156 lines
4.9 KiB
Python
156 lines
4.9 KiB
Python
#!/usr/bin/python
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from xml.dom import minidom, Node
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import urllib
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import time
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import datetime
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import hashlib
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import base64
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import hmac
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class PyMazonError(Exception):
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"""Holds information about an error that occured during a pymazon request"""
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def __init__(self, messages):
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self.__message = '\n'.join(messages)
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def __get_message(self):
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return self.__message
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def __str__(self):
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return repr(self.__message)
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message = property(fget=__get_message)
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class PyMazonBook:
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"""Stores information about a book retrieved via PyMazon."""
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def __init__(self, title, authors, publisher, year, isbn10, isbn13, edition):
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self.__title = title
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self.__authors = authors
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self.__publisher = publisher
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self.__year = year
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self.__isbn10 = isbn10
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self.__isbn13 = isbn13
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self.__edition = edition
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def __str__(self):
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return 'Title: ' + self.title + '\n' + \
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'Author(s): ' + ', '.join(self.authors) + '\n' \
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'Publisher: ' + self.publisher + '\n' + \
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'Year: ' + self.year + '\n' + \
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'ISBN-10: ' + self.isbn10 + '\n' + \
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'ISBN-13: ' + self.isbn13 + '\n' + \
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'Edition: ' + self.edition
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def __get_title(self):
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return self.__title
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def __get_authors(self):
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return self.__authors
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def __get_publisher(self):
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return self.__publisher
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def __get_year(self):
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return self.__year
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def __get_isbn10(self):
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return self.__isbn10
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def __get_isbn13(self):
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return self.__isbn13
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def __get_edition(self):
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return self.__edition
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title = property(fget=__get_title)
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authors = property(fget=__get_authors)
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publisher = property(fget=__get_publisher)
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year = property(fget=__get_year)
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isbn10 = property(fget=__get_isbn10)
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isbn13 = property(fget=__get_isbn13)
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edition = property(fget=__get_edition)
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class PyMazon:
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"""A method of looking up book information on Amazon."""
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def __init__(self, accesskey, secretkey):
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self.__key = accesskey
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self.__secret = secretkey
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self.__last_query_time = 0
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def __form_request(self, isbn):
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content = {}
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dstamp = datetime.datetime.utcfromtimestamp(time.time())
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content['Timestamp'] = dstamp.strftime('%Y-%m-%dT%H:%M:%S.000Z')
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content['Service'] = 'AWSECommerceService'
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content['Version'] = '2008-08-19'
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content['Operation'] = 'ItemLookup'
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content['ResponseGroup'] = 'ItemAttributes'
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content['IdType'] = 'ISBN'
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content['SearchIndex'] = 'Books'
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content['ItemId'] = isbn
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content['AWSAccessKeyId'] = self.__key
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URI_String = []
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for key, value in sorted(content.items()):
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URI_String.append('%s=%s' % (key, urllib.quote(value)))
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req = '&'.join(URI_String)
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to_sign_req = 'GET\necs.amazonaws.com\n/onca/xml\n' + req
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h = hmac.new(self.__secret, to_sign_req, hashlib.sha256)
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sig = base64.b64encode(h.digest())
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req += '&Signature=%s' % urllib.quote(sig)
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return 'http://ecs.amazonaws.com/onca/xml?' + req
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def __elements_text(self, element, name):
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result = []
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matching = element.getElementsByTagName(name)
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for match in matching:
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if len(match.childNodes) != 1:
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continue
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child = match.firstChild
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if child.nodeType != Node.TEXT_NODE:
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continue
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result.append(child.nodeValue.strip())
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return result
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def __format_errors(self, errors):
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error_list = []
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for error in errors:
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error_list.extend(self.__elements_text(error, 'Message'))
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return error_list
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def __extract_single(self, element, name):
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matches = self.__elements_text(element, name)
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if len(matches) == 0:
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return ''
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return matches[0]
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def lookup(self, isbn):
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file = urllib.urlretrieve(self.__form_request(isbn))[0]
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xmldoc = minidom.parse(file)
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cur_time = time.time()
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while cur_time - self.__last_query_time < 1.0:
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sleep(cur_time - self.__last_query_time)
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cur_time = time.time()
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self.__last_query_time = cur_time
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errors = xmldoc.getElementsByTagName('Errors')
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if len(errors) != 0:
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raise PyMazonError, self.__format_errors(errors)
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title = self.__extract_single(xmldoc, 'Title')
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authors = self.__elements_text(xmldoc, 'Author')
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publisher = self.__extract_single(xmldoc, 'Publisher')
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year = self.__extract_single(xmldoc, 'PublicationDate')[0:4]
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isbn10 = self.__extract_single(xmldoc, 'ISBN')
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isbn13 = self.__extract_single(xmldoc, 'EAN')
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edition = self.__extract_single(xmldoc, 'Edition')
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return PyMazonBook(title, authors, publisher, year, isbn10, isbn13, edition)
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