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|
use axum::{
extract::State,
http::StatusCode,
response::{
sse::{self, Sse},
IntoResponse, Response,
},
routing::get,
Router,
};
use axum_extra::extract::Query;
use chrono::{self, format::SecondsFormat};
use futures::stream::{self, Stream, StreamExt as _, TryStreamExt as _};
use super::repo::broadcast;
use crate::{
app::App,
channel::app::EventsError,
clock::RequestedAt,
error::InternalError,
header::LastEventId,
repo::{channel, login::Login},
};
pub fn router() -> Router<App> {
Router::new().route("/api/events", get(events))
}
#[derive(serde::Deserialize)]
struct EventsQuery {
#[serde(default, rename = "channel")]
channels: Vec<channel::Id>,
}
async fn events(
State(app): State<App>,
RequestedAt(now): RequestedAt,
_: Login, // requires auth, but doesn't actually care who you are
last_event_id: Option<LastEventId>,
Query(query): Query<EventsQuery>,
) -> Result<Events<impl Stream<Item = ChannelEvent>>, ErrorResponse> {
let resume_at = last_event_id.as_deref();
let streams = stream::iter(query.channels)
.then(|channel| {
let app = app.clone();
async move {
let events = app
.channels()
.events(&channel, &now, resume_at)
.await?
.map(ChannelEvent::wrap(channel));
Ok::<_, EventsError>(events)
}
})
.try_collect::<Vec<_>>()
.await
// impl From would take more code; this is used once.
.map_err(ErrorResponse)?;
let stream = stream::select_all(streams);
Ok(Events(stream))
}
struct Events<S>(S);
impl<S> IntoResponse for Events<S>
where
S: Stream<Item = ChannelEvent> + Send + 'static,
{
fn into_response(self) -> Response {
let Self(stream) = self;
let stream = stream.map(sse::Event::try_from);
Sse::new(stream)
.keep_alive(sse::KeepAlive::default())
.into_response()
}
}
struct ErrorResponse(EventsError);
impl IntoResponse for ErrorResponse {
fn into_response(self) -> Response {
let Self(error) = self;
match error {
not_found @ EventsError::ChannelNotFound(_) => {
(StatusCode::NOT_FOUND, not_found.to_string()).into_response()
}
resume_at @ EventsError::ResumeAtError(_) => {
(StatusCode::BAD_REQUEST, resume_at.to_string()).into_response()
}
other => InternalError::from(other).into_response(),
}
}
}
#[derive(serde::Serialize)]
struct ChannelEvent {
channel: channel::Id,
#[serde(flatten)]
message: broadcast::Message,
}
impl ChannelEvent {
fn wrap(channel: channel::Id) -> impl Fn(broadcast::Message) -> Self {
move |message| Self {
channel: channel.clone(),
message,
}
}
fn event_id(&self) -> String {
self.message
.sent_at
.to_rfc3339_opts(SecondsFormat::AutoSi, /* use_z */ true)
}
}
impl TryFrom<ChannelEvent> for sse::Event {
type Error = serde_json::Error;
fn try_from(value: ChannelEvent) -> Result<Self, Self::Error> {
let data = serde_json::to_string_pretty(&value)?;
let event = Self::default().id(value.event_id()).data(&data);
Ok(event)
}
}
|
