%eyre, %iris: Support Websocket

UIPS/UIP-01XX.md

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+---
+uip: "01XX"
+title: "%eyre/%iris: Support Websocket"
+description: "Support Websocket connections on Eyre/Iris"
+author: ~fidwed-sipwyn
+status: Draft
+type: Standards Track
+category: Kernel
+created: 2024-04-27
+---
+
+## Abstract
+
+This proposal adds Websocket functionality that works in a similar manner to the currently `%eyre`/`%iris` HTTP interface. Users who wish to receive Websocket connections will use the existing `%eyre`'s `%connect` `$task` to bind a URL path where the websocket handshakes will arrive (since they are technically also HTTP requests, this should be intuitive). To initiate a connection, users should pass a `%websocket-connect` `$task` to `%iris`. Once the connection is established, the client/server vanes interaction with the apps occurs through `%gall` pokes, facts and subscriptions.
+
+## Motivation
+
+Websocket support will allow Urbit to interact with a wider variety of systems/protocols.
+
+## Specification
+- **%eyre** will have a new `$gift` and a new `$task`:
+```hoon
+    ::  $gift
+    ::
+    ::  websocket-reponse: event to earth
+    ::
+    [%websocket-response event=websocket-event]
+    ::  $task
+    ::
+    ::  receives websocket event from earth
+    ::
+    [%websocket-event event=websocket-event]
+```
+- And the following new types:
+```hoon
+  ::  +websocket-connection: connection to be store in eyre state 
+  ::
+  +$  websocket-connection
+    $:  app=term
+        =inbound-request
+    ==
+  ::  +websocket-message:  websocket message content
+  ::
+  +$  websocket-message
+    $:  opcode=@ud
+        message=(unit data=octs)
+    ==
+  ::  +websocket-event:  inbound/outbound websocket event
+  ::
+  +$  websocket-event
+    $%  [%accept ~]
+        [%reject ~]
+        [%disconnect ~]
+        [%message message=websocket-message]
+    ==
+  ::
+```
+- **%iris** will have two new `$gift`s and two new `$task`s:
+```hoon
+  ::  $gift
+  ::
+  ::  %websocket-handshake: outbound websocket-handshake to earth
+  ::
+  [%websocket-handshake id=@ud url=@t]
+  ::  %websocket-response: event to earth
+  ::
+  [%websocket-response id=@ud websocket-event:eyre]
+  ::  $task
+  ::
+  ::  request to open websocket connection
+  :: 
+  [%websocket-connect app=term url=@t]
+  ::  receives websocket event from earth
+  ::
+  [%websocket-event id=@ud event=websocket-event:eyre]
+```
+- And a new type:
+```hoon
+  ::  +websocket-connection: websocket connection stored in iris state
+  ::
+  +$  websocket-connection
+    $:  app=term
+        =duct
+        id=@ud
+        url=@t
+        status=?(%pending %accepted)
+    ==
+```
+- %eyre will share the `$websocket-message` and `$websocket-event` types with %iris.
+- The only new `$task` that the app devs will utilize is the `%websocket-connect` from iris.
+- The existing `%cancel-request` `$task` from iris will be modified to also cancel websocket requests.
+- Server user flow: 
+  - The user exposes their app with the `%eyre`'s `%connect` `$task`.
+  - When a handshake comes from earth, `%eyre` subscribes to the app's `/websocket-server/[eyre-id]` path and sends a `%websocket-handshake` poke with `[eyre-id inbound-request]`. The `eyre-id` will be used to represent that particular connection.
+  - In response to `%websocket-handshake`, the user gives a fact with the `%accept` or `%reject` mark on `/websocket-server/[eyre-id]`.
+  - After `%accept`ed the app can give `%message`s facts on `/websocket-server/[eyre-id]` and receives messages that comes as `%websocket-server-message`s pokes, containing `[eyre-id websocket-message]`.
+  - If the subscription is kicked, then the connection is closed, or the user can give a fact with the `%disconnect` mark to close it.
+- Client user flow:
+   - The user sends a request to initiate the connection by passing the `%websocket-connect` `$task` to `%iris` with `[app=term url=@t]`.
+   - The user can cancel the request by using the `%cancel-request` `$task`.
+   - If the connection succeeds `%iris` will subscribe to `/websocket-client/id`, with `id` representing that particular connection.
+   - The app can give facts with the `%message` mark on `/websocket-client/id` and receives messages that comes as `%websocket-client-message`s pokes, containing `[id websocket-message]`.
+   - If the subscription is kicked, then the connection is closed, or the user can  give a fact with the `%disconnect` mark to close it.
+
+## Rationale
+
+The approach followed here is a way to add the intended feature while reutilizing some of the existing logic and without adding a new vane.
+
+## Backwards Compatibility
+
+Backwards compatibility is only affected if there are developers currently handling Websocket handshakes in the `%handle-http-request` poke.
+
+## Reference Implementation
+
+Incoming
+
+## Security Considerations
+
+Similar considerations as the currently HTTP implementation.
+
+## Copyright
+
+Copyright and related rights waived via [CC0](../LICENSE.md).