Building up a little db of "similar artists"

src/lastfm.rs

@@ -1,12 +1,9 @@
-use std::collections::HashMap;
-
 use serde::Deserialize;
 
 const BASE_URL: &str = "https://ws.audioscrobbler.com/2.0/";
 
 pub struct LastfmClient {
     api_key: String,
-    artist_cache: HashMap<String, Vec<SimilarArtist>>,
 }
 
 pub struct SimilarArtist {
@@ -18,6 +15,7 @@ pub struct SimilarArtist {
 // Last.fm returns {"error": N, "message": "..."} on failure
 #[derive(Deserialize)]
 struct ApiError {
+    #[allow(dead_code)]
     error: u32,
     message: String,
 }
@@ -44,46 +42,37 @@ struct ArtistEntry {
 
 impl LastfmClient {
     pub fn new(api_key: String) -> Self {
-        Self {
-            api_key,
-            artist_cache: HashMap::new(),
-        }
+        Self { api_key }
     }
 
     pub fn get_similar_artists(
-        &mut self,
+        &self,
         artist_mbid: &str,
-    ) -> Result<&[SimilarArtist], Box<dyn std::error::Error>> {
-        if !self.artist_cache.contains_key(artist_mbid) {
-            let url = format!(
-                "{}?method=artist.getSimilar&mbid={}&api_key={}&format=json",
-                BASE_URL, artist_mbid, self.api_key
-            );
-            let body: String = ureq::get(&url).call()?.body_mut().read_to_string()?;
+    ) -> Result<Vec<SimilarArtist>, Box<dyn std::error::Error>> {
+        let url = format!(
+            "{}?method=artist.getSimilar&mbid={}&api_key={}&format=json",
+            BASE_URL, artist_mbid, self.api_key
+        );
+        let body: String = ureq::get(&url).call()?.body_mut().read_to_string()?;
 
-            let artists = if let Ok(err) = serde_json::from_str::<ApiError>(&body) {
-                eprintln!("  Last.fm: {}", err.message);
-                Vec::new()
-            } else {
-                let resp: SimilarArtistsResponse = serde_json::from_str(&body)?;
-                resp.similarartists
-                    .artist
-                    .into_iter()
-                    .map(|a| {
-                        let mbid = a.mbid.filter(|s| !s.is_empty());
-                        SimilarArtist {
-                            name: a.name,
-                            mbid,
-                            match_score: a.match_score.parse().unwrap_or(0.0),
-                        }
-                    })
-                    .collect()
-            };
-
-            self.artist_cache.insert(artist_mbid.to_string(), artists);
+        if let Ok(err) = serde_json::from_str::<ApiError>(&body) {
+            eprintln!("  Last.fm: {}", err.message);
+            return Ok(Vec::new());
         }
 
-        Ok(self.artist_cache.get(artist_mbid).unwrap())
+        let resp: SimilarArtistsResponse = serde_json::from_str(&body)?;
+        Ok(resp
+            .similarartists
+            .artist
+            .into_iter()
+            .map(|a| {
+                let mbid = a.mbid.filter(|s| !s.is_empty());
+                SimilarArtist {
+                    name: a.name,
+                    mbid,
+                    match_score: a.match_score.parse().unwrap_or(0.0),
+                }
+            })
+            .collect())
     }
-
 }