如何在Firebase云功能之间传递数据

Question

I'm trying to fetch the current user id from the app by making https requests to call functions from the client app. It's working and I'm fetching the uid. The problem is whenever the onWrite() function is triggered I need to send notifications to a specific user under a specific user id. How can I pass the uid that I got from my https functions to the trigger functions?

I just retrieved the user id of the current user from the client app using an https.onCall(). Then in the trigger function, I'm trying to send notifications to a specific user classified by uid using expo push notifications API.

functions/index.js

const functions = require('firebase-functions');
var fetch = require('node-fetch')

const admin = require('firebase-admin')
admin.initializeApp(functions.config().firebase)


exports.getUid = functions.https.onCall((data, context) => {
    uid = data.text
    console.log(data.text)
})

exports.makerOrders = functions.database.ref('orders')
    .onWrite((snapShot, context) => {
        console.log('functions is triggered :)')

    return admin.database().ref('Notifications').child(uid)
        .once('value')
        .then((shot) => {
            var message = []

            var tokens = shot.val().expoTokens;

            if (tokens) {
                message.push({
                    "to": tokens,
                    "body": "Notifications are working fine :)"
                })
            }
            return Promise.all(message)
        }).then(message => {
            fetch('http://exp.host/--/api/v2/push/send', {
                method: "POST",
                headers: {
                    "Accept": "application/json",
                    "Content-Type": "application/json"
                },
                body: JSON.stringify(message)
            })
            return Promise.all(message)
        })
})

App.js

var uid = firebase.auth().currentUser.uid
var getUid = firebase.functions().httpsCallable('getUid')
getUid({text: uid}).then(result => {
  var msg = result.data
  console.log(msg)
  console.log('Called successfully :)')
}).catch(error => {
  console.log('Error :( in sending the requests')
});

I'm expecting to fetch the uid value of the current user from the app so that I can send push notifications to that specific user.

I can't able to retrieve the uid for the currently authed user.

Answer 1

In order to pass data between functions there are two ways of doing this. You can use a function that it is triggered by HTTP request or a function that is triggered by Pub/Sub topic .

HTTP:

1. Create a Cloud Function with HTTP trigger
2. Open the details of the created function and under the Trigger tab you will find the URL that triggers the function. Use that URL to parse data from another function.
3. In the other function run a request using that URL and add at the end '?data=DATA_T0_SEND'
4. Catch the data from the second function using return request.args.get('data')

Pub/Sub:

1. Create a Cloud Function that triggers by a Pub/Sub topic.
2. On the other function use the Pub/Sub library to send the data to the topic
3. When the functions will be triggered with the Pub/Sub event get the data
4. Now process the data from that event