Silences warnings from mongodb client (#5025)

* Silences warnings from mongodb client

* Update count, delete and finds to recommended implementations

* With new parser, readPref will be null by default

* Update flaky specs wih async/await style

* Adds gridstore adapter spec

* Use GridFSBucketStorage adapter

src/Adapters/Files/FilesAdapter.js

@@ -9,7 +9,7 @@
 // * getFileData(filename)
 // * getFileLocation(config, filename)
 //
-// Default is GridStoreAdapter, which requires mongo
+// Default is GridFSBucketAdapter, which requires mongo
 // and for the API server to be using the DatabaseController with Mongo
 // database adapter.
 

src/Adapters/Files/GridFSBucketAdapter.js

@@ -0,0 +1,95 @@
+/**
+ GridFSBucketAdapter
+ Stores files in Mongo using GridStore
+ Requires the database adapter to be based on mongoclient
+
+ @flow weak
+ */
+
+// @flow-disable-next
+import { MongoClient, GridFSBucket, Db } from 'mongodb';
+import { FilesAdapter } from './FilesAdapter';
+import defaults from '../../defaults';
+
+export class GridFSBucketAdapter extends FilesAdapter {
+  _databaseURI: string;
+  _connectionPromise: Promise<Db>;
+
+  constructor(mongoDatabaseURI = defaults.DefaultMongoURI) {
+    super();
+    this._databaseURI = mongoDatabaseURI;
+  }
+
+  _connect() {
+    if (!this._connectionPromise) {
+      this._connectionPromise = MongoClient.connect(this._databaseURI).then(
+        client => client.db(client.s.options.dbName)
+      );
+    }
+    return this._connectionPromise;
+  }
+
+  _getBucket() {
+    return this._connect().then(database => new GridFSBucket(database));
+  }
+
+  // For a given config object, filename, and data, store a file
+  // Returns a promise
+  async createFile(filename: string, data) {
+    const bucket = await this._getBucket();
+    const stream = await bucket.openUploadStream(filename);
+    await stream.write(data);
+    stream.end();
+    return new Promise((resolve, reject) => {
+      stream.on('finish', resolve);
+      stream.on('error', reject);
+    });
+  }
+
+  async deleteFile(filename: string) {
+    const bucket = await this._getBucket();
+    const documents = await bucket.find({ filename: filename }).toArray();
+    if (documents.length === 0) {
+      throw new Error('FileNotFound');
+    }
+    return Promise.all(
+      documents.map(doc => {
+        return bucket.delete(doc._id);
+      })
+    );
+  }
+
+  async getFileData(filename: string) {
+    const stream = await this.getDownloadStream(filename);
+    stream.read();
+    return new Promise((resolve, reject) => {
+      const chunks = [];
+      stream.on('data', data => {
+        chunks.push(data);
+      });
+      stream.on('end', () => {
+        resolve(Buffer.concat(chunks));
+      });
+      stream.on('error', err => {
+        reject(err);
+      });
+    });
+  }
+
+  getFileLocation(config, filename) {
+    return (
+      config.mount +
+      '/files/' +
+      config.applicationId +
+      '/' +
+      encodeURIComponent(filename)
+    );
+  }
+
+  async getDownloadStream(filename: string) {
+    const bucket = await this._getBucket();
+    return bucket.openDownloadStreamByName(filename);
+  }
+}
+
+export default GridFSBucketAdapter;