ElementTree findall() returning empty list

Question

I am trying to write a small script for interacting with the last.fm API.

I have a small bit of experience working with ElementTree, but the way I used it previously doesn't seem to be working, it instead returns an empty list.
I removed the API key as I don't know exactly how private it should be, and gave an example of the XML I am receiving in it's place.

Class for interacting with API:

from xml.etree import ElementTree import urllib import urllib2  class Last_fmWrapper(object):     def __init__(self):         self.last_fm_api_key = '*****************************'         self.api_url = 'http://ws.audioscrobbler.com/2.0/'     def get_now_playing(self, last_fm_user, method):         self.last_fm_user = last_fm_user         self.method = method         parameters = {'user':self.last_fm_user, 'api_key':self.last_fm_api_key, 'method':self.method}         encoded_parameters = urllib.urlencode(parameters)         request = urllib2.Request(self.api_url, encoded_parameters)         response = urllib2.urlopen(request)         api_results = ElementTree.parse(response).findall('track')         # why does api_results == []?      def compare_tasteometer(self):         pass      def register_user(self):         pass 

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Call to get_now_playing method of Last_fmWrapper():

from last_fm_wrapper import Last_fmWrapper last_fm = Last_fmWrapper() now_playing = last_fm.get_now_playing('BiriBiriRG', 'user.getRecentTracks') if now_playing == None:     print 'You not currently playing anything.' else:     print 'You are now playing {}'.format(now_playing) 

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Sample of xml I receive:

<?xml version="1.0" encoding="utf-8"?> <lfm status="ok"> <recenttracks user="BiriBiriRG" page="1" perPage="10" totalPages="18406" total="184058" > <track>                  <artist mbid="01809552-4f87-45b0-afff-2c6f0730a3be">Elvis Presley</artist> <name>Thrill Of Your Love</name> <streamable>1</streamable> <mbid></mbid>         <album mbid="c445fa3a-3b24-41d4-b955-b6ca560c6f7a">Love Songs</album>     <url>http://www.last.fm/music/Elvis+Presley/_/Thrill+Of+Your+Love</url>     <image size="small">http://userserve-ak.last.fm/serve/34s/69037914.png</image>     <image size="medium">http://userserve-ak.last.fm/serve/64s/69037914.png</image>     <image size="large">http://userserve-ak.last.fm/serve/126/69037914.png</image>     <image size="extralarge">http://userserve-ak.last.fm/serve/300x300/69037914.png</image>         <date uts="1328153196">2 Feb 2012, 03:26</date> </track> <track>                  <artist mbid="efc8a006-d0c6-4a9b-8cb1-91ca770fa2b9">Colbie Caillat</artist> <name>Oxygen</name> <streamable>1</streamable> <mbid></mbid>         <album mbid="2d297b29-a215-42fe-8a8c-dc8b502903b1">Coco</album>     <url>http://www.last.fm/music/Colbie+Caillat/_/Oxygen</url>     <image size="small">http://userserve-ak.last.fm/serve/34s/69229764.png</image>     <image size="medium">http://userserve-ak.last.fm/serve/64s/69229764.png</image>     <image size="large">http://userserve-ak.last.fm/serve/126/69229764.png</image>     <image size="extralarge">http://userserve-ak.last.fm/serve/300x300/69229764.png</image>         <date uts="1328152962">2 Feb 2012, 03:22</date> </track> <track>  

Answer 1

The problem is that findall only searches the immediate descendants of an element if it is given a tag name. You need to give it an XPath expression that will find track anywhere in the tree beneath it. So the following should work, for example:

api_results = ElementTree.parse(response).findall('.//track')