forked from cory/tildefriends
Cory McWilliams
a156cdea9f
git-svn-id: https://www.unprompted.com/svn/projects/tildefriends/trunk@3769 ed5197a5-7fde-0310-b194-c3ffbd925b24
65 lines
2.9 KiB
Markdown
65 lines
2.9 KiB
Markdown
# Tilde Friends Structure
|
|
[Back to index](#index)
|
|
|
|
Tilde Friends is a mostly-self-contained executable written in C.
|
|
|
|
In combines the following key components:
|
|
- A Secure Scuttlebutt (SSB) client/server. This talks with other SSB
|
|
instances, storing messages and blobs for anyone visible to local
|
|
users as they are encountered and sharing anything published locally
|
|
as appropriate.
|
|
- An sqlite database. This is where the SSB instance stores its data.
|
|
The general schema involves a `messages` table, storing mostly JSON,
|
|
a `blobs` table storing arbitrary blob data, and a `properties` table,
|
|
storing arbitrary state gleaned from `messages` and `blobs`, generally
|
|
updated on demand and incrementally.
|
|
- A QuickJS runtime. The core process runs stock scripts and has access
|
|
and permission to use all resources. All other processes, which
|
|
includes everything which runs untrusted code created by Tilde Friends
|
|
users, are strictly sandboxed in ways similar to how web browsers run
|
|
untrusted code. All attempts to access potentially sensitive resources
|
|
are mediated through the core process.
|
|
|
|
When run with no arguments, it starts a web server on
|
|
[http://localhost:12345/](http://localhost:12345/) and an SSB server.
|
|
|
|
## Web Interface
|
|
The Tilde Friends web server provides access to Tilde Friends applications,
|
|
which are arbitrary user-defined web applications.
|
|
|
|
At the top left, in addition to some basic navigation links, is an `edit`
|
|
link. Anyone can view, modify, and run in-place the code to any Tilde
|
|
Friends application by using the in-browser editor.
|
|
|
|
At the top right, one can `login` (to save work in their own space)
|
|
or `logout` (proceeding as a guest).
|
|
|
|
The rest of the page is an iframe belonging to the application.
|
|
|
|
## Special Paths
|
|
|
|
- `/~user/app/` - Tilde Friends application paths take the form `/~user/app/`, where `user`
|
|
is a username of a Tilde Friends account, and `app` is an arbitrary name
|
|
of an application saved by the given user.
|
|
- `/~user/app/file` - A raw file in an app.
|
|
- `/&blobid.ed25519` - A raw blob. Content-Type is inferred for at least
|
|
a few common image types.
|
|
|
|
## Communication Channels
|
|
Web Browser <-> Core <-> Sandbox
|
|
|
|
Visiting an application path delivers stock HTML and JavaScript which
|
|
establishes a WebSocket connection back to the server.
|
|
|
|
At this point, a new sandbox process is started in Tilde Friends, much
|
|
as a new sandboxed process might be started for a new tab in a web
|
|
browser. This process has a custom RPC connection to the core process
|
|
which holds the WebSocket connection to the browser.
|
|
|
|
The custom RPC communication between the sandbox process and the core
|
|
process facilitates passing and calling functions remotely. Calling a
|
|
function in another process returns a `Promise`.
|
|
|
|
An application will typically call `app.setDocument()` at startup to
|
|
populate the app's iframe in the web browser with its own client web
|
|
application resources. |