CODEWITHSUNDEEP
javascriptfirebasegoogle-cloud-firestoregoogle-cloud-functionsfirebase-cloud-messaging
Madhavam Shahi
Madhavam Shahi

Reputation: 1192

Firebase cloud functions nested listeners

Is it possible to achieve something like this? P.s it's not working, I don't know why.

exports.Myfunc = functions.firestore.document('collection/{id}').onCreate(async (snapshot, context) => {

const Id =snapshot.data().id;
const Token=snapshot.data().deviceToken;

functions.firestore.document('collection2/Id').onUpdate(async (snapshot, context) => {

  
const data1=snapshot.data().data;
const data2=snapshot.data().data2;
 
      
    var payload = {
        notification: {
            priority : "high",
            title: 'Notification',
            body: '<body>',
           
        },
        data: {
            "click_action": "FLUTTER_NOTIFICATION_CLICK",
            'data1':data1,
            'data2':data2,
            
        },
    };
 
    try {
        const response = await admin.messaging().sendToDevice(Token, payload);
        console.log('Notification sent successfully');
        
    } catch (err) {
        console.log(err);
    }



});

});

What i'm trying to do is, listening to document creation in a collection, and when created, then listening to updates in a particular document(whose id is given by the previous listener), and when, this document UPDATES, then sending a notification to the device token given by the previous listener.

How can I achieve this? Is there any other possible way of doing this,or something i need to keep in mind?

Please help.

Upvotes: 1

Views: 339

Answers (1)

Renaud Tarnec
Renaud Tarnec

Reputation: 83058

You cannot define a Cloud Function within a Cloud Function.

If I correctly understand what you want to achieve, you could do as follows:

Create a Cloud Function for Firestore that is triggered with onUpdate() in order to listen to changes to the documents of collection2. Similarly to what you did in your code:

exports.Myfunc = functions.firestore.document('collection2/Id')
  .onUpdate(async (change, context) => {
       // ...
       const docId = context.params.Id;
       // ...
  });

In this Cloud Function, verify if the document Id (context.params.Id) is within a list of Ids that you have saved somewhere in the Firestore database. E.g. as an Array in a specific doc (mind the maximum 1 MiB size for a document) or within dedicated docs in a specific collection.

If the Id is within the list, send the message.

You would populate this list of Ids, either from your Flutter app, when you create the document collection/{id}, or, if necessary (e.g. you want to restrict the read/write access to the list of Ids), via another Cloud Function.

PS: Note that in a Cloud Function that is triggered with onUpdate(), you should not do

exports.Myfunc = functions.firestore.document('collection2/Id').onUpdate(async (snapshot, context) => {
  //...
  const data1 = snapshot.data();  // <= this will not work
  //...
});

See the doc for more details.

Upvotes: 3

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