15 KiB
Core API
System Message: ERROR/3 (<stdin>, line 7)
Unknown directive type "versionadded".
.. versionadded:: 0.15
This section documents the Scrapy core API, and it's intended for developers of extensions and middlewares.
Crawler API
The main entry point to Scrapy API is the :class:`~scrapy.crawler.Crawler` object, passed to extensions through the from_crawler class method. This object provides access to all Scrapy core components, and it's the only way for extensions to access them and hook their functionality into Scrapy.
System Message: ERROR/3 (<stdin>, line 17); backlink
Unknown interpreted text role "class".System Message: ERROR/3 (<stdin>, line 22)
Unknown directive type "module".
.. module:: scrapy.crawler :synopsis: The Scrapy crawler
The Extension Manager is responsible for loading and keeping track of installed extensions and it's configured through the :setting:`EXTENSIONS` setting which contains a dictionary of all available extensions and their order similar to how you :ref:`configure the downloader middlewares <topics-downloader-middleware-setting>`.
System Message: ERROR/3 (<stdin>, line 25); backlink
Unknown interpreted text role "setting".System Message: ERROR/3 (<stdin>, line 25); backlink
Unknown interpreted text role "ref".The Crawler object must be instantiated with a :class:`scrapy.spiders.Spider` subclass and a :class:`scrapy.settings.Settings` object.
System Message: ERROR/3 (<stdin>, line 33); backlink
Unknown interpreted text role "class".System Message: ERROR/3 (<stdin>, line 33); backlink
Unknown interpreted text role "class".System Message: ERROR/3 (<stdin>, line 37)
Unknown directive type "attribute".
.. attribute:: settings
The settings manager of this crawler.
This is used by extensions & middlewares to access the Scrapy settings
of this crawler.
For an introduction on Scrapy settings see :ref:`topics-settings`.
For the API see :class:`~scrapy.settings.Settings` class.
System Message: ERROR/3 (<stdin>, line 48)
Unknown directive type "attribute".
.. attribute:: signals
The signals manager of this crawler.
This is used by extensions & middlewares to hook themselves into Scrapy
functionality.
For an introduction on signals see :ref:`topics-signals`.
For the API see :class:`~scrapy.signalmanager.SignalManager` class.
System Message: ERROR/3 (<stdin>, line 59)
Unknown directive type "attribute".
.. attribute:: stats
The stats collector of this crawler.
This is used from extensions & middlewares to record stats of their
behaviour, or access stats collected by other extensions.
For an introduction on stats collection see :ref:`topics-stats`.
For the API see :class:`~scrapy.statscollectors.StatsCollector` class.
System Message: ERROR/3 (<stdin>, line 70)
Unknown directive type "attribute".
.. attribute:: extensions
The extension manager that keeps track of enabled extensions.
Most extensions won't need to access this attribute.
For an introduction on extensions and a list of available extensions on
Scrapy see :ref:`topics-extensions`.
System Message: ERROR/3 (<stdin>, line 79)
Unknown directive type "attribute".
.. attribute:: engine
The execution engine, which coordinates the core crawling logic
between the scheduler, downloader and spiders.
Some extension may want to access the Scrapy engine, to inspect or
modify the downloader and scheduler behaviour, although this is an
advanced use and this API is not yet stable.
System Message: ERROR/3 (<stdin>, line 88)
Unknown directive type "attribute".
.. attribute:: spider
Spider currently being crawled. This is an instance of the spider class
provided while constructing the crawler, and it is created after the
arguments given in the :meth:`crawl` method.
System Message: ERROR/3 (<stdin>, line 94)
Unknown directive type "method".
.. method:: crawl(\*args, \**kwargs)
Starts the crawler by instantiating its spider class with the given
`args` and `kwargs` arguments, while setting the execution engine in
motion.
Returns a deferred that is fired when the crawl is finished.
System Message: ERROR/3 (<stdin>, line 102)
Unknown directive type "autoclass".
.. autoclass:: CrawlerRunner :members:
System Message: ERROR/3 (<stdin>, line 105)
Unknown directive type "autoclass".
.. autoclass:: CrawlerProcess :show-inheritance: :members: :inherited-members:
Settings API
System Message: ERROR/3 (<stdin>, line 115)
Unknown directive type "module".
.. module:: scrapy.settings :synopsis: Settings manager
System Message: ERROR/3 (<stdin>, line 118)
Unknown directive type "attribute".
.. attribute:: SETTINGS_PRIORITIES
Dictionary that sets the key name and priority level of the default
settings priorities used in Scrapy.
Each item defines a settings entry point, giving it a code name for
identification and an integer priority. Greater priorities take more
precedence over lesser ones when setting and retrieving values in the
:class:`~scrapy.settings.Settings` class.
.. highlight:: python
::
SETTINGS_PRIORITIES = {
'default': 0,
'command': 10,
'project': 20,
'spider': 30,
'cmdline': 40,
}
For a detailed explanation on each settings sources, see:
:ref:`topics-settings`.
This object stores Scrapy settings for the configuration of internal components, and can be used for any further customization.
After instantiation of this class, the new object will have the global default settings described on :ref:`topics-settings-ref` already populated.
System Message: ERROR/3 (<stdin>, line 148); backlink
Unknown interpreted text role "ref".Additional values can be passed on initialization with the values argument, and they would take the priority level. If the latter argument is a string, the priority name will be looked up in :attr:`~scrapy.settings.SETTINGS_PRIORITIES`. Otherwise, a expecific integer should be provided.
System Message: ERROR/3 (<stdin>, line 152); backlink
Unknown interpreted text role "attr".Once the object is created, new settings can be loaded or updated with the :meth:`~scrapy.settings.Settings.set` method, and can be accessed with the square bracket notation of dictionaries, or with the :meth:`~scrapy.settings.Settings.get` method of the instance and its value conversion variants. When requesting a stored key, the value with the highest priority will be retrieved.
System Message: ERROR/3 (<stdin>, line 158); backlink
Unknown interpreted text role "meth".System Message: ERROR/3 (<stdin>, line 158); backlink
Unknown interpreted text role "meth".System Message: ERROR/3 (<stdin>, line 165)
Unknown directive type "method".
.. method:: set(name, value, priority='project')
Store a key/value attribute with a given priority.
Settings should be populated *before* configuring the Crawler object
(through the :meth:`~scrapy.crawler.Crawler.configure` method),
otherwise they won't have any effect.
:param name: the setting name
:type name: string
:param value: the value to associate with the setting
:type value: any
:param priority: the priority of the setting. Should be a key of
:attr:`~scrapy.settings.SETTINGS_PRIORITIES` or an integer
:type priority: string or int
System Message: ERROR/3 (<stdin>, line 183)
Unknown directive type "method".
.. method:: setdict(values, priority='project')
Store key/value pairs with a given priority.
This is a helper function that calls
:meth:`~scrapy.settings.Settings.set` for every item of ``values``
with the provided ``priority``.
:param values: the settings names and values
:type values: dict
:param priority: the priority of the settings. Should be a key of
:attr:`~scrapy.settings.SETTINGS_PRIORITIES` or an integer
:type priority: string or int
System Message: ERROR/3 (<stdin>, line 198)
Unknown directive type "method".
.. method:: setmodule(module, priority='project')
Store settings from a module with a given priority.
This is a helper function that calls
:meth:`~scrapy.settings.Settings.set` for every globally declared
uppercase variable of ``module`` with the provided ``priority``.
:param module: the module or the path of the module
:type module: module object or string
:param priority: the priority of the settings. Should be a key of
:attr:`~scrapy.settings.SETTINGS_PRIORITIES` or an integer
:type priority: string or int
System Message: ERROR/3 (<stdin>, line 213)
Unknown directive type "method".
.. method:: get(name, default=None) Get a setting value without affecting its original type. :param name: the setting name :type name: string :param default: the value to return if no setting is found :type default: any
System Message: ERROR/3 (<stdin>, line 223)
Unknown directive type "method".
.. method:: getbool(name, default=False) Get a setting value as a boolean. For example, both ``1`` and ``'1'``, and ``True`` return ``True``, while ``0``, ``'0'``, ``False`` and ``None`` return ``False```` For example, settings populated through environment variables set to ``'0'`` will return ``False`` when using this method. :param name: the setting name :type name: string :param default: the value to return if no setting is found :type default: any
System Message: ERROR/3 (<stdin>, line 238)
Unknown directive type "method".
.. method:: getint(name, default=0) Get a setting value as an int :param name: the setting name :type name: string :param default: the value to return if no setting is found :type default: any
System Message: ERROR/3 (<stdin>, line 248)
Unknown directive type "method".
.. method:: getfloat(name, default=0.0) Get a setting value as a float :param name: the setting name :type name: string :param default: the value to return if no setting is found :type default: any
System Message: ERROR/3 (<stdin>, line 258)
Unknown directive type "method".
.. method:: getlist(name, default=None) Get a setting value as a list. If the setting original type is a list, a copy of it will be returned. If it's a string it will be split by ",". For example, settings populated through environment variables set to ``'one,two'`` will return a list ['one', 'two'] when using this method. :param name: the setting name :type name: string :param default: the value to return if no setting is found :type default: any
System Message: ERROR/3 (<stdin>, line 272)
Unknown directive type "method".
.. method:: getdict(name, default=None) Get a setting value as a dictionary. If the setting original type is a dictionary, a copy of it will be returned. If it's a string it will evaluated as a json dictionary. :param name: the setting name :type name: string :param default: the value to return if no setting is found :type default: any
System Message: ERROR/3 (<stdin>, line 284)
Unknown directive type "method".
.. method:: copy() Make a deep copy of current settings. This method returns a new instance of the :class:`Settings` class, populated with the same values and their priorities. Modifications to the new object won't be reflected on the original settings.
System Message: ERROR/3 (<stdin>, line 294)
Unknown directive type "method".
.. method:: freeze() Disable further changes to the current settings. After calling this method, the present state of the settings will become immutable. Trying to change values through the :meth:`~set` method and its variants won't be possible and will be alerted.
System Message: ERROR/3 (<stdin>, line 302)
Unknown directive type "method".
.. method:: frozencopy() Return an immutable copy of the current settings. Alias for a :meth:`~freeze` call in the object returned by :meth:`copy`
SpiderLoader API
System Message: ERROR/3 (<stdin>, line 313)
Unknown directive type "module".
.. module:: scrapy.loader :synopsis: The spider loader
This class is in charge of retrieving and handling the spider classes defined across the project.
Custom spider loaders can be employed by specifying their path in the :setting:`SPIDER_LOADER_CLASS` project setting. They must fully implement the :class:`scrapy.interfaces.ISpiderLoader` interface to guarantee an errorless execution.
System Message: ERROR/3 (<stdin>, line 321); backlink
Unknown interpreted text role "setting".System Message: ERROR/3 (<stdin>, line 321); backlink
Unknown interpreted text role "class".System Message: ERROR/3 (<stdin>, line 326)
Unknown directive type "method".
.. method:: from_settings(settings) This class method is used by Scrapy to create an instance of the class. It's called with the current project settings, and it loads the spiders found in the modules of the :setting:`SPIDER_MODULES` setting. :param settings: project settings :type settings: :class:`~scrapy.settings.Settings` instance
System Message: ERROR/3 (<stdin>, line 335)
Unknown directive type "method".
.. method:: load(spider_name) Get the Spider class with the given name. It'll look into the previously loaded spiders for a spider class with name `spider_name` and will raise a KeyError if not found. :param spider_name: spider class name :type spider_name: str
System Message: ERROR/3 (<stdin>, line 344)
Unknown directive type "method".
.. method:: list() Get the names of the available spiders in the project.
System Message: ERROR/3 (<stdin>, line 348)
Unknown directive type "method".
.. method:: find_by_request(request) List the spiders' names that can handle the given request. Will try to match the request's url against the domains of the spiders. :param request: queried request :type request: :class:`~scrapy.http.Request` instance
Signals API
System Message: ERROR/3 (<stdin>, line 361)
Unknown directive type "module".
.. module:: scrapy.signalmanager :synopsis: The signal manager
System Message: ERROR/3 (<stdin>, line 366)
Unknown directive type "method".
.. method:: connect(receiver, signal)
Connect a receiver function to a signal.
The signal can be any object, although Scrapy comes with some
predefined signals that are documented in the :ref:`topics-signals`
section.
:param receiver: the function to be connected
:type receiver: callable
:param signal: the signal to connect to
:type signal: object
System Message: ERROR/3 (<stdin>, line 380)
Unknown directive type "method".
.. method:: send_catch_log(signal, \*\*kwargs)
Send a signal, catch exceptions and log them.
The keyword arguments are passed to the signal handlers (connected
through the :meth:`connect` method).
System Message: ERROR/3 (<stdin>, line 387)
Unknown directive type "method".
.. method:: send_catch_log_deferred(signal, \*\*kwargs)
Like :meth:`send_catch_log` but supports returning `deferreds`_ from
signal handlers.
Returns a `deferred`_ that gets fired once all signal handlers
deferreds were fired. Send a signal, catch exceptions and log them.
The keyword arguments are passed to the signal handlers (connected
through the :meth:`connect` method).
System Message: ERROR/3 (<stdin>, line 398)
Unknown directive type "method".
.. method:: disconnect(receiver, signal)
Disconnect a receiver function from a signal. This has the opposite
effect of the :meth:`connect` method, and the arguments are the same.
System Message: ERROR/3 (<stdin>, line 403)
Unknown directive type "method".
.. method:: disconnect_all(signal)
Disconnect all receivers from the given signal.
:param signal: the signal to disconnect from
:type signal: object
Stats Collector API
There are several Stats Collectors available under the :mod:`scrapy.statscollectors` module and they all implement the Stats Collector API defined by the :class:`~scrapy.statscollectors.StatsCollector` class (which they all inherit from).
System Message: ERROR/3 (<stdin>, line 415); backlink
Unknown interpreted text role "mod".System Message: ERROR/3 (<stdin>, line 415); backlink
Unknown interpreted text role "class".System Message: ERROR/3 (<stdin>, line 420)
Unknown directive type "module".
.. module:: scrapy.statscollectors :synopsis: Stats Collectors
System Message: ERROR/3 (<stdin>, line 425)
Unknown directive type "method".
.. method:: get_value(key, default=None)
Return the value for the given stats key or default if it doesn't exist.
System Message: ERROR/3 (<stdin>, line 429)
Unknown directive type "method".
.. method:: get_stats()
Get all stats from the currently running spider as a dict.
System Message: ERROR/3 (<stdin>, line 433)
Unknown directive type "method".
.. method:: set_value(key, value)
Set the given value for the given stats key.
System Message: ERROR/3 (<stdin>, line 437)
Unknown directive type "method".
.. method:: set_stats(stats)
Override the current stats with the dict passed in ``stats`` argument.
System Message: ERROR/3 (<stdin>, line 441)
Unknown directive type "method".
.. method:: inc_value(key, count=1, start=0)
Increment the value of the given stats key, by the given count,
assuming the start value given (when it's not set).
System Message: ERROR/3 (<stdin>, line 446)
Unknown directive type "method".
.. method:: max_value(key, value)
Set the given value for the given key only if current value for the
same key is lower than value. If there is no current value for the
given key, the value is always set.
System Message: ERROR/3 (<stdin>, line 452)
Unknown directive type "method".
.. method:: min_value(key, value)
Set the given value for the given key only if current value for the
same key is greater than value. If there is no current value for the
given key, the value is always set.
System Message: ERROR/3 (<stdin>, line 458)
Unknown directive type "method".
.. method:: clear_stats()
Clear all stats.
The following methods are not part of the stats collection api but instead used when implementing custom stats collectors:
System Message: ERROR/3 (<stdin>, line 465)
Unknown directive type "method".
.. method:: open_spider(spider)
Open the given spider for stats collection.
System Message: ERROR/3 (<stdin>, line 469)
Unknown directive type "method".
.. method:: close_spider(spider)
Close the given spider. After this is called, no more specific stats
can be accessed or collected.