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use reqwest::Response;
use reqwest::header::LINK;
use hyperx::header::{Header, Link, RelationType};
use serde::Deserialize;
use url::Url;
use crate::entities::itemsiter::ItemsIter;
use super::{Mastodon, Result, deserialise};
pub struct Page<'a, T: for<'de> Deserialize<'de>> {
mastodon: &'a Mastodon,
next: Option<Url>,
prev: Option<Url>,
pub initial_items: Vec<T>,
}
macro_rules! pages {
($($direction:ident: $fun:ident),*) => {
$(
pub fn $fun(&mut self) -> Result<Option<Vec<T>>> {
let url = match self.$direction.take() {
Some(s) => s,
None => return Ok(None),
};
let response = self.mastodon.client.get(url)
.headers(self.mastodon.headers.clone())
.send()?;
let (prev, next) = get_links(&response)?;
self.next = next;
self.prev = prev;
deserialise(response)
}
)*
}
}
impl<'a, T: for<'de> Deserialize<'de>> Page<'a, T> {
pub fn new(mastodon: &'a Mastodon, response: Response) -> Result<Self> {
let (prev, next) = get_links(&response)?;
Ok(Page {
initial_items: deserialise(response)?,
next,
prev,
mastodon
})
}
pages! {
next: next_page,
prev: prev_page
}
}
impl<'a, T: Clone + for<'de> Deserialize<'de>> Page<'a, T> {
pub fn items_iter(self) -> impl Iterator<Item = T> + 'a
where T: 'a
{
ItemsIter::new(self)
}
}
fn get_links(response: &Response) -> Result<(Option<Url>, Option<Url>)> {
let mut prev = None;
let mut next = None;
let link_header = response.headers().get_all(LINK);
for value in &link_header {
let parsed: Link = Header::parse_header(&value)?;
for value in parsed.values() {
if let Some(relations) = value.rel() {
if relations.contains(&RelationType::Next) {
next = Some(Url::parse(value.link())?);
}
if relations.contains(&RelationType::Prev) {
prev = Some(Url::parse(value.link())?);
}
}
}
}
Ok((prev, next))
}