Is there a CPAN module or code snippet that I can use to modify local HTML files without using a regExp?
What I want to do :
Change the start tag ( example : <div> to <div id="newtag"> )
Add a tag before another ( example : </head> to <script type="text/javascript"> ...</script></head>
Remove tags
Read the content of a given tag. (<- ok this can be done with an XML / HTML parser.
If you have HTML, and not XHTML, then you don't want to be using an XML parser.
HTML::Parser is the standard HTML parser for Perl. Pretty much everything else is built on top of it.
HTML::TokeParser is an alternative interface to HTML::Parser. It returns things on demand instead of passing everything to callbacks.
HTML::TreeBuilder builds a DOM-like tree from the HTML, which you can then modify.
HTML::TreeBuilder::XPath extends HTML::TreeBuilder with XPath support.
HTML::Query extends HTML::TreeBuilder with jQuery-like selectors.
pQuery is another module that brings more complete jQuery compatibility to HTML::TreeBuilder.
CPAN
XML::XPATH
XML::Xerces
A simple CPAN search returns
XML Search
XPATH
XPATH Tutorial
It sounds like you are not familiar with XPath. Here is a quick tutorial to get you familiar. Its not Perl but it will explain the concepts.
Related
I'm writing a web scraper, and am a Perl novice. I'm using HTML::TreeBuilder to get the data I need, but I've run into a case I'm not sure how to handle. Here's some sample HTML:
<div class="anything" val="20" name="matchup">someUniqueData</div>
I want to extract the val from this HTML tag. I've been using findvalues() to do most of my work, but I don't know if this can pull data from inside tags. I've glossed over the documentation unsuccessfully. Is there a simple solution for this type of scrape?
You need (using HTML::TreeBuilder::XPath):
my ($val) = $tree->findvalues('//div[#class="anything"]/#val');
I'm looking for a QT HTML parser tool.
I have some html source code and I'd like to use XQuery on it.
I already tried using QWebPage + QWebElement, but I don't like this solution cause firstly it doesn't works on non-gui thread (because of QWebPage) and because we can't apply XPath but CSS Path.
The other solution I tried is QXmlQuery, it works great, but the only problem is that it doesn't works if there is an error on the page. For example, the first page I tried was missing systemId (in the DOCTYPE tag), so the parsing was aborted.
I heard we can use gecko for parsing but I have no idea how to use it with QT.
Have you some suggestions ?
Thanks
I recommend that you use tidy on your HTML page and then process it with XQuery.
Zorba is a C++ XQuery processor that provides a tidy module.
You can find a live example at http://www.zorba-xquery.com/html/demo#tQZu6aq1K4KoGJm9m0oIPwKRt04=
BaseX got a QT client and can use TagSoup for cleaning up HTML documents.
I'm sorry I cannot provide you with an QT example as I don't know QT at all.
I am storing user generated html code in the database, but some of the codes are broken (without end tags), so when this code will mess up the whole render of the page.
How could I prevent this sort of behaviour with ruby on rails.
Thanks
It's not too hard to do this with a proper HTML parser like Nokogiri which can perform clean-up as part of the processing method:
bad_html = '<div><p><strong>bad</p>'
puts Nokogiri.fragment(bad_html).to_s
# <div><p><strong>bad</strong></p></div>
Once parsed properly, you should have fully balanced tags.
My google-fu reveals surprisingly few hits, but here is the top one :)
Valid Well-formed HTML
Try using the h() escape function in your erb templates to sanitize. That should do the trick
Check out Loofah, an HTML sanitization library based on Nokogiri. This will also remove potentially unsafe HTML that could inject malicious script or embed objects on the page. You should also scrub out style blocks, which might mess up the markup on the page.
I am trying to load and parse html in adobe air. The main purpose being to extract title, meta tags and links. I have been trying the HTMLLoader but I get all sort of errors, mainly javascript uncaught exceptions.
I also tried to load the html content directly (using URLLoader) and push the text into HTMLLoader (using loadString(...)) but got the same error. Last resort was to try and load the text into xml and then use E4X queries or xpath, no luck there cause the html is not well formed.
My questions are:
Is there simple and reliable (air/action script) DOM component there (I do not need to display the page and headless mode will do)?
Is there any library to convert (crappy) html into well formed xml so I can use xpath/E4X
Any other suggestions on how to do this?
thx
ActionScript is supposed to be a superset of JavaScript, and thankfully, there's...
Pure JavaScript/ActionScript HTML Parser
created by Javascript guru and jQuery creator John Resig :-)
One approach is to run the HTML through HTMLtoXML() then use E4X as you please :)
Afaik:
No :-(
No :-(
I think the easiest way to grab title and meta tags is writing some regular expressions. You can load the page's HTML code into a string and then read out whatever you need like this:
var str:String = ""; // put HTML code in here
var pattern:RegExp = /<title>(.+)<\/title>/i;
trace(pattern.exec(str));
I have a couple of websites that I want to extract data from and based on previous experiences, this isn't as easy as it sound. Why? Simply because the HTML pages I have to parse aren't properly formatted (missing closing tag, etc.).
Considering that I have no constraints regarding the technology, language or tool that I can use, what are your suggestions to easily parse and extract data from HTML pages? I have tried HTML Agility Pack, BeautifulSoup, and even these tools aren't perfect (HTML Agility Pack is buggy, and BeautifulSoup parsing engine doesn't work with the pages I am passing to it).
You can use pretty much any language you like just don't try and parse HTML with regular expressions.
So let me rephrase that and say: you can use any language you like that has a HTML parser, which is pretty much everything invented in the last 15-20 years.
If you're having issues with particular pages I suggest you look into repairing them with HTML Tidy.
I think hpricot (linked by Colin Pickard) is ace. Add scrubyt to the mix and you get a great html scraping and browsing interface with the text matching power of Ruby http://scrubyt.org/
here is some example code from http://github.com/scrubber/scrubyt_examples/blob/7a219b58a67138da046aa7c1e221988a9e96c30e/twitter.rb
require 'rubygems'
require 'scrubyt'
# Simple exmaple for scraping basic
# information from a public Twitter
# account.
# Scrubyt.logger = Scrubyt::Logger.new
twitter_data = Scrubyt::Extractor.define do
fetch 'http://www.twitter.com/scobleizer'
profile_info '//ul[#class="about vcard entry-author"]' do
full_name "//li//span[#class='fn']"
location "//li//span[#class='adr']"
website "//li//a[#class='url']/#href"
bio "//li//span[#class='bio']"
end
end
puts twitter_data.to_xml
As language Java and as a open source library Jsoup will be a pretty solution for you.
hpricot may be what you are looking for.
You may try PHP's DOMDocument class. It has a couple of methods for loading HTML content. I usually make use of this class. My advises are to prepend a DOCTYPE element to the HTML in case it hasn't one and to inspect in Firebug the HTML that results after parsing. In some cases, where invalid markup is encountered, DOMDocument does a bit of rearrangement of the HTML elements. Also, if there's a meta tag specifying the charset inside the source be careful that it will be used internally by libxml when parsing the markup. Here's a little example
$html = file_get_contents('http://example.com');
$dom = new DOMDocument;
$oldValue = libxml_use_internal_errors(true);
$dom->loadHTML($html);
libxml_use_internal_errors($oldValue);
echo $dom->saveHTML();
Any language which works with HTML on DOM level is good.
for perl it is HTML::TreeBuilder module.