i m bulding a scalable chat app with RTDB and firestore
here is my raw structure of shards
SHARD1
Chats {
chat01: {
Info: {
// some info about this chatroom
},
Messages ...
}, ....
}
SHARD2...
now i have write triggers on all the info nodes of all the shards.
i want get the ID of the shard
How do i know what shard it actually ran on ?
[EDIT]
console.log(admin.app().name); // it prints "[DEFAULT]" in console
Puf and team please help
When a Realtime Database trigger is invoked, the second argument is an EventContext object that contains information about the database and node that was updated. That object contains a resource string, which has what you're looking for. According to the documentation for that string, it's name property will be formatted as:
projects/_/instances/<databaseInstance>/refs/<databasePath>
The databaseInstance string is what you're looking for. So, you can just split the string on "/" and take the 4th element of that array:
export const yourFunction = functions.database
.instance('yourShard')
.ref('yourNode')
.onCreate((snap, context) => {
const parts = context.resource.name.split('/')
const shard = parts[3]
console.log(shard)
})
If all you need is a reference to the location of the change, in order to perform some changes there, you can just use the ref property on the DataSnapshot that was delivered in the first argument, and build a path relative to there.
Related
I'm using flutter and firebase. I use pagination, max 5 documents per page. How do I know if there are more documents left to get from a firestore collection. I want to use this information to enable/disable a next page button presented to the user.
limit: 5 (5 documents each time)
orderBy: "date" (newest first)
startAfterDocument: latestDocument (just a variable that holds the latest document)
This is how I fetch the documents.
collection.limit(5).orderBy("date", descending: true).startAfterDocument(latestDocument).get()
I thought about checking if the number of docs received from firestore is equal to 5, then assume there are more docs to get. But this will not work if I there are a total of n * 5 docs in the collection.
I thought about getting the last document in the collection and store this and compare this to every doc in the batches I get, if there is a match then I know I've reach the end, but this means one excess read.
Or maybe I could keep on getting docs until I get an empty list and assume I've reached the end of the collection.
I still feel there are a much better solution to this.
Let me know if you need more info, this is my first question on this account.
There is no flag in the response to indicate there are more documents. The common solution is to request one more document than you need/display, and then use the presence of that last document as an indicator that there are more documents.
This is also what the database would have to do to include such a flag in its response, which is probably why this isn't an explicit option in the SDK.
You might also want to check the documentation on keeping a distributed count of the number of documents in a collection as that's another way to determine whether you need to enable the UI to load a next page.
here's a way to get a large data from firebase collection
let latestDoc = null; // this is to store the last doc from a query
//result
const dataArr = []; // this is to store the data getting from firestore
let loadMore = true; // this is to check if there's more data or no
const initialQuery = async () => {
const first = db
.collection("recipes-test")
.orderBy("title")
.startAfter(latestDoc || 0)
.limit(10);
const data = await first.get();
data.docs.forEach((doc) => {
// console.log("doc.data", doc.data());
dataArr.push(doc.data()); // pushing the data into the array
});
//! update latest doc
latestDoc = data.docs[data.docs.length - 1];
//! unattach event listeners if no more docs
if (data.empty) {
loadMore = false;
}
};
// running this through this function so we can actual await for the
//docs to get from firebase
const run = async () => {
// looping until we get all the docs
while (loadMore) {
console.log({ loadMore });
await initialQuery();
}
};
I am using Cloud Firestore as my database and I have collections of users where are stored basic information about user such as id, name, last name, email, company id.
Also I have collection of companies and in each company I have collection of tasks.
In each task I have one user assigned from collections of users (user data is replicated, so I have same data for that user as in collection users)
The problem is when I update user (change name or email...) from collection users because data is replicated that data is not changed in collection of tasks for that specific user.
Is there any way that using firestore when user from collection users is updated to automatically update it in collection of tasks?
This is quite a standard case in NoSQL databases, where we often denormalize data and need to keep these data in sync.
Basically you have two possible main approaches:
#1 Update from the client
When you update the "user" document, update at the same time the other documents (i.e. "tasks") which contain the user's details. You should use a batched write to do so: A batch of writes completes atomically and can write to multiple documents.
Something along the following lines:
// Get a new write batch
var batch = db.batch();
var userRef = db.collection('users').doc('...');
batch.update(userRef, {name: '....', foo: '....'});
let userTaskRef = db.collection('companies').doc('...').collection('tasks').doc('taskId1');
batch.update(userTaskRef, {name: '....'});
userTaskRef = db.collection('companies').doc('...').collection('tasks').doc('taskId2');
batch.update(userTaskRef, {name: '....'});
// ...
// Commit the batch
batch.commit().then(function () {
// ...
});
Note that you need to know which are "the other ("tasks") documents which contain the user's details": you may need to do a query to get these documents (and their DocumentReferences).
#2 Update in the back-end via a Cloud Function
Write and deploy a Cloud Function that is triggered when any "user" document is updated and which takes the value of this "user" document and update the "tasks" documents which contain the user's details.
Like for the first approach, you also need, in this case, to know which are "the other ("tasks") documents which contain the user's details.
Following your comment ("Is there any option to reference to another table or put foreign key?") here is a Cloud Function that will update all the ("tasks") documents that have their DocumentReference contained in a dedicated Array field taskRefs in the "user" doc. The Array members are of data type Reference.
exports.updateUser = functions.firestore
.document('users/{userId}')
.onUpdate((change, context) => {
const newValue = change.after.data();
const name = newValue.name;
const taskRefs = newValue.taskRefs;
const promises = taskRefs.map(ref => { ref.update({ name: name, foo: "bar" }) });
return Promise.all(promises);
});
You would most probably set the value of this taskRefs field in the "user" doc from your frontend. Something along the following lines with the JS SDK:
const db = firebase.firestore();
db.collection('users').doc('...').set({
field1: "foo",
field2: "bar",
taskRefs: [ // < = This is an Array of References
db.collection('tasks').doc('....'),
db.collection('tasks').doc('....')]
});
I am using a scheduled task in a Firebase Cloud Function to query an array which contains a number of objects that need to be updated if a matching condition exists. My current attempt is using the 'array-contains' method to get the objects, then loop over them to find a matching condition which will then batch update the items. This is my data structure:
I need to find an object that is <= the current time, and also if the 'active' value = false.
export const liveMeetingsTrigger = functions.runWith( { memory: '1GB' }).pubsub
.schedule('every 1 minutes').onRun(async context => {
const now = admin.firestore.Timestamp.now();
const liveMeetings = await admin.firestore().collection('fl_content').where('meeting', 'array-contains', 'liveMeetingDate').get();
const batch = admin.firestore().batch();
liveMeetings.forEach(doc => {
if(doc.data().liveMeetingDate <= now && doc.data().active == false){
batch.update(doc.ref,'active',true);
}
});
return await batch.commit();
});
I have also tried using an exact object in the query instead of just using 'liveMeetingDate', but still get no results back, any help would be great - thanks.
Debugging: As the array I am trying to reach is inside of the (map) object 'liveMeetings' i have tried the dot notation (liveMeetings.meeting) with no success. Also trying a new collection with the the 'meeting' array at top level has provided no success.
Simple logging in the console (liveMeetings.size) shows that nothing is being returned on the query, so therefore the logging does not even reach the loop in the code.
As explained in this anwser the following query will not work:
const liveMeetings = await admin.firestore().collection('fl_content').where('meeting', 'array-contains', 'liveMeetingDate').get();
because the meetings array contain some objects, instead of "simple" or primitive data (e.g. string, number...).
You could query it with the exact objects, like:
const obj = {active: false, liveMeetingDate: ..., meetingId: ..., ....};
const liveMeetings = await admin.firestore().collection('fl_content').where('meeting', 'array-contains', 'obj').get();
Another approach would be to create a new collection which contains the similar documents (same Document ID) but with a meeting Array that contains only the liveMeetingDate property.
Finally, note that since your Array is within a map, you need to do
await admin.firestore().collection('fl_content').where('liveMeetings.meeting', 'array-contains', ...).get();
(PS: I don't mark this question as duplicate since you expressly ask for more help in the comments of the duplicate question/answer)
I have an Event Collection in the Firestore database like this:
I want to use cloud firestore triggers. when a user attends an event, the capacity of the event will be -1, and when this field is updated I want to automatically update another field ("rankPoint") +3
to implement this, I need to Trigger a function when a document is updated
from firestore documentation, it will be like this
exports.updateUser = functions.firestore
.document('users/{userId}')
.onUpdate((change, context) => {
// Get an object representing the document
// e.g. {'name': 'Marie', 'age': 66}
const newValue = change.after.data();
// ...or the previous value before this update
const previousValue = change.before.data();
// access a particular field as you would any JS property
const name = newValue.name;
// perform desired operations ...
});
for my case, it should be 'events/{eventId}' right? but how do I get that eventID in the wildcard? does it come from client side? I mean in iOS/Android I will write the code to update like
db.collection("eventss").document("someEventIDHere").setData(data)
is it from the client?
Your function will only be delivered the document that matched your function's pattern (users/{userId}) that was changed. Other documents are not available until you query for them. So, if you want a document from you events collection, you will have to write some code to access it, then decide what to do from there.
It sounds like you're expecting there to be an eventId wildcard, but there is not. There is just the userId wildcard that you defined in your function. Other values will need to be derived from the data you have available in your user document.
I am monitoring for changes in node leaf jobs/{jobid}/proposals. Whenever I remove the proposals the function gets executed and reinsert proposals (this is the expected behavior).
The problem is When I remove its parent {job}, proposals gets reinserted in a new object with same parent ID. Is there a way to do a check if the parent exists? If so, reinsert proposal otherwise not.
exports.RecountProposals = functions.database.ref("/jobs/{jobid}/proposals").onWrite(event => {
const jobid = event.params.jobid;
if (!event.data.exists() && event.data.ref.parent.exists()) {
const propRef = admin.database().ref(`proposals/${jobid}`);
const counterRef = event.data.ref;
const collectionRef = counterRef.parent.child('proposals');
// Return the promise from counterRef.set() so our function
// waits for this async event to complete before it exits.
return propRef.once('value')
.then(messagesData => collectionRef.set(messagesData.numChildren()));
}
});
I am checking if parent exists but it is showing an error:
event.data.ref.parent.exists()
TypeError: event.data.ref.parent.exists is not a function
event.data.ref.parent is a Reference type object. As you can see from the linked doc, there is no exists() method on Reference. In Realtime Database, if you want to know if there is any data at a node, simply fetch the snapshot there and call val() on it to check to see if it's null. Reference objects are just paths, they don't contain any knowledge of data.
To put it another way, there is no such concept as a node that "exists" but contains no data, like an empty folder in a filesystem. For any given path that you can construct, the snapshot of the data there is either available (non-null) or not (null).