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use rustc_serialize::json::Json;
use std::thread;
use std::io::Read;
use std::time::Duration;
use std::str::FromStr;
use std::sync::mpsc;
use hyper::client::{Handler, Request, Response, Client};
use hyper::{Url, Next, Encoder, Decoder};
use hyper::net::HttpStream;
#[derive(Debug)]
pub struct PriceInfo {
pub ethusd: f32,
}
pub struct SetPriceHandler<F> {
set_price: F,
channel: mpsc::Sender<()>,
}
impl<F> Drop for SetPriceHandler<F> {
fn drop(&mut self) {
let _ = self.channel.send(());
}
}
impl<F: Fn(PriceInfo) + Sync + Send + 'static> Handler<HttpStream> for SetPriceHandler<F> {
fn on_request(&mut self, _: &mut Request) -> Next { Next::read().timeout(Duration::from_secs(3)) }
fn on_request_writable(&mut self, _: &mut Encoder<HttpStream>) -> Next { Next::read().timeout(Duration::from_secs(3)) }
fn on_response(&mut self, _: Response) -> Next { Next::read().timeout(Duration::from_secs(3)) }
fn on_response_readable(&mut self, r: &mut Decoder<HttpStream>) -> Next {
let mut body = String::new();
let info = r.read_to_string(&mut body)
.map_err(|e| format!("Unable to read response: {:?}", e))
.and_then(|_| self.process_response(&body));
if let Err(e) = info {
warn!("Failed to auto-update latest ETH price: {:?}", e);
}
Next::end()
}
}
impl<F: Fn(PriceInfo) + Sync + Send + 'static> SetPriceHandler<F> {
fn process_response(&self, body: &str) -> Result<(), String> {
let json = Json::from_str(body).map_err(|e| format!("Invalid JSON returned: {:?}", e))?;
let obj = json.find_path(&["result", "ethusd"]).ok_or("USD price not found".to_owned())?;
let ethusd = match *obj {
Json::String(ref s) => FromStr::from_str(s).ok(),
_ => None,
}.ok_or("Unexpected price format.".to_owned())?;
(self.set_price)(PriceInfo {
ethusd: ethusd,
});
Ok(())
}
}
impl PriceInfo {
pub fn get<F: Fn(PriceInfo) + Sync + Send + 'static>(set_price: F) {
thread::spawn(move || {
let url = FromStr::from_str("http://api.etherscan.io/api?module=stats&action=ethprice")
.expect("string known to be a valid URL; qed");
if let Err(e) = Self::request(url, set_price) {
warn!("Failed to auto-update latest ETH price: {:?}", e);
}
});
}
fn request<F: Fn(PriceInfo) + Send + Sync + 'static>(url: Url, set_price: F) -> Result<(), String> {
let (tx, rx) = mpsc::channel();
let client = Client::new().map_err(|e| format!("Unable to start client: {:?}", e))?;
client.request(
url,
SetPriceHandler {
set_price: set_price,
channel: tx,
},
).map_err(|_| "Request failed.".to_owned())?;
let _ = rx.recv().map_err(|e| format!("Request interrupted: {:?}", e))?;
client.close();
Ok(())
}
}
#[test] #[ignore]
fn should_get_price_info() {
use std::sync::Arc;
use std::time::Duration;
use util::log::init_log;
use util::{Condvar, Mutex};
init_log();
let done = Arc::new((Mutex::new(PriceInfo { ethusd: 0f32 }), Condvar::new()));
let rdone = done.clone();
PriceInfo::get(move |price| { let mut p = rdone.0.lock(); *p = price; rdone.1.notify_one(); });
let mut p = done.0.lock();
let t = done.1.wait_for(&mut p, Duration::from_millis(10000));
assert!(!t.timed_out());
assert!(p.ethusd != 0f32);
}