One of the requirements for following the tutorial is that the user have access to an HTTP server, and furthermore, one that supports the PUT method [put], since several of the exercises use it. For reasons that are not entirely clear, most HTTP servers available don’t support PUT at all, or otherwise only with a lot of extra work. So the options for the tutorial apparently are: require the attendees to locate and install an existing server that accepts PUT; run a server and then require anybody who wants to use the tutorial to acquire a username and login for it; or supply a minimal server that the user can easily install and use. We opted for the third.

Luckily, writing a simple server without the normal industrial-strength requirements of large-scale servers is fairly easy, and since we had already written one for the XForms Test Suite [ts], XContents [xc], we used that, a few hundred lines of C code, which we then compiled for a number of standard platforms. Unfortunately, during testing, we discovered that on Windows, one virus scanner falsely identified the server as malware, and so for the people who ran against that problem we also wrote a JavaScript version which runs under Node.

Since the tutorial demands a server that uses PUT, the tutorial itself could use it for its own purposes. In particular whenever the user navigates to a new chapter, the current state is saved so that should the user stop and log out, on return the tutorial is restarted at the last-used location.