[Cosmo-dev] Gzipping dojo.js

[Matthew Eernisse]

It's our old friend, IE6 again -- IE6 is known not to work reliably with 
gzipped content, despite the fact that it's supposed to support it.

 From the "Serving JavaScript Fast" article:

http://www.thinkvitamin.com/features/webapps/serving-javascript-fast

"Internet Explorer (versions 4 through 6) has some more interesting 
issues. When loading gzipped JavaScript, Internet Explorer will 
sometimes incorrectly decompress the resource, or halt compression 
halfway through, presenting half a file to the client. If you rely on 
your JavaScript working, you need to avoid sending gzipped content to 
Internet Explorer."

 From MS:

1. Content with "Content-Encoding: gzip" Is Always Cached Although You 
Use "Cache-Control: no-cache"

http://support.microsoft.com/kb/321722/EN-US/

This one is not so much of an issue for us, since IE has such a screwy 
caching mechanism in the first place -- we're now versioning the js 
directory, and we have to use the query string hack anyway when we want 
to make sure IE gets updated content.

2. Internet Explorer May Lose the First 2,048 Bytes of Data That Are 
Sent Back from a Web Server That Uses HTTP Compression

http://support.microsoft.com/default.aspx?scid=kb;en-us;Q312496

This is the biggie that you hear about the most.

It looks like a Service Pack was supposed to have fixed this, but I 
don't know if our supported browser configurations specify the latest 
Service Pack -- or if that's even feasible to require.

The 'workaround' for this problem is stated as "Disable HTTP compression 
by changing the Web server's configuration." :) (Although I think I also 
remember hearing someone mention adding 2K of blank space at the 
beginning of the file for IE to throw away.)

Bottom line is that we need to be able to ensure that IE6 always gets 
the unzipped file -- regardless of what type of content it purports to 
accept.

It looks like this stuff is fixed in IE7.


M.


Travis Vachon wrote:
>>
>> The compiled dojo.js added in 0.6.0 is 444Kb.  When gzipped (with 
>> regular compression), the size is 114Kb.
> 
> !!!!!!
> 
> :-D :-D
> 
> !!!!!!!
> 
> 
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