def parseRss(self, response):
"""Extract entry Requests from the RSS feed.
@type response: scrapy.http.response.html.HtmlResponse
@param response: the RSS feed
@rtype: generator of scrapy.http.request.Request
@return: the entry Requests
"""
self.logInfo("Feed: {0}".format(response.url))
self.contentExtractor = ContentExtractor(response.body, self.logInfo)
return imap(
lambda url: Request(
url=url,
callback=self.bufferEntries,
errback=self.bufferEntries,
dont_filter=True,
# meta={ "u": _ } is here to keep a "safe" copy of the source url.
# I don't trust response.url == (what was passed as Request url).
meta={ "u": url }),
self.contentExtractor.getRssLinks())
class RssCrawl(BaseSpider):
"""Initialize a crawl with a starting page by dowloading a RSS feed and all
its entries."""
name = "dummy"
def __init__(self, startAt, domain=None):
"""Instantiate for a given start url and domaine.
@type startAt: string
@param startAt: the starting point of the crawl
@type domain: string
@param domain: the domaine of the crawl
"""
super(RssCrawl, self).__init__(None)
if domain is None:
(_, domain, _, _, _) = urlsplit(startAt)
self.allowed_domains = (domain ,)
self.start_urls = (startAt, )
self.contentExtractor = None
self.bufferedPosts = list()
self.name = "{0}@{1}".format(self.__class__.__name__, domain)
def parse(self, response):
"""Extract the RSS feed Requests from the starting page Response.
@type response: scrapy.http.response.html.HtmlResponse
@param response: the starting page
@rtype: scrapy.http.request.Request
@return: the RSS feed Request
"""
rssLinks = extractRssLinks(parseHTML(response.body), response.url)
nextRequest = lambda _: Request(
url=rssLinks.next(),
callback=self.parseRss,
errback=nextRequest,
dont_filter=True)
try:
return nextRequest(None)
except StopIteration:
self.logError("No usable RSS feed.")
def parseRss(self, response):
"""Extract entry Requests from the RSS feed.
@type response: scrapy.http.response.html.HtmlResponse
@param response: the RSS feed
@rtype: generator of scrapy.http.request.Request
@return: the entry Requests
"""
self.logInfo("Feed: {0}".format(response.url))
self.contentExtractor = ContentExtractor(response.body, self.logInfo)
return imap(
lambda url: Request(
url=url,
callback=self.bufferEntries,
errback=self.bufferEntries,
dont_filter=True,
# meta={ "u": _ } is here to keep a "safe" copy of the source url.
# I don't trust response.url == (what was passed as Request url).
meta={ "u": url }),
self.contentExtractor.getRssLinks())
def bufferEntries(self, response):
"""Buffer the RSS entiry Responses, once there are all here pass the to
the overridable handleRssEntries method.
@type response: scrapy.http.response.html.HtmlResponse
@param response: the RSS feed
@rtype: generator of scrapy.http.request.Request
@return: the entry Requests
"""
self.bufferedPosts.append(response)
if len(self.bufferedPosts) == len(self.contentExtractor.getRssLinks()):
posts = tuple(ifilter(
lambda _: isinstance(_, Response),
self.bufferedPosts))
foreach(lambda _: self.contentExtractor.feed(_.body, _.meta["u"]), posts)
return self.handleRssEntries(posts)
def logDebug(self, string):
"""Log with spider name at debug level.
@type string: string
@param string: the string to log
"""
self.log(string, log.DEBUG)
def logInfo(self, string):
"""Log with spider name at info level.
@type string: string
@param string: the string to log
"""
self.log(string, log.INFO)
def logWarning(self, string):
"""Log with spider name at warning level.
@type string: string
@param string: the string to log
"""
self.log(string, log.WARNING)
def logError(self, string):
"""Log with spider name at error level.
@type string: string
@param string: the string to log
"""
self.log(string, log.ERROR)
def logCritical(self, string):
"""Log with spider name at critical level.
@type string: string
@param string: the string to log
"""
self.log(string, log.CRITICAL)
def handleRssEntries(self, posts):
"""Overridable method to process all RSS entry Responses.
@type posts: scrapy.http.posts.html.HtmlResponse
@param posts: the RSS entries Responses
@rtype: generator of scrapy.http.request.Request and scrapy.item.Item
@return: the next requests and items to process
"""
pass
