Re: CDATA the title and description?
Jon Hanna <jon-YK+g4hZFQDMeIZ0/[email protected]> Mon, 28 May 2007 00:09:06 +0100
| Newsgroups | gmane.network.syndication.rss.devel |
|---|---|
| Message-ID | <[email protected]> |
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Clinton Gallagher wrote:
> So it seems to be a general consensus that CDATA within the title and the
> description is widely supported at this point in time as a means to allow
> users to submit data such as the word AT&T in a title or description? What
> are the generally accepted pitfalls of using CDATA?
It's pretty depressing that "widely supported" can even be talked about
in this case. It's 9 years since XML became a recommendation. There are
kids out there younger than XML that understand CDATA, and some of the
parsers don't. :(
Anyway the biggest pitfall I can see with CDATA at the authors side is
the belief that you can pass anything through without having to worry
about escaping anything - there is the exception of the string "]]>".
Now granted the string ]]> doesn't come up very much in normal
conversation, but it certainly can come up in technical posts, etc. and
of course Murphy's law applies - if there's a set of inputs that will
cause failure someone will give you that set of inputs.
As such you still have to do escaping with anything you are putting into
a CDATA section so that ]]> gets replaced with ]]>]<![CDATA[]> (there
are a couple of other workable equivalents).
Personally, I tend to find it just as handy to escape & and < to &
and < (and > to > though in most cases that should be safe - but
again there are parsers that may think differently) especially since I
got into the habit of looking for those a long time ago when dealing
with HTML (not to say I never ever overlook that those characters could
be coming into a given piece of code, but I'm still well used to looking
out for them and not for ]]>
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<p>Clinton Gallagher wrote:<br>
> So it seems to be a general consensus that CDATA within the title and the<br>
> description is widely supported at this point in time as a means to allow<br>
> users to submit data such as the word AT&T in a title or description? What<br>
> are the generally accepted pitfalls of using CDATA?<br>
<br>
It's pretty depressing that "widely supported" can even be talked about <br>
in this case. It's 9 years since XML became a recommendation. There are <br>
kids out there younger than XML that understand CDATA, and some of the <br>
parsers don't. :(<br>
<br>
Anyway the biggest pitfall I can see with CDATA at the authors side is <br>
the belief that you can pass anything through without having to worry <br>
about escaping anything - there is the exception of the string "]]>". <br>
Now granted the string ]]> doesn't come up very much in normal <br>
conversation, but it certainly can come up in technical posts, etc. and <br>
of course Murphy's law applies - if there's a set of inputs that will <br>
cause failure someone will give you that set of inputs.<br>
<br>
As such you still have to do escaping with anything you are putting into <br>
a CDATA section so that ]]> gets replaced with ]]>]<![CDATA[<wbr>]> (there <br>
are a couple of other workable equivalents)<wbr>.<br>
<br>
Personally, I tend to find it just as handy to escape & and < to &amp; <br>
and &lt; (and > to &gt; though in most cases that should be safe - but <br>
again there are parsers that may think differently) especially since I <br>
got into the habit of looking for those a long time ago when dealing <br>
with HTML (not to say I never ever overlook that those characters could <br>
be coming into a given piece of code, but I'm still well used to looking <br>
out for them and not for ]]><br>
<br>
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