push notifications not working (using firebase cloud functions + expo)

Question

I am trying to implement push notifications for users, using expo tokens, firebase cloud functions, and a react native frontend.

This is how I did things on the frontend, which calls the function correctly:

const writeNotification = Firebase.functions().httpsCallable('writeNotification');
            writeNotification({ 
                type: 0,
                senderUID: this.state.likerUID,
                recieverUID: this.state.posterUID,
                postID: this.state.postID,
                likerUsername: this.state.likerUsername
            })
            .then((result) => {
                console.log(result)
            })
            .catch((error) => {
                console.log(error);
            });

Here is the cloud function:

exports.writeNotification = functions.https.onCall((data, context) => {

    //Get the information of the user who is going to recieve the notification
    admin.firestore()
    .collection('users')
    .doc(data.recieverUID)
    .get()
    .then(function(doc) {
        if (doc.exists) {
            //Find out if the user will accept push notifications
            if (doc.data().pushStatus) {

                var messages = []

                //Write the notification and add it to messages
                messages.push({
                    "to": doc.data().token,
                    "sound": "default",
                    "title":"you got a like!",
                    "body": data.likerUsername + " liked your post!"
                });

                //Post it to expo
                fetch('https://exp.host/--/api/v2/push/send', {
                    method: 'POST',
                    headers: {
                        'Accept': 'application/json',
                        'Content-Type': 'application/json',
                    },
                    body: JSON.stringify(messages)
                });

                return (
                    "notification written"
                )
            }
            else {
                console.log("doesnt accept push notifications: " + doc.data().username)
                return
            }
        } else {
            // doc.data() will be undefined in this case, so this wont even come up honestly
            console.log("No such document!");
            return
        }
    })
    .catch(function(error) {
        console.error("Error finding user: ", error);
    });

    return (
        true
    )
});

My issue is with the fetch, and am getting this error in the cloud function logs:

So it looks like the issue occurs when writing to expo. Am I doing that part wrong? Any help appreciated, this is my first time implementing push notifications

kalculated kalculated · Accepted Answer · 2021-01-14T03:02:42

I forgot to add this to the cloud functions file:

const fetch = require('node-fetch');

Code works now, getting push notifications :)

push notifications not working (using firebase cloud functions + expo)

1 Answers