Grabbing <title> tag with lxml's iterparse
Question
I'm running into a problem with using lxml's iterparse on my HTML. I'm trying to get the <title> 's text but this simple function doesn't work on complete web pages:
def get_title(str):
titleIter = etree.iterparse(StringIO(str), tag="title")
try:
for event, element in titleIter:
return element.text
# print "Script goes here when it doesn't work"
except etree.XMLSyntaxError:
return None
This function works fine on simple input like " <title>test</title> ", but when I give it a complete page it's unable to extract the title.
UPDATE: Here's the HTML I'm working with:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html dir="ltr" lang="it" xmlns="http://www.w3.org/1999/xhtml">
<head>
<link rel="icon" href="http://www.tricommerce.it/tricommerce.ico" />
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Tricommerce - Informazioni sulla privacy</title>
<meta name="description" content="Info sulla privacy" />
<meta name="keywords" content="Accessori notebook Alimentatori Case Cavi e replicatori Controllo ventole Lettori e masterizzatori Modding Pannelli & display Dissipatori Tastiere e mouse Ventole Griglie e filtri Hardware Accessori vari Box esterni Casse e cuffie Sistemi a liquido Paste termiche vendita modding thermaltake vantec vantecusa sunmbeam sunbeamtech overclock thermalright xmod aerocool arctic cooling arctic silver zalman colorsit colors-it sharkoon mitron acmecom Info sulla privacy" />
<meta name="robots" content="index, follow" />
<link rel="stylesheet" href="http://www.tricommerce.it/css/tricommerce.css" />
<link rel="stylesheet" href="css/static.css" />
<script type="text/javascript" src="http://www.tricommerce.it/javascript/vertical_scroll.js"></script>
<script type="text/javascript">
//<![CDATA[
function MM_preloadImages() { //v3.0
var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}
//]]>
</script>
<link rel="stylesheet" type="text/css" href="http://www.tricommerce.it/css/chromestyle.css" />
<script type="text/javascript" src="http://www.tricommerce.it/javascript/chrome.js">
/***********************************************
* AnyLink CSS Menu script- ? Dynamic Drive DHTML code library (www.dynamicdrive.com)
* This notice MUST stay intact for legal use
* Visit Dynamic Drive at http://www.dynamicdrive.com/ for full source code
***********************************************/
</script>
</head>
</html>
Also, a quick note on why I'm using iterparse-- it's because I don't want to load in the entire DOM just to get a single tag early on in the document.
1 answers
solution1
2 ACCPTED 2012-04-24 01:40:07
You might want to post at least a portion of the data you're actually trying to parse. Absent that information, here's a guess. If the <html> element defines a default XML namespace, you'll need to use that when looking for elements. For example, look at this simple document:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.w3.org/MarkUp/SCHEMA/xhtml11.xsd"
xml:lang="en">
<head>
<title>Document Title</title>
</head>
<body>
</body>
</html>
Given this input, the following will return no results:
>>> doc = etree.parse(open('foo.html'))
>>> doc.xpath('//title')
[]
This fails because we're look for a <title> element without specifying a namespace...and absent a namespace, the parser isn't going to find a match (because foo:title is different from bar:title , assuming that foo: and bar: are defined XML namespaces).
You can explicitly use a namespace with the ElementTree interface like this:
>>> doc.xpath('//html:title',
... namespaces={'html': 'http://www.w3.org/1999/xhtml'})
[<Element {http://www.w3.org/1999/xhtml}title at 0x1087910>]
And there's our match.
You can pass namespace prefixes to the tag argument of iterparse, too:
>>> titleIter = etree.iterparse(StringIO(str),
... tag='{http://www.w3.org/1999/xhtml}title')
>>> list(titleIter)
[(u'end', <Element {http://www.w3.org/1999/xhtml}title at 0x7fddb7c4b8c0>)]
If this doesn't solve your problem, post some sample input and we'll work from there.
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