CODEWITHSUNDEEP
javascriptfirebasefirebase-realtime-databasefirebase-cloud-messaginggoogle-cloud-functions
Lukayne
Lukayne

Reputation: 43

Cloud Functions for Firebase getting value of key

I am trying to get the value from author, but it says that it's undefined.

How do I get the value from a specific child from firebase in javascript in Cloud Functions for Firebase, the follwing code should work(?):

const functions = require('firebase-functions');                                          

const admin = require('firebase-admin');                                                  

admin.initializeApp(functions.config().firebase);                                         

exports.sendPushForHelp =                                                                 
functions.database.ref('/schools/Vittra/alarms/active/{id}').onCreate(event => {      
    const id = event.params.id;                                                       
    var eventSnapshot = event.data.val();                                             
    var ref = admin.database().ref("/schools/Vittra/alarms/{eventSnapshot}/authorId");
    ref.once('value').then(function(snapshot) {                                       
        var author = snapshot.val();                                                  
    });                                                                               






    const payLoad = {                                                                 
        notification: {                                                               
            title: String(eventSnapshot),                                             
            body: String(author),                                                     
            badge: '1',                                                               
            sound: 'Intruder.mp3'                                                     
        }                                                                             
    };                                                                                

return admin.database().ref('fcmToken').once('value').then(allToken => {                  
        if (allToken.val()) {                                                             
     const token = Object.keys(allToken.val());                                            
     return admin.messaging().sendToDevice(token, payLoad).then(response => 
{              

           });                                                                           

        };                                                                                
    });                                                                                   

});

Upvotes: 0

Views: 3657

Answers (2)

Doug Stevenson
Doug Stevenson

Reputation: 317677

You're ignoring the promise returned from this query:

ref.once('value').then(function(snapshot) {                                       
    var author = snapshot.val();                                                  
});

Before you can use the value of author, you need to but the code that depends on author inside the function that responds to that promise, more like this:

var author;

return ref.once('value').then(function(snapshot) {                                       
    author = snapshot.val();
    return admin.database().ref('fcmToken').once('value')
}).then(function(snapshot) {
    if (allToken.val()) {                                                             
        const token = Object.keys(allToken.val());                                            
        const payLoad = ...
        return admin.messaging().sendToDevice(token, payLoad)
    }
}).then(function(response) {
    // ...continue
})

The bottom line is that you need to learn how to chain your promises correctly.

Upvotes: 1

Satish Kumar
Satish Kumar

Reputation: 601

You have declared author inside the firebase callback.

    var eventSnapshot = event.data.val();                                             
    var ref = admin.database().ref("/schools/Vittra/alarms/{eventSnapshot}/authorId");
    ref.once('value').then(function(snapshot) {                                       
        var author = snapshot.val();  // Here is the problem                                                
    });

And you are using it here as :

const payLoad = {                                                                 
        notification: {                                                               
            title: String(eventSnapshot),                                             
            body: String(author), // <------                                                    
            badge: '1',                                                               
            sound: 'Intruder.mp3'                                                     
        }                                                                             
    };

define author outside like eventSnapshot , then you can use it further.

Use:

        var eventSnapshot = event.data.val();  
        var author = '';           
        var ref = admin.database().ref("/schools/Vittra/alarms/{eventSnapshot}/authorId");
        ref.once('value').then(function(snapshot) {                                       
            author = snapshot.val();                                                
        });

Upvotes: 0

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