Create new librespot-core crate

core/src/apresolve.rs

@@ -0,0 +1,58 @@
+const AP_FALLBACK : &'static str = "ap.spotify.com:80";
+const APRESOLVE_ENDPOINT : &'static str = "http://apresolve.spotify.com/";
+
+use std::str::FromStr;
+use futures::{Future, Stream};
+use hyper::{self, Uri, Client};
+use serde_json;
+use tokio_core::reactor::Handle;
+
+error_chain! { }
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct APResolveData {
+    ap_list: Vec<String>
+}
+
+pub fn apresolve(handle: &Handle) -> Box<Future<Item=String, Error=Error>> {
+    let url = Uri::from_str(APRESOLVE_ENDPOINT).expect("invalid AP resolve URL");
+
+    let client = Client::new(handle);
+    let response = client.get(url);
+
+    let body = response.and_then(|response| {
+        response.body().fold(Vec::new(), |mut acc, chunk| {
+            acc.extend_from_slice(chunk.as_ref());
+            Ok::<_, hyper::Error>(acc)
+        })
+    });
+    let body = body.then(|result| result.chain_err(|| "HTTP error"));
+    let body = body.and_then(|body| {
+        String::from_utf8(body).chain_err(|| "invalid UTF8 in response")
+    });
+
+    let data = body.and_then(|body| {
+        serde_json::from_str::<APResolveData>(&body)
+            .chain_err(|| "invalid JSON")
+    });
+
+    let ap = data.and_then(|data| {
+        let ap = data.ap_list.first().ok_or("empty AP List")?;
+        Ok(ap.clone())
+    });
+
+    Box::new(ap)
+}
+
+pub fn apresolve_or_fallback<E>(handle: &Handle)
+    -> Box<Future<Item=String, Error=E>>
+    where E: 'static
+{
+    let ap = apresolve(handle).or_else(|e| {
+        warn!("Failed to resolve Access Point: {}", e.description());
+        warn!("Using fallback \"{}\"", AP_FALLBACK);
+        Ok(AP_FALLBACK.into())
+    });
+
+    Box::new(ap)
+}