addSnapshotListener swift firestore behaviour

user_2001701 0
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I have a document in Cloud firestore to which I listen for updates. It has 2 fields, it has a field description and a field for a picture. The picture is approximately 0.2 mb and description is a few words. I wanted to know what would happen if I made changes to the description in the document, I wanted to know if addSnapshotListener actually downloads a fresh new copy of the document or just the field that has been changed.

I indeed see, by looking at how much data is being downloaded in Xcode, a new fresh copy of the document is downloaded.

This is not efficient at all, since the picture field is rarely changed, only the description might change in my application.

Is there a way to optimize this?

google-cloud-firestore firebase swift
2 Answers

Is there a way to optimize this?

Yes! Don't do that.

Firestore (and the realtime database) is not intended to store images or large datasets per field.

You should explore Storage and keep a reference (url) to the item stored in storage in your Firebase.

Cloud Storage is built for app developers who need to store and serve user-generated content, such as photos or videos.

By leveraging storage if you need to update or change a field in Firestore, you're only working with a small amount of data instead of an entire image worth.

To answer the question; if you read a document from Firebase, it does read the Document and it's child data.

Here's a link to the Storage Docs which shows how to capture a reference to the item uploaded to storage.

https://firebase.google.com/docs/storage/ios/upload-files

user_28519370

If you want to automatically sync the images to all clients and have them available offline, just put them in a separate document.

// Store your small, frequently changing text here: 
db.collection('users').doc(userId).set({email: vince@example.com})

// Store your image here: 
db.collection('user_profile_pic').doc(userId).set({data: <imagedata>})
user_306720
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