librespot/core/src/apresolve.rs

use std::error::Error;

use hyper::client::HttpConnector;
use hyper::{Body, Client, Method, Request, Uri};
use hyper_proxy::{Intercept, Proxy, ProxyConnector};
use serde::Deserialize;
use url::Url;

use super::AP_FALLBACK;

const APRESOLVE_ENDPOINT: &str = "http://apresolve.spotify.com:80";

#[derive(Clone, Debug, Deserialize)]
struct ApResolveData {
    ap_list: Vec<String>,
}

async fn try_apresolve(
    proxy: Option<&Url>,
    ap_port: Option<u16>,
) -> Result<String, Box<dyn Error>> {
    let port = ap_port.unwrap_or(443);

    let mut req = Request::new(Body::empty());
    *req.method_mut() = Method::GET;
    // panic safety: APRESOLVE_ENDPOINT above is valid url.
    *req.uri_mut() = APRESOLVE_ENDPOINT.parse().expect("invalid AP resolve URL");

    let response = if let Some(url) = proxy {
        // Panic safety: all URLs are valid URIs
        let uri = url.to_string().parse().unwrap();
        let proxy = Proxy::new(Intercept::All, uri);
        let connector = HttpConnector::new();
        let proxy_connector = ProxyConnector::from_proxy_unsecured(connector, proxy);
        Client::builder()
            .build(proxy_connector)
            .request(req)
            .await?
    } else {
        Client::new().request(req).await?
    };

    let body = hyper::body::to_bytes(response.into_body()).await?;
    let data: ApResolveData = serde_json::from_slice(body.as_ref())?;

    let ap = if ap_port.is_some() || proxy.is_some() {
        data.ap_list.into_iter().find_map(|ap| {
            if ap.parse::<Uri>().ok()?.port()? == port {
                Some(ap)
            } else {
                None
            }
        })
    } else {
        data.ap_list.into_iter().next()
    }
    .ok_or("empty AP List")?;

    Ok(ap)
}

pub async fn apresolve(proxy: Option<&Url>, ap_port: Option<u16>) -> String {
    try_apresolve(proxy, ap_port).await.unwrap_or_else(|e| {
        warn!("Failed to resolve Access Point: {}", e);
        warn!("Using fallback \"{}\"", AP_FALLBACK);
        AP_FALLBACK.into()
    })
}