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Fourmi/FourmiCrawler/spider.py
2014-06-01 20:18:03 +02:00

75 lines
2.7 KiB
Python

import re
from scrapy.spider import Spider
from scrapy import log
class FourmiSpider(Spider):
"""
A spider writen for the Fourmi Project which calls upon all available sources to request and scrape data.
"""
name = "FourmiSpider"
__sources = []
synonyms = []
def __init__(self, compound=None, selected_attributes=[".*"], *args, **kwargs):
"""
Initiation of the Spider
:param compound: compound that will be searched.
:param selected_attributes: A list of regular expressions that the attributes should match.
"""
super(FourmiSpider, self).__init__(*args, **kwargs)
self.synonyms.append(compound)
self.selected_attributes = selected_attributes;
def parse(self, response):
"""
The function that is called when a response to a request is available. This function distributes this to a
source which should be able to handle parsing the data.
:param response: A Scrapy Response object that should be parsed
:return: A list of Result items and new Request to be handled by the scrapy core.
"""
for source in self.__sources:
if re.match(source.website, response.url):
log.msg("Url: " + response.url + " -> Source: " + source.website, level=log.DEBUG)
return source.parse(response)
return None
def get_synonym_requests(self, compound):
"""
A function that generates new Scrapy Request for each source given a new synonym of a compound.
:param compound: A compound name
:return: A list of Scrapy Request objects
"""
requests = []
for parser in self.__sources:
parser_requests = parser.new_compound_request(compound)
if parser_requests is not None:
requests.append(parser_requests)
return requests
def start_requests(self):
"""
The function called by Scrapy for it's first Requests
:return: A list of Scrapy Request generated from the known synonyms using the available sources.
"""
requests = []
for synonym in self.synonyms:
requests.extend(self.get_synonym_requests(synonym))
return requests
def add_sources(self, sources):
"""
A function to add a new Parser objects to the list of available sources.
:param sources: A list of Source Objects.
"""
for parser in sources:
self.add_source(parser)
def add_source(self, source):
"""
A function add a new Parser object to the list of available parsers.
:param source: A Source Object
"""
self.__sources.append(source)
source.set_spider(self)