refactor: implement safer get chunk data (#416)

Author: clostao

backend/src/useCases/objects/files.ts

@@ -143,7 +143,7 @@ const retrieveAndReassembleFile = async (
   if (metadata.totalChunks === 1) {
     const chunkData = await NodesUseCases.getChunkData(metadata.chunks[0].cid)
     if (!chunkData) {
-      throw new Error('Chunk not found')
+      throw new Error(`Chunk not found: cid=${metadata.chunks[0].cid}`)
     }
 
     return Readable.from(chunkData)
@@ -167,7 +167,7 @@ const retrieveAndReassembleFile = async (
         )
 
         if (chunkedData.some((e) => e === undefined)) {
-          this.destroy(new Error('Chunk not found'))
+          this.destroy(new Error(`Chunk not found: cid=${chunks[0].cid}`))
           return
         }
 

backend/src/useCases/objects/nodes.ts

@@ -69,7 +69,13 @@ const getChunkData = async (cid: string | CID): Promise<Buffer | undefined> => {
 
   let ipldNodeBytes: Buffer | undefined = await nodesRepository
     .getNode(cidString)
-    .then((e) => (e ? Buffer.from(e.encoded_node, 'base64') : undefined))
+    .then((e) => {
+      if (!e || !e.encoded_node) {
+        return undefined
+      }
+
+      return Buffer.from(e.encoded_node, 'base64')
+    })
 
   if (!ipldNodeBytes) {
     ipldNodeBytes = await BlockstoreUseCases.getNode(cidString)