removed createInterceptDownload file and use existing code for http download

models/lib/fileStoreStrategy.js

@@ -1,6 +1,6 @@
 import fs from 'fs';
 import { createObjectId } from './grid/createObjectId';
-import { createInterceptDownload } from './fsHooks/createInterceptDownload';
+import { httpStreamOutput } from './httpStream.js'
 
 export const STORAGE_NAME_FILESYSTEM = "fs";
 export const STORAGE_NAME_GRIDFS     = "gridfs";
@@ -125,7 +125,15 @@ export class FileStoreStrategyGridFs extends FileStoreStrategy {
    * @param http the current http request
    */
   interceptDownload(http) {
-    const ret = createInterceptDownload(this.filesCollection, this.gridFsBucket, this.fileObj, http, this.versionName);
+    const readStream = this.getReadStream();
+    const downloadFlag = http?.params?.query?.download;
+
+    let ret = false;
+    if (readStream) {
+      ret = true;
+      httpStreamOutput(readStream, this.fileObj.name, http, downloadFlag, this.filesCollection.cacheControl);
+    }
+
     return ret;
   }
 
@@ -195,15 +203,23 @@ export class FileStoreStrategyGridFs extends FileStoreStrategy {
    * @return the GridFS Object-Id
    */
   getGridFsObjectId() {
-    const gridFsFileId = (this.fileObj.versions[this.versionName].meta || {})
-      .gridFsFileId;
     let ret;
+    const gridFsFileId = this.getGridFsFileId();
     if (gridFsFileId) {
       ret = createObjectId({ gridFsFileId });
     }
     return ret;
   }
 
+  /** returns the GridFS Object-Id
+   * @return the GridFS Object-Id
+   */
+  getGridFsFileId() {
+    const ret = (this.fileObj.versions[this.versionName].meta || {})
+      .gridFsFileId;
+    return ret;
+  }
+
   /** returns the property name of gridFsFileId
    * @return the property name of gridFsFileId
    */

models/lib/fsHooks/createInterceptDownload.js

@@ -1,47 +0,0 @@
-import { createObjectId } from '../grid/createObjectId';
-
-export const createInterceptDownload =
-  function interceptDownload(filesCollection, bucket, file, http, versionName) {
-    const { gridFsFileId } = file.versions[versionName].meta || {};
-    if (gridFsFileId) {
-      // opens the download stream using a given gfs id
-      // see: http://mongodb.github.io/node-mongodb-native/3.2/api/GridFSBucket.html#openDownloadStream
-      const gfsId = createObjectId({ gridFsFileId });
-      const readStream = bucket.openDownloadStream(gfsId);
-
-      readStream.on('data', data => {
-        http.response.write(data);
-      });
-
-      readStream.on('end', () => {
-        http.response.end(); // don't pass parameters to end() or it will be attached to the file's binary stream
-      });
-
-      readStream.on('error', () => {
-        // not found probably
-        // eslint-disable-next-line no-param-reassign
-        http.response.statusCode = 404;
-        http.response.end('not found');
-      });
-
-      http.response.setHeader('Cache-Control', filesCollection.cacheControl);
-      http.response.setHeader(
-        'Content-Disposition',
-        getContentDisposition(file.name, http?.params?.query?.download),
-      );
-    }
-    return Boolean(gridFsFileId); // Serve file from either GridFS or FS if it wasn't uploaded yet
-  };
-
-/**
- * Will initiate download, if links are called with ?download="true" queryparam.
- **/
-const getContentDisposition = (name, downloadFlag) => {
-  const dispositionType = downloadFlag === 'true' ? 'attachment;' : 'inline;';
-
-  const encodedName = encodeURIComponent(name);
-  const dispositionName = `filename="${encodedName}"; filename=*UTF-8"${encodedName}";`;
-  const dispositionEncoding = 'charset=utf-8';
-
-  return `${dispositionType} ${dispositionName} ${dispositionEncoding}`;
-};

models/lib/httpStream.js

@@ -0,0 +1,29 @@
+export const httpStreamOutput = function(readStream, name, http, downloadFlag, cacheControl) {
+    readStream.on('data', data => {
+      http.response.write(data);
+    });
+
+    readStream.on('end', () => {
+      // don't pass parameters to end() or it will be attached to the file's binary stream
+      http.response.end();
+    });
+
+    readStream.on('error', () => {
+      http.response.statusCode = 404;
+      http.response.end('not found');
+    });
+
+    http.response.setHeader('Cache-Control', cacheControl);
+    http.response.setHeader('Content-Disposition', getContentDisposition(name, http?.params?.query?.download));
+  };
+
+/** will initiate download, if links are called with ?download="true" queryparam */
+const getContentDisposition = (name, downloadFlag) => {
+  const dispositionType = downloadFlag === 'true' ? 'attachment;' : 'inline;';
+
+  const encodedName = encodeURIComponent(name);
+  const dispositionName = `filename="${encodedName}"; filename=*UTF-8"${encodedName}";`;
+  const dispositionEncoding = 'charset=utf-8';
+
+  return `${dispositionType} ${dispositionName} ${dispositionEncoding}`;
+};