class Spider(object):
"""
Asynchronous scraping framework.
"""
spider_name = None
# You can define here some urls and initial tasks
# with name "initial" will be created from these
# urls
# If the logic of generating initial tasks is complex
# then consider to use `task_generator` method instead of
# `initial_urls` attribute
initial_urls = []
class Meta:
# pylint: disable=no-init
#
# Meta.abstract means that this class will not be
# collected to spider registry by `grab crawl` CLI command.
# The Meta is inherited by descendant classes BUT
# Meta.abstract is reset to False in each descendant
abstract = True
# *************
# Class Methods
# *************
@classmethod
def update_spider_config(cls, config):
pass
@classmethod
def get_spider_name(cls):
if cls.spider_name:
return cls.spider_name
else:
return camel_case_to_underscore(cls.__name__)
# **************
# Public Methods
# **************
def __init__(
self,
thread_number=None,
network_try_limit=None, task_try_limit=None,
request_pause=NULL,
priority_mode='random',
meta=None,
config=None,
args=None,
parser_requests_per_process=10000,
parser_pool_size=1,
http_api_port=None,
network_service='threaded',
grab_transport='pycurl',
# Deprecated
transport=None,
only_cache=False,
):
"""
Arguments:
* thread-number - Number of concurrent network streams
* network_try_limit - How many times try to send request
again if network error was occurred, use 0 to disable
* task_try_limit - Limit of tries to execute some task
this is not the same as network_try_limit
network try limit limits the number of tries which
are performed automatically in case of network timeout
of some other physical error
but task_try_limit limits the number of attempts which
are scheduled manually in the spider business logic
* priority_mode - could be "random" or "const"
* meta - arbitrary user data
* retry_rebuild_user_agent - generate new random user-agent for each
network request which is performed again due to network error
* args - command line arguments parsed with `setup_arg_parser` method
"""
self.fatal_error_queue = Queue()
self.task_queue_parameters = None
self.http_api_port = http_api_port
self._started = None
assert grab_transport in ('pycurl', 'urllib3')
self.grab_transport_name = grab_transport
self.parser_requests_per_process = parser_requests_per_process
self.stat = Stat()
self.task_queue = None
if args is None:
self.args = {}
else:
self.args = args
if config is not None:
self.config = config
else:
self.config = {}
if meta:
self.meta = meta
else:
self.meta = {}
self.thread_number = (
thread_number or
int(self.config.get('thread_number',
DEFAULT_NETWORK_STREAM_NUMBER)))
self.task_try_limit = (
task_try_limit or
int(self.config.get('task_try_limit', DEFAULT_TASK_TRY_LIMIT)))
self.network_try_limit = (
network_try_limit or
int(self.config.get('network_try_limit',
DEFAULT_NETWORK_TRY_LIMIT)))
self._grab_config = {}
if priority_mode not in ['random', 'const']:
raise SpiderMisuseError('Value of priority_mode option should be '
'"random" or "const"')
else:
self.priority_mode = priority_mode
if only_cache:
raise_feature_is_deprecated('Cache feature')
self.work_allowed = True
if request_pause is not NULL:
warn('Option `request_pause` is deprecated and is not '
'supported anymore')
self.proxylist_enabled = None
self.proxylist = None
self.proxy = None
self.proxy_auto_change = False
self.interrupted = False
self.parser_pool_size = parser_pool_size
self.parser_service = ParserService(
spider=self,
pool_size=self.parser_pool_size,
)
if transport is not None:
warn('The "transport" argument of Spider constructor is'
' deprecated. Use "network_service" argument.')
network_service = transport
assert network_service in ('threaded',)
if network_service == 'threaded':
# pylint: disable=no-name-in-module, import-error
from grab.spider.network_service.threaded import (
NetworkServiceThreaded
)
self.network_service = NetworkServiceThreaded(
self, self.thread_number
)
self.task_dispatcher = TaskDispatcherService(self)
if self.http_api_port:
self.http_api_service = HttpApiService(self)
else:
self.http_api_service = None
self.task_generator_service = TaskGeneratorService(
self.task_generator(), self,
)
def setup_cache(self, *args, **kwargs):
raise_feature_is_deprecated('Cache feature')
def setup_queue(self, backend='memory', **kwargs):
"""
Setup queue.
:param backend: Backend name
Should be one of the following: 'memory', 'redis' or 'mongo'.
:param kwargs: Additional credentials for backend.
"""
if backend == 'mongo':
warn('Backend name "mongo" is deprecated. Use "mongodb" instead.')
backend = 'mongodb'
logger.debug('Using %s backend for task queue', backend)
mod = __import__('grab.spider.queue_backend.%s' % backend,
globals(), locals(), ['foo'])
self.task_queue = mod.QueueBackend(spider_name=self.get_spider_name(),
**kwargs)
def add_task(self, task, queue=None, raise_error=False):
"""
Add task to the task queue.
"""
if queue is None:
queue = self.task_queue
if queue is None:
raise SpiderMisuseError('You should configure task queue before '
'adding tasks. Use `setup_queue` method.')
if task.priority is None or not task.priority_set_explicitly:
task.priority = self.generate_task_priority()
task.priority_set_explicitly = False
else:
task.priority_set_explicitly = True
if not task.url.startswith(('http://', 'https://', 'ftp://',
'file://', 'feed://')):
self.stat.collect('task-with-invalid-url', task.url)
msg = 'Invalid task URL: %s' % task.url
if raise_error:
raise SpiderError(msg)
else:
logger.error(
'%s\nTraceback:\n%s', msg, ''.join(format_stack()),
)
return False
else:
# TODO: keep original task priority if it was set explicitly
# WTF the previous comment means?
queue.put(
task, priority=task.priority, schedule_time=task.schedule_time
)
return True
def stop(self):
"""
This method set internal flag which signal spider
to stop processing new task and shuts down.
"""
self.work_allowed = False
def load_proxylist(self, source, source_type=None, proxy_type='http',
auto_init=True, auto_change=True):
"""
Load proxy list.
:param source: Proxy source.
Accepts string (file path, url) or ``BaseProxySource`` instance.
:param source_type: The type of the specified source.
Should be one of the following: 'text_file' or 'url'.
:param proxy_type:
Should be one of the following: 'socks4', 'socks5' or'http'.
:param auto_change:
If set to `True` then automatical random proxy rotation
will be used.
Proxy source format should be one of the following (for each line):
- ip:port
- ip:port:login:password
"""
self.proxylist = ProxyList()
if isinstance(source, BaseProxySource):
self.proxylist.set_source(source)
elif isinstance(source, six.string_types):
if source_type == 'text_file':
self.proxylist.load_file(source, proxy_type=proxy_type)
elif source_type == 'url':
self.proxylist.load_url(source, proxy_type=proxy_type)
else:
raise SpiderMisuseError('Method `load_proxylist` received '
'invalid `source_type` argument: %s'
% source_type)
else:
raise SpiderMisuseError('Method `load_proxylist` received '
'invalid `source` argument: %s'
% source)
self.proxylist_enabled = True
self.proxy = None
if not auto_change and auto_init:
self.proxy = self.proxylist.get_random_proxy()
self.proxy_auto_change = auto_change
def process_next_page(self, grab, task, xpath,
resolve_base=False, **kwargs):
"""
Generate task for next page.
:param grab: Grab instance
:param task: Task object which should be assigned to next page url
:param xpath: xpath expression which calculates list of URLS
:param **kwargs: extra settings for new task object
Example::
self.follow_links(grab, 'topic', '//div[@class="topic"]/a/@href')
"""
try:
# next_url = grab.xpath_text(xpath)
next_url = grab.doc.select(xpath).text()
except IndexError:
return False
else:
url = grab.make_url_absolute(next_url, resolve_base=resolve_base)
page = task.get('page', 1) + 1
grab2 = grab.clone()
grab2.setup(url=url)
task2 = task.clone(task_try_count=1, grab=grab2,
page=page, **kwargs)
self.add_task(task2)
return True
def render_stats(self, timing=None):
if timing is not None:
warn('Option timing of method render_stats is deprecated.'
' There is no more timing feature.')
out = ['------------ Stats: ------------']
out.append('Counters:')
# Process counters
items = sorted(self.stat.counters.items(),
key=lambda x: x[0], reverse=True)
for item in items:
out.append(' %s: %s' % item)
out.append('')
out.append('Lists:')
# Process collections sorted by size desc
col_sizes = [(x, len(y)) for x, y in self.stat.collections.items()]
col_sizes = sorted(col_sizes, key=lambda x: x[1], reverse=True)
for col_size in col_sizes:
out.append(' %s: %d' % col_size)
out.append('')
# Process extra metrics
if 'download-size' in self.stat.counters:
out.append('Network download: %s' %
metric.format_traffic_value(
self.stat.counters['download-size']))
out.append('Queue size: %d' % self.task_queue.size()
if self.task_queue else 'NA')
out.append('Network streams: %d' % self.thread_number)
if self._started:
elapsed = time.time() - self._started
else:
elapsed = 0
hours, seconds = divmod(elapsed, 3600)
minutes, seconds = divmod(seconds, 60)
out.append('Time elapsed: %d:%d:%d (H:M:S)' % (
hours, minutes, seconds))
out.append('End time: %s' %
datetime.utcnow().strftime('%d %b %Y, %H:%M:%S UTC'))
return '\n'.join(out) + '\n'
# ********************************
# Methods for spider customization
# ********************************
def prepare(self):
"""
You can do additional spider customization here
before it has started working. Simply redefine
this method in your Spider class.
"""
def shutdown(self):
"""
You can override this method to do some final actions
after parsing has been done.
"""
pass
def update_grab_instance(self, grab):
"""
Use this method to automatically update config of any
`Grab` instance created by the spider.
"""
pass
def create_grab_instance(self, **kwargs):
# Back-ward compatibility for deprecated `grab_config` attribute
# Here I use `_grab_config` to not trigger warning messages
kwargs['transport'] = self.grab_transport_name
if self._grab_config and kwargs:
merged_config = deepcopy(self._grab_config)
merged_config.update(kwargs)
grab = Grab(**merged_config)
elif self._grab_config and not kwargs:
grab = Grab(**self._grab_config)
else:
grab = Grab(**kwargs)
return grab
def task_generator(self):
"""
You can override this method to load new tasks smoothly.
It will be used each time as number of tasks
in task queue is less then number of threads multiplied on 2
This allows you to not overload all free memory if total number of
tasks is big.
"""
if False: # pylint: disable=using-constant-test
# Some magic to make this function empty generator
yield ':-)'
return
# ***************
# Private Methods
# ***************
def check_task_limits(self, task):
"""
Check that task's network & try counters do not exceed limits.
Returns:
* if success: (True, None)
* if error: (False, reason)
"""
if task.task_try_count > self.task_try_limit:
return False, 'task-try-count'
if task.network_try_count > self.network_try_limit:
return False, 'network-try-count'
return True, None
def generate_task_priority(self):
if self.priority_mode == 'const':
return DEFAULT_TASK_PRIORITY
else:
return randint(*RANDOM_TASK_PRIORITY_RANGE)
def process_initial_urls(self):
if self.initial_urls:
for url in self.initial_urls:
self.add_task(Task('initial', url=url))
def get_task_from_queue(self):
try:
return self.task_queue.get()
except Empty:
size = self.task_queue.size()
if size:
return True
else:
return None
def setup_grab_for_task(self, task):
grab = self.create_grab_instance()
if task.grab_config:
grab.load_config(task.grab_config)
else:
grab.setup(url=task.url)
# Generate new common headers
grab.config['common_headers'] = grab.common_headers()
self.update_grab_instance(grab)
grab.setup_transport(self.grab_transport_name)
return grab
def is_valid_network_response_code(self, code, task):
"""
Answer the question: if the response could be handled via
usual task handler or the task failed and should be processed as error.
"""
return (code < 400 or code == 404 or
code in task.valid_status)
def process_parser_error(self, func_name, task, exc_info):
_, ex, _ = exc_info
self.stat.inc('spider:error-%s' % ex.__class__.__name__.lower())
logger.error(
'Task handler [%s] error\n%s',
func_name,
''.join(format_exception(*exc_info)),
)
# Looks strange but I really have some problems with
# serializing exception into string
try:
ex_str = six.text_type(ex)
except TypeError:
try:
ex_str = ex.decode('utf-8', 'ignore')
except TypeError:
ex_str = str(ex)
task_url = task.url if task else None
self.stat.collect('fatal', '%s|%s|%s|%s' % (
func_name, ex.__class__.__name__, ex_str, task_url
))
def find_task_handler(self, task):
callback = task.get('callback')
if callback:
return callback
else:
try:
handler = getattr(self, 'task_%s' % task.name)
except AttributeError:
raise NoTaskHandler('No handler or callback defined for '
'task %s' % task.name)
else:
return handler
def log_network_result_stats(self, res, task):
# Increase stat counters
self.stat.inc('spider:request-processed')
self.stat.inc('spider:task')
self.stat.inc('spider:task-%s' % task.name)
if (task.network_try_count == 1 and
task.task_try_count == 1):
self.stat.inc('spider:task-%s-initial' % task.name)
# Update traffic statistics
if res['grab'] and res['grab'].doc:
doc = res['grab'].doc
self.stat.inc('spider:download-size', doc.download_size)
self.stat.inc('spider:upload-size', doc.upload_size)
def process_grab_proxy(self, task, grab):
"""Assign new proxy from proxylist to the task"""
if task.use_proxylist:
if self.proxylist_enabled:
if self.proxy_auto_change:
self.change_active_proxy(task, grab)
if self.proxy:
grab.setup(proxy=self.proxy.get_address(),
proxy_userpwd=self.proxy.get_userpwd(),
proxy_type=self.proxy.proxy_type)
# pylint: disable=unused-argument
def change_active_proxy(self, task, grab):
self.proxy = self.proxylist.get_random_proxy()
# pylint: enable=unused-argument
def submit_task_to_transport(self, task, grab):
grab_config_backup = grab.dump_config()
self.process_grab_proxy(task, grab)
self.stat.inc('spider:request-network')
self.stat.inc('spider:task-%s-network' % task.name)
try:
# pylint: disable=no-member
self.network_service.start_task_processing(
task, grab, grab_config_backup)
# pylint: enable=no-member
except GrabInvalidUrl:
# TODO: log error
# TODO: show traceback
logger.debug('Task %s has invalid URL: %s',
task.name, task.url)
self.stat.collect('invalid-url', task.url)
def run(self):
self._started = time.time()
services = []
try:
self.prepare()
if self.task_queue is None:
self.setup_queue()
self.process_initial_urls()
services = [
self.task_dispatcher,
self.task_generator_service,
self.parser_service,
self.network_service,
]
if self.http_api_service:
self.http_api_service.start()
for srv in services:
srv.start()
while self.work_allowed:
try:
exc_info = self.fatal_error_queue.get(True, 0.5)
except Empty:
pass
else:
# The trackeback of fatal error MUST BE
# rendered by the sender
raise exc_info[1]
if self.is_idle():
for srv in services:
srv.pause()
if self.is_idle():
break
for srv in services:
srv.resume()
except KeyboardInterrupt:
self.interrupted = True
raise
finally:
# TODO:
if self.task_queue:
self.task_queue.close()
#print('Start stopping services')
for srv in services:
# Resume service if it has been paused
# to allow service to process stop signal
srv.resume()
srv.stop()
#print('Called .stop() for all services')
start = time.time()
while any(x.is_alive() for x in services):
time.sleep(0.1)
if time.time() - start > 10:
break
for srv in services:
if srv.is_alive():
print('The %s has not stopped :(' % srv)
self.stat.print_progress_line()
self.shutdown()
if self.task_queue:
self.task_queue.clear()
logger.debug('Work done')
def is_idle(self):
return (
not self.task_generator_service.is_alive()
and not self.task_queue.size()
and not self.task_dispatcher.input_queue.qsize()
and not self.parser_service.input_queue.qsize()
and not self.parser_service.is_busy()
and not self.network_service.get_active_threads_number()
and not self.network_service.is_busy()
)
def log_failed_network_result(self, res):
if res['ok']:
msg = 'http-%s' % res['grab'].doc.code
else:
msg = res['error_abbr']
self.stat.inc('error:%s' % msg)
def log_rejected_task(self, task, reason):
if reason == 'task-try-count':
self.stat.collect('task-count-rejected',
task.url)
elif reason == 'network-try-count':
self.stat.collect('network-count-rejected',
task.url)
else:
raise SpiderError('Unknown response from '
'check_task_limits: %s'
% reason)
# ################
# Deprecated Things
# #################
@property
def cache_reader_service(self):
raise_feature_is_deprecated('Cache feature')
@cache_reader_service.setter
def cache_reader_service(self, val):
raise_feature_is_deprecated('Cache feature')
@property
def cache_writer_service(self):
raise_feature_is_deprecated('Cache feature')
@cache_writer_service.setter
def cache_writer_service(self, val):
raise_feature_is_deprecated('Cache feature')
class Spider(object):
"""
Asynchronous scraping framework.
"""
spider_name = None
# You can define here some urls and initial tasks
# with name "initial" will be created from these
# urls
# If the logic of generating initial tasks is complex
# then consider to use `task_generator` method instead of
# `initial_urls` attribute
initial_urls = []
class Meta:
# pylint: disable=no-init
#
# Meta.abstract means that this class will not be
# collected to spider registry by `grab crawl` CLI command.
# The Meta is inherited by descendant classes BUT
# Meta.abstract is reset to False in each descendant
abstract = True
# *************
# Class Methods
# *************
@classmethod
def update_spider_config(cls, config):
pass
@classmethod
def get_spider_name(cls):
if cls.spider_name:
return cls.spider_name
else:
return camel_case_to_underscore(cls.__name__)
# **************
# Public Methods
# **************
def __init__(
self,
thread_number=None,
network_try_limit=None, task_try_limit=None,
request_pause=NULL,
priority_mode='random',
meta=None,
only_cache=False,
config=None,
args=None,
parser_requests_per_process=10000,
parser_pool_size=1,
http_api_port=None,
network_service='threaded',
grab_transport='pycurl',
# Deprecated
transport=None):
"""
Arguments:
* thread-number - Number of concurrent network streams
* network_try_limit - How many times try to send request
again if network error was occurred, use 0 to disable
* task_try_limit - Limit of tries to execute some task
this is not the same as network_try_limit
network try limit limits the number of tries which
are performed automatically in case of network timeout
of some other physical error
but task_try_limit limits the number of attempts which
are scheduled manually in the spider business logic
* priority_mode - could be "random" or "const"
* meta - arbitrary user data
* retry_rebuild_user_agent - generate new random user-agent for each
network request which is performed again due to network error
* args - command line arguments parsed with `setup_arg_parser` method
"""
self.fatal_error_queue = Queue()
self.task_queue_parameters = None
self.http_api_port = http_api_port
self._started = None
assert grab_transport in ('pycurl', 'urllib3')
self.grab_transport_name = grab_transport
self.parser_requests_per_process = parser_requests_per_process
self.stat = Stat()
self.task_queue = None
if args is None:
self.args = {}
else:
self.args = args
if config is not None:
self.config = config
else:
self.config = {}
if meta:
self.meta = meta
else:
self.meta = {}
self.thread_number = (
thread_number or
int(self.config.get('thread_number',
DEFAULT_NETWORK_STREAM_NUMBER)))
self.task_try_limit = (
task_try_limit or
int(self.config.get('task_try_limit', DEFAULT_TASK_TRY_LIMIT)))
self.network_try_limit = (
network_try_limit or
int(self.config.get('network_try_limit',
DEFAULT_NETWORK_TRY_LIMIT)))
self._grab_config = {}
if priority_mode not in ['random', 'const']:
raise SpiderMisuseError('Value of priority_mode option should be '
'"random" or "const"')
else:
self.priority_mode = priority_mode
self.only_cache = only_cache
self.work_allowed = True
if request_pause is not NULL:
warn('Option `request_pause` is deprecated and is not '
'supported anymore')
self.proxylist_enabled = None
self.proxylist = None
self.proxy = None
self.proxy_auto_change = False
self.interrupted = False
self.cache_reader_service = None
self.cache_writer_service = None
self.parser_pool_size = parser_pool_size
self.parser_service = ParserService(
spider=self,
pool_size=self.parser_pool_size,
)
if transport is not None:
warn('The "transport" argument of Spider constructor is'
' deprecated. Use "network_service" argument.')
network_service = transport
assert network_service in ('threaded',)
if network_service == 'threaded':
# pylint: disable=no-name-in-module, import-error
from grab.spider.network_service.threaded import (
NetworkServiceThreaded
)
self.network_service = NetworkServiceThreaded(
self, self.thread_number
)
self.task_dispatcher = TaskDispatcherService(self)
if self.http_api_port:
self.http_api_service = HttpApiService(self)
else:
self.http_api_service = None
self.task_generator_service = TaskGeneratorService(
self.task_generator(), self,
)
def setup_cache(self, backend='mongodb', database=None,
**kwargs):
"""
Setup cache.
:param backend: Backend name
Should be one of the following: 'mongo', 'mysql' or 'postgresql'.
:param database: Database name.
:param kwargs: Additional credentials for backend.
"""
if database is None:
raise SpiderMisuseError('setup_cache method requires database '
'option')
if backend == 'mongo':
warn('Backend name "mongo" is deprecated. Use "mongodb" instead.')
backend = 'mongodb'
mod = __import__('grab.spider.cache_backend.%s' % backend,
globals(), locals(), ['foo'])
backend = mod.CacheBackend(
database=database, spider=self, **kwargs
)
self.cache_reader_service = CacheReaderService(self, backend)
backend = mod.CacheBackend(
database=database, spider=self, **kwargs
)
self.cache_writer_service = CacheWriterService(self, backend)
def setup_queue(self, backend='memory', **kwargs):
"""
Setup queue.
:param backend: Backend name
Should be one of the following: 'memory', 'redis' or 'mongo'.
:param kwargs: Additional credentials for backend.
"""
if backend == 'mongo':
warn('Backend name "mongo" is deprecated. Use "mongodb" instead.')
backend = 'mongodb'
logger.debug('Using %s backend for task queue', backend)
mod = __import__('grab.spider.queue_backend.%s' % backend,
globals(), locals(), ['foo'])
self.task_queue = mod.QueueBackend(spider_name=self.get_spider_name(),
**kwargs)
def add_task(self, task, queue=None, raise_error=False):
"""
Add task to the task queue.
"""
if queue is None:
if self.cache_reader_service:
queue = self.cache_reader_service.input_queue
else:
queue = self.task_queue
if queue is None:
raise SpiderMisuseError('You should configure task queue before '
'adding tasks. Use `setup_queue` method.')
if task.priority is None or not task.priority_set_explicitly:
task.priority = self.generate_task_priority()
task.priority_set_explicitly = False
else:
task.priority_set_explicitly = True
if not task.url.startswith(('http://', 'https://', 'ftp://',
'file://', 'feed://')):
self.stat.collect('task-with-invalid-url', task.url)
msg = 'Invalid task URL: %s' % task.url
if raise_error:
raise SpiderError(msg)
else:
logger.error(
'%s\nTraceback:\n%s', msg, ''.join(format_stack()),
)
return False
else:
# TODO: keep original task priority if it was set explicitly
# WTF the previous comment means?
queue.put(
task, priority=task.priority, schedule_time=task.schedule_time
)
return True
def stop(self):
"""
This method set internal flag which signal spider
to stop processing new task and shuts down.
"""
self.work_allowed = False
def load_proxylist(self, source, source_type=None, proxy_type='http',
auto_init=True, auto_change=True):
"""
Load proxy list.
:param source: Proxy source.
Accepts string (file path, url) or ``BaseProxySource`` instance.
:param source_type: The type of the specified source.
Should be one of the following: 'text_file' or 'url'.
:param proxy_type:
Should be one of the following: 'socks4', 'socks5' or'http'.
:param auto_change:
If set to `True` then automatical random proxy rotation
will be used.
Proxy source format should be one of the following (for each line):
- ip:port
- ip:port:login:password
"""
self.proxylist = ProxyList()
if isinstance(source, BaseProxySource):
self.proxylist.set_source(source)
elif isinstance(source, six.string_types):
if source_type == 'text_file':
self.proxylist.load_file(source, proxy_type=proxy_type)
elif source_type == 'url':
self.proxylist.load_url(source, proxy_type=proxy_type)
else:
raise SpiderMisuseError('Method `load_proxylist` received '
'invalid `source_type` argument: %s'
% source_type)
else:
raise SpiderMisuseError('Method `load_proxylist` received '
'invalid `source` argument: %s'
% source)
self.proxylist_enabled = True
self.proxy = None
if not auto_change and auto_init:
self.proxy = self.proxylist.get_random_proxy()
self.proxy_auto_change = auto_change
def process_next_page(self, grab, task, xpath,
resolve_base=False, **kwargs):
"""
Generate task for next page.
:param grab: Grab instance
:param task: Task object which should be assigned to next page url
:param xpath: xpath expression which calculates list of URLS
:param **kwargs: extra settings for new task object
Example::
self.follow_links(grab, 'topic', '//div[@class="topic"]/a/@href')
"""
try:
# next_url = grab.xpath_text(xpath)
next_url = grab.doc.select(xpath).text()
except IndexError:
return False
else:
url = grab.make_url_absolute(next_url, resolve_base=resolve_base)
page = task.get('page', 1) + 1
grab2 = grab.clone()
grab2.setup(url=url)
task2 = task.clone(task_try_count=1, grab=grab2,
page=page, **kwargs)
self.add_task(task2)
return True
def render_stats(self, timing=None):
if timing is not None:
warn('Option timing of method render_stats is deprecated.'
' There is no more timing feature.')
out = ['------------ Stats: ------------']
out.append('Counters:')
# Process counters
items = sorted(self.stat.counters.items(),
key=lambda x: x[0], reverse=True)
for item in items:
out.append(' %s: %s' % item)
out.append('')
out.append('Lists:')
# Process collections sorted by size desc
col_sizes = [(x, len(y)) for x, y in self.stat.collections.items()]
col_sizes = sorted(col_sizes, key=lambda x: x[1], reverse=True)
for col_size in col_sizes:
out.append(' %s: %d' % col_size)
out.append('')
# Process extra metrics
if 'download-size' in self.stat.counters:
out.append('Network download: %s' %
metric.format_traffic_value(
self.stat.counters['download-size']))
out.append('Queue size: %d' % self.task_queue.size()
if self.task_queue else 'NA')
out.append('Network streams: %d' % self.thread_number)
if self._started:
elapsed = time.time() - self._started
else:
elapsed = 0
hours, seconds = divmod(elapsed, 3600)
minutes, seconds = divmod(seconds, 60)
out.append('Time elapsed: %d:%d:%d (H:M:S)' % (
hours, minutes, seconds))
out.append('End time: %s' %
datetime.utcnow().strftime('%d %b %Y, %H:%M:%S UTC'))
return '\n'.join(out) + '\n'
# ********************************
# Methods for spider customization
# ********************************
def prepare(self):
"""
You can do additional spider customization here
before it has started working. Simply redefine
this method in your Spider class.
"""
def shutdown(self):
"""
You can override this method to do some final actions
after parsing has been done.
"""
pass
def update_grab_instance(self, grab):
"""
Use this method to automatically update config of any
`Grab` instance created by the spider.
"""
pass
def create_grab_instance(self, **kwargs):
# Back-ward compatibility for deprecated `grab_config` attribute
# Here I use `_grab_config` to not trigger warning messages
kwargs['transport'] = self.grab_transport_name
if self._grab_config and kwargs:
merged_config = deepcopy(self._grab_config)
merged_config.update(kwargs)
grab = Grab(**merged_config)
elif self._grab_config and not kwargs:
grab = Grab(**self._grab_config)
else:
grab = Grab(**kwargs)
return grab
def task_generator(self):
"""
You can override this method to load new tasks smoothly.
It will be used each time as number of tasks
in task queue is less then number of threads multiplied on 2
This allows you to not overload all free memory if total number of
tasks is big.
"""
if False: # pylint: disable=using-constant-test
# Some magic to make this function empty generator
yield ':-)'
return
# ***************
# Private Methods
# ***************
def check_task_limits(self, task):
"""
Check that task's network & try counters do not exceed limits.
Returns:
* if success: (True, None)
* if error: (False, reason)
"""
if task.task_try_count > self.task_try_limit:
return False, 'task-try-count'
if task.network_try_count > self.network_try_limit:
return False, 'network-try-count'
return True, None
def generate_task_priority(self):
if self.priority_mode == 'const':
return DEFAULT_TASK_PRIORITY
else:
return randint(*RANDOM_TASK_PRIORITY_RANGE)
def process_initial_urls(self):
if self.initial_urls:
for url in self.initial_urls:
self.add_task(Task('initial', url=url))
def get_task_from_queue(self):
try:
return self.task_queue.get()
except Empty:
size = self.task_queue.size()
if size:
return True
else:
return None
def setup_grab_for_task(self, task):
grab = self.create_grab_instance()
if task.grab_config:
grab.load_config(task.grab_config)
else:
grab.setup(url=task.url)
# Generate new common headers
grab.config['common_headers'] = grab.common_headers()
self.update_grab_instance(grab)
grab.setup_transport(self.grab_transport_name)
return grab
def is_valid_network_response_code(self, code, task):
"""
Answer the question: if the response could be handled via
usual task handler or the task failed and should be processed as error.
"""
return (code < 400 or code == 404 or
code in task.valid_status)
def process_parser_error(self, func_name, task, exc_info):
_, ex, _ = exc_info
self.stat.inc('spider:error-%s' % ex.__class__.__name__.lower())
logger.error(
'Task handler [%s] error\n%s',
func_name,
''.join(format_exception(*exc_info)),
)
# Looks strange but I really have some problems with
# serializing exception into string
try:
ex_str = six.text_type(ex)
except TypeError:
try:
ex_str = ex.decode('utf-8', 'ignore')
except TypeError:
ex_str = str(ex)
task_url = task.url if task else None
self.stat.collect('fatal', '%s|%s|%s|%s' % (
func_name, ex.__class__.__name__, ex_str, task_url
))
def find_task_handler(self, task):
callback = task.get('callback')
if callback:
return callback
else:
try:
handler = getattr(self, 'task_%s' % task.name)
except AttributeError:
raise NoTaskHandler('No handler or callback defined for '
'task %s' % task.name)
else:
return handler
def log_network_result_stats(self, res, task):
# Increase stat counters
self.stat.inc('spider:request-processed')
self.stat.inc('spider:task')
self.stat.inc('spider:task-%s' % task.name)
if (task.network_try_count == 1 and
task.task_try_count == 1):
self.stat.inc('spider:task-%s-initial' % task.name)
# Update traffic statistics
if res['grab'] and res['grab'].doc:
doc = res['grab'].doc
if res.get('from_cache'):
self.stat.inc('spider:download-size-with-cache',
doc.download_size)
self.stat.inc('spider:upload-size-with-cache',
doc.upload_size)
else:
self.stat.inc('spider:download-size', doc.download_size)
self.stat.inc('spider:upload-size', doc.upload_size)
def process_grab_proxy(self, task, grab):
"""Assign new proxy from proxylist to the task"""
if task.use_proxylist:
if self.proxylist_enabled:
if self.proxy_auto_change:
self.change_active_proxy(task, grab)
if self.proxy:
grab.setup(proxy=self.proxy.get_address(),
proxy_userpwd=self.proxy.get_userpwd(),
proxy_type=self.proxy.proxy_type)
# pylint: disable=unused-argument
def change_active_proxy(self, task, grab):
self.proxy = self.proxylist.get_random_proxy()
# pylint: enable=unused-argument
def submit_task_to_transport(self, task, grab):
if self.only_cache:
self.stat.inc('spider:request-network-disabled-only-cache')
else:
grab_config_backup = grab.dump_config()
self.process_grab_proxy(task, grab)
self.stat.inc('spider:request-network')
self.stat.inc('spider:task-%s-network' % task.name)
try:
# pylint: disable=no-member
self.network_service.start_task_processing(
task, grab, grab_config_backup)
# pylint: enable=no-member
except GrabInvalidUrl:
# TODO: log error
# TODO: show traceback
logger.debug('Task %s has invalid URL: %s',
task.name, task.url)
self.stat.collect('invalid-url', task.url)
def run(self):
self._started = time.time()
services = []
try:
self.prepare()
if self.task_queue is None:
self.setup_queue()
self.process_initial_urls()
services = [
self.task_dispatcher,
self.task_generator_service,
self.parser_service,
self.network_service,
]
if self.http_api_service:
self.http_api_service.start()
if self.cache_reader_service:
services.insert(0, self.cache_reader_service)
if self.cache_writer_service:
services.insert(0, self.cache_writer_service)
for srv in services:
srv.start()
while self.work_allowed:
try:
exc_info = self.fatal_error_queue.get(True, 0.5)
except Empty:
pass
else:
# The trackeback of fatal error MUST BE
# rendered by the sender
raise exc_info[1]
if self.is_idle():
for srv in services:
srv.pause()
if self.is_idle():
break
for srv in services:
srv.resume()
except KeyboardInterrupt:
self.interrupted = True
raise
finally:
# TODO:
if self.task_queue:
self.task_queue.close()
#print('Start stopping services')
for srv in services:
# Resume service if it has been paused
# to allow service to process stop signal
srv.resume()
srv.stop()
#print('Called .stop() for all services')
start = time.time()
while any(x.is_alive() for x in services):
time.sleep(0.1)
if time.time() - start > 10:
break
for srv in services:
if srv.is_alive():
print('The %s has not stopped :(' % srv)
self.stat.print_progress_line()
self.shutdown()
if self.task_queue:
self.task_queue.clear()
logger.debug('Work done')
def is_idle(self):
result = (
not self.task_generator_service.is_alive()
and not self.task_queue.size()
and not self.task_dispatcher.input_queue.qsize()
and not self.parser_service.input_queue.qsize()
and not self.parser_service.is_busy()
and not self.network_service.get_active_threads_number()
and not self.network_service.is_busy()
)
if result and self.cache_reader_service:
result = result and (
not self.cache_reader_service.input_queue.size()
and not self.cache_writer_service.input_queue.qsize()
)
return result
def log_failed_network_result(self, res):
if res['ok']:
msg = 'http-%s' % res['grab'].doc.code
else:
msg = res['error_abbr']
self.stat.inc('error:%s' % msg)
def log_rejected_task(self, task, reason):
if reason == 'task-try-count':
self.stat.collect('task-count-rejected',
task.url)
elif reason == 'network-try-count':
self.stat.collect('network-count-rejected',
task.url)
else:
raise SpiderError('Unknown response from '
'check_task_limits: %s'
% reason)
def __init__(
self,
thread_number=None,
network_try_limit=None, task_try_limit=None,
request_pause=NULL,
priority_mode='random',
meta=None,
config=None,
args=None,
parser_requests_per_process=10000,
parser_pool_size=1,
http_api_port=None,
network_service='threaded',
grab_transport='pycurl',
# Deprecated
transport=None,
only_cache=False,
):
"""
Arguments:
* thread-number - Number of concurrent network streams
* network_try_limit - How many times try to send request
again if network error was occurred, use 0 to disable
* task_try_limit - Limit of tries to execute some task
this is not the same as network_try_limit
network try limit limits the number of tries which
are performed automatically in case of network timeout
of some other physical error
but task_try_limit limits the number of attempts which
are scheduled manually in the spider business logic
* priority_mode - could be "random" or "const"
* meta - arbitrary user data
* retry_rebuild_user_agent - generate new random user-agent for each
network request which is performed again due to network error
* args - command line arguments parsed with `setup_arg_parser` method
"""
self.fatal_error_queue = Queue()
self.task_queue_parameters = None
self.http_api_port = http_api_port
self._started = None
assert grab_transport in ('pycurl', 'urllib3')
self.grab_transport_name = grab_transport
self.parser_requests_per_process = parser_requests_per_process
self.stat = Stat()
self.task_queue = None
if args is None:
self.args = {}
else:
self.args = args
if config is not None:
self.config = config
else:
self.config = {}
if meta:
self.meta = meta
else:
self.meta = {}
self.thread_number = (
thread_number or
int(self.config.get('thread_number',
DEFAULT_NETWORK_STREAM_NUMBER)))
self.task_try_limit = (
task_try_limit or
int(self.config.get('task_try_limit', DEFAULT_TASK_TRY_LIMIT)))
self.network_try_limit = (
network_try_limit or
int(self.config.get('network_try_limit',
DEFAULT_NETWORK_TRY_LIMIT)))
self._grab_config = {}
if priority_mode not in ['random', 'const']:
raise SpiderMisuseError('Value of priority_mode option should be '
'"random" or "const"')
else:
self.priority_mode = priority_mode
if only_cache:
raise_feature_is_deprecated('Cache feature')
self.work_allowed = True
if request_pause is not NULL:
warn('Option `request_pause` is deprecated and is not '
'supported anymore')
self.proxylist_enabled = None
self.proxylist = None
self.proxy = None
self.proxy_auto_change = False
self.interrupted = False
self.parser_pool_size = parser_pool_size
self.parser_service = ParserService(
spider=self,
pool_size=self.parser_pool_size,
)
if transport is not None:
warn('The "transport" argument of Spider constructor is'
' deprecated. Use "network_service" argument.')
network_service = transport
assert network_service in ('threaded',)
if network_service == 'threaded':
# pylint: disable=no-name-in-module, import-error
from grab.spider.network_service.threaded import (
NetworkServiceThreaded
)
self.network_service = NetworkServiceThreaded(
self, self.thread_number
)
self.task_dispatcher = TaskDispatcherService(self)
if self.http_api_port:
self.http_api_service = HttpApiService(self)
else:
self.http_api_service = None
self.task_generator_service = TaskGeneratorService(
self.task_generator(), self,
)
def __init__(
self,
thread_number=None,
network_try_limit=None, task_try_limit=None,
request_pause=NULL,
priority_mode='random',
meta=None,
only_cache=False,
config=None,
args=None,
parser_requests_per_process=10000,
parser_pool_size=1,
http_api_port=None,
network_service='threaded',
grab_transport='pycurl',
# Deprecated
transport=None):
"""
Arguments:
* thread-number - Number of concurrent network streams
* network_try_limit - How many times try to send request
again if network error was occurred, use 0 to disable
* task_try_limit - Limit of tries to execute some task
this is not the same as network_try_limit
network try limit limits the number of tries which
are performed automatically in case of network timeout
of some other physical error
but task_try_limit limits the number of attempts which
are scheduled manually in the spider business logic
* priority_mode - could be "random" or "const"
* meta - arbitrary user data
* retry_rebuild_user_agent - generate new random user-agent for each
network request which is performed again due to network error
* args - command line arguments parsed with `setup_arg_parser` method
"""
self.fatal_error_queue = Queue()
self.task_queue_parameters = None
self.http_api_port = http_api_port
self._started = None
assert grab_transport in ('pycurl', 'urllib3')
self.grab_transport_name = grab_transport
self.parser_requests_per_process = parser_requests_per_process
self.stat = Stat()
self.task_queue = None
if args is None:
self.args = {}
else:
self.args = args
if config is not None:
self.config = config
else:
self.config = {}
if meta:
self.meta = meta
else:
self.meta = {}
self.thread_number = (
thread_number or
int(self.config.get('thread_number',
DEFAULT_NETWORK_STREAM_NUMBER)))
self.task_try_limit = (
task_try_limit or
int(self.config.get('task_try_limit', DEFAULT_TASK_TRY_LIMIT)))
self.network_try_limit = (
network_try_limit or
int(self.config.get('network_try_limit',
DEFAULT_NETWORK_TRY_LIMIT)))
self._grab_config = {}
if priority_mode not in ['random', 'const']:
raise SpiderMisuseError('Value of priority_mode option should be '
'"random" or "const"')
else:
self.priority_mode = priority_mode
self.only_cache = only_cache
self.work_allowed = True
if request_pause is not NULL:
warn('Option `request_pause` is deprecated and is not '
'supported anymore')
self.proxylist_enabled = None
self.proxylist = None
self.proxy = None
self.proxy_auto_change = False
self.interrupted = False
self.cache_reader_service = None
self.cache_writer_service = None
self.parser_pool_size = parser_pool_size
self.parser_service = ParserService(
spider=self,
pool_size=self.parser_pool_size,
)
if transport is not None:
warn('The "transport" argument of Spider constructor is'
' deprecated. Use "network_service" argument.')
network_service = transport
assert network_service in ('threaded',)
if network_service == 'threaded':
# pylint: disable=no-name-in-module, import-error
from grab.spider.network_service.threaded import (
NetworkServiceThreaded
)
self.network_service = NetworkServiceThreaded(
self, self.thread_number
)
self.task_dispatcher = TaskDispatcherService(self)
if self.http_api_port:
self.http_api_service = HttpApiService(self)
else:
self.http_api_service = None
self.task_generator_service = TaskGeneratorService(
self.task_generator(), self,
)