David Cramer's Blog - Latest Comments in Spaceless HTML in Django

Re: Spaceless HTML in Django

lericson — Mon, 23 Feb 2009 09:28:23 -0000

There are bigger fish to fry.

Re: Spaceless HTML in Django

Martyn Clement — Thu, 08 Jan 2009 06:54:58 -0000

I suggest this tag should be effective only on setting debug=False
Debugging html on viewing html source code is quite common.
That's what I did ;)

Re: Spaceless HTML in Django

Dougal Matthews — Sat, 20 Dec 2008 23:06:43 -0000

Shame it messes up the pre and textarea tags :( was gonna use it otherwise.

Intersting idea though!

Re: Spaceless HTML in Django

Dougal Matthews — Sat, 20 Dec 2008 23:06:04 -0000

Shame it messes up the

 and  tags :( was gonna use it otherwise.

Intersting idea though!

Re: Spaceless HTML in Django

Chris Kelly — Tue, 09 Dec 2008 17:15:06 -0000

The whitespace tag is really simple, it just finds the end of one tag and the beginning of another with whitespace in between, and removes said whitespace. It looks like it doesn't have any special cases, so it unfortunately affects textarea and pre tag content.

see: http://code.djangoproject.c...

Re: Spaceless HTML in Django

David Cramer — Fri, 05 Dec 2008 06:55:54 -0000

We GZIP as well. Sadly, everyone's still not on broadband today, so even shaving off 5 or 10k from the request can be quite useful (especially when the amount of time it takes to do that is immeasurable).

Re: Spaceless HTML in Django

Florent V. — Thu, 04 Dec 2008 10:52:26 -0000

Hello,

I'm curious: why outputting whitespace-less HTML when you could just use gzip compression on the server for HTML, XML, CSS and JavaScript, and get better results (like from 300 kB -- not kb ;) -- to, say, 120 kB)? Did you do some performance testing regarding that?

Unless gzipping your text output has a clear performance cost, I would keep my HTML code with whitespace (if not perfect, then at least decently readable code). Makes it easier to debug when you need to check the real thing (Firebug only shows what Firefox understands, not what it gets from the server).

Do you happen to use this method, then gzip (through mod_deflate for instance)? If so, how much do you save compared to a gzipped version with all whitespace intact?

Re: Spaceless HTML in Django

Bartek — Tue, 02 Dec 2008 10:12:24 -0000

Very nice and simple trick. Thanks

Re: Spaceless HTML in Django

Peter Bengtsson — Tue, 02 Dec 2008 08:45:18 -0000

I wrote this snippet:
http://www.djangosnippets.o...
to (very) efficiently whitespace optimize inline CSS which might be interesting for you and your Jinja too.

Re: Spaceless HTML in Django

Roger — Tue, 02 Dec 2008 07:59:53 -0000

or the end*

Re: Spaceless HTML in Django

Roger — Tue, 02 Dec 2008 07:59:27 -0000

The appropriate place for cached content to be effected would be at the start of the end? :-/

Re: Spaceless HTML in Django

Martin Mahner — Tue, 02 Dec 2008 06:40:32 -0000

I had problems with highlighted (pygments) text in pre-tags which results in unindented code *cry*. But that's a very special condition.

Re: Spaceless HTML in Django

Martin Mahner — Tue, 02 Dec 2008 06:29:23 -0000

Ups, I wasn't aware that there is a real "strip_spaces_between_tags" function. Sorry for the noise :D

Re: Spaceless HTML in Django

David Cramer — Tue, 02 Dec 2008 06:27:09 -0000

Have you confirmed this? I believe the whitespace tag is designed to avoid that, but I haven't fully tested it.

Re: Spaceless HTML in Django

Martin Mahner — Tue, 02 Dec 2008 06:25:18 -0000

The drawback of this is, that it also steals the whitespace in pre and textarea tags.

Re: Spaceless HTML in Django

Mikkel Høgh — Tue, 02 Dec 2008 06:05:00 -0000

Note that Content-Type will usually be 'text/html; charset=utf-8', not just 'text/html' (since Content-Type without a charset is unsafe).

Re: Spaceless HTML in Django

Andreas — Tue, 02 Dec 2008 02:32:54 -0000

Clever trick! Debuggers could always use firebug if they want it indented nice. Everyone should do this + gzip + expires header if plausible

Re: Spaceless HTML in Django

David Cramer — Tue, 02 Dec 2008 00:57:25 -0000

It's mostly indentation that actually contributed to the whitespace :)

Re: Spaceless HTML in Django

Tom — Tue, 02 Dec 2008 00:52:41 -0000

So... every third byte was whitespace? That's a bit hard to believe, even as a worst-case. Still, if you saw improvements, then my congratulations.

I would suggest, though (as I see others have), that people facing the same problem have a look at simply gzipping their text-based output at the webserver level. Since the action's probably happening on the webhead either way, it's unlikely to be much more costly in CPU terms, and it's even simpler to implement than your solution (it typically just takes a line or two in .htaccess if you're using Apache). Gzipping will certainly remove any overhead that whitespace represents.

Re: Spaceless HTML in Django

David Cramer — Mon, 01 Dec 2008 23:13:39 -0000

Does mod_deflate allow removing the extra whitespace? In your example you are correct, that it's not a huge savings for that individual request, and gzip I would highly recommend, but the CPU time is negligible.

Re: Spaceless HTML in Django

Josh — Mon, 01 Dec 2008 21:28:13 -0000

Very interesting thoughts. I'll have to play around with it sometime. Thanks!

Re: Spaceless HTML in Django

danielnaab — Mon, 01 Dec 2008 21:19:53 -0000

I've considered this before, but wondered if there was much benefit over gzip (which I would recommend using even with whitespace stripping). Does a whitespace-removed, gzipped response save enough space to justify the (admittedly reasonable) CPU cost of whitespace-removal?

Re: Spaceless HTML in Django

Honza — Mon, 01 Dec 2008 21:18:40 -0000

Is that really worth it?

taking a file:
index.html - 91565 bytes

code:
>>> f = open('index.short', 'w')
>>> f.write( short( file( 'index.html' ).read() ).encode('utf-8') )
>>> f.close()

produces:
index.short - 69915

and my favorite - gzip:
index.gz - 14709
index.short.gz - 13319

examples from zena.centrum.cz where we have some nasty whitespace in our HTML...

Knowing this, I would take mod_deflate in (insert your favorite web server) over any python space stripping anytime...

Re: Spaceless HTML in Django

Sam McDonald — Mon, 01 Dec 2008 20:24:24 -0000

I like it a lot. I have been wondering if there was an easy way to do this, and there is. I will definitely have use for this soon.

Re: Spaceless HTML in Django

Subsume — Mon, 01 Dec 2008 20:13:41 -0000

Pretty hot yet simple. Thanks Mistar Cramar.