docs/topics/settings.rst
.. _topics-settings:
The Scrapy settings allows you to customize the behaviour of all Scrapy components, including the core, extensions, pipelines and spiders themselves.
The infrastructure of the settings provides a global namespace of key-value mappings that the code can use to pull configuration values from. The settings can be populated through different mechanisms, which are described below.
The settings are also the mechanism for selecting the currently active Scrapy project (in case you have many).
For a list of available built-in settings see: :ref:topics-settings-ref.
.. _topics-settings-module-envvar:
When you use Scrapy, you have to tell it which settings you're using. You can
do this by using an environment variable, SCRAPY_SETTINGS_MODULE.
The value of SCRAPY_SETTINGS_MODULE should be in Python path syntax, e.g.
myproject.settings. Note that the settings module should be on the
Python :ref:import search path <tut-searchpath>.
.. _populating-settings:
Settings can be populated using different mechanisms, each of which has a different precedence:
Command-line settings <cli-settings> (highest precedence)Spider settings <spider-settings>Project settings <project-settings>Add-on settings <addon-settings>Command-specific default settings <cmd-default-settings>Global default settings <default-settings> (lowest precedence).. _cli-settings:
Settings set in the command line have the highest precedence, overriding any other settings.
You can explicitly override one or more settings using the -s (or
--set) command-line option.
.. highlight:: sh
Example::
scrapy crawl myspider -s LOG_LEVEL=INFO -s LOG_FILE=scrapy.log
.. _spider-settings:
:ref:Spiders <topics-spiders> can define their own settings that will take
precedence and override the project ones.
.. note:: :ref:Pre-crawler settings <pre-crawler-settings> cannot be defined
per spider, and :ref:reactor settings <reactor-settings> should not have
a different value per spider when :ref:running multiple spiders in the same process <run-multiple-spiders>.
One way to do so is by setting their :attr:~scrapy.Spider.custom_settings
attribute:
.. code-block:: python
import scrapy
class MySpider(scrapy.Spider):
name = "myspider"
custom_settings = {
"SOME_SETTING": "some value",
}
It's often better to implement :meth:~scrapy.Spider.update_settings instead,
and settings set there should use the "spider" priority explicitly:
.. code-block:: python
import scrapy
class MySpider(scrapy.Spider):
name = "myspider"
@classmethod
def update_settings(cls, settings):
super().update_settings(settings)
settings.set("SOME_SETTING", "some value", priority="spider")
.. versionadded:: 2.11
It's also possible to modify the settings in the
:meth:~scrapy.Spider.from_crawler method, e.g. based on :ref:spider arguments <spiderargs> or other logic:
.. code-block:: python
import scrapy
class MySpider(scrapy.Spider):
name = "myspider"
@classmethod
def from_crawler(cls, crawler, *args, **kwargs):
spider = super().from_crawler(crawler, *args, **kwargs)
if "some_argument" in kwargs:
spider.settings.set(
"SOME_SETTING", kwargs["some_argument"], priority="spider"
)
return spider
.. _project-settings:
Scrapy projects include a settings module, usually a file called
settings.py, where you should populate most settings that apply to all your
spiders.
.. seealso:: :ref:topics-settings-module-envvar
.. _addon-settings:
:ref:Add-ons <topics-addons> can modify settings. They should do this with
"addon" priority where possible.
.. _cmd-default-settings:
Each :ref:Scrapy command <topics-commands> can have its own default settings,
which override the :ref:global default settings <default-settings>.
Those command-specific default settings are specified in the
default_settings attribute of each command class.
.. _default-settings:
The scrapy.settings.default_settings module defines global default values
for some :ref:built-in settings <topics-settings-ref>.
.. note:: :command:startproject generates a settings.py file that sets
some settings to different values.
The reference documentation of settings indicates the default value if one
exists. If :command:`startproject` sets a value, that value is documented
as default, and the value from ``scrapy.settings.default_settings`` is
documented as “fallback”.
Setting values must be :ref:picklable <pickle-picklable>.
When a setting references a callable object to be imported by Scrapy, such as a class or a function, there are two different ways you can specify that object:
As a string containing the import path of that object
As the object itself
For example:
.. skip: next .. code-block:: python
from mybot.pipelines.validate import ValidateMyItem
ITEM_PIPELINES = { # passing the classname... ValidateMyItem: 300, # ...equals passing the class path "mybot.pipelines.validate.ValidateMyItem": 300, }
.. note:: Passing non-callable objects is not supported.
.. highlight:: python
In a spider, settings are available through self.settings:
.. code-block:: python
class MySpider(scrapy.Spider):
name = "myspider"
start_urls = ["http://example.com"]
def parse(self, response):
print(f"Existing settings: {self.settings.attributes.keys()}")
.. note::
The settings attribute is set in the base Spider class after the spider
is initialized. If you want to use settings before the initialization
(e.g., in your spider's __init__() method), you'll need to override the
:meth:~scrapy.Spider.from_crawler method.
:ref:Components <topics-components> can also :ref:access settings <component-settings>.
The settings object can be used like a :class:dict (e.g.
settings["LOG_ENABLED"]). However, to support non-string setting values,
which may be passed from the command line as strings, it is recommended to use
one of the methods provided by the :class:~scrapy.settings.Settings API.
.. _component-priority-dictionaries:
A component priority dictionary is a :class:dict where keys are
:ref:components <topics-components> and values are component priorities. For
example:
.. skip: next .. code-block:: python
{
"path.to.ComponentA": None,
ComponentB: 100,
}
A component can be specified either as a class object or through an import path.
.. warning:: Component priority dictionaries are regular :class:dict objects.
Be careful not to define the same component more than once, e.g. with
different import path strings or defining both an import path and a
:class:type object.
A priority can be an :class:int or :data:None.
A component with priority 1 goes before a component with priority 2. What
going before entails, however, depends on the corresponding setting. For
example, in the :setting:DOWNLOADER_MIDDLEWARES setting, components have
their
:meth:~scrapy.downloadermiddlewares.DownloaderMiddleware.process_request
method executed before that of later components, but have their
:meth:~scrapy.downloadermiddlewares.DownloaderMiddleware.process_response
method executed after that of later components.
A component with priority :data:None is disabled.
Some component priority dictionaries get merged with some built-in value. For
example, :setting:DOWNLOADER_MIDDLEWARES is merged with
:setting:DOWNLOADER_MIDDLEWARES_BASE. This is where :data:None comes in
handy, allowing you to disable a component from the base setting in the regular
setting:
.. code-block:: python
DOWNLOADER_MIDDLEWARES = {
"scrapy.downloadermiddlewares.offsite.OffsiteMiddleware": None,
}
The following settings work slightly differently than all other settings.
.. _pre-crawler-settings:
Pre-crawler settings are settings used before the
:class:~scrapy.crawler.Crawler object is created.
These settings cannot be :ref:set from a spider <spider-settings>.
These settings are:
TWISTED_REACTOR_ENABLEDSPIDER_LOADER_CLASS and settings used by the corresponding
spider loader class, e.g. :setting:SPIDER_MODULES and
:setting:SPIDER_LOADER_WARN_ONLY for the default spider loader class... _reactor-settings:
Reactor settings are settings tied to the :doc:Twisted reactor <twisted:core/howto/reactor-basics>.
These settings can be defined from a spider. However, because only 1 reactor
can be used per process, these settings cannot use a different value per spider
when :ref:running multiple spiders in the same process <run-multiple-spiders>.
In general, if different spiders define different values, the first defined value is used. However, if two spiders request a different reactor, an exception is raised.
These settings are:
:setting:ASYNCIO_EVENT_LOOP (not possible to set per-spider when using
:class:~scrapy.crawler.AsyncCrawlerProcess, see below)
:setting:TWISTED_DNS_RESOLVER and settings used by the corresponding
component, e.g. :setting:DNSCACHE_ENABLED, :setting:DNSCACHE_SIZE
and :setting:DNS_TIMEOUT for the default one.
:setting:REACTOR_THREADPOOL_MAXSIZE
:setting:TWISTED_REACTOR (ignored when using
:class:~scrapy.crawler.AsyncCrawlerProcess, see below)
:setting:ASYNCIO_EVENT_LOOP and :setting:TWISTED_REACTOR are used upon
installing the reactor. The rest of the settings are applied when starting
the reactor.
There is an additional restriction for :setting:TWISTED_REACTOR and
:setting:ASYNCIO_EVENT_LOOP when using
:class:~scrapy.crawler.AsyncCrawlerProcess: when this class is instantiated,
it installs :class:~twisted.internet.asyncioreactor.AsyncioSelectorReactor,
ignoring the value of :setting:TWISTED_REACTOR and using the value of
:setting:ASYNCIO_EVENT_LOOP that was passed to
:meth:AsyncCrawlerProcess.__init__() <scrapy.crawler.AsyncCrawlerProcess.__init__>. If a different value for
:setting:TWISTED_REACTOR or :setting:ASYNCIO_EVENT_LOOP is provided later,
e.g. in :ref:per-spider settings <spider-settings>, an exception will be
raised.
All of these settings, except for :setting:ASYNCIO_EVENT_LOOP, are only used
when the Twisted reactor is used, i.e. when :setting:TWISTED_REACTOR_ENABLED
is True.
.. _topics-settings-ref:
Here's a list of all available Scrapy settings, in alphabetical order, along with their default values and the scope where they apply.
The scope, where available, shows where the setting is being used, if it's tied to any particular component. In that case the module of that component will be shown, typically an extension, middleware or pipeline. It also means that the component must be enabled in order for the setting to have any effect.
.. setting:: ADDONS
Default: {}
A dict containing paths to the add-ons enabled in your project and their
priorities. For more information, see :ref:topics-addons.
.. setting:: AWS_ACCESS_KEY_ID
Default: None
The AWS access key used by code that requires access to Amazon Web services_,
such as the :ref:S3 feed storage backend <topics-feed-storage-s3>.
.. setting:: AWS_SECRET_ACCESS_KEY
Default: None
The AWS secret key used by code that requires access to Amazon Web services_,
such as the :ref:S3 feed storage backend <topics-feed-storage-s3>.
.. setting:: AWS_SESSION_TOKEN
Default: None
The AWS security token used by code that requires access to Amazon Web services,
such as the :ref:S3 feed storage backend <topics-feed-storage-s3>, when using
temporary security credentials.
.. _temporary security credentials: https://docs.aws.amazon.com/IAM/latest/UserGuide/security-creds.html
.. setting:: AWS_ENDPOINT_URL
Default: None
Endpoint URL used for S3-like storage, for example Minio or s3.scality.
.. setting:: AWS_USE_SSL
Default: None
Use this option if you want to disable SSL connection for communication with S3 or S3-like storage. By default SSL will be used.
.. setting:: AWS_VERIFY
Default: None
Verify SSL connection between Scrapy and S3 or S3-like storage. By default SSL verification will occur.
.. setting:: AWS_REGION_NAME
Default: None
The name of the region associated with the AWS client.
.. setting:: ASYNCIO_EVENT_LOOP
Default: None
Import path of a given asyncio event loop class.
If the asyncio reactor is enabled (see :setting:TWISTED_REACTOR) this setting can be used to specify the
asyncio event loop to be used with it. Set the setting to the import path of the
desired asyncio event loop class. If the setting is set to None the default asyncio
event loop will be used.
If you are installing the asyncio reactor manually using the :func:~scrapy.utils.reactor.install_reactor
function, you can use the event_loop_path parameter to indicate the import path of the event loop
class to be used.
Note that the event loop class must inherit from :class:asyncio.AbstractEventLoop.
.. caution:: Please be aware that, when using a non-default event loop
(either defined via :setting:ASYNCIO_EVENT_LOOP or installed with
:func:~scrapy.utils.reactor.install_reactor), Scrapy will call
:func:asyncio.set_event_loop, which will set the specified event loop
as the current loop for the current OS thread.
.. setting:: BOT_NAME
Default: <project name> (:ref:fallback <default-settings>: 'scrapybot')
The name of the bot implemented by this Scrapy project (also known as the project name). This name will be used for the logging too.
It's automatically populated with your project name when you create your
project with the :command:startproject command.
.. setting:: CONCURRENT_ITEMS
Default: 100
Maximum number of concurrent items (per response) to process in parallel in
:ref:item pipelines <topics-item-pipeline>.
.. setting:: CONCURRENT_REQUESTS
Default: 16
The maximum number of concurrent (i.e. simultaneous) requests that will be performed by the Scrapy downloader.
.. setting:: CONCURRENT_REQUESTS_PER_DOMAIN
Default: 1 (:ref:fallback <default-settings>: 8)
The maximum number of concurrent (i.e. simultaneous) requests that will be performed to any single domain.
See also: :ref:topics-autothrottle and its
:setting:AUTOTHROTTLE_TARGET_CONCURRENCY option.
.. setting:: DEFAULT_DROPITEM_LOG_LEVEL
Default: "WARNING"
Default :ref:log level <levels> of messages about dropped items.
When an item is dropped by raising :exc:scrapy.exceptions.DropItem from the
:func:process_item method of an :ref:item pipeline <topics-item-pipeline>,
a message is logged, and by default its log level is the one configured in this
setting.
You may specify this log level as an integer (e.g. 20), as a log level
constant (e.g. logging.INFO) or as a string with the name of a log level
constant (e.g. "INFO").
When writing an item pipeline, you can force a different log level by setting
:attr:scrapy.exceptions.DropItem.log_level in your
:exc:scrapy.exceptions.DropItem exception. For example:
.. code-block:: python
from scrapy.exceptions import DropItem
class MyPipeline: def process_item(self, item): if not item.get("price"): raise DropItem("Missing price data", log_level="INFO") return item
.. setting:: DEFAULT_ITEM_CLASS
Default: 'scrapy.Item'
The default class that will be used for instantiating items in the :ref:the Scrapy shell <topics-shell>.
.. setting:: DEFAULT_REQUEST_HEADERS
Default:
.. code-block:: python
{
"Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
"Accept-Language": "en",
}
The default headers used for Scrapy HTTP Requests. They're populated in the
:class:~scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware.
.. caution:: Cookies set via the Cookie header are not considered by the
:ref:cookies-mw. If you need to set cookies for a request, use the
:class:Request.cookies <scrapy.Request> parameter. This is a known
current limitation that is being worked on.
.. setting:: DEPTH_LIMIT
Default: 0
Scope: scrapy.spidermiddlewares.depth.DepthMiddleware
The maximum depth that will be allowed to crawl for any site. If zero, no limit will be imposed.
.. setting:: DEPTH_PRIORITY
Default: 0
Scope: scrapy.spidermiddlewares.depth.DepthMiddleware
An integer that is used to adjust the :attr:~scrapy.Request.priority of
a :class:~scrapy.Request based on its depth.
The priority of a request is adjusted as follows:
.. skip: next .. code-block:: python
request.priority = request.priority - (depth * DEPTH_PRIORITY)
As depth increases, positive values of DEPTH_PRIORITY decrease request
priority (BFO), while negative values increase request priority (DFO). See
also :ref:faq-bfo-dfo.
.. note::
This setting adjusts priority **in the opposite way** compared to
other priority settings :setting:`REDIRECT_PRIORITY_ADJUST`
and :setting:`RETRY_PRIORITY_ADJUST`.
.. setting:: DEPTH_STATS_VERBOSE
Default: False
Scope: scrapy.spidermiddlewares.depth.DepthMiddleware
Whether to collect verbose depth stats. If this is enabled, the number of requests for each depth is collected in the stats.
.. setting:: DNSCACHE_ENABLED
Default: True
Whether to enable DNS in-memory cache.
.. note::
This setting is only used by
:class:~scrapy.resolver.CachingThreadedResolver and
:class:~scrapy.resolver.CachingHostnameResolver. It has no effect when
:setting:TWISTED_REACTOR_ENABLED is False, and may have no effect
either when :setting:DNS_RESOLVER is set to a different resolver.
.. setting:: DNSCACHE_SIZE
Default: 10000
DNS in-memory cache size, see :setting:DNSCACHE_ENABLED.
.. setting:: TWISTED_DNS_RESOLVER
Default: 'scrapy.resolver.CachingThreadedResolver'
The class to be used by Twisted to resolve DNS names. The default
scrapy.resolver.CachingThreadedResolver supports specifying a timeout for
DNS requests via the :setting:DNS_TIMEOUT setting, but works only with IPv4
addresses. Scrapy provides an alternative resolver,
scrapy.resolver.CachingHostnameResolver, which supports IPv4/IPv6 addresses but does not
take the :setting:DNS_TIMEOUT setting into account.
.. note::
This setting has no effect when :setting:TWISTED_REACTOR_ENABLED is False.
.. setting:: DNS_TIMEOUT
Default: 60
Timeout for processing of DNS queries in seconds. Float is supported.
.. note::
This setting is only used by
:class:~scrapy.resolver.CachingThreadedResolver. It has no effect when
:setting:TWISTED_REACTOR_ENABLED is False, and may have no effect
either when :setting:DNS_RESOLVER is set to a different resolver.
.. setting:: DOWNLOADER
Default: 'scrapy.core.downloader.Downloader'
The downloader to use for crawling.
.. setting:: DOWNLOADER_CLIENT_TLS_CIPHERS
Default: 'DEFAULT'
Use this setting to customize the TLS/SSL ciphers used by the HTTPS download handler.
The setting should contain a string in the OpenSSL cipher list format_,
these ciphers will be used as client ciphers. Changing this setting may be
necessary to access certain HTTPS websites: for example, you may need to use
'DEFAULT:!DH' for a website with weak DH parameters or enable a
specific cipher that is not included in DEFAULT if a website requires it.
.. _OpenSSL cipher list format: https://docs.openssl.org/master/man1/openssl-ciphers/#cipher-list-format
.. note::
Handling of this setting needs to be implemented inside the :ref:`download
handler <topics-download-handlers>`, so it's not guaranteed to be supported
by all 3rd-party handlers. It's currently unsupported by
:class:`~scrapy.core.downloader.handlers._httpx.HttpxDownloadHandler`.
.. setting:: DOWNLOADER_CLIENT_TLS_METHOD
Default: 'TLS'
Use this setting to customize the TLS/SSL method used by the HTTPS download handler.
This setting must be one of these string values:
'TLS': maps to OpenSSL's TLS_method() (a.k.a SSLv23_method()),
which allows protocol negotiation, starting from the highest supported
by the platform; default, recommended'TLSv1.0': this value forces HTTPS connections to use TLS version 1.0 ;
set this if you want the behavior of Scrapy<1.1'TLSv1.1': forces TLS version 1.1'TLSv1.2': forces TLS version 1.2.. note::
Handling of this setting needs to be implemented inside the :ref:`download
handler <topics-download-handlers>`, so it's not guaranteed to be supported
by all 3rd-party handlers. It's currently unsupported by
:class:`~scrapy.core.downloader.handlers._httpx.HttpxDownloadHandler`.
.. setting:: DOWNLOADER_CLIENT_TLS_VERBOSE_LOGGING
Default: False
Setting this to True will enable DEBUG level messages about TLS connection
parameters after establishing HTTPS connections. The kind of information logged
depends on the implementation of the download handler and the versions of
the TLS-related libraries.
.. note::
Handling of this setting needs to be implemented inside the :ref:`download
handler <topics-download-handlers>`, so it's not guaranteed to be supported
by all 3rd-party handlers.
.. setting:: DOWNLOADER_MIDDLEWARES
Default: {}
A dict containing the downloader middlewares enabled in your project, and their
orders. For more info see :ref:topics-downloader-middleware-setting.
.. setting:: DOWNLOADER_MIDDLEWARES_BASE
Default:
.. code-block:: python
{
"scrapy.downloadermiddlewares.offsite.OffsiteMiddleware": 50,
"scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware": 100,
"scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware": 300,
"scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware": 350,
"scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware": 400,
"scrapy.downloadermiddlewares.useragent.UserAgentMiddleware": 500,
"scrapy.downloadermiddlewares.retry.RetryMiddleware": 550,
"scrapy.downloadermiddlewares.ajaxcrawl.AjaxCrawlMiddleware": 560,
"scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware": 580,
"scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware": 590,
"scrapy.downloadermiddlewares.redirect.RedirectMiddleware": 600,
"scrapy.downloadermiddlewares.cookies.CookiesMiddleware": 700,
"scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware": 750,
"scrapy.downloadermiddlewares.stats.DownloaderStats": 850,
"scrapy.downloadermiddlewares.httpcache.HttpCacheMiddleware": 900,
}
A dict containing the downloader middlewares enabled by default in Scrapy. Low
orders are closer to the engine, high orders are closer to the downloader. You
should never modify this setting in your project, modify
:setting:DOWNLOADER_MIDDLEWARES instead. For more info see
:ref:topics-downloader-middleware-setting.
.. setting:: DOWNLOADER_STATS
Default: True
Whether to enable downloader stats collection.
.. setting:: DOWNLOAD_DELAY
Default: 1 (:ref:fallback <default-settings>: 0)
Minimum seconds to wait between 2 consecutive requests to the same domain.
Use :setting:DOWNLOAD_DELAY to throttle your crawling speed, to avoid hitting
servers too hard.
Decimal numbers are supported. For example, to send a maximum of 4 requests every 10 seconds::
DOWNLOAD_DELAY = 2.5
This setting is also affected by the :setting:RANDOMIZE_DOWNLOAD_DELAY
setting, which is enabled by default.
Note that :setting:DOWNLOAD_DELAY can lower the effective per-domain
concurrency below :setting:CONCURRENT_REQUESTS_PER_DOMAIN. If the response
time of a domain is lower than :setting:DOWNLOAD_DELAY, the effective
concurrency for that domain is 1. When testing throttling configurations, it
usually makes sense to lower :setting:CONCURRENT_REQUESTS_PER_DOMAIN first,
and only increase :setting:DOWNLOAD_DELAY once
:setting:CONCURRENT_REQUESTS_PER_DOMAIN is 1 but a higher throttling is
desired.
.. _spider-download_delay-attribute:
.. note::
This delay can be set per spider using :attr:`download_delay` spider attribute.
It is also possible to change this setting per domain, although it requires
non-trivial code. See the implementation of the :ref:AutoThrottle <topics-autothrottle> extension for an example.
.. setting:: DOWNLOAD_BIND_ADDRESS
Default: None
The default local outgoing address for download-handler connections.
This setting can be either:
a host address as a string (e.g. "127.0.0.2"), in which case the local
port is chosen automatically, or
a (host, port) tuple (e.g. ("127.0.0.2", 50000)) to bind to both a
specific local interface and a specific local port.
For example:
.. code-block:: python
# Bind to this local address
DOWNLOAD_BIND_ADDRESS = "127.0.0.2"
.. code-block:: python
# Bind to this local address and local port
DOWNLOAD_BIND_ADDRESS = ("127.0.0.2", 5000)
If set, built-in HTTP download handlers use this value by default.
Set the :reqmeta:bindaddress request meta key to override it for a specific
request.
.. note::
Handling of this setting needs to be implemented inside the :ref:`download
handler <topics-download-handlers>`, so it's not guaranteed to be supported
by all 3rd-party handlers. Specifying the port is unsupported by
:class:`~scrapy.core.downloader.handlers._httpx.HttpxDownloadHandler`.
.. setting:: DOWNLOAD_HANDLERS
Default: {}
A dict containing the :ref:download handlers <topics-download-handlers>
enabled in your project.
See :setting:DOWNLOAD_HANDLERS_BASE for example format.
.. setting:: DOWNLOAD_HANDLERS_BASE
Default:
.. code-block:: python
{
"data": "scrapy.core.downloader.handlers.datauri.DataURIDownloadHandler",
"file": "scrapy.core.downloader.handlers.file.FileDownloadHandler",
"http": "scrapy.core.downloader.handlers.http11.HTTP11DownloadHandler",
"https": "scrapy.core.downloader.handlers.http11.HTTP11DownloadHandler",
"s3": "scrapy.core.downloader.handlers.s3.S3DownloadHandler",
"ftp": "scrapy.core.downloader.handlers.ftp.FTPDownloadHandler",
}
(when :setting:TWISTED_REACTOR_ENABLED is True)
.. code-block:: python
{
"data": "scrapy.core.downloader.handlers.datauri.DataURIDownloadHandler",
"file": "scrapy.core.downloader.handlers.file.FileDownloadHandler",
"http": "scrapy.core.downloader.handlers._httpx.HttpxDownloadHandler",
"https": "scrapy.core.downloader.handlers._httpx.HttpxDownloadHandler",
"s3": "scrapy.core.downloader.handlers.s3.S3DownloadHandler",
"ftp": None,
}
(when :setting:TWISTED_REACTOR_ENABLED is False)
A dict containing the :ref:download handlers <topics-download-handlers>
enabled by default in Scrapy. You should never modify this setting in your
project, modify :setting:DOWNLOAD_HANDLERS instead.
You can disable any of these download handlers by assigning None to their
URI scheme in :setting:DOWNLOAD_HANDLERS. E.g., to disable the built-in FTP
handler (without replacement), place this in your settings.py:
.. code-block:: python
DOWNLOAD_HANDLERS = {
"ftp": None,
}
.. setting:: DOWNLOAD_SLOTS
Default: {}
Allows to define concurrency/delay parameters on per slot (domain) basis:
.. code-block:: python
DOWNLOAD_SLOTS = {
"quotes.toscrape.com": {"concurrency": 1, "delay": 2, "randomize_delay": False},
"books.toscrape.com": {"delay": 3, "randomize_delay": False},
}
.. note::
For other downloader slots default settings values will be used:
- :setting:`DOWNLOAD_DELAY`: ``delay``
- :setting:`CONCURRENT_REQUESTS_PER_DOMAIN`: ``concurrency``
- :setting:`RANDOMIZE_DOWNLOAD_DELAY`: ``randomize_delay``
.. setting:: DOWNLOAD_TIMEOUT
Default: 180
The amount of time (in secs) that the downloader will wait before timing out.
.. note::
This timeout can be per-request using the :reqmeta:`download_timeout`
:attr:`.Request.meta` key.
.. note::
Handling of this setting needs to be implemented inside the :ref:`download
handler <topics-download-handlers>`, so it's not guaranteed to be supported
by all 3rd-party handlers.
.. setting:: DOWNLOAD_MAXSIZE .. reqmeta:: download_maxsize
Default: 1073741824 (1 GiB)
The maximum response body size (in bytes) allowed. Bigger responses are aborted and ignored.
This applies both before and after compression. If decompressing a response body would exceed this limit, decompression is aborted and the response is ignored.
Use 0 to disable this limit.
.. note::
This limit can be set per-request using the :reqmeta:`download_maxsize`
:attr:`.Request.meta` key.
.. note::
Checking responses before decompressing them needs to be implemented inside
the :ref:`download handler <topics-download-handlers>`, so it's not
guaranteed to be supported by all 3rd-party handlers.
.. setting:: DOWNLOAD_WARNSIZE .. reqmeta:: download_warnsize
Default: 33554432 (32 MiB)
If the size of a response exceeds this value, before or after compression, a warning will be logged about it.
Use 0 to disable this limit.
.. note::
This limit can be set per-request using the :reqmeta:`download_warnsize`
:attr:`.Request.meta` key.
.. note::
Checking responses before decompressing them needs to be implemented inside
the :ref:`download handler <topics-download-handlers>`, so it's not
guaranteed to be supported by all 3rd-party handlers.
.. setting:: DOWNLOAD_FAIL_ON_DATALOSS
Default: True
Whether or not to fail on broken responses, that is, when the declared
Content-Length does not match content sent by the server or a chunked
response was not properly finished. If True, these responses raise a
:exc:~scrapy.exceptions.ResponseDataLossError exception. If False, these
responses are passed through and the flag dataloss is added to the
response, i.e.: 'dataloss' in response.flags is True.
Optionally, this can be set per-request basis by using the
:reqmeta:download_fail_on_dataloss Request.meta key to False.
.. note::
A broken response, or data loss error, may happen under several
circumstances, from server misconfiguration to network errors to data
corruption. It is up to the user to decide if it makes sense to process
broken responses considering they may contain partial or incomplete content.
If :setting:RETRY_ENABLED is True and this setting is set to True,
the :exc:~scrapy.exceptions.ResponseDataLossError failure will be retried
as usual.
.. note::
Handling of this setting needs to be implemented inside the :ref:`download
handler <topics-download-handlers>`, so it's not guaranteed to be supported
by all 3rd-party handlers.
.. warning::
This setting is ignored by the
:class:`~scrapy.core.downloader.handlers.http2.H2DownloadHandler`
:ref:`download handler <topics-download-handlers>`. In case of a data loss
error, the corresponding HTTP/2 connection may be corrupted, affecting other
requests that use the same connection; hence, a ``ResponseFailed([InvalidBodyLengthError])``
failure is always raised for every request that was using that connection.
.. setting:: DOWNLOAD_VERIFY_CERTIFICATES
Default: False
Whether the HTTPS download handlers should verify the server TLS certificate when making a request and abort the request if the verification fails.
.. note::
Handling of this setting needs to be implemented inside the :ref:`download
handler <topics-download-handlers>`, so it's not guaranteed to be supported
by all 3rd-party handlers. The exact behavior of a handler (e.g. whether
certificate problems are logged when this setting is set to ``False``)
depends on its implementation.
.. setting:: DUPEFILTER_CLASS
Default: 'scrapy.dupefilters.RFPDupeFilter'
The class used to detect and filter duplicate requests.
The default, :class:~scrapy.dupefilters.RFPDupeFilter, filters based on the
:setting:REQUEST_FINGERPRINTER_CLASS setting.
To change how duplicates are checked, you can point :setting:DUPEFILTER_CLASS
to a custom subclass of :class:~scrapy.dupefilters.RFPDupeFilter that
overrides its __init__ method to use a :ref:different request fingerprinting class <custom-request-fingerprinter>. For example:
.. code-block:: python
from scrapy.dupefilters import RFPDupeFilter
from scrapy.utils.request import fingerprint
class CustomRequestFingerprinter:
def fingerprint(self, request):
return fingerprint(request, include_headers=["X-ID"])
class CustomDupeFilter(RFPDupeFilter):
def __init__(self, path=None, debug=False, *, fingerprinter=None):
super().__init__(
path=path, debug=debug, fingerprinter=CustomRequestFingerprinter()
)
To disable duplicate request filtering set :setting:DUPEFILTER_CLASS to
'scrapy.dupefilters.BaseDupeFilter'. Note that not filtering out duplicate
requests may cause crawling loops. It is usually better to set
the dont_filter parameter to True on the __init__ method of a
specific :class:~scrapy.Request object that should not be filtered out.
A class assigned to :setting:DUPEFILTER_CLASS must implement the following
interface::
class MyDupeFilter:
@classmethod
def from_crawler(cls, crawler):
"""Returns an instance of this duplicate request filtering class
based on the current Crawler instance."""
return cls()
def request_seen(self, request):
"""Returns ``True`` if *request* is a duplicate of another request
seen in a previous call to :meth:`request_seen`, or ``False``
otherwise."""
return False
def open(self):
"""Called before the spider opens. It may return a deferred."""
pass
def close(self, reason):
"""Called before the spider closes. It may return a deferred."""
pass
def log(self, request, spider):
"""Logs that a request has been filtered out.
It is called right after a call to :meth:`request_seen` that
returns ``True``.
If :meth:`request_seen` always returns ``False``, such as in the
case of :class:`~scrapy.dupefilters.BaseDupeFilter`, this method
may be omitted.
"""
pass
.. autoclass:: scrapy.dupefilters.BaseDupeFilter
.. autoclass:: scrapy.dupefilters.RFPDupeFilter
.. setting:: DUPEFILTER_DEBUG
Default: False
By default, RFPDupeFilter only logs the first duplicate request.
Setting :setting:DUPEFILTER_DEBUG to True will make it log all duplicate requests.
.. setting:: EDITOR
Default: vi (on Unix systems) or the IDLE editor (on Windows)
The editor to use for editing spiders with the :command:edit command.
Additionally, if the EDITOR environment variable is set, the :command:edit
command will prefer it over the default setting.
.. setting:: EXTENSIONS
Default: {}
:ref:Component priority dictionary <component-priority-dictionaries> of
enabled extensions. See :ref:topics-extensions.
.. setting:: EXTENSIONS_BASE
Default:
.. code-block:: python
{
"scrapy.extensions.corestats.CoreStats": 0,
"scrapy.extensions.telnet.TelnetConsole": 0,
"scrapy.extensions.memusage.MemoryUsage": 0,
"scrapy.extensions.memdebug.MemoryDebugger": 0,
"scrapy.extensions.closespider.CloseSpider": 0,
"scrapy.extensions.feedexport.FeedExporter": 0,
"scrapy.extensions.logstats.LogStats": 0,
"scrapy.extensions.spiderstate.SpiderState": 0,
"scrapy.extensions.throttle.AutoThrottle": 0,
}
A dict containing the extensions available by default in Scrapy, and their orders. This setting contains all stable built-in extensions. Keep in mind that some of them need to be enabled through a setting.
For more information See the :ref:extensions user guide <topics-extensions>
and the :ref:list of available extensions <topics-extensions-ref>.
.. setting:: FEED_TEMPDIR
The Feed Temp dir allows you to set a custom folder to save crawler
temporary files before uploading with :ref:FTP feed storage <topics-feed-storage-ftp> and
:ref:Amazon S3 <topics-feed-storage-s3>.
.. setting:: FEED_STORAGE_GCS_ACL
The Access Control List (ACL) used when storing items to :ref:Google Cloud Storage <topics-feed-storage-gcs>.
For more information on how to set this value, please refer to the column JSON API in Google Cloud documentation <https://docs.cloud.google.com/storage/docs/access-control/lists>_.
.. setting:: FORCE_CRAWLER_PROCESS
Default: False
If False, :ref:Scrapy commands that need a CrawlerProcess <topics-commands-crawlerprocess> will decide between using
:class:scrapy.crawler.AsyncCrawlerProcess and
:class:scrapy.crawler.CrawlerProcess based on the value of the
:setting:TWISTED_REACTOR setting, but ignoring its value in :ref:per-spider settings <spider-settings>.
If True, these commands will always use
:class:~scrapy.crawler.CrawlerProcess.
Set this to True if you want to set :setting:TWISTED_REACTOR to a
non-default value in :ref:per-spider settings <spider-settings>.
.. setting:: FTP_PASSIVE_MODE
Default: True
Whether or not to use passive mode when initiating FTP transfers.
.. note::
Handling of this setting needs to be implemented inside the :ref:`download
handler <topics-download-handlers>`, so it's not guaranteed to be supported
by all 3rd-party handlers.
.. reqmeta:: ftp_password .. setting:: FTP_PASSWORD
Default: "guest"
The password to use for FTP connections when there is no "ftp_password"
in Request meta.
.. note::
Paraphrasing RFC 1635_, although it is common to use either the password
"guest" or one's e-mail address for anonymous FTP,
some FTP servers explicitly ask for the user's e-mail address
and will not allow login with the "guest" password.
.. _RFC 1635: https://datatracker.ietf.org/doc/html/rfc1635
.. note::
Handling of this setting needs to be implemented inside the :ref:`download
handler <topics-download-handlers>`, so it's not guaranteed to be supported
by all 3rd-party handlers.
.. reqmeta:: ftp_user .. setting:: FTP_USER
Default: "anonymous"
The username to use for FTP connections when there is no "ftp_user"
in Request meta.
.. note::
Handling of this setting needs to be implemented inside the :ref:`download
handler <topics-download-handlers>`, so it's not guaranteed to be supported
by all 3rd-party handlers.
.. setting:: GCS_PROJECT_ID
Default: None
The Project ID that will be used when storing data on Google Cloud Storage_.
.. setting:: ITEM_PIPELINES
Default: {}
A dict containing the item pipelines to use, and their orders. Order values are arbitrary, but it is customary to define them in the 0-1000 range. Lower orders process before higher orders.
Example:
.. code-block:: python
ITEM_PIPELINES = { "mybot.pipelines.validate.ValidateMyItem": 300, "mybot.pipelines.validate.StoreMyItem": 800, }
.. setting:: ITEM_PIPELINES_BASE
Default: {}
A dict containing the pipelines enabled by default in Scrapy. You should never
modify this setting in your project, modify :setting:ITEM_PIPELINES instead.
.. setting:: JOBDIR
Default: None
A string indicating the directory for storing the state of a crawl when
:ref:pausing and resuming crawls <topics-jobs>.
.. setting:: LOG_ENABLED
Default: True
Whether to enable logging.
.. setting:: LOG_ENCODING
Default: 'utf-8'
The encoding to use for logging.
.. setting:: LOG_FILE
Default: None
File name to use for logging output. If None, standard error will be used.
.. setting:: LOG_FILE_APPEND
Default: True
If False, the log file specified with :setting:LOG_FILE will be
overwritten (discarding the output from previous runs, if any).
.. setting:: LOG_FORMAT
Default: '%(asctime)s [%(name)s] %(levelname)s: %(message)s'
String for formatting log messages. Refer to the
:ref:Python logging documentation <logrecord-attributes> for the whole
list of available placeholders.
.. setting:: LOG_DATEFORMAT
Default: '%Y-%m-%d %H:%M:%S'
String for formatting date/time, expansion of the %(asctime)s placeholder
in :setting:LOG_FORMAT. Refer to the
:ref:Python datetime documentation <strftime-strptime-behavior> for the
whole list of available directives.
.. setting:: LOG_FORMATTER
Default: :class:scrapy.logformatter.LogFormatter
The class to use for :ref:formatting log messages <custom-log-formats> for different actions.
.. setting:: LOG_LEVEL
Default: 'DEBUG'
Minimum level to log. Available levels are: CRITICAL, ERROR, WARNING,
INFO, DEBUG. For more info see :ref:topics-logging.
.. setting:: LOG_STDOUT
Default: False
If True, all standard output (and error) of your process will be redirected
to the log. For example if you print('hello') it will appear in the Scrapy
log.
.. setting:: LOG_SHORT_NAMES
Default: False
If True, the logs will just contain the root path. If it is set to False
then it displays the component responsible for the log output
.. setting:: LOG_VERSIONS
Default: ["lxml", "libxml2", "cssselect", "parsel", "w3lib", "Twisted", "Python", "pyOpenSSL", "cryptography", "Platform"]
Logs the installed versions of the specified items.
An item can be any installed Python package.
The following special items are also supported:
libxml2
Platform (:func:platform.platform)
Python
.. setting:: LOGSTATS_INTERVAL
Default: 60.0
The interval (in seconds) between each logging printout of the stats
by :class:~scrapy.extensions.logstats.LogStats.
.. setting:: MEMDEBUG_ENABLED
Default: False
Whether to enable memory debugging.
.. setting:: MEMDEBUG_NOTIFY
Default: []
When memory debugging is enabled a memory report will be sent to the specified addresses if this setting is not empty, otherwise the report will be written to the log.
Example::
MEMDEBUG_NOTIFY = ['[email protected]']
.. setting:: MEMUSAGE_ENABLED
Default: True
Scope: scrapy.extensions.memusage.MemoryUsage
Whether to enable the memory usage extension. This extension keeps track of
a peak memory used by the process (it writes it to stats). It can also
optionally shutdown the Scrapy process when it exceeds a memory limit
(see :setting:MEMUSAGE_LIMIT_MB).
See :ref:topics-extensions-ref-memusage.
.. setting:: MEMUSAGE_LIMIT_MB
Default: 0
Scope: scrapy.extensions.memusage.MemoryUsage
The maximum amount of memory to allow (in megabytes) before shutting down
Scrapy (if :setting:MEMUSAGE_ENABLED is True). If zero, no check will be
performed.
See :ref:topics-extensions-ref-memusage.
.. setting:: MEMUSAGE_CHECK_INTERVAL_SECONDS
Default: 60.0
Scope: scrapy.extensions.memusage.MemoryUsage
The :ref:Memory usage extension <topics-extensions-ref-memusage>
checks the current memory usage, versus the limits set by
:setting:MEMUSAGE_LIMIT_MB and :setting:MEMUSAGE_WARNING_MB,
at fixed time intervals.
This sets the length of these intervals, in seconds.
See :ref:topics-extensions-ref-memusage.
.. setting:: MEMUSAGE_WARNING_MB
Default: 0
Scope: scrapy.extensions.memusage.MemoryUsage
The maximum amount of memory to allow (in megabytes) before sending a
:signal:memusage_warning_reached signal (if :setting:MEMUSAGE_ENABLED is
True). If zero, no signal will be sent.
See :ref:topics-extensions-ref-memusage.
.. setting:: NEWSPIDER_MODULE
Default: "<project name>.spiders" (:ref:fallback <default-settings>: "")
Module where to create new spiders using the :command:genspider command.
Example::
NEWSPIDER_MODULE = 'mybot.spiders_dev'
.. setting:: RANDOMIZE_DOWNLOAD_DELAY
Default: True
If enabled, Scrapy will wait a random amount of time (between 0.5 * :setting:DOWNLOAD_DELAY and 1.5 * :setting:DOWNLOAD_DELAY) while fetching requests from the same
website.
This randomization decreases the chance of the crawler being detected (and subsequently blocked) by sites which analyze requests looking for statistically significant similarities in the time between their requests.
The randomization policy is the same used by wget_ --random-wait option.
If :setting:DOWNLOAD_DELAY is zero (default) this option has no effect.
.. _wget: https://www.gnu.org/software/wget/manual/wget.html
.. setting:: REACTOR_THREADPOOL_MAXSIZE
Default: 10
The maximum limit for Twisted Reactor thread pool size. This is common multi-purpose thread pool used by various Scrapy components. Threaded DNS Resolver, BlockingFeedStorage, S3FilesStore just to name a few. Increase this value if you're experiencing problems with insufficient blocking IO.
.. setting:: REDIRECT_PRIORITY_ADJUST
Default: +2
Scope: scrapy.downloadermiddlewares.redirect.RedirectMiddleware
Adjust redirect request priority relative to original request:
.. setting:: ROBOTSTXT_OBEY
Default: True (:ref:fallback <default-settings>: False)
If enabled, Scrapy will respect robots.txt policies. For more information see
:ref:topics-dlmw-robots.
.. note::
While the default value is ``False`` for historical reasons,
this option is enabled by default in settings.py file generated
by ``scrapy startproject`` command.
.. setting:: ROBOTSTXT_PARSER
Default: 'scrapy.robotstxt.ProtegoRobotParser'
The parser backend to use for parsing robots.txt files. For more information see
:ref:topics-dlmw-robots.
.. setting:: ROBOTSTXT_USER_AGENT
ROBOTSTXT_USER_AGENT ^^^^^^^^^^^^^^^^^^^^
Default: None
The user agent string to use for matching in the robots.txt file. If None,
the User-Agent header you are sending with the request or the
:setting:USER_AGENT setting (in that order) will be used for determining
the user agent to use in the robots.txt file.
.. setting:: SCHEDULER
Default: :class:~scrapy.core.scheduler.Scheduler
The scheduler class to be used for crawling. See :ref:topics-scheduler for
details.
.. setting:: SCHEDULER_DEBUG
Default: False
Setting to True will log debug information about the requests scheduler.
This currently logs (only once) if the requests cannot be serialized to disk.
Stats counter (scheduler/unserializable) tracks the number of times this happens.
Example entry in logs::
1956-01-31 00:00:00+0800 [scrapy.core.scheduler] ERROR: Unable to serialize request:
<GET http://example.com> - reason: cannot serialize <Request at 0x9a7c7ec>
(type Request)> - no more unserializable requests will be logged
(see 'scheduler/unserializable' stats counter)
.. setting:: SCHEDULER_DISK_QUEUE
Default: 'scrapy.squeues.PickleLifoDiskQueue'
Type of disk queue that will be used by the scheduler. Other available types
are scrapy.squeues.PickleFifoDiskQueue,
scrapy.squeues.MarshalFifoDiskQueue,
scrapy.squeues.MarshalLifoDiskQueue.
.. setting:: SCHEDULER_MEMORY_QUEUE
Default: 'scrapy.squeues.LifoMemoryQueue'
Type of in-memory queue used by the scheduler. Other available type is:
scrapy.squeues.FifoMemoryQueue.
.. setting:: SCHEDULER_PRIORITY_QUEUE
Default: :class:~scrapy.pqueues.DownloaderAwarePriorityQueue
Type of priority queue used by the scheduler.
Another available type is :class:~scrapy.pqueues.ScrapyPriorityQueue.
:class:~scrapy.pqueues.DownloaderAwarePriorityQueue works better than
:class:~scrapy.pqueues.ScrapyPriorityQueue when you crawl many different
domains in parallel.
.. setting:: SCHEDULER_START_DISK_QUEUE
Default: 'scrapy.squeues.PickleFifoDiskQueue'
Type of disk queue (see :setting:JOBDIR) that the :ref:scheduler <topics-scheduler> uses for :ref:start requests <start-requests>.
For available choices, see :setting:SCHEDULER_DISK_QUEUE.
.. queue-common-starts
Use None or "" to disable these separate queues entirely, and instead
have start requests share the same queues as other requests.
.. note::
Disabling separate start request queues makes :ref:`start request order
<start-request-order>` unintuitive: start requests will be sent in order
only until :setting:`CONCURRENT_REQUESTS` is reached, then remaining start
requests will be sent in reverse order.
.. queue-common-ends
.. setting:: SCHEDULER_START_MEMORY_QUEUE
Default: 'scrapy.squeues.FifoMemoryQueue'
Type of in-memory queue that the :ref:scheduler <topics-scheduler> uses for
:ref:start requests <start-requests>.
For available choices, see :setting:SCHEDULER_MEMORY_QUEUE.
.. include:: settings.rst :start-after: queue-common-starts :end-before: queue-common-ends
.. setting:: SCRAPER_SLOT_MAX_ACTIVE_SIZE
Default: 5_000_000
Soft limit (in bytes) for response data being processed.
While the sum of the sizes of all responses being processed is above this value, Scrapy does not process new requests.
.. setting:: SPIDER_CONTRACTS
Default: {}
A dict containing the spider contracts enabled in your project, used for
testing spiders. For more info see :ref:topics-contracts.
.. setting:: SPIDER_CONTRACTS_BASE
Default:
.. code-block:: python
{
"scrapy.contracts.default.UrlContract": 1,
"scrapy.contracts.default.ReturnsContract": 2,
"scrapy.contracts.default.ScrapesContract": 3,
}
A dict containing the Scrapy contracts enabled by default in Scrapy. You should
never modify this setting in your project, modify :setting:SPIDER_CONTRACTS
instead. For more info see :ref:topics-contracts.
You can disable any of these contracts by assigning None to their class
path in :setting:SPIDER_CONTRACTS. E.g., to disable the built-in
ScrapesContract, place this in your settings.py:
.. code-block:: python
SPIDER_CONTRACTS = {
"scrapy.contracts.default.ScrapesContract": None,
}
.. setting:: SPIDER_LOADER_CLASS
Default: 'scrapy.spiderloader.SpiderLoader'
The class that will be used for loading spiders, which must implement the
:ref:topics-api-spiderloader.
.. setting:: SPIDER_LOADER_WARN_ONLY
Default: False
By default, when Scrapy tries to import spider classes from :setting:SPIDER_MODULES,
it will fail loudly if there is any ImportError or SyntaxError exception.
But you can choose to silence this exception and turn it into a simple
warning by setting SPIDER_LOADER_WARN_ONLY = True.
.. setting:: SPIDER_MIDDLEWARES
Default: {}
A dict containing the spider middlewares enabled in your project, and their
orders. For more info see :ref:topics-spider-middleware-setting.
.. setting:: SPIDER_MIDDLEWARES_BASE
Default:
.. code-block:: python
{
"scrapy.spidermiddlewares.httperror.HttpErrorMiddleware": 50,
"scrapy.spidermiddlewares.referer.RefererMiddleware": 700,
"scrapy.spidermiddlewares.urllength.UrlLengthMiddleware": 800,
"scrapy.spidermiddlewares.depth.DepthMiddleware": 900,
}
A dict containing the spider middlewares enabled by default in Scrapy, and
their orders. Low orders are closer to the engine, high orders are closer to
the spider. For more info see :ref:topics-spider-middleware-setting.
.. setting:: SPIDER_MODULES
Default: ["<project name>.spiders"] (:ref:fallback <default-settings>: [])
A list of modules where Scrapy will look for spiders.
Example:
.. code-block:: python
SPIDER_MODULES = ["mybot.spiders_prod", "mybot.spiders_dev"]
.. setting:: STATS_CLASS
Default: 'scrapy.statscollectors.MemoryStatsCollector'
The class to use for collecting stats, who must implement the
:ref:topics-api-stats.
.. setting:: STATS_DUMP
Default: True
Dump the :ref:Scrapy stats <topics-stats> (to the Scrapy log) once the spider
finishes.
For more info see: :ref:topics-stats.
.. setting:: TELNETCONSOLE_ENABLED
Default: True (False when :setting:TWISTED_REACTOR_ENABLED is False)
A boolean which specifies if the :ref:telnet console <topics-telnetconsole>
will be enabled (provided its extension is also enabled).
.. setting:: TEMPLATES_DIR
Default: templates dir inside scrapy module
The directory where to look for templates when creating new projects with
:command:startproject command and new spiders with :command:genspider
command.
The project name must not conflict with the name of custom files or directories
in the project subdirectory.
.. setting:: TWISTED_REACTOR_ENABLED
Default: True
Whether to install and use the Twisted reactor.
If this is set to True, Scrapy will use the Twisted reactor and will
install one according to the :setting:TWISTED_REACTOR setting value when
appropriate (e.g. when running via :ref:the command-line tool <topics-commands>). This is the traditional mode of using Scrapy.
If this is set to False, Scrapy will use the asyncio event loop directly
and will not attempt to install or use a reactor. Features that require a
reactor won't be available, but Twisted APIs that don't require a reactor,
including :class:~twisted.internet.defer.Deferred and
:class:~twisted.python.failure.Failure, will still be available. On the other
hand, limitations related to Twisted reactors (such as not being able to start
a reactor in the same process where a reactor was previously started and
stopped) will not apply. This mode is currently experimental and may not be
suitable for production use. It may also not be supported by 3rd-party code.
See :ref:asyncio-without-reactor for more information about this mode.
.. note:: This setting can't be set :ref:per-spider <spider-settings>.
.. versionadded:: 2.15.0
.. setting:: TWISTED_REACTOR
Default: "twisted.internet.asyncioreactor.AsyncioSelectorReactor"
Import path of a given :mod:~twisted.internet.reactor.
Scrapy will install this reactor if no other reactor is installed yet, such as
when the scrapy CLI program is invoked or when using the
:class:~scrapy.crawler.AsyncCrawlerProcess class or the
:class:~scrapy.crawler.CrawlerProcess class.
If you are using the :class:~scrapy.crawler.AsyncCrawlerRunner class or the
:class:~scrapy.crawler.CrawlerRunner class, you also
need to install the correct reactor manually. You can do that using
:func:~scrapy.utils.reactor.install_reactor:
.. autofunction:: scrapy.utils.reactor.install_reactor
If a reactor is already installed,
:func:~scrapy.utils.reactor.install_reactor has no effect.
:class:~scrapy.crawler.AsyncCrawlerRunner and other similar classes raise an
exception if the installed reactor does not match the
:setting:TWISTED_REACTOR setting; therefore, having top-level
:mod:~twisted.internet.reactor imports in project files and imported
third-party libraries will make Scrapy raise an exception when it checks which
reactor is installed.
In order to use the reactor installed by Scrapy:
.. skip: next .. code-block:: python
import scrapy
from twisted.internet import reactor
class QuotesSpider(scrapy.Spider):
name = "quotes"
def __init__(self, *args, **kwargs):
self.timeout = int(kwargs.pop("timeout", "60"))
super(QuotesSpider, self).__init__(*args, **kwargs)
async def start(self):
reactor.callLater(self.timeout, self.stop)
urls = ["https://quotes.toscrape.com/page/1"]
for url in urls:
yield scrapy.Request(url=url, callback=self.parse)
def parse(self, response):
for quote in response.css("div.quote"):
yield {"text": quote.css("span.text::text").get()}
def stop(self):
self.crawler.engine.close_spider(self, "timeout")
which raises an exception, becomes:
.. code-block:: python
import scrapy
class QuotesSpider(scrapy.Spider):
name = "quotes"
def __init__(self, *args, **kwargs):
self.timeout = int(kwargs.pop("timeout", "60"))
super(QuotesSpider, self).__init__(*args, **kwargs)
async def start(self):
from twisted.internet import reactor
reactor.callLater(self.timeout, self.stop)
urls = ["https://quotes.toscrape.com/page/1"]
for url in urls:
yield scrapy.Request(url=url, callback=self.parse)
def parse(self, response):
for quote in response.css("div.quote"):
yield {"text": quote.css("span.text::text").get()}
def stop(self):
self.crawler.engine.close_spider(self, "timeout")
If this setting is set None, Scrapy will use the existing reactor if one is
already installed, or install the default reactor defined by Twisted for the
current platform.
.. versionchanged:: 2.13
The default value was changed from None to
"twisted.internet.asyncioreactor.AsyncioSelectorReactor".
For additional information, see :doc:core/howto/choosing-reactor.
.. setting:: URLLENGTH_LIMIT
Default: 2083
Scope: spidermiddlewares.urllength
The maximum URL length to allow for crawled URLs.
This setting can act as a stopping condition in case of URLs of ever-increasing
length, which may be caused for example by a programming error either in the
target server or in your code. See also :setting:REDIRECT_MAX_TIMES and
:setting:DEPTH_LIMIT.
Use 0 to allow URLs of any length.
The default value is copied from the Microsoft Internet Explorer maximum URL length_, even though this setting exists for different reasons.
.. _Microsoft Internet Explorer maximum URL length: https://web.archive.org/web/20250206050143/https://support.microsoft.com/en-us/topic/maximum-url-length-is-2-083-characters-in-internet-explorer-174e7c8a-6666-f4e0-6fd6-908b53c12246
.. setting:: USER_AGENT
Default: "Scrapy/VERSION (+https://scrapy.org)"
The default User-Agent to use when crawling, unless overridden. This user agent is
also used by :class:~scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware
if :setting:ROBOTSTXT_USER_AGENT setting is None and
there is no overriding User-Agent header specified for the request.
.. setting:: WARN_ON_GENERATOR_RETURN_VALUE
Default: True
When enabled, Scrapy will warn if generator-based callback methods (like
parse) contain return statements with non-None values. This helps detect
potential mistakes in spider development.
Disable this setting to prevent syntax errors that may occur when dynamically modifying generator function source code during runtime, skip AST parsing of callback functions, or improve performance in auto-reloading development environments.
The following settings are documented elsewhere, please check each specific case to see how to enable and use them.
.. settingslist::
.. _Amazon web services: https://aws.amazon.com/ .. _Google Cloud Storage: https://cloud.google.com/storage/