Author image Michael De La Rue


In internet technology robots (sometimes misleadingly called agents, which could be confused with the suggestion of artificial intelligences, an entirely different and somewhat more Science Fiction kind of thing) are all programs which are designed to automatically, without human supervision make access to the World Wide Web.

When robots were originally proposed, there was a feeling that they could seriously endanger the internet its self by using so much network resource that they would make it impossible to use the internet for anything else. For this reason clear rules were proposed to limit what the robots did and how the did it. These original proposals can be summarised as.

    To some extent, this prediction has been proved true. The automatic downloading of files is generating a real over-use of the internet. However, almost all of this `automatic' usage is coming from people downloading WWW pages in Netscape which then downloads all of the image files and other junk attached to those files.

So what's the solution?

Ban Netscape? No. The original design of the internet largely assumed that it's users were sociable friendly people who liked eachother. Remember it wasn't even the academics, but the army. If you were allowed to use the network (security could be built in for this, of course) then you were on our side.

Nowadays, the internet is no longer used like this and ways have to be found to control network usage of even people who are deliberately trying to make life as difficult as possible. Crackers, vandals and Netscape users (not that they're deliberate) alike.

For these reasons, the calculation in favour of robots has become alot better. They're already used in a large way by such people as Alta-Vista, Infoseek etc. for gathering their information, and even if you set up your robot to do the maximum damage, it wouldn't be likely to be much worse than some people doing random browsing across a site with multiple copies of netscape.

The only way to stop people from downloading vast tracts of pages from your site automatically is to have some kind of defences which automatically stop connections from sites which aren't behaving as you would like them to.

What limits do we now impose on our robot?

We don't want people to have to stop our robot. We want them to like us.. so I've been conservative. I like to be careful, so I've stuck to the original rules. In the case of this robot, they work very well.

We use and follow the Robot Rules provided from /robots.txt on web sites. We can't do the same on ftp sites because this isn't a standard and isn't written into libwww-perl. It probably could and should be.

By default we wait some time between each check and are careful about which sites we are checking. You can turn this off and may find that you want to if you are checking your own local network. You shouldn't turn this off unless you know that you have reasonable permission from every computer involved. I don't know when that would be though. Possibly you are checking from a dialup connection and feel that you have paid for every byte that tranfers. I use the Tardis Project's links which are paid for by the University of Edinburgh. So I do all my checking at night when they don't need or use the bandwidth anyway. Even then I do it slowly, just incase someone happens to be doing something at that time.

For more information about robots and the related rules please see

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