feat: show score not in dataset error

src/mscz.ts

@@ -11,8 +11,13 @@ export const fetchMscz = async (scoreinfo: ScoreInfo, _fetch = fetch): Promise<A
     const url = scoreinfo.msczCidUrl
     msczBufferP = (async (): Promise<ArrayBuffer> => {
       const r0 = await _fetch(url)
-      assertRes(r0)
+      // ipfs-http-gateway specific error
+      // may read further error msg as json
+      if (r0.status !== 500) {
+        assertRes(r0)
+      }
       const cidRes = await r0.json()
+
       const r = await _fetch(scoreinfo.getMsczUrl(cidRes))
       assertRes(r)
       const data = await r.arrayBuffer()

src/scoreinfo.ts

@@ -24,9 +24,17 @@ export abstract class ScoreInfo {
     return `https://ipfs.infura.io:5001/api/v0/block/stat?arg=${this.msczIpfsRef}`
   }
 
-  getMsczUrl (cidRes: { Key: string }): string {
+  getMsczUrl (cidRes: { Key: string; Message: string }): string {
     const cid = cidRes.Key
-    if (!cid) throw new Error('score not in dataset')
+    if (!cid) {
+      // read further error msg
+      const err = cidRes.Message
+      if (err.includes('no link named')) { // file not found
+        throw new Error('score not in dataset')
+      } else {
+        throw new Error(err)
+      }
+    }
     return `https://ipfs.infura.io/ipfs/${cid}`
   }
 }