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Page/Request instance creation decomposition in backends #10

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merged 1 commit into from
Mar 2, 2015
Merged

Page/Request instance creation decomposition in backends #10

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10 changes: 7 additions & 3 deletions crawlfrontier/contrib/backends/memory/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -48,9 +48,7 @@ def request_error(self, request, error):
def _get_or_create_request(self, request):
fingerprint = request.meta['fingerprint']
if fingerprint not in self.requests:
new_request = request.copy()
new_request.meta['created_at'] = datetime.datetime.utcnow()
new_request.meta['depth'] = 0
new_request = self._create_request(request)
self.requests[fingerprint] = new_request
self.manager.logger.backend.debug('Creating request %s' % new_request)
return new_request, True
Expand All @@ -59,6 +57,12 @@ def _get_or_create_request(self, request):
self.manager.logger.backend.debug('Request exists %s' % request)
return page, False

def _create_request(self, request):
new_request = request.copy()
new_request.meta['created_at'] = datetime.datetime.utcnow()
new_request.meta['depth'] = 0
return new_request

def _compare_pages(self, first, second):
raise NotImplementedError

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36 changes: 24 additions & 12 deletions crawlfrontier/contrib/backends/sqlalchemy/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -122,7 +122,8 @@ def frontier_stop(self):

def add_seeds(self, seeds):
for seed in seeds:
db_page, _ = self._get_or_create_db_page(url=seed.url, fingerprint=seed.meta['fingerprint'])
db_page, _ = self._get_or_create_db_page(url=seed.url, fingerprint=seed.meta['fingerprint'],
request_or_response=seed)
self.session.commit()

def get_next_requests(self, max_next_requests):
Expand All @@ -134,35 +135,34 @@ def get_next_requests(self, max_next_requests):
next_pages = []
for db_page in query:
db_page.state = Page.State.QUEUED
request = self.manager.request_model(url=db_page.url)
request = self._create_request(db_page) # FIXME: we loose all the Request metadata here: methods, meta...
next_pages.append(request)
self.session.commit()
return next_pages

def page_crawled(self, response, links):
db_page, _ = self._get_or_create_db_page(url=response.url, fingerprint=response.meta['fingerprint'])
db_page, _ = self._get_or_create_db_page(url=response.url, fingerprint=response.meta['fingerprint'],
request_or_response=response)
db_page.state = Page.State.CRAWLED
db_page.status_code = response.status_code
# TODO: a performance bottle-neck on big volumes, operations should be batched here
for link in links:
db_page_from_link, created = self._get_or_create_db_page(url=link.url, fingerprint=link.meta['fingerprint'])
db_page_from_link, created = self._get_or_create_db_page(url=link.url, fingerprint=link.meta['fingerprint'],
request_or_response=link)
if created:
db_page_from_link.depth = db_page.depth+1
self.session.commit()

def request_error(self, request, error):
db_page, _ = self._get_or_create_db_page(url=request.url, fingerprint=request.meta['fingerprint'])
db_page, _ = self._get_or_create_db_page(url=request.url, fingerprint=request.meta['fingerprint'],
request_or_response=request)
db_page.state = Page.State.ERROR
db_page.error = error
self.session.commit()

def _get_or_create_db_page(self, url, fingerprint):
def _get_or_create_db_page(self, url, fingerprint, request_or_response):
if not self._request_exists(fingerprint):
db_request = self.page_model()
db_request.fingerprint = fingerprint
db_request.state = Page.State.NOT_CRAWLED
db_request.url = url
db_request.depth = 0
db_request.created_at = datetime.datetime.utcnow()
db_request = self._create_page(url, fingerprint, request_or_response)
self.session.add(db_request)
self.manager.logger.backend.debug('Creating request %s' % db_request)
return db_request, True
Expand All @@ -171,6 +171,18 @@ def _get_or_create_db_page(self, url, fingerprint):
self.manager.logger.backend.debug('Request exists %s' % db_request)
return db_request, False

def _create_page(self, url, fingerprint, request_or_response):
page = self.page_model()
page.fingerprint = fingerprint
page.state = Page.State.NOT_CRAWLED
page.url = url
page.depth = 0
page.created_at = datetime.datetime.utcnow()
return page

def _create_request(self, db_page):
return self.manager.request_model(url=db_page.url)

def _request_exists(self, fingerprint):
q = self.page_model.query(self.session).filter_by(fingerprint=fingerprint)
return self.session.query(q.exists()).scalar()
Expand Down