Creating a File Server using ASP.NET Core 2.1 Static Files Middleware

One of the coolest features of ASP.NET Core is the ability to serve static files on HTTP requests without any server-side processing. This means that you can leverage this technology to build your own file server to serve static files over the wire. I managed to code a quick solution over the weekend to be able to upload/download files to one of my servers easily with this technology.

It all started with this Tweet:

The issue here is that both of us spend loads of time taking pictures and videos of our daughter and end up sharing all this data via Whatsapp. By the end of the day we both have the same information but in different resolutions and qualities which makes our life quite difficult when trying to guess which picture has the highest quality for printing (we tend to print most of the pictures). So we needed something simpler and quicker where to store all this pictures and videos (keeping the highest possible quality) and that it would be easier for both of us to share.

.NET Core and Ngrok to the rescue. 

With Ngrok, I can easily expose one of my websites to the world via one of the ngrok tunnels. I do own a professional account with them and it really made my life much easier as I can expose whatever I need to the world without having to tinker with my router. This helps me to expose services from my Raspberry Pi's and from my Servers.

Using .NET Core Static files middleware, I was able to build a quick solution (accessible via any browser and mobile responsive) with just 300 lines of code.

The main features of the application are:

• Multiple file uploader (up to 300 Mb).
• Multiple file downloader.
• Daily browsable functionality (it allows you to navigate on each day to see the list of files uploaded).
• Thumbnail automatic generation using MagicScaler.
• Automatic movie conversion via CloudConvert (this allows me to share videos between mobile devices as iPhones generate .mov files which cannot be played on Android devices).
• Keep the existing quality of the file (full size). This means uploading huge files into the File server.
• Cookie authentication with Policies.

You can see the flow in the image below:

Sample code for the file uploader can be found below:

To list the files, I use the File provider in ASP.NET Core which uses the static file middleware to locate static files, in my case pictures and videos.


There are quite a lot of things to do to improve the application but now anyone who uses the application can easily upload/download pictures from one of my servers which is monitored and constantly backed up so no picture gets lost. Also segregating pictures by dates helps a lot to find the one you were looking for.

I'm really impressed with the latest release of .NET Core (note that this has been built with .NET Core 2.1 and there is already a 2.2 preview version available) as the request are really fast and you can't even notice any lag even browsing with your phone on 3G which gives a nice user experience.

This is how it looks when browsing from my phone:

Source code will be available soon on my Github page as I'm trying to figure out one of the issues with https redirection which still does not work correctly and without it, it doesn't make sense.

Jordi Corbilla