diff --git a/examples/express.ts b/examples/express.ts
index baa56a5c..fb881848 100644
--- a/examples/express.ts
+++ b/examples/express.ts
@@ -1,57 +1,25 @@
 import * as express from 'express';
-import { DiskFile, DiskStorage, OnComplete, uploadx, UploadxResponse } from 'node-uploadx';
+import { DiskFile, DiskStorage, uploadx } from 'node-uploadx';
+import { join } from 'path';
 
 const app = express();
 
-const auth: express.Handler = (req, res, next) => {
-  // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
-  (req as any)['user'] = { id: '92be348f-172d-5f69-840d-100f79e4d1ef' };
-  next();
-};
-
-app.use(auth);
-
-type OnCompleteBody = {
-  message: string;
-  id: string;
-};
-
-const onComplete: OnComplete<DiskFile, UploadxResponse<OnCompleteBody>> = file => {
-  const message = `File upload is finished, path: ${file.name}`;
-  console.log(message);
-  return {
-    statusCode: 200,
-    message,
-    id: file.id,
-    headers: { ETag: file.id }
-  };
+const onComplete: express.RequestHandler = async (req, res, next) => {
+  const file = req.body as DiskFile;
+  await file.lock(() => res.status(423).json({ message: 'processing' }));
+  const sha1 = await file.hash();
+  await file.move(join('upload', file.originalName));
+  await file.delete();
+  await file.lock(() => res.json({ ...file, sha1 }));
+  return res.json({ ...file, sha1 });
 };
 
 const storage = new DiskStorage({
   directory: 'upload',
-  maxMetadataSize: '1mb',
-  onComplete,
-  expiration: { maxAge: '1h', purgeInterval: '10min' },
-  validation: {
-    mime: { value: ['video/*'], response: [415, { message: 'video only' }] },
-    size: {
-      value: 500_000_000,
-      isValid(file) {
-        this.response = [
-          412,
-          { message: `The file size(${file.size}) is larger than ${this.value as number} bytes` }
-        ];
-        return file.size <= this.value;
-      }
-    },
-    mtime: {
-      isValid: file => !!file.metadata.lastModified,
-      response: [403, { message: 'Missing `lastModified` property' }]
-    }
-  }
+  expiration: { maxAge: '12h', purgeInterval: '1h' }
 });
 
-app.use('/files', uploadx({ storage }));
+app.use('/files', uploadx.upload({ storage }), onComplete);
 
 app.listen(3002, () => {
   console.log('listening on port:', 3002);
diff --git a/packages/core/src/handlers/base-handler.ts b/packages/core/src/handlers/base-handler.ts
index 6d3c0716..b8aa0f7e 100644
--- a/packages/core/src/handlers/base-handler.ts
+++ b/packages/core/src/handlers/base-handler.ts
@@ -3,6 +3,7 @@ import * as http from 'http';
 import * as url from 'url';
 import {
   BaseStorage,
+  Completed,
   DiskStorage,
   DiskStorageOptions,
   File,
@@ -129,14 +130,16 @@ export abstract class BaseHandler<TFile extends Readonly<File>>
 
     handler
       .call(this, req, res)
-      .then(async (file: TFile | UploadList): Promise<void> => {
+      .then(async (file: TFile | UploadList | Completed<TFile>): Promise<void> => {
         if ('status' in file && file.status) {
           this.log('[%s]: %s', file.status, file.name);
           this.listenerCount(file.status) && this.emit(file.status, file);
           if (file.status === 'completed') {
             req['_body'] = true;
             req['body'] = file;
-            const completed = (await this.storage.onComplete(file)) as UploadxResponse;
+            const completed = (await this.storage.onComplete(
+              file as Completed<TFile>
+            )) as UploadxResponse;
             next ? next() : this.finish(req as any, res, completed || file);
           }
           return;
diff --git a/packages/core/src/storages/disk-storage.ts b/packages/core/src/storages/disk-storage.ts
index c6a5d58f..f6671d8c 100644
--- a/packages/core/src/storages/disk-storage.ts
+++ b/packages/core/src/storages/disk-storage.ts
@@ -1,6 +1,15 @@
 import * as http from 'http';
 import { resolve as pathResolve } from 'path';
-import { ensureFile, ERRORS, fail, fsp, getWriteStream, HttpError } from '../utils';
+import {
+  ensureFile,
+  ERRORS,
+  fail,
+  fileChecksum,
+  fsp,
+  getWriteStream,
+  HttpError,
+  move
+} from '../utils';
 import { File, FileInit, FilePart, hasContent, isCompleted, isValidPart } from './file';
 import { BaseStorage, BaseStorageOptions } from './storage';
 import { METAFILE_EXTNAME, MetaStorage } from './meta-storage';
@@ -8,7 +17,13 @@ import { LocalMetaStorage, LocalMetaStorageOptions } from './local-meta-storage'
 
 const INVALID_OFFSET = -1;
 
-export class DiskFile extends File {}
+export interface DiskFile extends File {
+  lock: (lockFn: () => any) => Promise<any>;
+  move: (dest: string) => Promise<any>;
+  copy: (dest: string) => Promise<any>;
+  delete: () => Promise<any>;
+  hash: (algorithm?: 'sha1' | 'md5', encoding?: 'hex' | 'base64') => Promise<string>;
+}
 
 export type DiskStorageOptions = BaseStorageOptions<DiskFile> & {
   /**
@@ -51,8 +66,20 @@ export class DiskStorage extends BaseStorage<DiskFile> {
     return super.normalizeError(error);
   }
 
+  buildCompletedFile(file: DiskFile): DiskFile {
+    const completed = { ...file };
+    completed.lock = async lockFn => Promise.resolve('TODO:');
+    completed.delete = () => this.delete(file.name);
+    completed.hash = (algorithm?: 'sha1' | 'md5', encoding?: 'hex' | 'base64') =>
+      fileChecksum(this.getFilePath(file.name), algorithm, encoding);
+    completed.copy = async (dest: string) => fsp.copyFile(this.getFilePath(file.name), dest);
+    completed.move = async (dest: string) => move(this.getFilePath(file.name), dest);
+
+    return completed;
+  }
+
   async create(req: http.IncomingMessage, fileInit: FileInit): Promise<DiskFile> {
-    const file = new DiskFile(fileInit);
+    const file = new File(fileInit) as DiskFile;
     file.name = this.namingFunction(file);
     await this.validate(file);
     const path = this.getFilePath(file.name);
@@ -72,6 +99,7 @@ export class DiskStorage extends BaseStorage<DiskFile> {
       if (file.bytesWritten === INVALID_OFFSET) return fail(ERRORS.FILE_CONFLICT);
       if (isCompleted(file)) {
         await this.saveMeta(file);
+        return this.buildCompletedFile(file);
       }
       return file;
     } catch (err) {
diff --git a/packages/core/src/utils/fs.ts b/packages/core/src/utils/fs.ts
index 1d97a1e0..0755f5a9 100644
--- a/packages/core/src/utils/fs.ts
+++ b/packages/core/src/utils/fs.ts
@@ -1,12 +1,44 @@
-import { createWriteStream, promises as fsp, WriteStream } from 'fs';
+import { createHash, HexBase64Latin1Encoding } from 'crypto';
+import { createReadStream, createWriteStream, promises as fsp, WriteStream } from 'fs';
 import { dirname, posix } from 'path';
 
+function isError(error: unknown): error is NodeJS.ErrnoException {
+  return error instanceof Error;
+}
+
+export function fileChecksum(
+  filePath: string,
+  algorithm: 'sha1' | 'md5' = 'md5',
+  encoding: HexBase64Latin1Encoding = 'hex'
+): Promise<string> {
+  return new Promise(resolve => {
+    const hash = createHash(algorithm);
+    createReadStream(filePath)
+      .on('data', data => hash.update(data))
+      .on('end', () => resolve(hash.digest(encoding)));
+  });
+}
+
+export async function copy(src: string, dest: string): Promise<void> {
+  return fsp.copyFile(src, dest);
+}
+
+export async function move(src: string, dest: string): Promise<void> {
+  try {
+    await fsp.rename(src, dest);
+  } catch (e) {
+    if (isError(e) && e.code === 'EXDEV') {
+      await copy(src, dest);
+      await fsp.unlink(src);
+    }
+  }
+}
 /**
  * Ensures that the directory exists
  * @param dir
  */
-export async function ensureDir(dir: string): Promise<void> {
-  await fsp.mkdir(dir, { recursive: true });
+export function ensureDir(dir: string): Promise<void> {
+  return fsp.mkdir(dir, { recursive: true });
 }
 
 /**
diff --git a/packages/s3/src/s3-storage.ts b/packages/s3/src/s3-storage.ts
index 89f19938..86dfb5e4 100644
--- a/packages/s3/src/s3-storage.ts
+++ b/packages/s3/src/s3-storage.ts
@@ -37,10 +37,14 @@ import { S3MetaStorage, S3MetaStorageOptions } from './s3-meta-storage';
 
 const BUCKET_NAME = 'node-uploadx';
 
-export class S3File extends File {
+export interface S3File extends File {
   Parts?: Part[];
-  UploadId = '';
+  UploadId?: string;
   uri?: string;
+  lock: (lockFn: () => any) => Promise<any>;
+  move: (dest: any) => Promise<any>;
+  copy: (dest: any) => Promise<any>;
+  delete: () => Promise<any>;
 }
 
 export type S3StorageOptions = BaseStorageOptions<S3File> &
@@ -121,7 +125,7 @@ export class S3Storage extends BaseStorage<S3File> {
   }
 
   async create(req: http.IncomingMessage, config: FileInit): Promise<S3File> {
-    const file = new S3File(config);
+    const file = new File(config) as S3File;
     file.name = this.namingFunction(file);
     await this.validate(file);
     try {
@@ -226,7 +230,7 @@ export class S3Storage extends BaseStorage<S3File> {
   }
 
   private _checkBucket(): void {
-    this.client.send(new HeadBucketCommand({ Bucket: this.bucket }), (err: AWSError, data) => {
+    this.client.send(new HeadBucketCommand({ Bucket: this.bucket }), (err: AWSError) => {
       if (err) {
         throw err;
       }