This is a simple file sharing system. You can upload files and retreive a code. Then, anyone can use the code to download them again.

• open a terminal and cd into the project directory
• run npm install to install all the required dependencies.
• run npm run dev to start the server in development mode

• open a terminal and cd into the project directory
• run npm install --prefix client to install dependencies.
• run npm start --prefix client

You can build the production ready JS bundle using npm run heroku-postbuild

The Backend is a Node.js Express REST API. The application's entry point is src/app.ts. It is connecting to a remote MongoDB cloud instance to store user credentials and the filenames of their uploads.

In config.ts, I load different environment variables and export them, so they can be easily referenced in the code.

upload.ts is the route where files can get uploaded (using express-fileupload plugin). A zip file is created using the adm-zip package and a unique ID is assigned to it. Then, it is stored in the server's uploads folder.

download.ts is a route where a user can specify the id of a file they want to download and the corresponding file gets sent to them.

The users route contains multiple "subroutes":

The createUser endpoint retreives new user credentials. It encrypts the password and generates a JWT token from the data using generateToken.ts. Then, the user data is stored on the MongoDB database.

In the login endpoint, the user can send their username and password. I am using the bcrypt library to hash the password and check if it matches the hash stored in the db. Then, I generate a JWT that the user can use for authentication and send it back.

The authenticateToken function is a middleware that checks if the token in the Authorization header is valid. If not, it sends a 403 (Forbidden) HTTP response code.

This functionality is used in myUploads.ts. There are two endpoints. If you send a GET request, you get a list of the filenames of all your uploads from the database.

If you send a DELETE request containing a filename, it will look in the DB if the file is uploaded by the user and delete it from the server if true.

We are using the mongoose model in User.ts to query the database. It provides a good developer experience because it is designed in an object-oriented way.