Re: comment: UA sniffing in Best Practice Recipes for Publishing RDF Vocabularies

Damian Dollahite,

Many thanks for pointing this out.  I have added it to the
list of issues for discussion when work on this draft resumes
in a new chartered working group.

Best regards,
Tom Baker

On Thu, Apr 06, 2006 at 07:59:03AM -0500, Damian Dollahite wrote:
> In the mod_rewrite examples in "Best Practice Recipes for Publishing RDF 
> Vocabularies", the rewrite condition
> 
>    RewriteCond %{HTTP_USER_AGENT} ^Mozilla/.*
> 
> looks problematic to me.  According to the text, this is meant to ensure 
> that Internet Explorer 6 will receive the the HTML document in spite of 
> a broken Content-Accept header. I'm not an expert on UA strings or 
> mod_rewrite, but I believe this condition will actually be true for at 
> least a dozen other UAs, some of which may be Semantic Web applications 
> that are looking for the RDF version.
> 
> For historical reasons, "Mozilla" at the beginning of a UA string does 
> not indicate any particular application or vendor. It merely indicates 
> that the developer believes that their layout engine will render HTML 
> the same way that the indicated version of Netscape Navigator will.  The 
> specific application identifier comes later in the string.
> 
> Netscape Navigator 6+, Mozilla Suite, Mozilla Firefox, SeaMonkey, 
> Konqueror, and probably several other web browsers put "Mozilla/5.0" at 
> the beginning of their UA strings. Semantic Web clients built as Firefox 
> extensions or XULRunner applications are also likely to have 
> "Mozilla/5.0" at the beginning of their UA strings; some may just send 
> Firefox's UA string.  I would suggest a more specific condition that 
> targets ONLY the problem browsers, such as
> 
>    RewriteCond %{HTTP_USER_AGENT} MSIE
> 
> or
> 
>    RewriteCond %{HTTP_USER_AGENT} ^Mozilla/4.*
> 
> if matching Netscape 4.x is also desirable.  According to the Microsoft 
> Knowledge Base, all versions of MSIE claim "Mozilla/4.0" compatibility.
> 
> -- 
> M. Damian Dollahite
> 



-- 
Dr. Thomas Baker                      baker@sub.uni-goettingen.de
SUB - Goettingen State                            +49-551-39-3883
and University Library                           +49-30-8109-9027
Papendiek 14, 37073 Göttingen

Received on Thursday, 6 April 2006 16:04:14 UTC