::  Posts  ::  RSS  ::  ◂◂RSS  ::  Contact

Repeated HTML Text Is Cheap

February 19th, 2014
tech  [html]
The Guardian recently moved from guardian.co.uk to www.theguardian.com and wrote up their experiences. Among them:

At this point, however, all the URLs on the site still pointed to www.guardian.co.uk. We attempted to fix this by implementing relative URLs across our site, but a lengthy investigation proved that this would be more difficult than it should have been. Instead, we wrote a filter which detected the HTTP Host header. If the host was www.theguardian.com, we would rewrite all the URLs on the site to be www.theguardian.com. If the Host was www.guardian.co.uk we would rewrite all the URLs on the site to be www.guardian.co.uk. This was a simple configuration change that swapped one domain for another, per request.

Wait, they're using absolute urls instead of relative? Isn't that inefficient, repeating http://www.theguardian.com for every single link? That's 295 times:

    $ curl -s http://www.theguardian.com/us | sed 's~http:~^http:~g' \
       | tr '^' '\n' | grep -c http://www.theguardian.com/

But how much bigger is this making their site, after all?

    $ curl -s http://www.theguardian.com/us | wc -c
    $ curl -s http://www.theguardian.com/us \
       | sed s'~http://www.theguardian.com~~' | wc -c
    $ python -c 'print 222491-214795'
    $ python -c 'print "%.2f%%" % (7696.0 / 214795 * 100)'
So they're using an extra 7.7kB and making their site 3.6% bigger, right? Except almost everyone will be downloading the site with gzip enabled:
    $ curl -s http://www.theguardian.com/us | wc -c
    $ curl -s -H 'Accept-Encoding: gzip' \
       http://www.theguardian.com/us | wc -c
In other words, if you request the page simply it's 222k but if your browser sends Accept-Encoding: gzip with the request, and any browser you're likely to use does this, then it's only 34k. This is equivalent to downloading the page and then gzipping it ourselves:
    $ curl -s http://www.theguardian.com/us | gzip | wc -c

Now gzip compression does well with simple repeated strings, so how well does it handle these absolute urls? Let's repeat the test from above, this time encoding with gzip before counting bytes:

    $ curl -s http://www.theguardian.com/us | gzip | wc -c
    $ curl -s http://www.theguardian.com/us \
       | sed s'~http://www.theguardian.com~~' | gzip | wc -c
    $ python -c 'print 33576-33347'
    $ python -c 'print "%.2f%%" % (229.0 / 33347 * 100)'
So yes, they could save some bytes by switching to relative urls, but the savings are under 1%.

Comment via: google plus, facebook

Recent posts on blogs I like:

Absolute scale corrupts absolutely

The Internet has gotten too big. Growing up, I, like many computery people of my generation, was an idealist. I believed that better, faster communication would be an unmitigated improvement to society. "World peace through better communication,"…

via apenwarr August 19, 2019


At naptime Anna listens to recordings of novels recorded by Jeff’s grandmother. It is the main way she will know Winnie, as it is the main way I have ever known Winnie. Some of the recordings are missing parts, and Suzie often fills in the first few sente…

via The whole sky August 18, 2019

One Night Ultimate Werewolf

I really like One Night Ultimate Werewolf (ONUW), and recommend trying it out. The Daybreak expansion is also good (but I’d skip the later games in the series). App For those who’ve played a lot and wish the night took 20 seconds rather than a few minutes…

via The sideways view August 18, 2019

more     (via openring)

More Posts:

  ::  Posts  ::  RSS  ::  ◂◂RSS  ::  Contact