chore: adding mocked S3 bucket for local filestore

.gitignore

@@ -2,4 +2,7 @@
 node_modules
 
 # Output files
-dist
+dist
+
+# local filestore
+localFileStore

fileStore.ts

@@ -0,0 +1,47 @@
+
+import EventEmitter from 'node:events';
+import * as fs from 'node:fs';
+
+export default (() => {
+    const base = './localFileStore/'
+    const metaPath = `${base}_meta.json`
+    if (fs.existsSync(base) === false) {
+        fs.mkdirSync(base)
+    }
+    if (fs.existsSync(metaPath) === false) {
+        fs.writeFileSync(metaPath, JSON.stringify({}))
+    }
+    return {
+        file: (filePath: string) => {
+            const fullPath = `${base}${filePath}`
+            return {
+                exists: () => {
+                    return [fs.existsSync(fullPath)]
+                },
+                download: async () => {
+                    return [new Uint8Array(fs.readFileSync(fullPath))]
+                },
+                createWriteStream: () => {
+                    return fs.createWriteStream(fullPath)
+                },
+                createReadStream: () => {
+                    return fs.createReadStream(fullPath)
+                },
+                save: (fileContent: string, meta?: undefined | any) => {
+                    if (typeof meta === 'object') {
+                        const rawMeta = fs.readFileSync(metaPath);
+                        const _meta = JSON.parse(rawMeta.toString())
+                        _meta[fullPath] = meta.metadata
+                        fs.writeFileSync(metaPath, JSON.stringify(_meta))
+                    }
+                    fs.writeFileSync(fullPath, fileContent)
+                },
+                getMetadata: () => {
+                    const rawMeta = fs.readFileSync(metaPath);
+                    const _meta = JSON.parse(rawMeta.toString())
+                    return [_meta[fullPath]]
+                }
+            }
+        }
+    }
+})();

index.ts

@@ -1,18 +1,24 @@
 import { Database } from '@hocuspocus/extension-database';
 import { Logger } from '@hocuspocus/extension-logger';
 import { Server } from '@hocuspocus/server';
-import { Storage } from '@google-cloud/storage';
+import { Bucket, Storage } from '@google-cloud/storage';
 import { utils } from './stream-helper'
 import cors from 'cors';
 import express from 'express';
 import expressWebsockets from 'express-ws';
 import ShortUniqueId from 'short-unique-id';
+import fileStore from './fileStore';
 
 const uid = new ShortUniqueId({ length: 20 });
 
 const serverPort = parseInt(process.env.SERVER_PORT || '8080');
-const storageClient = new Storage();
-const storageBucket = storageClient.bucket(process.env.BUCKET_NAME || 'athene-diagram-files');
+let storageBucket: Bucket | typeof fileStore;
+if (process.env.BUCKET_NAME) {
+    const storageClient = new Storage();
+    storageBucket = storageClient.bucket(process.env.BUCKET_NAME);
+} else {
+    storageBucket = fileStore
+}
 
 const server = Server.configure({
     extensions: [