent. This effectively removes the extra children.
return parentRef.update(updates);
}
return null;
});
how do I convert this to Firestore version from RTDB?
thank you
Related
i have created cloud function which will trigger onCreate() when new value is add to node Sample/Pen.whenever the new node is created in Sample/Pen, i wanted to create another node which is Final/Pen but the values of key-value pair should be zero.
The following will do the job:
exports.finalPen = functions.database
.ref('/Sample/Pen/{penId}')
.onCreate((snap, context) => {
const createdData = snap.val(); // data that was created
return admin
.database()
.ref('Final/Pen/' + snap.key)
.set(setAllToZero(createdData));
});
const setAllToZero = function(pen) {
Object.keys(pen).forEach(function(key) {
pen[key] = 0;
});
return pen;
};
I have a Firebase Cloud Function that assigns a number to a user on onWrite. The following code works but something is wrong because the console logs state Function returned undefined, expected Promise or value.
I'm also not sure how to refer to the root from inside the onWrite so I've created several "parent" entries that refer to each other. I'm sure there is a better way.
onWrite triggers on this:
/users/{uid}/username
The trigger counts the children in /usernumbers and then writes an entry here with the uid and the child count + 1:
/usernumbers/uoNEKjUDikJlkpLm6n0IPm7x8Zf1 : 5
Cloud Function:
'use strict';
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
exports.setCount = functions.database.ref('/users/{uid}/username').onWrite((change, context) => {
const uid = context.params.uid;
const parent1 = change.after.ref.parent; //uid
const parent2 = parent1.ref.parent; //users
const parent3usernumbers = parent2.ref.parent.child('/usernumbers/');
const parent3usernumbersuid = parent2.ref.parent.child('/usernumbers/'+uid);
parent3usernumbers.once("value")
.then(function(snapshot) {
var a = snapshot.numChildren();
return parent3usernumbersuid.transaction((current) => {
return (a + 1);
}).then(() => {
return console.log('User Number Written', uid, a);
});
});
});
Is there a better way to do this? How can I get the Function Returned Undefined error to go away?
I should also mention it takes a few seconds for the 'usernumber' entry to be written. I'm guessing it's waiting for the function to return something.
Your function have to return a Promise :
exports.setCount = functions.database.ref('/users/{uid}/username').onWrite((change, context) => {
const uid = context.params.uid;
const parent1 = change.after.ref.parent; //uid
const parent2 = parent1.ref.parent; //users
const parent3usernumbers = parent2.ref.parent.child('/usernumbers/');
const parent3usernumbersuid = parent2.ref.parent.child('/usernumbers/'+uid);
return new Promise((resolve, reject) => {
parent3usernumbers.once("value").then(function(snapshot) {
var a = snapshot.numChildren();
return parent3usernumbersuid.transaction((current) => {
return (a + 1);
}).then(() => {
console.log('User Number Written', uid, a);
resolve({uid : uid, a : a})
}).catch(function(e) {
reject(e)
})
});
});
});
Currently, I am running two cloud functions. One adds information to posts while another deletes old posts, as such :
exports.reveal = functions.database.ref('/reveals/{postIDthatWasRevealed}/revealed').onUpdate((change, context) => {
const revealedValue = change.after.val()
if (revealedValue === true) {
var updates = {}
const postID = context.params.postIDthatWasRevealed
console.log(postID)
return admin.firestore().collection('posters').doc(postID).get().then(snapshot => {
const value = snapshot.data()
console.log(value)
// console.log(value)
const posterID = value.posterID
const posterName = value.posterName
const profileImage = value.profileImage
const postKey = value.key
return admin.database().ref('/convoID/' + postID).once('value', (snapshot) => {
if (snapshot.exists()) {
const convoIDCollection = snapshot.val()
for (var child in convoIDCollection) {
const convoID = child
updates["/conversations/"+convoID+"/information/reciever/Name"] = posterName
updates["/conversations/"+convoID+"/information/reciever/profileImage"] = profileImage
updates["/conversations/"+convoID+"/key"] = postKey
}
}
const currentTime = Date.now()
const addedTime = currentTime + 172800000
const batch = admin.firestore().batch()
const postFireStoreRef = admin.firestore().collection('posts').doc(postID)
batch.update(postFireStoreRef,{"revealedDate": currentTime})
batch.update(postFireStoreRef,{"timeOfDeletion": addedTime})
batch.update(postFireStoreRef,{"information": {"posterID":posterID,"posterName":posterName,"profileImage":profileImage} })
batch.update(postFireStoreRef,{"key":postKey})
return batch.commit(), admin.database().ref().update(updates)
})
})
}
else {
return null
}
})
^That post adds information to a post when it gets enough likes. The posts are stored in firestore, and when a firebase node associated with the post gets enough likes, some information will be downloaded appended to the firestore post entity. In theory, it should not even take one read as the data from the firestore entity is never downloaded, merely modified. The second function running is as follows :
exports.hourly_job = functions.pubsub.topic('hourly-tick').onPublish((change,context) => {
const currentTime = Date.now()
const getPostsForDate = admin.firestore().collection('posts').where('timeOfDeletion', '<', currentTime)
return getPostsForDate.get().then(snapshot => {
const updates = {}
const batch = admin.firestore().batch()
snapshot.forEach((doc) => {
var key = doc.id
console.log(key)
const convos = database().ref('/convoID/' + key).once('value', (snapshot) => {
if (snapshot.exists){
for (var child in snapshot) {
const convoID = child
console.log(child+"shit")
updates["conversations/" + value] = null
}
}
})
updates["/convoID/"+ key] = null
updates["/reveals/" + key] = null
updates["/postDetails/" + key] = null
const postFireStoreRef = admin.firestore().collection('posts').doc(key)
const posterRef = admin.firestore().collection('posters').doc(key)
batch.delete(postFireStoreRef)
batch.delete(posterRef)
})
return admin.database().ref().update(updates), batch.commit()
})
})
Each minute, this queriers firestore for old posts. At most, it may return two to three posts, leading to a few reads. However, after testing these functions out for an hour, the Google App Engine Quota shows Ten Thousand Reads while I was expecting close to twenty to fifty. Additionally, the entire day the functions had only been deployed such that they ran only 87 times. Are these functions not optimized? Is there a way to monitor where the read operations are coming from?
Edit : It seems that each time I am triggering the deletion function (actually changing the timestamp of a post such that it will be deleted when the. deletion function is called every minute) my reads increase by a couple of hundred...
I have observed this behavior occasionally with both onCreate and onDelete triggers.
Both the executions happened for the same document created in firestore. There's only one document there so I don't understand how it could trigger the handler twice. the handler itself is very simple:
module.exports = functions.firestore.document('notes/{noteId}').onCreate((event) => {
const db = admin.firestore();
const params = event.params;
const data = event.data.data();
// empty
});
this doesn't happen all the time. What am I missing?
See the Cloud Firestore Triggers Limitations and Guarantees:
Delivery of function invocations is not currently guaranteed. As the
Cloud Firestore and Cloud Functions integration improves, we plan to
guarantee "at least once" delivery. However, this may not always be
the case during beta. This may also result in multiple invocations
for a single event, so for the highest quality functions ensure that
the functions are written to be idempotent.
There is a Firecast video with tips for implementing idempotence.
Also two Google Blog posts: the first, the second.
Based on #saranpol's answer we use the below for now. We have yet to check if we actually get any duplicate event ids though.
const alreadyTriggered = eventId => {
// Firestore doesn't support forward slash in ids and the eventId often has it
const validEventId = eventId.replace('/', '')
const firestore = firebase.firestore()
return firestore.runTransaction(async transaction => {
const ref = firestore.doc(`eventIds/${validEventId}`)
const doc = await transaction.get(ref)
if (doc.exists) {
console.error(`Already triggered function for event: ${validEventId}`)
return true
} else {
transaction.set(ref, {})
return false
}
})
}
// Usage
if (await alreadyTriggered(context.eventId)) {
return
}
In my case I try to use eventId and transaction to prevent onCreate sometimes triggered twice
(you may need to save eventId in list and check if it exist if your function actually triggered often)
const functions = require('firebase-functions')
const admin = require('firebase-admin')
const db = admin.firestore()
exports = module.exports = functions.firestore.document('...').onCreate((snap, context) => {
const prize = 1000
const eventId = context.eventId
if (!eventId) {
return false
}
// increment money
const p1 = () => {
const ref = db.doc('...')
return db.runTransaction(t => {
return t.get(ref).then(doc => {
let money_total = 0
if (doc.exists) {
const eventIdLast = doc.data().event_id_last
if (eventIdLast === eventId) {
throw 'duplicated event'
}
const m0 = doc.data().money_total
if(m0 !== undefined) {
money_total = m0 + prize
}
} else {
money_total = prize
}
return t.set(ref, {
money_total: money_total,
event_id_last: eventId
}, {merge: true})
})
})
}
// will execute p2 p3 p4 if p1 success
const p2 = () => {
...
}
const p3 = () => {
...
}
const p4 = () => {
...
}
return p1().then(() => {
return Promise.all([p2(), p3(), p4()])
}).catch((error) => {
console.log(error)
})
})
Late to the party, I had this issue but having a min instance solved the issue for me
Upon looking #xaxsis attached screenshot, my function took almost the amount of time about 15 seconds for the first request and about 1/4 of that for the second request
// The Cloud Functions for Firebase SDK to create Cloud Functions and
setup triggers.
const functions = require('firebase-functions');
// The Firebase Admin SDK to access the Firebase Realtime Database.
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);
exports.giveCard = functions.firestore
.document('Profiles/{profileId}/cards/{cardsId}/_given/{_givenID}')
.onWrite((event) => {
// Get the field values of what I am working with
const oldGiven = event.data.previous.data()['given'];
const newGiven = event.data.data()['given'];
// Get the cardID to make sure that is there
const cardID = event.params.cardsId;
// An array to go through
const give_profiles = event.data.data()['given_profiles'];
// error cardDatatwo is returned as undefined
const cardDatatwo = newGiven.parent;
// error cardDatathree is returned as undefined
const cardDatathree = event.data.ref.root
// // error cardDatafour cannot read propoerty of undefined
// const cardDatafour = cardDatathree.child('Profiles/{profileId}/cards/{cardsId}')
// error cardDatafive 'The value of cardfive is DocumentReference...
const cardDatafive = event.data.ref.firestore.doc('Profiles/{profileId}/cards/{cardsId}');
// Check that the values have changed
if (newGiven == oldGiven) return;
if (newGiven !== undefined) {
console.log('The old value of given is', oldGiven);
console.log('The new value of given is', newGiven);
console.log('The value of the card is', cardID);
console.log('The value of the cardtwo is', cardDatatwo);
console.log('The value of the cardthree is', cardDatathree);
// console.log('The value of the cardfour is', cardDatafour);
console.log('The value of the cardfive is', cardDatafive);
for (var profile of give_profiles) {
console.log(profile);
};
return;
}
return console.log("No given value");
});
I am having great difficulty in getting the root for Firestore working with Cloud Functions. It works differently of course.
I am try to get a value up the path towards the root after an onUpdate has been fired further down.
.parent does not work
functions.database.ref of course does not work as that's the realtime database
and cannot use
firebase.firestore() is also not working in node
and event.data.ref.firestore.doc comes back as undefined.
I am sure have gone through every option.
Hope you can help.
Wo
According to the documentation, you can access collections via firestore, like this:
exports.giveCard = functions.firestore
.document('Profiles/{profileId}/cards/{cardsId}/_given/{_givenID}')
.onWrite((event) => {
// other code
const ref = event.data.ref.firestore.doc('your/path/here');
return ref.set({foo: 'bar'}).then(res => {
console.log('Document written');
});
});
You can use firestore to build a path to whatever part of the database you're seeking to access. You can also use event.data.ref.parent, like so:
exports.giveCard = functions.firestore
.document('Profiles/{profileId}/cards/{cardsId}/_given/{_givenID}')
.onWrite((event) => {
// other code
const parentref = event.data.ref.parent;
const grandparentref = parentref.parent; // gets to cardsId
return grandparentref.set({foo: 'bar'}).then(res => {
console.log('Document written');
});
});