Updating a list or relationships in a document

[autumn notch]

Hi guys. I don't know if this issue is serious enough for a support ticket.

I want to create a chat app and I need some advice. I have a chat collection that should have the chat ID, participants ID, and a list of messages.

At first, I thought about each message being a JSON encoded string. Later, I thought I could use relationships instead. But here is the thing - using either lists or relationships seem to have the same limitation. In Firebase, I could just set a document based on a given path and it can add the message to an existing list. But here in Appwrite, if I want to create a new message, I have to update the whole document each time, either I'm using lists or relationships.

Please what workarounds are there?

[elfin rivet]

What features does your chat app support? Group chat/Multiple participants? Other type of message content like media(images, videos,etc)? Quote feature?

How would your current document model/permission look like?

And what is the intention behind a json encoded string?

[autumn notch]

Just something similar to Twitter DMs

[autumn notch]

Private chat, can send media files

[autumn notch]

Haven't quite decided on the model and permission yet. I was planning these out when I got stuck on the question I raised.

The JSON encoded string would contain the sender id, the sent time, attachment id, is read, the message, etc.

[elfin rivet]

1on1 chat. There can only be one convo between these two. So each chat have their own document collection. And message model could be as simple as String "message" and String "senderId". Appwrite will create $createdAt automatically for you, so you can use that to show the latest message

Create and read permissions for both participants and. And update or delete only for those who created the message

I think for other types of message you could use a prefix within the message.

<<TEXT>>Hey, how are you?
<<ATTACHMENT/IMAGE>>{{file of media from appwrite storage}}

If it is of type Text you just cut out the prefix and show the text

and for image you use the id to show the image

or you could add an enum and decide how to show the message based on that

I assume you know the id of the participant you chat with. You can use as collectionId:

• Smaller userId starts first then append the userId of the second participant and use some fast hashing algorithm to create a hash out of that

[autumn notch]

Yeah, enum make more sense

[elfin rivet]

This way you don't even need an extra collection so store the chat Ids

[autumn notch]

Hmm. So how do you query this? Say you want to get a list of chats a user has

[elfin rivet]

Haven't considered that. Yeah then you can save it

[autumn notch]

In the last chat app I built with Realm, each chat object had a "participantsIDs" attribute. That way I could easily get a user's chats by querying the attribute using contains

But all in all, thanks for your help. I learnt a thing or two

I'd also like to know if there's a limit on the documents a collection could possibly hold

[elfin rivet]

There is not really a limit

[autumn notch]

Alright.

Thank you

[elfin rivet]

And even if there would be one it wake take a long time for you to reach it lmao

I literally inserted over 50m documents to a collection to test its effiency

It all still works fine

[autumn notch]

Oh wow.

[autumn notch]

Alright thanks for the info.

I was wondering if to keep all the messages in a single collection or create a separate collection for each chat as you earlier mentioned

[elfin rivet]

I would recommend separate collection for each chat

Otherwise you would have to include a chatId to the message model as well

[autumn notch]

Yes, this.

[elfin rivet]

In the first approach you only store the chatId once somewhere

[autumn notch]

I'm just tryna avoid having to write more cloud functions 😅

[elfin rivet]

but if each message contains chatId that can add up quite quickly

[autumn notch]

True this.

[autumn notch]

I'll do this anyways. Seems a lot cleaner

[elfin rivet]

Yeah and I think permissions are somewhat easier to maintain I think

[autumn notch]

Yeah. Thank you 🙏🏽

[elfin rivet]

For image attachments you could create a function:
Everytime a user uploads an image to a bucket where the chatId act as bucketId, a function gets triggered an creates a document in the chat collection with

message: <fileId>
type: image
senderId: <userId of sender>

[autumn notch]

Hi there.

I seem to have some doubts about this collection. I need to have a realtime subscription to the user's chats. If for instance, the user has 25 chats (which means 25 unique collections), does this mean that I will have to create a realtime subscription for the 25 collections? Isn't that too much?

[elfin rivet]

No. You are just subscribed to the 25 channels but you will only maintain one websocket connection

[autumn notch]

You mean it's possible to listen to multiple collection changes in one code block?

[elfin rivet]

Yeah

[autumn notch]

Thank you. I found this
https://appwrite.io/docs/apis/realtime#subscribe-to-multiple-channel

[elfin rivet]

If you have doubts, there is not really a downside to it

I mean you are interested in those 25 chats am I right?

[autumn notch]

Like, it doesn't affect my backend efficiency?

[autumn notch]

yes

[elfin rivet]

Compared to a single collection approach it does not make a difference.

I use realtime extensivley and subscribe to a lot of channels and I personally do not feel any degradation because of that

[autumn notch]

Hmm. Alright then

Thanks for your help

One more question

Will the multiple channel sub work across different databases?

[elfin rivet]

Yes

[autumn notch]

Even without specifying the database ID?

[elfin rivet]

Yeah

That channel would just be called "documents" then

It will listen to all database events for which the user has permissions for

[autumn notch]

Alright

Thank you