How to transfer files wirelessly to any device in a local network

Recently, I was presented with an interesting challenge: I wanted to transfer files wirelessly in my local network to any device, meaning that any platform should support it. Basically, I wanted to transfer files between my computer and any device with WLAN and a web browser. So I began searching for a solution, which I will write about in this blog post.

So basically, my solution should take care of a few things:

really easy to use in order to deploy quickly
no proprietary software (I don't want to depend on anything)
I want to understand how it works (=open source)
it should work without an internet connection (only local wifi network)
it should work on any device with WLAN and a very basic browser

For example I would like to be able to share files between my computer and old WebOS, Windows Phone, Blackberry and Symbian phones (of course iOS and Android as well) . Those phones have very outdated browsers, so my solution should take that into account and not be too fancy. Hence, the solution will be inherently insecure, as those old mobile operating systems don't have the latest certificates and stuff, so please keep that in mind!

Running a local server with upload capability

The most logical solution is to use some kind of local server, which should be really easy to start. There are many solutions, such as php -S, but since I am not that familiar with PHP I will use Python. We would just need to run the server on 0.0.0.0 to make it accessible from any device in the local network (as opposed to 127.0.0.1).

Python server

Since Python has already a fantastic simple server, which can be invoked with python -m http.server, if you have Python 3 (if you have Python 2 you can use python -m SimpleHTTPServer). We would just need to add an upload capability to it.

Python comes preinstalled on most operating systems

The advantage of Python is that it comes preinstalled on most UNIX systems, like Linux, OSX or MacOS (and can be installed really easily on Windows). Also, it is just very pleasant to work with as it is very easy to understand.

Python http.server with upload

With Python comes also the http.server (or SimpleHTTPServer respectively) bit preinstalled. However, by default it cannot parse POST request. And that we really need to do.

There are a lot of discussions about this topic, for example on Stack overflow. Long story short, I have found finished code as a gist on github (you can find it here). This code I have forked into a program called ftransfer. You can find it and the source code here.

Using ftransfer for easy file transfer in the local network

There are detailed instructions in the README.md in my repository about the installation.

It is really as easy as it gets!