Re: generating an html intro text ...

Edward Kay wrote:

-----Original Message----- From: Jochem Maas [mailto:jochem@iamjochem.com] Sent: 18 June 2007 13:18 To: tedd Cc: [php] PHP General List Subject: Re: [PHP] generating an html intro text ... tedd wrote:

At 11:39 AM +0200 6/14/07, Jochem Maas wrote:

original string:

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The problem as I see it is covering all the possibilities that may occur even if the text is well formed. Like what if someone introduces a span that sets a color for a paragraph, such as: <span color:"yellow"; >Dolore magna aliquam erat volutpat ut wisi enim ad minim veniam quis nostrud. Consectetuer adipiscing elit sed diam nonummy nibh euismod tincidunt ut laoreet exerci tation ullamcorper suscipit lobortis! <b>Decima eodem modo </b>typi qui nunc nobis videntur parum clari fiant sollemnes in.<span> And the </b> tag as well as the </span> tag is outside the 256 limit? You would have to search out and pull in all closing tags. So, I guess an algorithm could be:

roughly speaking yes this is what is would do, except:

First, grab 256 characters -- The string. If The string is shorter, then quit.

the algo should only be counting 'content characters', i.e. anything that is html markup should not go towards the string length count, additionally html entities such as '&amp;' should be considered as a single character.

Second, determine what tags are not closed. Third, create closing tags and add them to the end of The string (in proper order). Fourth, then remove the same number of non-html characters from the end of The string.

what the code should do (mmore or less) is quite clear - writing something flexible & robust to actually do it (and do it fast) is quite another matter. I have been looking at Edward Vermillon's code but I suspect that what he sent me is not quite what I'm looking for for a number of reasons: 1. it deals primarily with custom bbcode like markup 2. I have a couple of doubts about the handling of html entities 3. performance that said I still have to look at it in depth before making any real conclusions as to it's viability (and or the possiblity to rework the code to fit my needs). I'm also looking at an alternative where by I go through the string and truncate it at the character (or characters that represent an html entity) that reresents the Nth 'content character' and then feeding the truncated string to the Tidy extension and let it figure out the html cleaning part ... does anyone have experience using tidy to clean (make valid) html snippets using Tidy, that they would like to share?

A few thoughts I've had on this problem: Assuming it is well formed HTML, you could use a stack. Parse the string putting all opening tags on the stack and then removing them when the close tag is found. This will leave you with all the un-closed tags and in the correct order. Remember that some tags can be self closing (<br /> etc). Could you use one of the XML extensions to build a DOM of the snippet? I've not used them much myself, but I'm guessing they could handle most of the tag stripping and matching...

I'm sure Tidy could be employed to do this job. Grab your target length of text, backtrack until you find < or >. If it's a < then chop that bit off. Then give it to Tidy to fix the HTML. That should close off any open tags and give you a properly formed snippet. Or you could implement the same functionality yourself quite easily, and it doesn't need to be well-formed HTML but you would need to check for tags that don't need closing (img, br, etc). -Stut -- http://stut.net/