From 785ec1ee07504e18acdd8ab4996342b6b9903af4 Mon Sep 17 00:00:00 2001
From: Joachim Van Herwegen <joachimvh@gmail.com>
Date: Thu, 3 Sep 2020 10:46:26 +0200
Subject: [PATCH] fix: Don't buffer data before sending response with
 InMemoryResourceStore

---
 src/storage/InMemoryResourceStore.ts            | 17 ++++++++++++-----
 test/unit/storage/InMemoryResourceStore.test.ts |  6 +++---
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/storage/InMemoryResourceStore.ts b/src/storage/InMemoryResourceStore.ts
index f2cfb8d28..46e7bb007 100644
--- a/src/storage/InMemoryResourceStore.ts
+++ b/src/storage/InMemoryResourceStore.ts
@@ -1,3 +1,4 @@
+import { PassThrough } from 'stream';
 import arrayifyStream from 'arrayify-stream';
 import streamifyArray from 'streamify-array';
 import { RuntimeConfig } from '../init/RuntimeConfig';
@@ -113,7 +114,7 @@ export class InMemoryResourceStore implements ResourceStore {
 
   /**
    * Checks if the relative path is in the store.
-   * @param identifier - Incoming identifier.
+   * @param path - Incoming identifier.
    *
    * @throws {@link NotFoundHttpError}
    * If the path is not in the store.
@@ -127,7 +128,7 @@ export class InMemoryResourceStore implements ResourceStore {
   /**
    * Copies the Representation by draining the original data stream and creating a new one.
    *
-   * @param data - Incoming Representation.
+   * @param source - Incoming Representation.
    */
   private async copyRepresentation(source: Representation): Promise<Representation> {
     const arr = await arrayifyStream(source.data);
@@ -147,13 +148,19 @@ export class InMemoryResourceStore implements ResourceStore {
    * @returns The resulting Representation.
    */
   private async generateRepresentation(path: string): Promise<Representation> {
+    // Note: when converting to a complete ResourceStore and using readable-stream
+    // object mode should be set correctly here (now fixed due to Node 10)
     const source = this.store[path];
-    const arr = await arrayifyStream(source.data);
-    source.data = streamifyArray([ ...arr ]);
+    const streamInternal = new PassThrough({ writableObjectMode: true, readableObjectMode: true });
+    const streamOutput = new PassThrough({ writableObjectMode: true, readableObjectMode: true });
+    source.data.pipe(streamInternal);
+    source.data.pipe(streamOutput);
+
+    source.data = streamInternal;
 
     return {
       binary: source.binary,
-      data: streamifyArray([ ...arr ]),
+      data: streamOutput,
       metadata: source.metadata,
     };
   }
diff --git a/test/unit/storage/InMemoryResourceStore.test.ts b/test/unit/storage/InMemoryResourceStore.test.ts
index 8e8d26e30..dd5b79044 100644
--- a/test/unit/storage/InMemoryResourceStore.test.ts
+++ b/test/unit/storage/InMemoryResourceStore.test.ts
@@ -1,11 +1,11 @@
 import { Readable } from 'stream';
-import arrayifyStream from 'arrayify-stream';
 import streamifyArray from 'streamify-array';
 import { RuntimeConfig } from '../../../src/init/RuntimeConfig';
 import { Representation } from '../../../src/ldp/representation/Representation';
 import { RepresentationMetadata } from '../../../src/ldp/representation/RepresentationMetadata';
 import { InMemoryResourceStore } from '../../../src/storage/InMemoryResourceStore';
 import { NotFoundHttpError } from '../../../src/util/errors/NotFoundHttpError';
+import { readableToString } from '../../../src/util/Util';
 
 const base = 'http://test.com/';
 
@@ -46,7 +46,7 @@ describe('A InMemoryResourceStore', (): void => {
       data: expect.any(Readable),
       metadata: representation.metadata,
     });
-    await expect(arrayifyStream(result.data)).resolves.toEqual([ dataString ]);
+    await expect(readableToString(result.data)).resolves.toEqual(dataString);
   });
 
   it('can add resources to previously added resources.', async(): Promise<void> => {
@@ -64,7 +64,7 @@ describe('A InMemoryResourceStore', (): void => {
       data: expect.any(Readable),
       metadata: representation.metadata,
     });
-    await expect(arrayifyStream(result.data)).resolves.toEqual([ dataString ]);
+    await expect(readableToString(result.data)).resolves.toEqual(dataString);
   });
 
   it('can delete data.', async(): Promise<void> => {