class MemoryBaseBackend(Backend):
"""
Base class for in-memory heapq Backend objects.
"""
component_name = 'Memory Base Backend'
def __init__(self, manager):
self.manager = manager
self.requests = {}
self.heap = Heap(self._compare_pages)
@classmethod
def from_manager(cls, manager):
return cls(manager)
def frontier_start(self):
pass
def frontier_stop(self):
pass
def add_seeds(self, seeds):
for seed in seeds:
request, _ = self._get_or_create_request(seed)
self.heap.push(request)
def get_next_requests(self, max_next_requests, **kwargs):
return self.heap.pop(max_next_requests)
def page_crawled(self, response, links):
for link in links:
request, created = self._get_or_create_request(link)
if created:
request.meta['depth'] = response.request.meta.get('depth', 0) + 1
self.heap.push(request)
def request_error(self, request, error):
pass
def _get_or_create_request(self, request):
fingerprint = request.meta['fingerprint']
if fingerprint not in self.requests:
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
else:
page = self.requests[fingerprint]
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
def test_heap_obj(self):
obj = type('obj', (object, ), {})
a = obj()
a.score = 3
b = obj()
b.score = 1
c = obj()
c.score = 2
heap = Heap(lambda x, y: cmp(x.score, y.score))
heap.push(a)
heap.push(b)
heap.push(c)
assert heap.pop(3) == [b, c, a]
assert heap.pop(1) == []
def test_heap_obj(self):
obj = type("obj", (object,), {})
a = obj()
a.score = 3
b = obj()
b.score = 1
c = obj()
c.score = 2
heap = Heap(lambda x, y: cmp(x.score, y.score))
heap.push(a)
heap.push(b)
heap.push(c)
assert heap.pop(3) == [b, c, a]
assert heap.pop(1) == []
def test_heap_order(self):
heap = Heap(cmp)
heap.push(5)
heap.push(2)
heap.push(3)
heap.push(4)
heap.push(1)
assert heap.pop(1) == [1]
assert heap.pop(3) == [2, 3, 4]
assert heap.pop(10) == [5]
assert heap.pop(1) == []
def test_heap_order(self):
heap = Heap(cmp)
heap.push(5)
heap.push(2)
heap.push(3)
heap.push(4)
heap.push(1)
assert heap.pop(1) == [1]
assert heap.pop(3) == [2, 3, 4]
assert heap.pop(10) == [5]
assert heap.pop(1) == []
class HeapTest(unittest.TestCase):
def setUp(self):
self.heap = Heap(compare_request)
def test_push(self):
self.heap.push(req1)
self.heap.push(req2)
assert len(self.heap) == 2
def test_pop0_as_pop0(self):
print len(self.heap)
self.heap.push(req1)
req = self.heap.pop(0)
assert len(req) == 1
assert req[0] == req1
self.heap.push(req1)
req = self.heap.pop(1)
assert len(req) == 1
assert req[0] == req1
def test_pop_smallest_in_heap(self):
self.heap.push(req1)
self.heap.push(req2)
req = self.heap.pop(0)
assert req[0] == req2
def test_push_limit(self):
self.heap = Heap(compare_request, limit=2)
self.heap.push(req1)
self.heap.push(req2)
p = self.heap.push(req3)
assert p == req2
assert len(self.heap) == 2
assert self.heap.pop(2) == [req3, req1]
class MemoryBaseBackend(Backend):
"""
Base class for in-memory heapq Backend objects.
"""
component_name = 'Memory Base Backend'
def __init__(self, manager):
self.manager = manager
self.requests = {}
self.heap = Heap(self._compare_pages)
@classmethod
def from_manager(cls, manager):
return cls(manager)
def frontier_start(self):
pass
def frontier_stop(self):
pass
def add_seeds(self, seeds):
for seed in seeds:
request, _ = self._get_or_create_request(seed)
self.heap.push(request)
def get_next_requests(self, max_next_requests, **kwargs):
return self.heap.pop(max_next_requests)
def page_crawled(self, response, links):
for link in links:
request, created = self._get_or_create_request(link)
if created:
request.meta['depth'] = response.request.meta.get('depth',
0) + 1
self.heap.push(request)
def request_error(self, request, error):
pass
def _get_or_create_request(self, request):
fingerprint = request.meta['fingerprint']
if fingerprint not in self.requests:
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
else:
page = self.requests[fingerprint]
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