How to read data of multiple user id in a single request in cloud functions on firebase

Question

I am using Firebase Database for my Android application and cloud functions. As Firebase stores data in JSON format. Each user has some unique id which assigns to user.

I want to know if there is any way to get multiple users data on a single request. If you see below code it will fetch data only of passed user id.

db
    .ref("/users/" + request.query.userId)
    .once("value")
    .then(function(snapshot) {

I have 10 user ids of which I want to get data on a single request in nodejs. What is the way to get this ?

score 3 · Accepted Answer · answered Aug 05 '17 at 12:27

3

Store them in an array like this:

var promArr = []
var snapshotData = []
promArr.push(
db
    .ref("/users/" + request.query.userId) //put here unique usernames
    .once("value")
    .then(function(snapshot) {
    snapshotData.push(snapshot.val())
    })
return Promise.all(promArr).then(snap =>  {
//loop through snapshotData here
})

answered Aug 05 '17 at 12:27

J. Doe

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1

@Williams: this is indeed the common approach and is not as slow as you may think, since Firebase pipelines the requests over a single connection. For an explanation of that, see my answer here http://stackoverflow.com/questions/35931526/speed-up-fetching-posts-for-my-social-network-app-by-using-query-instead-of-obse/35932786#35932786 – Frank van Puffelen Aug 05 '17 at 14:45
@FrankvanPuffelen Thanks, your posts are really helpful :) – N Sharma Aug 06 '17 at 18:31

score 3 · Answer 2 · answered Mar 01 '18 at 23:43

This can be written much cleaner:

const records = [
  admin.database().ref(`users/${userId1}`).once('value'),
  admin.database().ref(`users/${userId2}`).once('value'),
];

return Promise.all(records).then(snapshots => {
   const record1 = snapshots[0].val();
   const record2 = snapshots[1].val();
});

How to read data of multiple user id in a single request in cloud functions on firebase

2 Answers2