Misleading example in Apache 2 doc

[Jose Kahan <jo...@w3.org>]

!

I'm not sure if I should mail this here or open a
new bugzilla report. Please advice.

The Content Negotiation doc is using a misleading
example in this section:

 http://httpd.apache.org/docs/2.2/content-negotiation.html#better

[[
 Example

 SetEnvIf Cookie "language=(.+)" prefer-language=$1
 Header append Vary cookie
]]


That regular expression won't work if the cookie has other attributes
in addition to the language one. One of our users got caught
by it. A quick search on the web shows that many people have had
this problem too.

Here's a correct regular expression that will return the language
attribute value, regardless of the contents of the cookie:

[[
SetEnvIf Cookie "language=([a-z|A-Z][a-z|A-Z|-]+)" prefer-language=$1
]]

The expression looks bigger because it takes into account not
only strings like "en", but also "zh-hans". I added upper and lower
case as cookies are case insensitive and I'm not sure if Apache converts
cookies to lower-case at some point. If it's always lower case,
we can simplify the regular expression to:

[[
SetEnvIf Cookie "language=([a-z][a-z|-]+)" prefer-language=$1
]]


Could you update the example in the doc accordingly?

Thanks!

-jose

Re: Misleading example in Apache 2 doc (fix)

[Jose Kahan <jo...@w3.org>]

Hi André,

> language\s*=\s*([^;,\s]+)

Your expression works well and is simpler than mine.

+1 to update the doc with it instead of my proposal.

Thanks :)

-jose

Re: Misleading example in Apache 2 doc (fix)

[André Malo <nd...@perlig.de>]

* Jose Kahan wrote:

[adding docs@]

> I didn't do my homework completely. According to
> RFC 2910, Cookie tokens may be separated by
> white space. The correct regular expression is:
>
> [[
>  SetEnvIf Cookie "language\s*=\s*([a-z|A-Z][a-z|A-Z|-]+)"
> prefer-language=$1 ]]

Also, why are you allowing pipe characters within the language spec? ;-)

How about simply:

language\s*=\s*([a-zA-Z-]+)

?

Maybe

language\s*=\s*([^;,\s]+)

is even better (more flexible). dunno.

nd
-- 
my @japh = (sub{q~Just~},sub{q~Another~},sub{q~Perl~},sub{q~Hacker~});
my $japh = q[sub japh { }]; print join       #########################
 [ $japh =~ /{(.)}/] -> [0] => map $_ -> ()  #            André Malo #
=> @japh;                                    # http://pub.perlig.de/ #

Re: Misleading example in Apache 2 doc (fix)

[André Malo <nd...@perlig.de>]

* Jose Kahan wrote:

[adding docs@]

> I didn't do my homework completely. According to
> RFC 2910, Cookie tokens may be separated by
> white space. The correct regular expression is:
>
> [[
>  SetEnvIf Cookie "language\s*=\s*([a-z|A-Z][a-z|A-Z|-]+)"
> prefer-language=$1 ]]

Also, why are you allowing pipe characters within the language spec? ;-)

How about simply:

language\s*=\s*([a-zA-Z-]+)

?

Maybe

language\s*=\s*([^;,\s]+)

is even better (more flexible). dunno.

nd
-- 
my @japh = (sub{q~Just~},sub{q~Another~},sub{q~Perl~},sub{q~Hacker~});
my $japh = q[sub japh { }]; print join       #########################
 [ $japh =~ /{(.)}/] -> [0] => map $_ -> ()  #            André Malo #
=> @japh;                                    # http://pub.perlig.de/ #

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Misleading example in Apache 2 doc (fix)

[Jose Kahan <jo...@w3.org>]

I didn't do my homework completely. According to
RFC 2910, Cookie tokens may be separated by
white space. The correct regular expression is:

[[
 SetEnvIf Cookie "language\s*=\s*([a-z|A-Z][a-z|A-Z|-]+)" prefer-language=$1
]]

Thanks!

-jose