CODEWITHSUNDEEP
firebasegoogle-cloud-functionsgoogle-cloud-firestore
Dyan
Dyan

Reputation: 1753

How to count documents in cloud firestore?

I'm having issues implementing a counter using the firestore DB. I have a collection of documents where the document has a field that is updated at some point.

Collection Object Field:true Object Field:false Object Field:true

I need to count all the fields where the value is equals to true. The app is updated from multiple devices at the same time.

How can I accomplish this? Do I need to use the distributed counters approach o just with a cloud function would be enough

Upvotes: 1

Views: 3720

Answers (2)

Noah Stevan
Noah Stevan

Reputation: 151

Use cloud functions. simple example:

// database in the 'posts' collection
  {
    title: "My great post",
    categories: {
    "technology": true,
    "opinion": false,
    "cats": true
  }

Cloud functions script:

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp({
    credential: admin.credential.applicationDefault()
});

const docRef = admin.firestore().collection('post')
.where('categories', '==', true)
.get()
.then((result) => {
    res.send(result.size());    //return the count
}).catch(function(error){
    console.log("got an error",error);        
})
exports.countFunction = functions.https.onRequest(...);

Upvotes: 1

Jason Berryman
Jason Berryman

Reputation: 4898

Cloud Firestore has a limit of one write per document/second. I would not advise having multiple users writing to the same document at the same time. You should definitely use the Distributed Counters method.

Upvotes: 1

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