Resolve dealer and spclient access points (#795)

Cargo.toml

@@ -31,7 +31,6 @@ version = "0.2.0"
 [dependencies.librespot-core]
 path = "core"
 version = "0.2.0"
-features = ["apresolve"]
 
 [dependencies.librespot-metadata]
 path = "metadata"

core/Cargo.toml

@@ -23,8 +23,8 @@ futures-util = { version = "0.3", default-features = false, features = ["alloc",
 hmac = "0.11"
 httparse = "1.3"
 http = "0.2"
-hyper = { version = "0.14", optional = true, features = ["client", "tcp", "http1"] }
-hyper-proxy = { version = "0.9.1", optional = true, default-features = false }
+hyper = { version = "0.14", features = ["client", "tcp", "http1"] }
+hyper-proxy = { version = "0.9.1", default-features = false }
 log = "0.4"
 num-bigint = { version = "0.4", features = ["rand"] }
 num-integer = "0.1"
@@ -53,6 +53,3 @@ vergen = "3.0.4"
 [dev-dependencies]
 env_logger = "0.8"
 tokio = {version = "1.0", features = ["macros"] }
-
-[features]
-apresolve = ["hyper", "hyper-proxy"]

core/src/apresolve.rs

@@ -1,30 +1,67 @@
 use std::error::Error;
 
 use hyper::client::HttpConnector;
-use hyper::{Body, Client, Method, Request};
+use hyper::{Body, Client, Request};
 use hyper_proxy::{Intercept, Proxy, ProxyConnector};
 use serde::Deserialize;
 use url::Url;
 
-use super::ap_fallback;
+const APRESOLVE_ENDPOINT: &str =
+    "http://apresolve.spotify.com/?type=accesspoint&type=dealer&type=spclient";
 
-const APRESOLVE_ENDPOINT: &str = "http://apresolve.spotify.com:80";
+// These addresses probably do some geo-location based traffic management or at least DNS-based
+// load balancing. They are known to fail when the normal resolvers are up, so that's why they
+// should only be used as fallback.
+const AP_FALLBACK: &str = "ap.spotify.com";
+const DEALER_FALLBACK: &str = "dealer.spotify.com";
+const SPCLIENT_FALLBACK: &str = "spclient.wg.spotify.com";
 
-#[derive(Clone, Debug, Deserialize)]
+const FALLBACK_PORT: u16 = 443;
+
+pub type SocketAddress = (String, u16);
+
+#[derive(Clone, Debug, Default, Deserialize)]
 struct ApResolveData {
-    ap_list: Vec<String>,
+    accesspoint: Vec<String>,
+    dealer: Vec<String>,
+    spclient: Vec<String>,
 }
 
-async fn try_apresolve(
-    proxy: Option<&Url>,
-    ap_port: Option<u16>,
-) -> Result<(String, u16), Box<dyn Error>> {
-    let port = ap_port.unwrap_or(443);
+#[derive(Clone, Debug, Deserialize)]
+pub struct AccessPoints {
+    pub accesspoint: SocketAddress,
+    pub dealer: SocketAddress,
+    pub spclient: SocketAddress,
+}
 
-    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");
+fn select_ap(data: Vec<String>, fallback: &str, ap_port: Option<u16>) -> SocketAddress {
+    let port = ap_port.unwrap_or(FALLBACK_PORT);
+
+    let mut aps = data.into_iter().filter_map(|ap| {
+        let mut split = ap.rsplitn(2, ':');
+        let port = split
+            .next()
+            .expect("rsplitn should not return empty iterator");
+        let host = split.next()?.to_owned();
+        let port: u16 = port.parse().ok()?;
+        Some((host, port))
+    });
+
+    let ap = if ap_port.is_some() {
+        aps.find(|(_, p)| *p == port)
+    } else {
+        aps.next()
+    };
+
+    ap.unwrap_or_else(|| (String::from(fallback), port))
+}
+
+async fn try_apresolve(proxy: Option<&Url>) -> Result<ApResolveData, Box<dyn Error>> {
+    let req = Request::builder()
+        .method("GET")
+        .uri(APRESOLVE_ENDPOINT)
+        .body(Body::empty())
+        .unwrap();
 
     let response = if let Some(url) = proxy {
         // Panic safety: all URLs are valid URIs
@@ -43,51 +80,53 @@ async fn try_apresolve(
     let body = hyper::body::to_bytes(response.into_body()).await?;
     let data: ApResolveData = serde_json::from_slice(body.as_ref())?;
 
-    let mut aps = data.ap_list.into_iter().filter_map(|ap| {
-        let mut split = ap.rsplitn(2, ':');
-        let port = split
-            .next()
-            .expect("rsplitn should not return empty iterator");
-        let host = split.next()?.to_owned();
-        let port: u16 = port.parse().ok()?;
-        Some((host, port))
-    });
-    let ap = if ap_port.is_some() || proxy.is_some() {
-        aps.find(|(_, p)| *p == port)
-    } else {
-        aps.next()
-    }
-    .ok_or("no valid AP in list")?;
-
-    Ok(ap)
+    Ok(data)
 }
 
-pub async fn apresolve(proxy: Option<&Url>, ap_port: Option<u16>) -> (String, u16) {
-    try_apresolve(proxy, ap_port).await.unwrap_or_else(|e| {
-        warn!("Failed to resolve Access Point: {}, using fallback.", e);
-        ap_fallback()
-    })
+pub async fn apresolve(proxy: Option<&Url>, ap_port: Option<u16>) -> AccessPoints {
+    let data = try_apresolve(proxy).await.unwrap_or_else(|e| {
+        warn!("Failed to resolve access points: {}, using fallbacks.", e);
+        ApResolveData::default()
+    });
+
+    let accesspoint = select_ap(data.accesspoint, AP_FALLBACK, ap_port);
+    let dealer = select_ap(data.dealer, DEALER_FALLBACK, ap_port);
+    let spclient = select_ap(data.spclient, SPCLIENT_FALLBACK, ap_port);
+
+    AccessPoints {
+        accesspoint,
+        dealer,
+        spclient,
+    }
 }
 
 #[cfg(test)]
 mod test {
     use std::net::ToSocketAddrs;
 
-    use super::try_apresolve;
+    use super::apresolve;
 
     #[tokio::test]
     async fn test_apresolve() {
-        let ap = try_apresolve(None, None).await.unwrap();
+        let aps = apresolve(None, None).await;
 
         // Assert that the result contains a valid host and port
-        ap.to_socket_addrs().unwrap().next().unwrap();
+        aps.accesspoint.to_socket_addrs().unwrap().next().unwrap();
+        aps.dealer.to_socket_addrs().unwrap().next().unwrap();
+        aps.spclient.to_socket_addrs().unwrap().next().unwrap();
     }
 
     #[tokio::test]
     async fn test_apresolve_port_443() {
-        let ap = try_apresolve(None, Some(443)).await.unwrap();
+        let aps = apresolve(None, Some(443)).await;
 
-        let port = ap.to_socket_addrs().unwrap().next().unwrap().port();
+        let port = aps
+            .accesspoint
+            .to_socket_addrs()
+            .unwrap()
+            .next()
+            .unwrap()
+            .port();
         assert_eq!(port, 443);
     }
 }

core/src/lib.rs

@@ -8,6 +8,7 @@ use librespot_protocol as protocol;
 #[macro_use]
 mod component;
 
+mod apresolve;
 pub mod audio_key;
 pub mod authentication;
 pub mod cache;
@@ -27,17 +28,3 @@ pub mod spotify_id;
 #[doc(hidden)]
 pub mod util;
 pub mod version;
-
-fn ap_fallback() -> (String, u16) {
-    (String::from("ap.spotify.com"), 443)
-}
-
-#[cfg(feature = "apresolve")]
-mod apresolve;
-
-#[cfg(not(feature = "apresolve"))]
-mod apresolve {
-    pub async fn apresolve(_: Option<&url::Url>, _: Option<u16>) -> (String, u16) {
-        super::ap_fallback()
-    }
-}

core/src/session.rs

@@ -67,7 +67,9 @@ impl Session {
         credentials: Credentials,
         cache: Option<Cache>,
     ) -> Result<Session, SessionError> {
-        let ap = apresolve(config.proxy.as_ref(), config.ap_port).await;
+        let ap = apresolve(config.proxy.as_ref(), config.ap_port)
+            .await
+            .accesspoint;
 
         info!("Connecting to AP \"{}:{}\"", ap.0, ap.1);
         let mut conn = connection::connect(&ap.0, ap.1, config.proxy.as_ref()).await?;