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 setting 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 is also the mechanism for selecting the currently active Scrapy project (in case you have many).

For a list of available built-in settings see: Built-in settings reference.

Designating the settings

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, or the --settings argument of the scrapy-ctl.py script.

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 import search path.

Populating the settings

Settings can be populated using different mechanisms, each of which having a different precedence. Here is the list of them in decreasing order of precedence:

  1. Global overrides (most precedence)
  2. Environment variables
  3. scrapy_settings
  4. Default settings per-command
  5. Default global settings (less precedence)

This mechanisms are described with more detail below.

1. Global overrides

Global overrides are the ones that takes most precedence, and are usually populated by command line options.

Example::
>>> from scrapy.conf import settings
>>> settings.overrides['LOG_ENABLED'] = True

You can also override one (or more) settings from command line using the --set command line argument.

Example:

scrapy-ctl.py crawl domain.com --set LOG_FILE=scrapy.log

2. Environment variables

You can populate settings using environment variables prefixed with SCRAPY_. For example, to change the log file location un Unix systems:

$ export SCRAPY_LOG_FILE=scrapy.log
$ scrapy-ctl.py crawl example.com

In Windows systems, you can change the environment variables from the Control Panel following these guidelines.

3. scrapy_settings

scrapy_settings is the standard configuration file for your Scrapy project. It’s where most of your custom settings will be populated.

4. Default settings per-command

Each scrapy-ctl.py command can have its own default settings, which override the global default settings. Those custom command settings are located inside the scrapy.conf.commands module, or you can specify custom settings to override per-comand inside your project, by writing them in the module referenced by the COMMANDS_SETTINGS_MODULE setting. Those settings will take more

5. Default global settings

The global defaults are located in scrapy.conf.default_settings and documented in the Built-in settings reference section.

How to access settings

Here’s an example of the simplest way to access settings from Python code:

>>> from scrapy.conf import settings
>>> print settings['LOG_ENABLED']
True

In other words, settings can be accesed like a dict, but it’s usually preferred to extract the setting in the format you need it to avoid type errors. In order to do that you’ll have to use one of the following methods:

class scrapy.conf.Settings

The Settings object is automatically instantiated when the scrapy.conf module is loaded, and it’s usually accessed like this:

>>> from scrapy.conf import settings
Settings.get(name, default=None)

Get a setting value without affecting its original type.

name is a string with the setting name

default is the value to return if no setting is found

Settings.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.

name is a string with the setting name

default is the value to return if no setting is found

Settings.getint(name, default=0)

Get a setting value as an int

name is a string with the setting name

default is the value to return if no setting is found

Settings.getfloat(name, default=0.0)

Get a setting value as a float

name is a string with the setting name

default is the value to return if no setting is found

Settings.getlist(name, default=None)

Get a setting value as a list. If the setting original type is a list it will be returned verbatim. If it’s a string it will be splitted by ”,”.

For example, settings populated through environment variables set to 'one,two' will return a list [‘one’, ‘two’] when using this method.

name is a string with the setting name

default is the value to return if no setting is found

Rationale for setting names

Setting names are usually prefixed with the component that they configure. For example, proper setting names for a fictional robots.txt extension would be ROBOTSTXT_ENABLED, ROBOTSTXT_OBEY, ROBOTSTXT_CACHEDIR, etc.

Built-in settings reference

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.

BOT_NAME

Default: scrapybot

The name of the bot implemented by this Scrapy project (also known as the project name). This will be used to construct the User-Agent by default, and also for logging.

It’s automatically populated with your project name when you create your project with the scrapy-ctl.py startproject command.

BOT_VERSION

Default: 1.0

The version of the bot implemented by this Scrapy project. This will be used to construct the User-Agent by default.

COMMANDS_MODULE

Default: '' (empty string)

A module to use for looking for custom Scrapy commands. This is used to add custom command for your Scrapy project.

Example:

COMMANDS_MODULE = 'mybot.commands'

COMMANDS_SETTINGS_MODULE

Default: '' (empty string)

A module to use for looking for custom Scrapy command settings.

Example:

COMMANDS_SETTINGS_MODULE = 'mybot.conf.commands'

CONCURRENT_ITEMS

Default: 100

Maximum number of concurrent items (per response) to process in parallel in the Item Processor (also known as the Item Pipeline).

CONCURRENT_REQUESTS_PER_SPIDER

Default: 8

Specifies how many concurrent (ie. simultaneous) requests will be performed per open spider.

CONCURRENT_SPIDERS

Default: 8

Maximum number of spiders to scrape in parallel.

COOKIES_DEBUG

Default: False

Enable debugging message of Cookies Downloader Middleware.

DEFAULT_ITEM_CLASS

Default: 'scrapy.item.Item'

The default class that will be used for instantiating items in the the Scrapy shell.

DEFAULT_REQUEST_HEADERS

Default:

{
    '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 DefaultHeadersMiddleware.

DEFAULT_RESPONSE_ENCODING

Default: 'ascii'

The default encoding to use for TextResponse objects (and subclasses) when no encoding is declared and no encoding could be inferred from the body.

DEPTH_LIMIT

Default: 0

The maximum depth that will be allowed to crawl for any site. If zero, no limit will be imposed.

DEPTH_STATS

Default: True

Whether to collect depth stats.

DOWNLOADER_DEBUG

Default: False

Whether to enable the Downloader debugging mode.

DOWNLOADER_MIDDLEWARES

Default:: {}

A dict containing the downloader middlewares enabled in your project, and their orders. For more info see Activating a downloader middleware.

DOWNLOADER_MIDDLEWARES_BASE

Default:

{
    'scrapy.contrib.downloadermiddleware.robotstxt.RobotsTxtMiddleware': 100,
    'scrapy.contrib.downloadermiddleware.httpauth.HttpAuthMiddleware': 300,
    'scrapy.contrib.downloadermiddleware.useragent.UserAgentMiddleware': 400,
    'scrapy.contrib.downloadermiddleware.retry.RetryMiddleware': 500,
    'scrapy.contrib.downloadermiddleware.defaultheaders.DefaultHeadersMiddleware': 550,
    'scrapy.contrib.downloadermiddleware.redirect.RedirectMiddleware': 600,
    'scrapy.contrib.downloadermiddleware.cookies.CookiesMiddleware': 700,
    'scrapy.contrib.downloadermiddleware.httpproxy.HttpProxyMiddleware': 750,
    'scrapy.contrib.downloadermiddleware.httpcompression.HttpCompressionMiddleware': 800,
    'scrapy.contrib.downloadermiddleware.stats.DownloaderStats': 850,
    'scrapy.contrib.downloadermiddleware.httpcache.HttpCacheMiddleware': 900,
}

A dict containing the downloader middlewares enabled by default in Scrapy. You should never modify this setting in your project, modify DOWNLOADER_MIDDLEWARES instead. For more info see Activating a downloader middleware.

DOWNLOADER_STATS

Default: True

Whether to enable downloader stats collection.

DOWNLOAD_DELAY

Default: 0

The amount of time (in secs) that the downloader should wait before downloading consecutive pages from the same spider. This can be used to throttle the crawling speed to avoid hitting servers too hard. Decimal numbers are supported. Example:

DOWNLOAD_DELAY = 0.25    # 250 ms of delay

This setting is also affected by the RANDOMIZE_DOWNLOAD_DELAY setting (which is enabled by default). By default, Scrapy doesn’t wait a fixed amount of time between requests, but uses a random interval between 0.5 and 1.5 * DOWNLOAD_DELAY.

Another way to change the download delay (per spider, instead of globally) is by using the download_delay spider attribute, which takes more precedence than this setting.

DOWNLOAD_TIMEOUT

Default: 180

The amount of time (in secs) that the downloader will wait before timing out.

DUPEFILTER_CLASS

Default: 'scrapy.contrib.dupefilter.RequestFingerprintDupeFilter'

The class used to detect and filter duplicate requests.

The default (RequestFingerprintDupeFilter) filters based on request fingerprint (using scrapy.utils.request.request_fingerprint) and grouping per domain.

ENCODING_ALIASES

Default: {}

A mapping of custom encoding aliases for your project, where the keys are the aliases (and must be lower case) and the values are the encodings they map to.

This setting extends the ENCODING_ALIASES_BASE setting which contains some default mappings.

ENCODING_ALIASES_BASE

Default:

{
    # gb2312 is superseded by gb18030
    'gb2312': 'gb18030',
    'chinese': 'gb18030',
    'csiso58gb231280': 'gb18030',
    'euc- cn': 'gb18030',
    'euccn': 'gb18030',
    'eucgb2312-cn': 'gb18030',
    'gb2312-1980': 'gb18030',
    'gb2312-80': 'gb18030',
    'iso- ir-58': 'gb18030',
    # gbk is superseded by gb18030
    'gbk': 'gb18030',
    '936': 'gb18030',
    'cp936': 'gb18030',
    'ms936': 'gb18030',
    # latin_1 is a subset of cp1252
    'latin_1': 'cp1252',
    'iso-8859-1': 'cp1252',
    'iso8859-1': 'cp1252',
    '8859': 'cp1252',
    'cp819': 'cp1252',
    'latin': 'cp1252',
    'latin1': 'cp1252',
    'l1': 'cp1252',
    # others
    'zh-cn': 'gb18030',
    'win-1251': 'cp1251',
    'macintosh' : 'mac_roman',
    'x-sjis': 'shift_jis',
}

The default encoding aliases defined in Scrapy. Don’t override this setting in your project, override ENCODING_ALIASES instead.

The reason why ISO-8859-1 (and all its aliases) are mapped to CP1252 is due to a well known browser hack. For more information see: Character encodings in HTML.

EXTENSIONS

Default:: {}

A dict containing the extensions enabled in your project, and their orders.

EXTENSIONS_BASE

Default:

{
    'scrapy.contrib.corestats.CoreStats': 0,
    'scrapy.webservice.WebService': 0,
    'scrapy.telnet.TelnetConsole': 0,
    'scrapy.contrib.memusage.MemoryUsage': 0,
    'scrapy.contrib.memdebug.MemoryDebugger': 0,
    'scrapy.contrib.closedomain.CloseDomain': 0,
}

The list of available extensions. Keep in mind that some of them need need to be enabled through a setting. By default, this setting contains all stable built-in extensions.

For more information See the extensions user guide and the list of available extensions.

GROUPSETTINGS_ENABLED

Default: False

Whether to enable group settings where spiders pull their settings from.

GROUPSETTINGS_MODULE

Default: '' (empty string)

The module to use for pulling settings from, if the group settings is enabled.

ITEM_PIPELINES

Default: []

The item pipelines to use (a list of classes).

Example:

ITEM_PIPELINES = [
    'mybot.pipeline.validate.ValidateMyItem',
    'mybot.pipeline.validate.StoreMyItem'
]

LOG_ENABLED

Default: True

Whether to enable logging.

LOG_ENCODING

Default: 'utf-8'

The encoding to use for logging.

LOG_FILE

Default: None

File name to use for logging output. If None, standard error will be used.

LOG_LEVEL

Default: 'DEBUG'

Minimum level to log. Available levels are: CRITICAL, ERROR, WARNING, INFO, DEBUG. For more info see Logging.

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.

MEMDEBUG_ENABLED

Default: False

Whether to enable memory debugging.

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]']

MEMUSAGE_ENABLED

Default: False

Scope: scrapy.contrib.memusage

Whether to enable the memory usage extension that will shutdown the Scrapy process when it exceeds a memory limit, and also notify by email when that happened.

See Memory usage extension.

MEMUSAGE_LIMIT_MB

Default: 0

Scope: scrapy.contrib.memusage

The maximum amount of memory to allow (in megabytes) before shutting down Scrapy (if MEMUSAGE_ENABLED is True). If zero, no check will be performed.

See Memory usage extension.

MEMUSAGE_NOTIFY_MAIL

Default: False

Scope: scrapy.contrib.memusage

A list of emails to notify if the memory limit has been reached.

Example:

MEMUSAGE_NOTIFY_MAIL = ['[email protected]']

See Memory usage extension.

MEMUSAGE_REPORT

Default: False

Scope: scrapy.contrib.memusage

Whether to send a memory usage report after each domain has been closed.

See Memory usage extension.

MEMUSAGE_WARNING_MB

Default: 0

Scope: scrapy.contrib.memusage

The maximum amount of memory to allow (in megabytes) before sending a warning email notifying about it. If zero, no warning will be produced.

NEWSPIDER_MODULE

Default: ''

Module where to create new spiders using the genspider command.

Example:

NEWSPIDER_MODULE = 'mybot.spiders_dev'

RANDOMIZE_DOWNLOAD_DELAY

Default: True

If enabled, Scrapy will wait a random amount of time (between 0.5 and 1.5 * DOWNLOAD_DELAY) while fetching requests from the same spider.

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 times.

The randomization policy is the same used by wget --random-wait option.

If DOWNLOAD_DELAY is zero (default) this option has no effect.

REDIRECT_MAX_TIMES

Default: 20

Defines the maximun times a request can be redirected. After this maximun the request’s response is returned as is. We used Firefox default value for the same task.

REDIRECT_MAX_METAREFRESH_DELAY

Default: 100

Some sites use meta-refresh for redirecting to a session expired page, so we restrict automatic redirection to a maximum delay (in seconds)

REDIRECT_PRIORITY_ADJUST

Default: +2

Adjust redirect request priority relative to original request. A negative priority adjust means more priority.

REQUEST_HANDLERS

Default: {}

A dict containing the request downloader handlers enabled in your project. See REQUEST_HANDLERS_BASE for example format.

REQUEST_HANDLERS_BASE

Default:

{
    'file': 'scrapy.core.downloader.handlers.file.download_file',
    'http': 'scrapy.core.downloader.handlers.http.download_http',
    'https': 'scrapy.core.downloader.handlers.http.download_http',
}

A dict containing the request download handlers enabled by default in Scrapy. You should never modify this setting in your project, modify REQUEST_HANDLERS instead.

REQUESTS_QUEUE_SIZE

Default: 0

Scope: scrapy.contrib.spidermiddleware.limit

If non zero, it will be used as an upper limit for the amount of requests that can be scheduled per domain.

ROBOTSTXT_OBEY

Default: False

Scope: scrapy.contrib.downloadermiddleware.robotstxt

If enabled, Scrapy will respect robots.txt policies. For more information see RobotsTxtMiddleware

SCHEDULER

Default: 'scrapy.core.scheduler.Scheduler'

The scheduler to use for crawling.

SCHEDULER_ORDER

Default: 'DFO'

Scope: scrapy.core.scheduler

The order to use for the crawling scheduler. Available orders are:

  • 'BFO': Breadth-first order - typically consumes more memory but reaches most relevant pages earlier.
  • 'DFO': Depth-first order - typically consumes less memory than but takes longer to reach most relevant pages.

SCHEDULER_MIDDLEWARES

Default:: {}

A dict containing the scheduler middlewares enabled in your project, and their orders.

SCHEDULER_MIDDLEWARES_BASE

Default:

SCHEDULER_MIDDLEWARES_BASE = {
    'scrapy.contrib.schedulermiddleware.duplicatesfilter.DuplicatesFilterMiddleware': 500,
}

A dict containing the scheduler middlewares enabled by default in Scrapy. You should never modify this setting in your project, modify SCHEDULER_MIDDLEWARES instead.

SPIDER_MIDDLEWARES

Default:: {}

A dict containing the spider middlewares enabled in your project, and their orders. For more info see Activating a spider middleware.

SPIDER_MIDDLEWARES_BASE

Default:

{
    'scrapy.contrib.spidermiddleware.httperror.HttpErrorMiddleware': 50,
    'scrapy.contrib.itemsampler.ItemSamplerMiddleware': 100,
    'scrapy.contrib.spidermiddleware.requestlimit.RequestLimitMiddleware': 200,
    'scrapy.contrib.spidermiddleware.offsite.OffsiteMiddleware': 500,
    'scrapy.contrib.spidermiddleware.referer.RefererMiddleware': 700,
    'scrapy.contrib.spidermiddleware.urllength.UrlLengthMiddleware': 800,
    'scrapy.contrib.spidermiddleware.depth.DepthMiddleware': 900,
}

A dict containing the spider middlewares enabled by default in Scrapy. You should never modify this setting in your project, modify SPIDER_MIDDLEWARES instead. For more info see Activating a spider middleware.

SPIDER_MODULES

Default: []

A list of modules where Scrapy will look for spiders.

Example:

SPIDER_MODULES = ['mybot.spiders_prod', 'mybot.spiders_dev']

STATS_CLASS

Default: 'scrapy.stats.collector.MemoryStatsCollector'

The class to use for collecting stats (must implement the Stats Collector API, or subclass the StatsCollector class).

STATS_DUMP

Default: False

Dump (to log) domain-specific stats collected when a domain is closed, and all global stats when the Scrapy process finishes (ie. when the engine is shutdown).

STATS_ENABLED

Default: True

Enable stats collection.

STATSMAILER_RCPTS

Default: [] (empty list)

Send Scrapy stats after domains finish scrapy. See StatsMailer for more info.

TELNETCONSOLE_ENABLED

Default: True

Scope: scrapy.management.telnet

A boolean which specifies if the telnet management console will be enabled (provided its extension is also enabled).

TELNETCONSOLE_PORT

Default: 6023

The port to use for the telnet console. If set to None or 0, a dynamically assigned port is used. For more info see Telnet Console.

TEMPLATES_DIR

Default: templates dir inside scrapy module

The directory where to look for template when creating new projects with scrapy-ctl.py startproject command.

URLLENGTH_LIMIT

Default: 2083

Scope: contrib.spidermiddleware.urllength

The maximum URL length to allow for crawled URLs. For more information about the default value for this setting see: http://www.boutell.com/newfaq/misc/urllength.html

USER_AGENT

Default: "%s/%s" % (BOT_NAME, BOT_VERSION)

The default User-Agent to use when crawling, unless overrided.