WebExp2 Experimenter's Manual - School of Informatics - University ...

7 Publishing an experiment on the web
The previous section explained how to get an experiment running locally for testing. This section will explain
how to get your WebExp2 experiment running across the web. This involves setting up a web server, and
publishing your experiment webpages.
7.1 Making experiments available on the web
To run your experiments across the web, you must make them available to users on the web. Ordinarily you
could publish webpages on a web server which is managed for you, and indeed this is all you need to do for the
pages containing the experiment client. However, the experiment clients need to contact your WebExp2 server
to retrieve and return information, and you have to run this experiment server yourself and make it available
via a web server. The only way to do this is to run your own web server.
7.2 Preparing for the Server
This section describes how to prepare for publishing your experiments on the web. If you are setting up WebExp2
for the first time and just want to test your experiments locally, you can skip to section 3.1.
7.2.1 Setting up a web server
You will need a web server in order to provide your experiments to the world via your computer. This is a
program such as Apache which runs on the computer and communicates with the world wide web via a port,
which is a virtual ‘door’ to the files or services you want to make available. You can restrict what is visible by
configuring your web server to supply particular files only to particular groups of people.
When you have a web server such as Apache set up, you should place the WebExp2 folder somewhere in the
public html tree. Ensure your data directory is not accessible from the web, by for example creating an Apache
.htaccess file with the command deny from all in it.
7.2.2 Opening a port
You will need to ensure you have a dedicated port open on the computer where you run the WebExp2 server.
This is the channel through which the server application can communicate with clients out on the web. Your
web server will already use port 80 to supply HTML and other files to browsers via http; you will need to open
a second port for WebExp2.
WebExp2 uses port 6789 by default, but any available port will do. If you use a different port, you will need to
specify it when you set up experiments, and when you start the server. Note that port numbers 1024−49151 are
‘registered’ and many are used for specific services; if you use one of these ports, a participant may have trouble
if they happen to be using one of these services. For this reason we suggest you stick to the default of 6789,
which is not currently associated with a particular service, or that you use a port in the range 49152 − 65535,
which are unregistered.
If you do not know how to open a port on your computer, or do not have the permissions, you should be able
to make a request to your system administrator or support to open port 6789 (or another). You can explain
that it is for running experiments via a client-server system.
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