206 lines
5.7 KiB
Rust
206 lines
5.7 KiB
Rust
/*
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* meli - jmap module.
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*
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* Copyright 2019 Lukas Werling (lluchs)
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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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use std::fmt;
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use std::time::Duration;
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/// A single Server-Sent Event.
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#[derive(Debug)]
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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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/// Parse a single line of an event-stream.
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///
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/// The line may end with a newline.
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///
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/// You will have to call this function multiple times until it returns `ParseResult::Dispatch`.
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/// Make sure to clear the event struct for the next line, then.
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///
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/// To handle the `Last-Event-ID` header, check the `id` field for each finished event.
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///
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/// # Examples
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///
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/// ```
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/// # use eventsource::event::{Event, ParseResult, parse_event_line};
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/// let mut event = Event::new();
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/// assert_eq!(parse_event_line("id: 42", &mut event), ParseResult::Next);
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/// assert_eq!(parse_event_line("data: foobar", &mut event), ParseResult::Next);
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/// assert_eq!(parse_event_line("", &mut event), ParseResult::Dispatch);
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/// // The event is finished now.
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/// assert_eq!(event.id, Some("42".into()));
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/// assert_eq!(event.data, "foobar\n");
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/// // Now clear and continue.
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/// event.clear();
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/// // ...
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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 {
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id: None,
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event_type: None,
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data: "".to_string(),
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}
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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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impl fmt::Display for Event {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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if let Some(ref id) = self.id {
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write!(f, "id: {}\n", id)?;
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}
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if let Some(ref event_type) = self.event_type {
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write!(f, "event: {}\n", event_type)?;
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}
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for line in self.data.lines() {
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write!(f, "data: {}\n", line)?;
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}
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Ok(())
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn basic_event_display() {
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assert_eq!(
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"data: hello world\n",
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Event {
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id: None,
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event_type: None,
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data: "hello world".to_string()
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}
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.to_string()
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);
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assert_eq!(
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"id: foo\ndata: hello world\n",
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Event {
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id: Some("foo".to_string()),
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event_type: None,
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data: "hello world".to_string()
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}
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.to_string()
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);
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assert_eq!(
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"event: bar\ndata: hello world\n",
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Event {
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id: None,
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event_type: Some("bar".to_string()),
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data: "hello world".to_string()
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}
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.to_string()
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);
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}
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#[test]
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fn multiline_event_display() {
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assert_eq!(
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"data: hello\ndata: world\n",
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Event {
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id: None,
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event_type: None,
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data: "hello\nworld".to_string()
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}
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.to_string()
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);
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assert_eq!(
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"data: hello\ndata: \ndata: world\n",
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Event {
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id: None,
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event_type: None,
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data: "hello\n\nworld".to_string()
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}
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.to_string()
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);
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}
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}
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