ptth/crates/ptth_multi_call_server/src/download.rs

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use std::{
ffi::OsString,
io::{
self,
Write,
},
time::Duration,
};
use anyhow::{
anyhow,
bail,
};
use futures_util::StreamExt;
use reqwest::{
StatusCode,
};
use sha2::{
Digest,
Sha512,
};
use tokio::{
sync::mpsc,
task::{
spawn,
spawn_blocking,
},
};
pub async fn main (args: &[OsString]) -> anyhow::Result <()> {
let mut url = None;
let mut expected_sha512 = None;
let mut args = args [1..].into_iter ();
loop {
let arg = match args.next () {
None => break,
Some (x) => x,
};
match arg.to_str ().ok_or_else (|| anyhow! ("All arguments must be valid UTF-8"))?
{
"--help" => println! ("For now, just look at the source code"),
"--expect-sha512" => {
let expected = args.next ().ok_or_else (|| anyhow! ("--expect-sha512 needs an argument"))?;
expected_sha512 = Some (expected.to_str ().ok_or_else (|| anyhow! ("--expect-sha512's argument must be valid Unicode"))?);
}
arg => {
url = Some (arg);
break;
},
}
}
let url = match url {
None => bail! ("URL argument is required"),
Some (x) => x,
};
// Cookie 01FYZ3W64SM6KYNP48J6EWSCEF
// Try to keep the Clients similar here
let client = reqwest::Client::builder ()
.connect_timeout (Duration::from_secs (30))
.build ()?;
let resp = client.get (url)
.send ().await?;
if resp.status () != StatusCode::OK {
bail! ("Expected 200 OK, got {}", resp.status ());
}
let mut resp_stream = resp.bytes_stream ();
// The hasher is owned by a task because it makes ownership simpler
let (mut hash_tx, mut hash_rx) = mpsc::channel (1);
let hasher_task = spawn_blocking (move || {
let mut hasher = Sha512::new ();
while let Some (chunk) = tokio::runtime::Handle::current ().block_on (hash_rx.recv ()) {
hasher.update (&chunk);
}
anyhow::Result::<_>::Ok (hasher.finalize ())
});
while let Some (chunk) = resp_stream.next ().await {
let chunk = chunk?;
hash_tx.send (chunk.clone ()).await?;
{
let chunk = chunk.clone ();
spawn_blocking (move || {
io::stdout ().write_all (&chunk)?;
anyhow::Result::<_>::Ok (())
}).await??;
}
}
drop (hash_tx);
let hash = hasher_task.await??;
let actual_sha512 = hex::encode (&hash);
match expected_sha512 {
None => eprintln! ("Actual SHA512 = {}", actual_sha512),
Some (expected) => if ! actual_sha512.starts_with (&expected) {
bail! ("Expected SHA512 prefix {}, actual SHA512 {}", expected, actual_sha512);
},
}
Ok (())
}