i want to use Google Cloud Functions to count documents in firestore and show a counter in the app.
So I have the following code which is working:
const functions = require('firebase-functions');
const admin = require('firebase-admin');
const {FieldValue} = require("@google-cloud/firestore/build/src");
admin.initializeApp(functions.config().functions);
const doc = admin.firestore().collection('users').doc('CF7FOjfZ0iOlwXBc59AAEM7Qx1').collection('user').doc('general');
exports.countDocs = functions.firestore
.document('/users/CF7FOjfZ0iOlwXBc59AAEM7Qx1/trainings/{trainings}')
.onWrite((change, context) => {
if (!change.before.exists) {
// New document Created : add one to count
doc.update({numberOfDocs: FieldValue.increment(1)});
} else if (change.before.exists && change.after.exists) {
// Updating existing document : Do nothing
} else if (!change.after.exists) {
// Deleting document : subtract one from count
doc.update({numberOfDocs: FieldValue.increment(-1)});
}
});
Now I have the problem, that I need to get the uid of current user. I don't know how to do that. For Realtime firebase there is a possible solution with context, but Google has not implemented this for Firestore.
If you want to keep a count for each user, that'd be:
admin.initializeApp(functions.config().functions);
exports.countDocs = functions.firestore
.document('/users/{uid}/trainings/{trainings}')
// Capture uid here 👆
.onWrite((change, context) => {
const doc = admin.firestore().collection('users').doc(context.params.uid).collection('user').doc('general');
// User uid here 👆
if (!change.before.exists) {
// New document Created : add one to count
doc.update({numberOfDocs: FieldValue.increment(1)});
} else if (change.before.exists && change.after.exists) {
// Updating existing document : Do nothing
} else if (!change.after.exists) {
// Deleting document : subtract one from count
doc.update({numberOfDocs: FieldValue.increment(-1)});
}
});