Source code for grab.base

# -*- coding: utf-8 -*-
# Copyright: 2011, Grigoriy Petukhov
# Author: Grigoriy Petukhov (
# License: BSD
The core of grab package: the Grab class.
import logging
import os
from random import randint
from copy import copy, deepcopy
import threading
import itertools
import collections
import email
from datetime import datetime
import weakref

import six
from six.moves.urllib.parse import urljoin
from weblib.html import find_base_url
from weblib.http import normalize_http_values, normalize_unicode

from grab.document import Document
from grab import error
from grab.cookie import CookieManager
from grab.proxylist import ProxyList, parse_proxy_line
from grab.deprecated import DeprecatedThings

__all__ = ('Grab',)
# This counter will used in enumerating network queries.
# Its value will be displayed in logging messages and also used
# in names of dumps
# I use mutable module variable to allow different
# instances of Grab to maintain single counter
# This could be helpful in debugging when your script
# creates multiple Grab instances - in case of shared counter
# grab instances do not overwrite dump logs
REQUEST_COUNTER = itertools.count(1)
    'dom_build_time': 0,
MUTABLE_CONFIG_KEYS = ('post', 'multipart_post', 'headers', 'cookies')
    'pycurl': 'grab.transport.curl.CurlTransport',
    'urllib3': 'grab.transport.urllib3.Urllib3Transport',

# pylint: disable=invalid-name
logger = logging.getLogger('grab.base')
# Logger to handle network activity
# It is done as separate logger to allow you easily
# control network logging separately from other grab logs
logger_network = logging.getLogger('')
# pylint: enable=invalid-name

def copy_config(config, mutable_config_keys=MUTABLE_CONFIG_KEYS):
    Copy grab config with correct handling of mutable config values.

    cloned_config = copy(config)
    # Apply ``copy`` function to mutable config values
    for key in mutable_config_keys:
        cloned_config[key] = copy(config[key])
    return cloned_config

def default_config():
    # TODO: Maybe config should be splitted into two entities:
    # 1) config which is not changed during request
    # 2) changeable settings
    return dict(
        # Common

        # Debugging
        # Only for curl transport

        # Only for selenium transport
        selenium_wait=1,  # in seconds

        # Proxy

        # Method, Post

        # Headers, User-Agent, Referer

        # Cookies

        # Timeouts

        # Connection

        # Response processing

        # Content compression

        # Network interface

        # Redirects

        # Authentication

        # Character set to which any unicode data should be encoded
        # before get placed in request
        # This setting is overwritten after each request with
        # charset of retrieved document

        # Charset to use for converting content of response
        # into unicode, by default it is detected automatically

        # Content type control how DOM are built
        # For html type HTML DOM builder is used
        # For xml type XML DOM builder is used

        # Fix &#X; entities, where X between 128 and 160
        # Such entities are parsed by modern browsers as
        # windows-1251 entities independently of the real charset of
        # the document, If this option is True then such entities
        # will be replaced with correct unicode entities e.g.:
        # — ->  —

        # Convert document body to lower case before building LXML tree
        # It does not affect `self.doc.body`

        # Strip null bytes from document body before building lXML tree
        # It does not affect `self.doc.body`

        # Internal object to store

[docs]class Grab(DeprecatedThings): __slots__ = ( 'request_head', 'request_body', #'request_log', 'proxylist', 'config', 'transport', 'transport_param', 'request_method', 'request_counter', '__weakref__', 'cookies', 'meta', 'exception', # Dirty hack to make it possible to inherit Grab from # multiple base classes with __slots__ '_doc', ) # Attributes which should be processed when clone # of Grab instance is creating clonable_attributes = ('request_head', 'request_body', #'request_log', 'proxylist') # Complex config items which points to mutable objects mutable_config_keys = copy(MUTABLE_CONFIG_KEYS) # # Public methods #
[docs] def __init__(self, document_body=None, transport=None, **kwargs): """ Create Grab instance """ self.meta = {} self._doc = None self.config = default_config() self.config['common_headers'] = self.common_headers() self.cookies = CookieManager() self.proxylist = ProxyList() self.exception = None # makes pylint happy self.request_counter = None self.request_head = None self.request_body = None self.request_method = None self.transport_param = transport self.transport = None self.reset() if kwargs: self.setup(**kwargs) if document_body is not None: self.setup_document(document_body)
def _get_doc(self): if self._doc is None: self._doc = Document(self) return self._doc def _set_doc(self, obj): self._doc = obj doc = property(_get_doc, _set_doc)
[docs] def setup_transport(self, transport_param, reset=False): if self.transport is not None and not reset: raise error.GrabMisuseError( 'Transport is already set up. Use' ' setup_transport(..., reset=True) to explicitly setup' ' new transport') if transport_param is None: transport_param = DEFAULT_TRANSPORT if isinstance(transport_param, six.string_types): if transport_param in TRANSPORT_ALIAS: transport_param = TRANSPORT_ALIAS[transport_param] if '.' not in transport_param: raise error.GrabMisuseError('Unknown transport: %s' % transport_param) else: mod_path, cls_name = transport_param.rsplit('.', 1) try: cls = TRANSPORT_CACHE[(mod_path, cls_name)] except KeyError: mod = __import__(mod_path, globals(), locals(), ['foo']) cls = getattr(mod, cls_name) TRANSPORT_CACHE[(mod_path, cls_name)] = cls self.transport = cls() elif isinstance(transport_param, collections.Callable): self.transport = transport_param() else: raise error.GrabMisuseError('Option `transport` should be string ' 'or class or callable. Got %s' % type(transport_param))
[docs] def reset(self): """ Reset all attributes which could be modified during previous request or which is not initialized yet if this is the new Grab instance. This methods is automatically called before each network request. """ self.request_head = None #self.request_log = None self.request_body = None self.request_method = None self.request_counter = None self.exception = None if self.transport: self.transport.reset()
[docs] def clone(self, **kwargs): """ Create clone of Grab instance. Cloned instance will have the same state: cookies, referrer, response document data :param **kwargs: overrides settings of cloned grab instance """ grab = Grab(transport=self.transport_param) grab.config = self.dump_config() grab.doc = self.doc.copy() grab.doc.grab = weakref.proxy(grab) for key in self.clonable_attributes: setattr(grab, key, getattr(self, key)) grab.cookies = deepcopy(self.cookies) if kwargs: grab.setup(**kwargs) return grab
[docs] def adopt(self, grab): """ Copy the state of another `Grab` instance. Use case: create backup of current state to the cloned instance and then restore the state from it. """ self.load_config(grab.config) self.doc = grab.doc.copy(new_grab=self) for key in self.clonable_attributes: setattr(self, key, getattr(grab, key)) self.cookies = deepcopy(grab.cookies)
[docs] def dump_config(self): """ Make clone of current config. """ conf = copy_config(self.config, self.mutable_config_keys) conf['state'] = { 'cookiejar_cookies': list(self.cookies.cookiejar), } return conf
[docs] def load_config(self, config): """ Configure grab instance with external config object. """ self.config = copy_config(config, self.mutable_config_keys) if 'cookiejar_cookies' in config['state']: self.cookies = CookieManager.from_cookie_list( config['state']['cookiejar_cookies'])
[docs] def setup(self, **kwargs): """ Setting up Grab instance configuration. """ for key in kwargs: if key not in self.config.keys(): raise error.GrabMisuseError('Unknown option: %s' % key) if 'url' in kwargs: if self.config.get('url'): kwargs['url'] = self.make_url_absolute(kwargs['url']) self.config.update(kwargs)
[docs] def go(self, url, **kwargs): # pylint: disable=invalid-name """ Go to ``url`` Args: :url: could be absolute or relative. If relative then t will be appended to the absolute URL of previous request. """ return self.request(url=url, **kwargs)
[docs] def download(self, url, location, **kwargs): """ Fetch document located at ``url`` and save to to ``location``. """ doc = self.go(url, **kwargs) with open(location, 'wb') as out: out.write(doc.body) return len(doc.body)
def prepare_request(self, **kwargs): """ Configure all things to make real network request. This method is called before doing real request via transport extension. """ if self.transport is None: self.setup_transport(self.transport_param) self.reset() self.request_counter = next(REQUEST_COUNTER) if kwargs: self.setup(**kwargs) if self.proxylist.size() and self.config['proxy_auto_change']: self.change_proxy() self.request_method = self.detect_request_method() self.transport.process_config(self) def log_request(self, extra=''): """ Send request details to logging system. """ # pylint: disable=no-member thread_name = threading.currentThread().getName().lower() # pylint: enable=no-member if thread_name == 'mainthread': thread_name = '' else: thread_name = '-%s' % thread_name if self.config['proxy']: if self.config['proxy_userpwd']: auth = ' with authorization' else: auth = '' proxy_info = ' via %s proxy of type %s%s' % ( self.config['proxy'], self.config['proxy_type'], auth) else: proxy_info = '' if extra: extra = '[%s] ' % extra logger_network.debug( '[%s%s] %s%s %s%s', ('%02d' % self.request_counter if self.request_counter is not None else 'NA'), thread_name, extra, self.request_method or 'GET', self.config['url'], proxy_info)
[docs] def request(self, **kwargs): """ Perform network request. You can specify grab settings in ``**kwargs``. Any keyword argument will be passed to ``self.config``. Returns: ``Document`` objects. """ self.prepare_request(**kwargs) refresh_count = 0 while True: self.log_request() try: self.transport.request() except error.GrabError as ex: self.exception = ex self.reset_temporary_options() if self.config['log_dir']: self.save_failed_dump() raise else: doc = self.process_request_result() if self.config['follow_location']: if doc.code in (301, 302, 303, 307, 308): if doc.headers.get('Location'): refresh_count += 1 if refresh_count > self.config['redirect_limit']: raise error.GrabTooManyRedirectsError() else: url = doc.headers.get('Location') self.prepare_request( url=self.make_url_absolute(url), referer=None) continue if self.config['follow_refresh']: refresh_url = self.doc.get_meta_refresh_url() if refresh_url is not None: refresh_count += 1 if refresh_count > self.config['redirect_limit']: raise error.GrabTooManyRedirectsError() else: self.prepare_request( url=self.make_url_absolute(refresh_url), referer=None) continue return doc
def process_request_result(self, prepare_response_func=None): """ Process result of real request performed via transport extension. """ now = datetime.utcnow() # TODO: move into separate method if self.config['debug_post']: post = self.config['post'] or self.config['multipart_post'] if isinstance(post, dict): post = list(post.items()) if post: if isinstance(post, six.string_types): post = normalize_unicode( post[:self.config['debug_post_limit']]) + b'...' else: items = normalize_http_values( post, charset=self.config['charset']) new_items = [] for key, value in items: if len(value) > self.config['debug_post_limit']: value = value[ :self.config['debug_post_limit']] + b'...' else: value = value new_items.append((key, value)) post = '\n'.join('%-25s: %s' % x for x in new_items) if post: logger_network.debug('[%02d] POST request:\n%s\n', self.request_counter, post) # It's important to delete old POST data after request is performed. # If POST data is not cleared then next request will try to use them # again! self.reset_temporary_options() if prepare_response_func: self.doc = prepare_response_func(self.transport, self) else: self.doc = self.transport.prepare_response(self) # Workaround if self.doc.grab is None: self.doc.grab = weakref.proxy(self) if self.config['reuse_cookies']: self.cookies.update(self.doc.cookies) self.doc.timestamp = now self.config['charset'] = self.doc.charset if self.config['log_file']: with open(self.config['log_file'], 'wb') as out: out.write(self.doc.body) if self.config['cookiefile']: self.cookies.save_to_file(self.config['cookiefile']) if self.config['reuse_referer']: self.config['referer'] = self.doc.url self.copy_request_data() # Should be called after `copy_request_data` if self.config['log_dir']: self.save_dumps() return self.doc def reset_temporary_options(self): self.config['post'] = None self.config['multipart_post'] = None self.config['method'] = None self.config['body_storage_filename'] = None def save_failed_dump(self): """ Save dump of failed request for debugging. This method is called then fatal network exception is raised. The saved dump could be used for debugging the reason of the failure. """ # try/except for safety, to not break live spiders try: # FIXME if (self.transport.__class__.__name__ == 'Urllib3Transport' and not getattr(self.transport, '_response', None)): self.doc = None else: self.doc = self.transport.prepare_response(self) self.copy_request_data() self.save_dumps() except Exception as ex: # pylint: disable=broad-except logger.error('', exc_info=ex) def copy_request_data(self): # TODO: Maybe request object? self.request_head = self.transport.request_head self.request_body = self.transport.request_body #self.request_log = self.transport.request_log def setup_document(self, content, **kwargs): """ Setup `response` object without real network requests. Useful for testing and debuging. All ``**kwargs`` will be passed to `Document` constructor. """ self.reset() if isinstance(content, six.text_type): raise error.GrabMisuseError('Method `setup_document` accepts only ' 'byte string in `content` argument.') # Configure Document instance doc = Document(grab=self) doc.body = content doc.status = '' doc.head = b'HTTP/1.1 200 OK\r\n\r\n' doc.parse(charset=kwargs.get('document_charset')) doc.code = 200 doc.total_time = 0 doc.connect_time = 0 doc.name_lookup_time = 0 doc.url = '' for key, value in kwargs.items(): setattr(doc, key, value) self.doc = doc
[docs] def change_proxy(self, random=True): """ Set random proxy from proxylist. """ if self.proxylist.size(): if random: proxy = self.proxylist.get_random_proxy() else: proxy = self.proxylist.get_next_proxy() self.setup(proxy=proxy.get_address(), proxy_userpwd=proxy.get_userpwd(), proxy_type=proxy.proxy_type) else: logger.debug('Proxy list is empty')
# # Private methods # @classmethod def common_headers(cls): """ Build headers which sends typical browser. """ return { 'Accept': 'text/xml,application/xml,application/xhtml+xml' ',text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.%d' % randint(2, 5), 'Accept-Language': 'en-us,en;q=0.%d' % (randint(5, 9)), 'Accept-Charset': 'utf-8,windows-1251;q=0.7,*;q=0.%d' % randint(5, 7), 'Keep-Alive': '300', } def save_dumps(self): # pylint: disable=no-member thread_name = threading.currentThread().getName().lower() # pylint: enable=no-member if thread_name == 'mainthread': thread_name = '' else: thread_name = '-%s' % thread_name file_name = os.path.join(self.config['log_dir'], '%02d%s.log' % ( self.request_counter, thread_name)) with open(file_name, 'wb') as out: out.write(b'Request headers:\n') out.write(self.request_head) out.write(b'\n') out.write(b'Request body:\n') out.write(self.request_body) out.write(b'\n\n') out.write(b'Response headers:\n') out.write(self.doc.head if (self.doc and self.doc.head) else b'') file_extension = 'html' file_name = os.path.join(self.config['log_dir'], '%02d%s.%s' % ( self.request_counter, thread_name, file_extension))
[docs] def make_url_absolute(self, url, resolve_base=False): """ Make url absolute using previous request url as base url. """ if self.config['url']: if resolve_base: ubody = self.doc.unicode_body() base_url = find_base_url(ubody) if base_url: return urljoin(base_url, url) return urljoin(self.config['url'], url) else: return url
def detect_request_method(self): """ Analyze request config and find which request method will be used. Returns request method in upper case This method needs simetime when `process_config` method was not called yet. """ method = self.config['method'] if method: method = method.upper() else: if self.config['post'] or self.config['multipart_post']: method = 'POST' else: method = 'GET' return method
[docs] def clear_cookies(self): """ Clear all remembered cookies. """ self.config['cookies'] = {} self.cookies.clear()
[docs] def setup_with_proxyline(self, line, proxy_type='http'): # TODO: remove from base class # maybe to proxylist? host, port, user, pwd = parse_proxy_line(line) server_port = '%s:%s' % (host, port) self.setup(proxy=server_port, proxy_type=proxy_type) if user: userpwd = '%s:%s' % (user, pwd) self.setup(proxy_userpwd=userpwd)
def __getstate__(self): """ Reset cached lxml objects which could not be pickled. """ state = {} for cls in type(self).mro(): cls_slots = getattr(cls, '__slots__', ()) for slot in cls_slots: if slot != '__weakref__': if hasattr(self, slot): state[slot] = getattr(self, slot) if state['_doc']: state['_doc'].grab = weakref.proxy(self) return state def __setstate__(self, state): for slot, value in state.items(): setattr(self, slot, value) @property def request_headers(self): first_head = self.request_head.decode('utf-8').split('\r\n\r\n')[0] lines = first_head.split('\r\n') lines = [x for x in lines if ':' in x] return email.message_from_string('\n'.join(lines))
# For backward compatibility # WTF??? BaseGrab = Grab