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hiextr.py
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hiextr.py
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#!/usr/bin/env python
# -*- coding: utf-8 -*-
import sys
import traceback as tb
import lxml.html as html
html.HtmlElement.__repr__ = html.tostring
class Empty(object):
def __eq__(self, other):
if isinstance(other, Empty):
return True
return False
def __str__(self):
return 'NULL'
class Extr(object):
def match(self, content):
#print content, type(content), self._is_empty(content)
if self._is_empty(content):
return Empty()
elif isinstance(content, (list, html.HtmlElement, basestring)):
#print '==================='
#print content
#print '==================='
try:
ret = self.match_impl(content)
except:
print >> sys.stderr, 'Failed while extracting', content
tb.print_exc()
ret = Empty()
else:
#print content
raise TypeError('unknown type')
return ret
#def match_impl(self, content):
# return content
def extr_file(self, fname):
with open(fname, 'r') as f:
return self.extr_txt(f.read())
def extr_txt(self, txt):
return self.match(html.fromstring(txt))
def _is_empty(self, content):
return isinstance(content, Empty) \
or content is None \
or (isinstance(content, (tuple, list)) \
and (len(content) == 0 \
or all(c is None for c in content)))
def __rshift__(self, other):
return Seq(self, other)
def __lshift__(self, other):
return Foreach(self, other)
def __or__(self, other):
return Or(self, other)
def __and__(self, other):
return And(self, other)
class One(Extr):
def __init__(self, expr, trans=None):
self.expr = expr
if trans is None:
trans = lambda x: x
self.trans = trans
def match_impl(self, content):
#print '==================='
#print content
m = content.xpath(self.expr)
#print '--\n--'.join([ unicode(mi).encode('utf8') for mi in m ])
if len(m) == 0:
return Empty()
elif len(m) > 1:
#print m
#print len(m)
raise RuntimeError('more than one matched: ' + str(m))
return self.trans(m[0])
class All(Extr):
def __init__(self, expr, trans=None):
self.expr = expr
if trans is None:
trans = lambda x: x
self.trans = trans
def match_impl(self, content):
m = content.xpath(self.expr)
#print m, len(m)
if len(m) > 0:
ret = [self.trans(mi) for mi in m]
#print ret
return ret
else:
return None
class And(Extr):
def __init__(self, *extr_list):
self.extr_list = []
for extr in extr_list:
if isinstance(extr, basestring):
self.extr_list.append(One(extr))
elif isinstance(extr, Extr):
self.extr_list.append(extr)
else:
raise TypeError('Unknown extractor type: ' + str(extr.__class__))
def match_impl(self, content):
#print self.extr_list
ret = [extr.match(content) for extr in self.extr_list]
return ret
class Dict(Extr):
def __init__(self, extr_dict, flat=True):
self.extr_dict = {}
for name, extr in extr_dict.iteritems():
if isinstance(extr, basestring):
self.extr_dict[name] = One(extr)
elif isinstance(extr, Extr):
self.extr_dict[name] = extr
else:
raise TypeError('Unknown extractor type: ' + str(extr.__class__))
self.flat = flat
def match_impl(self, content):
#print '-------------------'
#print content
ret = {}
for name, extr in self.extr_dict.iteritems():
m = extr.match(content)
if isinstance(m, dict) and self.flat:
ret.update(m)
else:
ret[name] = m
#print ret
return ret
class NamedDict(Extr):
def __init__(self, names):
self.names = names
def match_impl(self, content):
ret = {}
for i, n in enumerate(self.names):
if n:
ret[n] = content[i]
return ret
class Seq(Extr):
def __init__(self, *extrs):
self.extrs = extrs
def match_impl(self, content):
ret = content
for extr in self.extrs:
ret = extr.match(ret)
if self._is_empty(ret):
ret = Empty()
break
return ret
class Or(Extr):
def __init__(self, *extrs):
self.extrs = extrs
def match_impl(self, content):
for extr in self.extrs:
try:
ret = extr.match(content)
except:
continue
if not self._is_empty(ret):
break
return ret
class Foreach(Extr):
def __init__(self, extr1, extr2):
self.extr1 = extr1
self.extr2 = extr2
def match_impl(self, content):
ret1 = self.extr1.match(content)
#print ret1
if self._is_empty(ret1):
return Empty()
elif isinstance(ret1, list):
ret2 = [self.extr2.match(c) for c in ret1]
#print ret2
#print self.extr2
else:
ret2 = extr.match(ret1)
return ret2
#class Map(Extr):
#
# def __init__(self, func):
# self.func = func
#
# def match_impl(self, content):
# return self.func(content)
class Trans(Extr):
def __init__(self, func):
self.func = func
def match_impl(self, content):
return self.func(content)
def test1():
html_doc = """
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title"><b>The Dormouse's story</b></p>
<p class="story">Once upon a time there were three little sisters; and their names were
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>
"""
#<p class="story">...</p>
ht = html.fromstring(html_doc)
mt = One('//body/p[@class="story"]') >> \
Dict(dict(
a = 'a[@id="link1"]/text()',
b = One('a[@id="link2"]/text()') >> Trans(lambda x: x.upper()),
c = One('a[@id="not_exist"]/text()') | One('a[@id="link3"]/text()'),
text = All('.//text()') >> Trans(lambda x: ' '.join(x))
))
# it should output:
# {'a': 'Elsie', 'text': 'Once upon a time there were three little sisters; and their names were\n Elsie ,\n Lacie and\n Tillie ;\n and they lived at the bottom of a well.', 'c': 'Tillie', 'b': 'LACIE'}
print mt.match(ht)
mt = All('//body/p[@class="story"]/a') \
<< Dict(dict(
url = './@href',
name = './text()'
))
# this got a list of objects
# [{'url': 'http://example.com/elsie', 'name': 'Elsie'}, {'url': 'http://example.com/lacie', 'name': 'Lacie'}, {'url': 'http://example.com/tillie', 'name': 'Tillie'}]
print mt.match(ht)
def main():
test1()
return
if __name__ == '__main__':
main()