egg_mode_extras/limits/
stream.rs

1use egg_mode::{
2    cursor::{Cursor, CursorIter},
3    error::{Error, Result},
4    tweet::{Timeline, Tweet},
5    Response,
6};
7use futures::{future::LocalBoxFuture, FutureExt, TryFutureExt};
8use serde::de::DeserializeOwned;
9
10pub(crate) type ResponseFuture<'a, T> = LocalBoxFuture<'a, Result<Response<T>>>;
11
12pub trait Pageable<'a> {
13    type Item: 'static;
14    type Page;
15
16    fn load(&mut self) -> ResponseFuture<'a, Self::Page>;
17    fn update(&mut self, response: &mut Response<Self::Page>) -> bool;
18    fn extract(page: Self::Page) -> Vec<Self::Item>;
19}
20
21impl<T: Cursor + DeserializeOwned + 'static> Pageable<'static> for CursorIter<T> {
22    type Item = T::Item;
23    type Page = T;
24
25    fn load(&mut self) -> ResponseFuture<'static, Self::Page> {
26        self.call().boxed_local()
27    }
28    fn update(&mut self, response: &mut Response<Self::Page>) -> bool {
29        self.previous_cursor = response.previous_cursor_id();
30        self.next_cursor = response.next_cursor_id();
31        self.next_cursor == 0
32    }
33    fn extract(page: Self::Page) -> Vec<Self::Item> {
34        page.into_inner()
35    }
36}
37
38pub struct TimelineScrollback {
39    timeline: Option<Timeline>,
40    is_started: bool,
41}
42
43impl TimelineScrollback {
44    pub fn new(timeline: Timeline) -> TimelineScrollback {
45        TimelineScrollback {
46            timeline: Some(timeline),
47            is_started: false,
48        }
49    }
50
51    fn lift_response(
52        pair: (Timeline, Response<Vec<Tweet>>),
53    ) -> Response<(Option<Timeline>, Vec<Tweet>)> {
54        let (timeline, response) = pair;
55        Response::map(response, |tweets| (Some(timeline), tweets))
56    }
57}
58
59impl Pageable<'static> for TimelineScrollback {
60    type Item = Tweet;
61    type Page = (Option<Timeline>, Vec<Tweet>);
62
63    fn load(&mut self) -> ResponseFuture<'static, Self::Page> {
64        if let Some(timeline) = self.timeline.take() {
65            if self.is_started {
66                timeline
67                    .older(None)
68                    .map_ok(TimelineScrollback::lift_response)
69                    .boxed_local()
70            } else {
71                self.is_started = true;
72                timeline
73                    .start()
74                    .map_ok(TimelineScrollback::lift_response)
75                    .boxed_local()
76            }
77        } else {
78            // This shouldn't happen.
79            futures::future::err(Error::InvalidResponse("Problem retrieving timeline", None))
80                .boxed_local()
81        }
82    }
83    fn update(&mut self, response: &mut Response<Self::Page>) -> bool {
84        self.timeline = response.response.0.take();
85        response.response.1.is_empty()
86    }
87    fn extract(page: Self::Page) -> Vec<Self::Item> {
88        page.1
89    }
90}
egg_mode_extras/limits/stream.rs

egg_mode_extras/limits/
stream.rs
