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.
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.
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:
- Global overrides (most precedence)
- Environment variables
- scrapy_settings
- Default settings per-command
- Default global settings (less precedence)
This mechanisms are described with more detail below.
Global overrides are the ones that takes most precedence, and are usually populated by command line options.
>>> 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
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.
scrapy_settings is the standard configuration file for your Scrapy project. It’s where most of your custom settings will be populated.
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
The global defaults are located in scrapy.conf.default_settings and documented in the Built-in settings reference section.
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:
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
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
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
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
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
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
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.
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.
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.
Default: 1.0
The version of the bot implemented by this Scrapy project. This will be used to construct the User-Agent by default.
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'
Default: '' (empty string)
A module to use for looking for custom Scrapy command settings.
Example:
COMMANDS_SETTINGS_MODULE = 'mybot.conf.commands'
Default: 100
Maximum number of concurrent items (per response) to process in parallel in the Item Processor (also known as the Item Pipeline).
Default: 'scrapy.item.Item'
The default class that will be used for instantiating items in the the Scrapy shell.
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: '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.
Default: 0
The maximum depth that will be allowed to crawl for any site. If zero, no limit will be imposed.
Default: 'scrapy.contrib.spiderscheduler.FifoSpiderScheduler'
The Spider Scheduler to use. The spider scheduler returns the next spider to scrape.
Default:: {}
A dict containing the downloader middlewares enabled in your project, and their orders. For more info see Activating a downloader middleware.
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.
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
Default: 180
The amount of time (in secs) that the downloader will wait before timing out.
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.
Default:: {}
A dict containing the extensions enabled in your project, and their orders.
Default:
{
'scrapy.contrib.corestats.CoreStats': 0,
'scrapy.management.web.WebConsole': 0,
'scrapy.management.telnet.TelnetConsole': 0,
'scrapy.contrib.webconsole.scheduler.SchedulerQueue': 0,
'scrapy.contrib.webconsole.livestats.LiveStats': 0,
'scrapy.contrib.webconsole.spiderctl.Spiderctl': 0,
'scrapy.contrib.webconsole.enginestatus.EngineStatus': 0,
'scrapy.contrib.webconsole.stats.StatsDump': 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.
Default: False
Whether to enable group settings where spiders pull their settings from.
Default: '' (empty string)
The module to use for pulling settings from, if the group settings is enabled.
Default: []
The item pipelines to use (a list of classes).
Example:
ITEM_PIPELINES = [
'mybot.pipeline.validate.ValidateMyItem',
'mybot.pipeline.validate.StoreMyItem'
]
Default: None
File name to use for logging output. If None, standard input (or error) will be used depending on the value of the LOG_STDOUT setting.
Default: 'DEBUG'
Minimum level to log. Available levels are: CRITICAL, ERROR, WARNING, INFO, DEBUG. For more info see Logging.
Default: False
If enabled logging will be sent to standard output, otherwise standard error will be used.
Default: 'scrapy@localhost'
Email to use as sender address for sending emails using the Scrapy e-mail sending facility.
Default: 'localhost'
Host to use for sending emails using the Scrapy e-mail sending facility.
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 = ['user@example.com']
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.
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.
Default: False
Scope: scrapy.contrib.memusage
A list of emails to notify if the memory limit has been reached.
Example:
MEMUSAGE_NOTIFY_MAIL = ['user@example.com']
Default: False
Scope: scrapy.contrib.memusage
Whether to send a memory usage report after each domain has been closed.
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.
Default: ''
Module where to create new spiders using the genspider command.
Example:
NEWSPIDER_MODULE = 'mybot.spiders_dev'
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.
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)
Default: +2
Adjust redirect request priority relative to original request. A negative priority adjust means more priority.
Default: {}
A dict containing the request downloader handlers enabled in your project. See REQUEST_HANDLERS_BASE for example format.
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.
Default: 8
Specifies how many concurrent (ie. simultaneous) requests will be performed per open spider.
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.
Default: False
Scope: scrapy.contrib.downloadermiddleware.robotstxt
If enabled, Scrapy will respect robots.txt policies. For more information see RobotsTxtMiddleware
Default: 'BFO'
Scope: scrapy.core.scheduler
The order to use for the crawling scheduler. Available orders are:
Default:: {}
A dict containing the scheduler middlewares enabled in your project, and their orders.
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.
Default:: {}
A dict containing the spider middlewares enabled in your project, and their orders. For more info see Activating a spider middleware.
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.
Default: []
A list of modules where Scrapy will look for spiders.
Example:
SPIDER_MODULES = ['mybot.spiders_prod', 'mybot.spiders_dev']
Default: 'scrapy.stats.collector.MemoryStatsCollector'
The class to use for collecting stats (must implement the Stats Collector API, or subclass the StatsCollector class).
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).
Default: [] (empty list)
Send Scrapy stats after domains finish scrapy. See StatsMailer for more info.
Default: True
Scope: scrapy.management.telnet
A boolean which specifies if the telnet management console will be enabled (provided its extension is also enabled).
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.
Default: templates dir inside scrapy module
The directory where to look for template when creating new projects with scrapy-ctl.py startproject command.
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
Default: "%s/%s" % (BOT_NAME, BOT_VERSION)
The default User-Agent to use when crawling, unless overrided.
Default: True
A boolean which specifies if the web management console will be enabled (provided its extension is also enabled).
Default: None
A file to use for logging HTTP requests made to the web console. If unset web the log is sent to standard scrapy log.
Default: 6080
The port to use for the web console. If set to None or 0, a dynamically assigned port is used. For more info see Web Console.