matrix_sdk/widget/mod.rs
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// Copyright 2023 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//! Widget API implementation.
use std::{fmt, time::Duration};
use async_channel::{Receiver, Sender};
use ruma::api::client::delayed_events::DelayParameters;
use serde::de::{self, Deserialize, Deserializer, Visitor};
use tokio::sync::mpsc::{unbounded_channel, UnboundedSender};
use tokio_util::sync::{CancellationToken, DropGuard};
use self::{
machine::{
Action, IncomingMessage, MatrixDriverRequestData, MatrixDriverResponse, SendEventRequest,
WidgetMachine,
},
matrix::MatrixDriver,
};
use crate::{room::Room, Result};
mod capabilities;
mod filter;
mod machine;
mod matrix;
mod settings;
pub use self::{
capabilities::{Capabilities, CapabilitiesProvider},
filter::{EventFilter, MessageLikeEventFilter, StateEventFilter},
settings::{
ClientProperties, EncryptionSystem, VirtualElementCallWidgetOptions, WidgetSettings,
},
};
/// An object that handles all interactions of a widget living inside a webview
/// or iframe with the Matrix world.
#[derive(Debug)]
pub struct WidgetDriver {
settings: WidgetSettings,
/// Raw incoming messages from the widget (normally formatted as JSON).
///
/// These can be both requests and responses.
from_widget_rx: Receiver<String>,
/// Raw outgoing messages from the client (SDK) to the widget (normally
/// formatted as JSON).
///
/// These can be both requests and responses.
to_widget_tx: Sender<String>,
/// Drop guard for an event handler forwarding all events from the Matrix
/// room to the widget.
///
/// Only set if a subscription happened ([`Action::Subscribe`]).
event_forwarding_guard: Option<DropGuard>,
}
/// A handle that encapsulates the communication between a widget driver and the
/// corresponding widget (inside a webview or iframe).
#[derive(Clone, Debug)]
pub struct WidgetDriverHandle {
/// Raw incoming messages from the widget driver to the widget (normally
/// formatted as JSON).
///
/// These can be both requests and responses. Users of this API should not
/// care what's what though because they are only supposed to forward
/// messages between the webview / iframe, and the SDK's widget driver.
to_widget_rx: Receiver<String>,
/// Raw outgoing messages from the widget to the widget driver (normally
/// formatted as JSON).
///
/// These can be both requests and responses. Users of this API should not
/// care what's what though because they are only supposed to forward
/// messages between the webview / iframe, and the SDK's widget driver.
from_widget_tx: Sender<String>,
}
impl WidgetDriverHandle {
/// Receive a message from the widget driver.
///
/// The message must be passed on to the widget.
///
/// Returns `None` if the widget driver is no longer running.
pub async fn recv(&self) -> Option<String> {
self.to_widget_rx.recv().await.ok()
}
/// Send a message from the widget to the widget driver.
///
/// Returns `false` if the widget driver is no longer running.
pub async fn send(&self, message: String) -> bool {
self.from_widget_tx.send(message).await.is_ok()
}
}
impl WidgetDriver {
/// Creates a new `WidgetDriver` and a corresponding set of channels to let
/// the widget (inside a webview or iframe) communicate with it.
pub fn new(settings: WidgetSettings) -> (Self, WidgetDriverHandle) {
let (from_widget_tx, from_widget_rx) = async_channel::unbounded();
let (to_widget_tx, to_widget_rx) = async_channel::unbounded();
let driver = Self { settings, from_widget_rx, to_widget_tx, event_forwarding_guard: None };
let channels = WidgetDriverHandle { from_widget_tx, to_widget_rx };
(driver, channels)
}
/// Run client widget API state machine in a given joined `room` forever.
///
/// The function returns once the widget is disconnected or any terminal
/// error occurs.
pub async fn run(
mut self,
room: Room,
capabilities_provider: impl CapabilitiesProvider,
) -> Result<(), ()> {
// Create a channel so that we can conveniently send all messages to it.
//
// It will receive:
// - all incoming messages from the widget
// - all responses from the Matrix driver
// - all events from the Matrix driver, if subscribed
let (incoming_msg_tx, mut incoming_msg_rx) = unbounded_channel();
// Forward all of the incoming messages from the widget.
tokio::spawn({
let incoming_msg_tx = incoming_msg_tx.clone();
let from_widget_rx = self.from_widget_rx.clone();
async move {
while let Ok(msg) = from_widget_rx.recv().await {
let _ = incoming_msg_tx.send(IncomingMessage::WidgetMessage(msg));
}
}
});
// Create widget API machine.
let (mut widget_machine, initial_actions) = WidgetMachine::new(
self.settings.widget_id().to_owned(),
room.room_id().to_owned(),
self.settings.init_on_content_load(),
);
let matrix_driver = MatrixDriver::new(room.clone());
// Process initial actions that "initialise" the widget api machine.
for action in initial_actions {
self.process_action(&matrix_driver, &incoming_msg_tx, &capabilities_provider, action)
.await?;
}
// Process incoming messages as they're coming in.
while let Some(msg) = incoming_msg_rx.recv().await {
for action in widget_machine.process(msg) {
self.process_action(
&matrix_driver,
&incoming_msg_tx,
&capabilities_provider,
action,
)
.await?;
}
}
Ok(())
}
/// Process a single [`Action`].
async fn process_action(
&mut self,
matrix_driver: &MatrixDriver,
incoming_msg_tx: &UnboundedSender<IncomingMessage>,
capabilities_provider: &impl CapabilitiesProvider,
action: Action,
) -> Result<(), ()> {
match action {
Action::SendToWidget(msg) => {
self.to_widget_tx.send(msg).await.map_err(|_| ())?;
}
Action::MatrixDriverRequest { request_id, data } => {
let response = match data {
MatrixDriverRequestData::AcquireCapabilities(cmd) => {
let obtained = capabilities_provider
.acquire_capabilities(cmd.desired_capabilities)
.await;
Ok(MatrixDriverResponse::CapabilitiesAcquired(obtained))
}
MatrixDriverRequestData::GetOpenId => {
matrix_driver.get_open_id().await.map(MatrixDriverResponse::OpenIdReceived)
}
MatrixDriverRequestData::ReadMessageLikeEvent(cmd) => matrix_driver
.read_message_like_events(cmd.event_type.clone(), cmd.limit)
.await
.map(MatrixDriverResponse::MatrixEventRead),
MatrixDriverRequestData::ReadStateEvent(cmd) => matrix_driver
.read_state_events(cmd.event_type.clone(), &cmd.state_key)
.await
.map(MatrixDriverResponse::MatrixEventRead),
MatrixDriverRequestData::SendMatrixEvent(req) => {
let SendEventRequest { event_type, state_key, content, delay } = req;
// The widget api action does not use the unstable prefix:
// `org.matrix.msc4140.delay` so we
// cannot use the `DelayParameters` here and need to convert
// manually.
let delay_event_parameter = delay.map(|d| DelayParameters::Timeout {
timeout: Duration::from_millis(d),
});
matrix_driver
.send(event_type, state_key, content, delay_event_parameter)
.await
.map(MatrixDriverResponse::MatrixEventSent)
}
MatrixDriverRequestData::UpdateDelayedEvent(req) => matrix_driver
.update_delayed_event(req.delay_id, req.action)
.await
.map(MatrixDriverResponse::MatrixDelayedEventUpdate),
};
// Forward the matrix driver response to the incoming message stream.
incoming_msg_tx
.send(IncomingMessage::MatrixDriverResponse { request_id, response })
.map_err(|_| ())?;
}
Action::Subscribe => {
// Only subscribe if we are not already subscribed.
if self.event_forwarding_guard.is_some() {
return Ok(());
}
let (stop_forwarding, guard) = {
let token = CancellationToken::new();
(token.child_token(), token.drop_guard())
};
self.event_forwarding_guard = Some(guard);
let mut matrix = matrix_driver.events();
let incoming_msg_tx = incoming_msg_tx.clone();
tokio::spawn(async move {
loop {
tokio::select! {
_ = stop_forwarding.cancelled() => {
// Upon cancellation, stop this task.
return;
}
Some(event) = matrix.recv() => {
// Forward all events to the incoming messages stream.
let _ = incoming_msg_tx.send(IncomingMessage::MatrixEventReceived(event));
}
}
}
});
}
Action::Unsubscribe => {
self.event_forwarding_guard = None;
}
}
Ok(())
}
}
// TODO: Decide which module this type should live in
#[derive(Clone, Debug)]
pub(crate) enum StateKeySelector {
Key(String),
Any,
}
impl<'de> Deserialize<'de> for StateKeySelector {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: Deserializer<'de>,
{
struct StateKeySelectorVisitor;
impl Visitor<'_> for StateKeySelectorVisitor {
type Value = StateKeySelector;
fn expecting(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "a string or `true`")
}
fn visit_bool<E>(self, v: bool) -> Result<Self::Value, E>
where
E: de::Error,
{
if v {
Ok(StateKeySelector::Any)
} else {
Err(E::invalid_value(de::Unexpected::Bool(v), &self))
}
}
fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
where
E: de::Error,
{
self.visit_string(v.to_owned())
}
fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
where
E: de::Error,
{
Ok(StateKeySelector::Key(v))
}
}
deserializer.deserialize_any(StateKeySelectorVisitor)
}
}
#[cfg(test)]
mod tests {
use assert_matches::assert_matches;
use serde_json::json;
use super::StateKeySelector;
#[test]
fn state_key_selector_from_true() {
let state_key = serde_json::from_value(json!(true)).unwrap();
assert_matches!(state_key, StateKeySelector::Any);
}
#[test]
fn state_key_selector_from_string() {
let state_key = serde_json::from_value(json!("test")).unwrap();
assert_matches!(state_key, StateKeySelector::Key(k) if k == "test");
}
#[test]
fn state_key_selector_from_false() {
let result = serde_json::from_value::<StateKeySelector>(json!(false));
assert_matches!(result, Err(e) if e.is_data());
}
#[test]
fn state_key_selector_from_number() {
let result = serde_json::from_value::<StateKeySelector>(json!(5));
assert_matches!(result, Err(e) if e.is_data());
}
}