Cache album art (#495)

psst-gui/src/webapi/cache.rs

@@ -1,9 +1,12 @@
 use std::{
+    collections::hash_map::DefaultHasher,
     fs::{self, File},
+    hash::{Hash, Hasher},
     path::PathBuf,
     sync::Arc,
 };
 
+use druid::image;
 use druid::ImageBuf;
 use lru_cache::LruCache;
 use parking_lot::Mutex;
@@ -31,6 +34,30 @@ impl WebApiCache {
         self.images.lock().insert(uri, image);
     }
 
+    pub fn get_image_from_disk(&self, uri: &Arc<str>) -> Option<ImageBuf> {
+        let hash = Self::hash_uri(uri);
+        self.key("images", &format!("{:016x}", hash))
+            .and_then(|path| std::fs::read(path).ok())
+            .and_then(|bytes| image::load_from_memory(&bytes).ok())
+            .map(ImageBuf::from_dynamic_image)
+    }
+
+    pub fn save_image_to_disk(&self, uri: &Arc<str>, data: &[u8]) {
+        let hash = Self::hash_uri(uri);
+        if let Some(path) = self.key("images", &format!("{:016x}", hash)) {
+            if let Some(parent) = path.parent() {
+                let _ = std::fs::create_dir_all(parent);
+            }
+            let _ = std::fs::write(path, data);
+        }
+    }
+
+    fn hash_uri(uri: &str) -> u64 {
+        let mut hasher = DefaultHasher::new();
+        uri.hash(&mut hasher);
+        hasher.finish()
+    }
+
     pub fn get(&self, bucket: &str, key: &str) -> Option<File> {
         self.key(bucket, key).and_then(|path| File::open(path).ok())
     }

psst-gui/src/webapi/client.rs

@@ -726,6 +726,15 @@ impl WebApi {
     }
 
     pub fn get_image(&self, uri: Arc<str>) -> Result<ImageBuf, Error> {
+        if let Some(cached_image) = self.cache.get_image(&uri) {
+            return Ok(cached_image);
+        }
+
+        if let Some(disk_cached_image) = self.cache.get_image_from_disk(&uri) {
+            self.cache.set_image(uri.clone(), disk_cached_image.clone());
+            return Ok(disk_cached_image);
+        }
+
         let response = self.agent.get(&uri).call()?;
         let format = match response.content_type() {
             "image/jpeg" => Some(ImageFormat::Jpeg),
@@ -734,6 +743,10 @@ impl WebApi {
         };
         let mut body = Vec::new();
         response.into_reader().read_to_end(&mut body)?;
+
+        // Save raw image data to disk cache
+        self.cache.save_image_to_disk(&uri, &body);
+
         let image = if let Some(format) = format {
             image::load_from_memory_with_format(&body, format)?
         } else {