Step 13.14: Create pictures store

api/server/collections/pictures.ts

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+import { MongoObservable } from 'meteor-rxjs';
+import { UploadFS } from 'meteor/jalik:ufs';
+import { Meteor } from 'meteor/meteor';
+import * as sharp from 'sharp';
+import { Picture, DEFAULT_PICTURE_URL } from '../models';
+
+export interface PicturesCollection<T> extends MongoObservable.Collection<T> {
+  getPictureUrl(selector?: Object | string, platform?: string): string;
+}
+
+export const Pictures =
+  new MongoObservable.Collection<Picture>('pictures') as PicturesCollection<Picture>;
+
+export const PicturesStore = new UploadFS.store.GridFS({
+  collection: Pictures.collection,
+  name: 'pictures',
+  filter: new UploadFS.Filter({
+    contentTypes: ['image/*']
+  }),
+  permissions: new UploadFS.StorePermissions({
+    insert: picturesPermissions,
+    update: picturesPermissions,
+    remove: picturesPermissions
+  }),
+  transformWrite(from, to) {
+    // Resize picture, then crop it to 1:1 aspect ratio, then compress it to 75% from its original quality
+    const transform = sharp().resize(800,800).min().crop().toFormat('jpeg', {quality: 75});
+    from.pipe(transform).pipe(to);
+  }
+});
+
+// Gets picture's url by a given selector
+Pictures.getPictureUrl = function (selector, platform = "") {
+  const prefix = platform === "android" ? "/android_asset/www" :
+    platform === "ios" ? "" : "";
+
+  const picture = this.findOne(selector) || {};
+  return picture.url || prefix + DEFAULT_PICTURE_URL;
+};
+
+function picturesPermissions(userId: string): boolean {
+  return Meteor.isServer || !!userId;
+}