class NewCrawl(RssCrawl):
"""newcrawl"""
name = "newcrawl"
def __init__(self, startat, maxdownloads=None):
"""Instantiate a newcrawl spider for a given start url maxdownloads.
@type startat: string
@param startat: the starting point of the crawl
@type maxdownloads: integer
@param maxdownloads: the maximum number of pages to download
"""
super(self.__class__, self).__init__(startat)
self.maxDownloads = maxdownloads
self.downloadsSoFar = 0
self.seen = set()
self.isBlogPost = None
self.priorityHeuristic = None
def handleRssEntries(self, posts):
"""Handles all web-feed entries."""
self.isBlogPost = buildUrlFilter(
imap(lambda _: _.url, posts),
self.logDebug)
self.priorityHeuristic = PriorityHeuristic(self.isBlogPost)
return iflatmap(lambda _: self.crawl(_), posts)
def crawl(self, response):
"""Recursive crawling function emitting both PostItems in the item
pipeline and further requests to be crawled.
"""
parsedBody = parseHTML(response.body)
if self.maxDownloads and self.downloadsSoFar > self.maxDownloads:
reactor.stop()
elif self.isBlogPost(response.url):
# self.logInfo("> " + response.url)
self.downloadsSoFar += 1
yield PostItem(url=response.url, parsedBodies=(parsedBody,))
newUrls = set(ifilter(
lambda _: _ not in self.seen,
extractLinks(parsedBody)))
self.seen.update(newUrls)
self.priorityHeuristic.feed(response.url, newUrls)
for newUrl in newUrls:
yield Request(
url=newUrl,
callback=self.crawl,
priority=self.priorityHeuristic(newUrl))
def handleRssEntries(self, posts):
"""Handles all web-feed entries."""
self.isBlogPost = buildUrlFilter(
imap(lambda _: _.url, posts),
self.logDebug)
self.priorityHeuristic = PriorityHeuristic(self.isBlogPost)
return iflatmap(lambda _: self.crawl(_), posts)
