fast_down/http/
prefetch.rs

1use crate::{
2    UrlInfo,
3    http::{GetResponse, HttpClient, HttpError, HttpHeaders, HttpRequestBuilder, HttpResponse},
4    url_info::FileId,
5};
6use content_disposition;
7use std::{borrow::Borrow, future::Future};
8use url::Url;
9
10pub trait Prefetch<Client: HttpClient> {
11    type Error;
12    fn prefetch(
13        &self,
14        url: Url,
15    ) -> impl Future<Output = Result<(UrlInfo, GetResponse<Client>), Self::Error>> + Send;
16}
17
18impl<Client: HttpClient, BorrowClient: Borrow<Client> + Sync> Prefetch<Client> for BorrowClient {
19    type Error = HttpError<Client>;
20    async fn prefetch(&self, url: Url) -> Result<(UrlInfo, GetResponse<Client>), Self::Error> {
21        prefetch(self.borrow(), url).await
22    }
23}
24
25fn get_filename(headers: &impl HttpHeaders, url: &Url) -> String {
26    headers
27        .get("content-disposition")
28        .ok()
29        .and_then(|s| content_disposition::parse_content_disposition(s).filename_full())
30        .map(|s| urlencoding::decode(&s).map(String::from).unwrap_or(s))
31        .filter(|s| !s.trim().is_empty())
32        .or_else(|| {
33            url.path_segments()
34                .and_then(|mut segments| segments.next_back())
35                .map(|s| urlencoding::decode(s).unwrap_or(s.into()))
36                .filter(|s| !s.trim().is_empty())
37                .map(|s| s.to_string())
38        })
39        .unwrap_or_else(|| url.to_string())
40}
41
42async fn prefetch<Client: HttpClient>(
43    client: &Client,
44    url: Url,
45) -> Result<(UrlInfo, GetResponse<Client>), HttpError<Client>> {
46    let resp = client
47        .get(url, None)
48        .send()
49        .await
50        .map_err(HttpError::Request)?;
51    let headers = resp.headers();
52    let supports_range = headers
53        .get("accept-ranges")
54        .map(|v| v == "bytes")
55        .unwrap_or(false);
56    let size = headers
57        .get("content-length")
58        .ok()
59        .and_then(|v| v.parse().ok())
60        .unwrap_or(0);
61    let final_url = resp.url();
62    Ok((
63        UrlInfo {
64            final_url: final_url.clone(),
65            name: get_filename(headers, final_url),
66            size,
67            supports_range,
68            fast_download: size > 0 && supports_range,
69            file_id: FileId::new(headers.get("etag").ok(), headers.get("last-modified").ok()),
70        },
71        resp,
72    ))
73}
fast_down/http/prefetch.rs

fast_down/http/
prefetch.rs
