Add audio preview, image and head file support

core/src/session.rs

@@ -373,6 +373,16 @@ impl Session {
         self.0.data.write().user_data.attributes.extend(attributes)
     }
 
+    pub fn get_user_attribute(&self, key: &str) -> Option<String> {
+        self.0
+            .data
+            .read()
+            .user_data
+            .attributes
+            .get(key)
+            .map(Clone::clone)
+    }
+
     fn weak(&self) -> SessionWeak {
         SessionWeak(Arc::downgrade(&self.0))
     }

core/src/spclient.rs

@@ -10,6 +10,7 @@ use hyper::{
 };
 use protobuf::Message;
 use rand::Rng;
+use thiserror::Error;
 
 use crate::{
     apresolve::SocketAddress,
@@ -31,6 +32,18 @@ component! {
 
 pub type SpClientResult = Result<Bytes, Error>;
 
+#[derive(Debug, Error)]
+pub enum SpClientError {
+    #[error("missing attribute {0}")]
+    Attribute(String),
+}
+
+impl From<SpClientError> for Error {
+    fn from(err: SpClientError) -> Self {
+        Self::failed_precondition(err)
+    }
+}
+
 #[derive(Copy, Clone, Debug)]
 pub enum RequestStrategy {
     TryTimes(usize),
@@ -290,4 +303,50 @@ impl SpClient {
 
         Ok(stream)
     }
+
+    pub async fn request_url(&self, url: String) -> SpClientResult {
+        let request = Request::builder()
+            .method(&Method::GET)
+            .uri(url)
+            .body(Body::empty())?;
+
+        self.session().http_client().request_body(request).await
+    }
+
+    // Audio preview in 96 kbps MP3, unencrypted
+    pub async fn get_audio_preview(&self, preview_id: &FileId) -> SpClientResult {
+        let attribute = "audio-preview-url-template";
+        let template = self
+            .session()
+            .get_user_attribute(attribute)
+            .ok_or_else(|| SpClientError::Attribute(attribute.to_string()))?;
+
+        let url = template.replace("{id}", &preview_id.to_base16());
+
+        self.request_url(url).await
+    }
+
+    // The first 128 kB of a track, unencrypted
+    pub async fn get_head_file(&self, file_id: FileId) -> SpClientResult {
+        let attribute = "head-files-url";
+        let template = self
+            .session()
+            .get_user_attribute(attribute)
+            .ok_or_else(|| SpClientError::Attribute(attribute.to_string()))?;
+
+        let url = template.replace("{file_id}", &file_id.to_base16());
+
+        self.request_url(url).await
+    }
+
+    pub async fn get_image(&self, image_id: FileId) -> SpClientResult {
+        let attribute = "image-url";
+        let template = self
+            .session()
+            .get_user_attribute(attribute)
+            .ok_or_else(|| SpClientError::Attribute(attribute.to_string()))?;
+        let url = template.replace("{file_id}", &image_id.to_base16());
+
+        self.request_url(url).await
+    }
 }