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#[macro_use]
extern crate log;
#[macro_use]
extern crate failure_derive;
extern crate chrono;
extern crate digest;
extern crate failure;
extern crate filetime;
extern crate futures;
extern crate hex_view;
extern crate reqwest;
extern crate tokio;
mod errors;
mod hashing;
mod states;
use chrono::{DateTime, Utc};
use digest::Digest;
pub use errors::*;
use futures::{future::ok as OkFuture, Future};
use hashing::*;
use reqwest::{
async::{Client, RequestBuilder, Response},
header::{IF_MODIFIED_SINCE, LAST_MODIFIED},
StatusCode,
};
pub use states::*;
use std::{
io,
path::{Path, PathBuf},
sync::Arc
};
pub struct AsyncFetcher<'a> {
client: &'a Client,
from_url: String,
progress: Option<Arc<dyn Fn(FetchEvent) + Send + Sync>>
}
impl<'a> AsyncFetcher<'a> {
pub fn new(client: &'a Client, from_url: String) -> Self {
Self { client, from_url, progress: None }
}
pub fn with_progress_callback<F: Fn(FetchEvent) + Send + Sync + 'static>(mut self, func: impl Into<Arc<F>>) -> Self {
self.progress = Some(func.into());
self
}
pub fn request_to_path(self, to_path: PathBuf) -> ResponseState<impl RequestFuture> {
let (req, current) = self.set_if_modified_since(&to_path, self.client.get(&self.from_url));
let cb = self.progress.clone();
ResponseState {
future: req
.send()
.and_then(|resp| resp.error_for_status())
.map(move |resp| check_response(resp, current, cb)),
path: to_path,
progress: self.progress,
}
}
pub fn request_to_path_with_checksum<D: Digest>(
self,
to_path: PathBuf,
checksum: &str,
) -> ResponseState<impl RequestFuture> {
let cb = self.progress.clone();
let future: Box<
dyn Future<Item = Option<(Response, Option<DateTime<Utc>>)>, Error = reqwest::Error>
+ Send,
> = if hash_from_path::<D>(&to_path, &checksum).is_ok() {
Box::new(OkFuture(None))
} else {
let req = self.client.get(&self.from_url);
let future = req
.send()
.and_then(|resp| resp.error_for_status())
.map(move |resp| check_response(resp, None, cb));
Box::new(future)
};
ResponseState {
future,
path: to_path,
progress: self.progress
}
}
fn set_if_modified_since(
&self,
to_path: &Path,
mut req: RequestBuilder,
) -> (RequestBuilder, Option<DateTime<Utc>>) {
let date = if to_path.exists() {
let when = self.date_time(&to_path).unwrap();
let rfc = when.to_rfc2822();
req = req.header(IF_MODIFIED_SINCE, rfc);
Some(when)
} else {
None
};
(req, date)
}
fn date_time(&self, to_path: &Path) -> io::Result<DateTime<Utc>> {
Ok(DateTime::from(to_path.metadata()?.modified()?))
}
}
fn check_response(
resp: Response,
current: Option<DateTime<Utc>>,
progress: Option<Arc<dyn Fn(FetchEvent) + Send + Sync>>
) -> Option<(Response, Option<DateTime<Utc>>)> {
if resp.status() == StatusCode::NOT_MODIFIED {
if let Some(cb) = progress {
cb(FetchEvent::AlreadyFetched)
}
None
} else {
let date = resp
.headers()
.get(LAST_MODIFIED)
.and_then(|h| h.to_str().ok())
.and_then(|header| DateTime::parse_from_rfc2822(header).ok())
.map(|tz| tz.with_timezone(&Utc));
let fetch = date
.as_ref()
.and_then(|server| current.map(|current| (server, current)))
.map_or(true, |(&server, current)| current < server);
if fetch {
if let Some(cb) = progress {
cb(FetchEvent::Get)
}
Some((resp, date))
} else {
if let Some(cb) = progress {
cb(FetchEvent::AlreadyFetched)
}
None
}
}
}
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub enum FetchEvent {
Get,
AlreadyFetched,
Processing,
Progress(u64),
Total(u64),
DownloadComplete,
Finished
}