semaphores

src/subsonic.rs

@@ -6,6 +6,8 @@ pub use album_list::AlbumListType;
 use adw::glib;
 use bytes::Bytes;
 use rand::Rng;
+use std::sync::Arc;
+use tokio::sync::Semaphore;
 use tracing::{event, Level};
 
 fn runtime() -> &'static tokio::runtime::Runtime {
@@ -56,6 +58,7 @@ impl From<reqwest::Error> for Error {
 pub struct Client {
     client: reqwest::Client,
     base_url: reqwest::Url,
+    sem: Arc<Semaphore>,
 }
 
 fn random_salt(length: usize) -> String {
@@ -106,6 +109,7 @@ impl Client {
                 .user_agent(crate::USER_AGENT)
                 .build()?,
             base_url,
+            sem: Arc::new(Semaphore::new(20)), // 20 requests at one time
         })
     }
 
@@ -121,7 +125,10 @@ impl Client {
         // note that this is why those silly bounds on T are needed, because we're
         // sending back the result of the query from another thread
         let future = request.send();
+        let sem = Arc::clone(&self.sem);
         runtime().spawn(async move {
+            let _permit = sem.acquire().await.unwrap();
+
             // wrap this logic in a fn so we can use ?
             async fn perform<T: serde::de::DeserializeOwned + Send + 'static>(
                 response: Result<reqwest::Response, reqwest::Error>,
@@ -195,7 +202,10 @@ impl Client {
         let (sender, receiver) = async_channel::bounded(1);
 
         let future = self.client.get(self.cover_art_url(id, size)).send();
+        let sem = Arc::clone(&self.sem);
         runtime().spawn(async move {
+            let _permit = sem.acquire().await.unwrap();
+
             async fn perform(
                 response: Result<reqwest::Response, reqwest::Error>,
             ) -> Result<Bytes, Error> {