feat: use a second PassThrough if the hash will need to read the stre…

…am (#578)

* feat: use a second PassThrough if the hash will need to read the stream

* docs: update comment

src/Asset/Asset.router.ts

@@ -31,7 +31,7 @@ export class AssetRouter extends Router {
       withAssetPackAuthorization,
       asMiddleware(this.assetBelongsToPackMiddleware),
       getUploader({
-        getFileKey: async (file) => {
+        getFileStreamKey: async (file) => {
           const hash = await hashV1(file.stream)
           return new S3Content().getFileKey(hash)
         },

src/Item/Item.router.ts

@@ -141,7 +141,7 @@ export class ItemRouter extends Router {
       withItemExists,
       withItemAuthorization,
       getUploader({
-        getFileKey: async (file) => {
+        getFileStreamKey: async (file) => {
           const hash = await hashV1(file.stream)
           return new S3Content().getFileKey(hash)
         },

src/S3/types.ts

@@ -12,7 +12,8 @@ export type MulterFile = Express.Multer.File
 export type GetFileKey = (file: MulterFile, req: Request) => Promise<string>
 
 export type UploaderOptions = Partial<{
-  getFileKey: GetFileKey
   maxFileSize: number
   mimeTypes: string[]
+  getFileKey: GetFileKey
+  getFileStreamKey: GetFileKey
 }>

src/S3/uploads.ts

@@ -7,24 +7,44 @@ import { GetFileKey, UploaderOptions, MulterFile } from './types'
 
 export function getUploader({
   getFileKey,
+  getFileStreamKey,
   maxFileSize = MAX_FILE_SIZE,
   mimeTypes,
 }: UploaderOptions = {}) {
   let options: multer.Options = {
     limits: {
       fileSize: maxFileSize,
     },
-    storage: new Storage(getFileKey || defaultGetFileKey, mimeTypes),
+    storage: new Storage(
+      getFileKey || defaultGetFileKey,
+      getFileStreamKey,
+      mimeTypes
+    ),
   }
   return multer(options)
 }
 
 class Storage implements multer.StorageEngine {
   constructor(
     public getFileKey: GetFileKey,
+    public getFileStreamKey?: GetFileKey,
     public validMimeTypes?: string[]
   ) {}
 
+  getKey(file: MulterFile, req: Request) {
+    // If "getFileStreamKey" is defined, we need to create a new PassThrough stream since the function
+    // will need a stream to read from. If not, we assume the function won't use a stream to generate the key.
+    return this.getFileStreamKey
+      ? this.getFileStreamKey(
+          {
+            ...file,
+            stream: file.stream.pipe(new PassThrough()),
+          },
+          req
+        )
+      : this.getFileKey(file, req)
+  }
+
   async _handleFile(
     req: Request,
     file: MulterFile,
@@ -43,12 +63,12 @@ class Storage implements multer.StorageEngine {
 
     // The original stream comes from file.stream. The reading of the stream is kicked of when we pipe it into the first PassThrough
     // This allows for both operations, the upload and the file key generation to be done "simultaneously" without keeping the entire stream data in memory
-    const fileStream1 = new PassThrough()
+
+    const uploadStream = file.stream.pipe(new PassThrough())
 
     const [key] = await Promise.all([
-      this.getFileKey({ ...file, stream: fileStream1 }, req),
-      file.stream.pipe(fileStream1),
-      uploadFile(id, file.stream, ACL.publicRead),
+      this.getKey(file, req),
+      uploadFile(id, uploadStream, ACL.publicRead),
     ])
 
     // move file to key