Recently, I’ve been finding a few requests using an agent named “Hatena Antenna” in my web access logs. Performing a search on Google pulled up a number of Japanese pages but no English explanations. As I was not happy with this result, I asked my friend Aya to give me the gist of the page which came up first in a Google search for “Hatena Antenna”. This entry is intended for those curious with what shows up in their access logs.

In short, Hatena Antenna is a tool which tracks a webpage to determine whether or not it has been updated. If the page has changed, the program will download a copy. Aya claims that the site linked to above maintains a list of “favourite” sites for a user which are then polled using Hatena Antenna. This is done through use of the HTTP HEAD method, which returns the time of the document’s last modification.

Here’s a sample of Hatena Antenna in action:

aaa.bb.cc.dd - - [03/Jan/2003:17:18:28 -0500] 
    "HEAD /blog/ HTTP/1.1" 200 0 "-" "Hatena Antenna/0.4"
aaa.bb.cc.dd - - [03/Jan/2003:17:18:30 -0500] 
    "GET /blog/ HTTP/1.1" 200 42323 "-" "Hatena Antenna/0.4"

Unfortunately, my weblog is dynamically generated and so the time returned in a response to the HEAD method is always the current time. When Blosxom 0+6i stabilises, I might consider using its new static rendering techniques, thereby fixing this problem.