Samuel
ok, let's break it down. at the core of atproto is the data. it lives own your own computer (or someone hosts it for you). think of it as a hard drive with JSON files on it data is structured (i.e. has a type), and can references other records on other peoples' computer with a URI like a hyperlink
Diagram labelled network state Two areas, my data storage and your data storage In my data storage, there is a post and a like. the like has an arrow to a post in your data storage
Lu wilson@todepond.com· 2 Nov 2024
okay let me get this straight... it's like this, right? to participate in this particular microblogging site we're all on, it has to go through the first-party appview?
75 184 654
Samuel
ok, let's say we want to see some posts. we can ask our PDS for some records, but that's not very interesting because it's just my stuff. we have a hyperlink to the post I liked, but that's a bit inconvenient because I'd need to go all the way to Lu's machine to see what it is
The above diagram with an arrow pointing to my data storage written beneath the arrow is "curl https://pds.mozzius.dev/fictional.getAllRecords" and beneath that is content from my data service again 2 1 76
Samuel
in order to make sense of the network, we're going to build a cache of all the content, so we can query it without needing to check each machine individual. think of it like Google's search index, except instead of googlebot scraping all the data, the PDSes offer a websocket that sends data instead
The data storage boxes now have "websocket" arrows pointing to a database symbol labelled "network cache" 3 1 81
Samuel
ok, we're getting somewhere. but to make sense of this big pile of data, we're going to offer some opinionated APIs. for example, a "getTimeline" API that returns all "post" records, with a computed count of how many "like" records are pointed at them now, we can fetch a timeline!
Now the "network cache" is in a box labelled AppView. also inside the appview is a box labelled "machine that calculates vote counts" beneath that is curl for "https://api.bsky.app/getTimeline" which returns posts from both data storages, and one of the post has a field of "likes: 1" 2 7 106
Samuel
this "AppView" service provides a "view" of the network. It will ignore records it doesn't know or care about, and derive useful information from the data it has now, since the data just sits on the web, and AppViews are downstream of the data, you can run another one and arrive at the same view!
The previous diagram, except the AppView section has been duplicated with the duplicate labelled "Alt AppView" 2 7 89
Samuel
so, imo the network (with multiple AppViews in play) looks like this. when you use a client, you ask an AppView to give you an opinionated view of the whole network. It acts as a cache in front of any number of hosts, which unlocks stuff like global search and accurate like counts (wild, right!)
Same diagram as the last one except the curl command has been replaced with a box with a butterfly emoji in it labelled "App" 6 4 80
Samuel
and to wrap things up, this is what writes look like. your client writes the new record to your PDS, which flows out down to the AppViews' caches, where it'll finally reach your client again (we're thinking of letting AppViews make writes on your behalf, but that's an optional UX/DX optimisation)
A green arrow labelled "write" goes from the App to your Data Storage at the top of the diagram. the Websocket arrows from your PDS to the AppViews are colored green along with the databases in the AppViews 7 16 97
mehiel
The UX/DX is about updating the current AppView's cache instantly for example and avoid the network delay at the place that the user interacts with at the time?
1
mehiel
It will stay as the source of truth. The update will reach the PDS finally as it is now but it will go through the AppView which enables it to instantly update it's data as well and reflect the changes in the UI.
1
Liberal Rebound
Would your device have to sign the object/post with your SK which is normally stored or managed by your PDS then, to prevent people from taking advantage of the network delay gap to fake records, or is it already granted like a temp key for signing on each login session?