mirror of https://git.meli.delivery/meli/meli
melib/jmap: add event source support WIP
Reading resources: RFC8620 - The JSON Meta Application Protocol (JMAP), 7.3. Event Source https://datatracker.ietf.org/doc/html/rfc8620#section-7.3 https://html.spec.whatwg.org/multipage/server-sent-events.html#server-sent-events Signed-off-by: Manos Pitsidianakis <manos@pitsidianak.is>jmap-eventsource
Manos Pitsidianakis
3 months ago
parent
e9dd6becc3
commit
d902097acd
@ -0,0 +1,290 @@
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//
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// meli
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//
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// Copyright 2021 Emmanouil Pitsidianakis <manos@pitsidianak.is>
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//
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// This file is part of meli.
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//
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// meli is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// meli is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with meli. If not, see <http://www.gnu.org/licenses/>.
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//
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// SPDX-License-Identifier: EUPL-1.2 OR GPL-3.0-or-later
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use futures::io::{AsyncReadExt, AsyncWriteExt};
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use isahc::{
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config::{Configurable, RedirectPolicy},
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AsyncReadResponseExt, HttpClient,
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};
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use std::sync::Arc;
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use std::time::{Duration, Instant};
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use crate::error::Result;
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use crate::jmap::{methods::RequestUrlTemplate, JmapConnection, JmapServerConf, Store};
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const DEFAULT_RETRY: u64 = 5000;
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/// A single Server-Sent Event.
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#[derive(Debug, Default)]
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pub struct Event {
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/// Corresponds to the `id` field.
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pub id: Option<String>,
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/// Corresponds to the `event` field.
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pub event_type: Option<String>,
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/// All `data` fields concatenated by newlines.
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pub data: String,
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}
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/// Possible results from parsing a single event-stream line.
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#[derive(Debug, PartialEq)]
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pub enum ParseResult {
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/// Line parsed successfully, but the event is not complete yet.
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Next,
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/// The event is complete now. Pass a new (empty) event for the next call.
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Dispatch,
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/// Set retry time.
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SetRetry(Duration),
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}
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pub fn parse_event_line(line: &str, event: &mut Event) -> ParseResult {
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let line = line.trim_end_matches(|c| c == '\r' || c == '\n');
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if line == "" {
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ParseResult::Dispatch
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} else {
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let (field, value) = if let Some(pos) = line.find(':') {
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let (f, v) = line.split_at(pos);
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// Strip : and an optional space.
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let v = &v[1..];
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let v = if v.starts_with(' ') { &v[1..] } else { v };
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(f, v)
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} else {
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(line, "")
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};
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match field {
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"event" => {
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event.event_type = Some(value.to_string());
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}
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"data" => {
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event.data.push_str(value);
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event.data.push('\n');
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}
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"id" => {
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event.id = Some(value.to_string());
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}
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"retry" => {
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if let Ok(retry) = value.parse::<u64>() {
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return ParseResult::SetRetry(Duration::from_millis(retry));
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}
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}
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_ => (), // ignored
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}
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ParseResult::Next
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}
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}
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impl Event {
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/// Creates an empty event.
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pub fn new() -> Event {
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Event::default()
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}
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/// Returns `true` if the event is empty.
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///
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/// An event is empty if it has no id or event type and its data field is empty.
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pub fn is_empty(&self) -> bool {
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self.id.is_none() && self.event_type.is_none() && self.data.is_empty()
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}
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/// Makes the event empty.
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pub fn clear(&mut self) {
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self.id = None;
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self.event_type = None;
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self.data.clear();
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}
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}
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/// A client for a Server-Sent Events endpoint.
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///
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/// Read events by iterating over the client.
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pub struct EventSourceConnection {
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pub client: Arc<HttpClient>,
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pub store: Arc<Store>,
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pub server_conf: JmapServerConf,
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response: Option<isahc::AsyncBody>,
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url: Arc<RequestUrlTemplate>,
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last_event_id: Option<String>,
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last_try: Option<Instant>,
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pub retry: Duration,
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}
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impl EventSourceConnection {
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pub async fn new(conn: &JmapConnection) -> Result<Self> {
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let url = {
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let g = conn.session_guard().await?;
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g.event_source_url.clone()
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};
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debug!("event_source {:?}", &url);
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Ok(Self {
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client: conn.client.clone(),
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server_conf: conn.server_conf.clone(),
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store: conn.store.clone(),
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response: None,
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url,
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last_event_id: None,
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last_try: None,
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retry: Duration::from_millis(DEFAULT_RETRY),
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})
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}
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pub async fn next_request(&mut self) -> Result<()> {
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use isahc::{http, http::request::Request, prelude::*};
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let mut request = Request::get(self.url.url.as_str())
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.timeout(std::time::Duration::from_secs(10))
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.header(http::header::ACCEPT, "text/event-stream")
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.ssl_options(if self.server_conf.danger_accept_invalid_certs {
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isahc::config::SslOption::DANGER_ACCEPT_INVALID_CERTS
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| isahc::config::SslOption::DANGER_ACCEPT_INVALID_HOSTS
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| isahc::config::SslOption::DANGER_ACCEPT_REVOKED_CERTS
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} else {
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isahc::config::SslOption::NONE
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})
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.redirect_policy(RedirectPolicy::Limit(10));
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request = if self.server_conf.use_token {
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request
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.authentication(isahc::auth::Authentication::none())
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.header(
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http::header::AUTHORIZATION,
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format!("Bearer {}", &self.server_conf.server_password),
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)
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} else {
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request
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.authentication(isahc::auth::Authentication::basic())
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.credentials(isahc::auth::Credentials::new(
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&self.server_conf.server_username,
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&self.server_conf.server_password,
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))
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};
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if let Some(ref id) = self.last_event_id {
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request = request.header("Last-Event-ID", id.as_str());
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}
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let request = request.body(()).map_err(|err| err.to_string())?;
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debug!(&request);
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let mut response = self.client.send_async(request).await?;
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debug!(&response);
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//debug_assert!(response.status().is_success());
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/*
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let mut headers = HeaderMap::with_capacity(2);
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headers.insert(ACCEPT, HeaderValue::from_str("text/event-stream").unwrap());
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if let Some(ref id) = self.last_event_id {
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headers.insert("Last-Event-ID", HeaderValue::from_str(id).unwrap());
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}
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let res = self.client.get(self.url.clone()).headers(headers).send()?;
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*/
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// Check status code and Content-Type.
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{
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let status = response.status();
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if !status.is_success() {
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let res_text = response.text().await?;
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return Err(debug!(format!("{} {}", status.as_str(), res_text)).into());
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}
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if let Some(content_type_hv) = response.headers().get(isahc::http::header::CONTENT_TYPE)
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{
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if content_type_hv.to_str().unwrap() != "text/event-stream" {
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log::error!("got content-type: {}", content_type_hv.to_str().unwrap());
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}
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/*
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let content_type = content_type_hv
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.to_str()
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.unwrap()
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.to_string()
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.parse::<mime::Mime>()
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.unwrap();
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// Compare type and subtype only, MIME parameters are ignored.
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if (content_type.type_(), content_type.subtype())
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!= (mime::TEXT, mime::EVENT_STREAM)
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{
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return Err(ErrorKind::InvalidContentType(content_type.clone()).into());
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}
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*/
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}
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}
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self.response = Some(response.into_body());
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Ok(())
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}
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pub async fn next_event(&mut self) -> Result<Event> {
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let mut line = Vec::new();
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'main_loop: loop {
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match self.response.as_mut() {
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None => {
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// wait for the next request.
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if let Some(last_try) = self.last_try {
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let elapsed = last_try.elapsed();
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if elapsed < self.retry {
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crate::utils::futures::sleep(self.retry - elapsed).await;
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}
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}
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// Set here in case the request fails.
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self.last_try = Some(Instant::now());
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self.next_request().await?;
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}
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Some(reader) => {
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let mut event = Event::new();
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loop {
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match reader.read(&mut line).await {
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Ok(0) => {
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// EOF or a stream error, retry after timeout
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self.last_try = Some(Instant::now());
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self.response = None;
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continue 'main_loop;
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}
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// Got new bytes from stream
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Ok(_n) => {
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log::trace!("read line {}", String::from_utf8_lossy(&line));
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if let Ok(s) = std::str::from_utf8(&line) {
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match parse_event_line(s, &mut event) {
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ParseResult::Next => {} // okay, just continue
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ParseResult::Dispatch => {
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if let Some(ref id) = event.id {
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self.last_event_id = Some(id.clone());
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}
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return Ok(event);
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}
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ParseResult::SetRetry(ref retry) => {
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self.retry = *retry;
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}
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}
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}
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line.clear();
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}
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Err(err) => {
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// EOF or a stream error, retry after timeout
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self.last_try = Some(Instant::now());
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self.response = None;
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debug!(&err);
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continue 'main_loop;
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}
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}
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}
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}
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}
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}
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}
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}
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