Error 'failed to load external entity' when using Python lxml
In concert with what mzjn said, if you do want to pass a string to etree.parse(), just wrap it in a StringIO object.
Example:
from lxml import etreefrom StringIO import StringIOmyString = "<html><p>blah blah blah</p></html>"tree = etree.parse(StringIO(myString))This method is used in the lxml documentation.
etree.parse(source) expects source to be one of
- a file name/path
- a file object
- a file-like object
- a URL using the HTTP or FTP protocol
The problem is that you are supplying the XML content as a string.
You can also do without urllib2.urlopen(). Just use
tree = etree.parse("http://www.greenbuttondata.org/data/15MinLP_15Days.xml")Demonstration (using lxml 2.3.4):
>>> from lxml import etree>>> tree = etree.parse("http://www.greenbuttondata.org/data/15MinLP_15Days.xml")>>> tree.getroot()<Element {http://www.w3.org/2005/Atom}feed at 0xedaa08>>>> In a competing answer, it is suggested that lxml fails because of the stylesheet referenced by the processing instruction in the document. But that is not the problem here. lxml does not try to load the stylesheet, and the XML document is parsed just fine if you do as described above.
If you want to actually load the stylesheet, you have to be explicit about it. Something like this is needed:
from lxml import etreetree = etree.parse("http://www.greenbuttondata.org/data/15MinLP_15Days.xml")# Create an _XSLTProcessingInstruction objectpi = tree.xpath("//processing-instruction()")[0] # Parse the stylesheet and return an ElementTreexsl = pi.parseXSL()
lxml docs for parse says To parse from a string, use the fromstring() function instead.
parse(...) parse(source, parser=None, base_url=None) Return an ElementTree object loaded with source elements. If no parser is provided as second argument, the default parser is used. The ``source`` can be any of the following: - a file name/path - a file object - a file-like object - a URL using the HTTP or FTP protocol To parse from a string, use the ``fromstring()`` function instead. Note that it is generally faster to parse from a file path or URL than from an open file object or file-like object. Transparent decompression from gzip compressed sources is supported (unless explicitly disabled in libxml2).