pymeds/item.py

#!/usr/bin/env python
# Copyright 2009 John-Mark Gurney <jmg@funkthat.com>

__version__ = '$Change$'
# $Id$

import FileDIDL
import xml.dom.minidom
from DIDLLite import StorageFolder, Item, Resource, ResourceList
from FSStorage import FSObject, registerklassfun

def getElementText(elm, strip=True):
	s = ''.join(x.nodeValue for x in elm.childNodes)
	if strip:
		s = s.strip()

	return s

class ItemObject(FSObject, Item):
	def __init__(self, *args, **kwargs):
		path = kwargs.pop('path')
		dom = kwargs.pop('dom')

		FSObject.__init__(self, path)
		Item.__init__(self, *args, **kwargs)

		self.checkUpdate(dom=dom)

	_attrconv = [
		('size', 'size', int),
		('bitrate', 'bitrate', int),
		('sampleFrequency', 'sampleFrequency', int),
		('nrAudioChannels', 'nrAudioChannels', int),
		]

	@staticmethod
	def _addattrib(res, attr, dom, element, fun=lambda x: x):
		data = dom.getElementsByTagName(element)
		if data:
			setattr(res, attr, fun(getElementText(data[0])))

	def doUpdate(self, dom=None):
		if dom is None:
			dom = xml.dom.minidom.parse(open(self.FSpath))
		obj = dom.getElementsByTagName('Object')[0]
		self.res = ResourceList()
		for i in obj.getElementsByTagName('res'):
			mtel = i.getElementsByTagName('mimetype')
			rtpel = i.getElementsByTagName('rtppayloadtype')
			if mtel:
				mt = getElementText(mtel[0])
				pi = 'http-get:*:%s:*' % mt
			elif rtpel:
				pt = getElementText(rtpel[0])
				pi = 'rtsp-rtp-udp:*:%s:*' % pt
			else:
				print 'missing mimetype or rtppayloadtype element, skipping...'
				continue

			url = getElementText(i.getElementsByTagName('url')[0])
			r = Resource(url, pi)
			for j in self._attrconv:
				self._addattrib(r, j[0], i, j[1], *j[2:])
			self.res.append(r)

		super(ItemObject, self).doUpdate()

def canHandle(fobj):
	# XXX - create schema and validate
	dom = xml.dom.minidom.parse(fobj)
	#print 'ch:', `dom`
	obj = dom.getElementsByTagName('Object')[0]
	mtel = obj.getElementsByTagName('mimetype')
	rtpel = obj.getElementsByTagName('rtpmimetype')
	if mtel:
		mt = getElementText(mtel[0])
	elif rtpel:
		mt = getElementText(rtpel[0])
	else:
		raise ValueError('failed to find mimetpe or rtppayloadtype')

	#print 'ch:', `obj`, `mt`

	return dom, mt

def detectitem(path, fobj):
	#print 'di:', `path`, `fobj`
	try:
		dom, mt = canHandle(fobj)
	except:
		#import traceback
		#traceback.print_exc()
		return None, None

	klass, mt = FileDIDL.buildClassMT(ItemObject, path, mimetype=mt)

	#print 'match:', `klass`, `mt`
	return klass, { 'path': path, 'dom': dom }

registerklassfun(detectitem)