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: 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
.
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:
- Command line options (most precedence)
- Settings per-spider
- Project settings module
- Default settings per-command
- Default global settings (less precedence)
The population of these settings sources is taken care of internally, but a manual handling is possible using API calls. See the Settings API topic for reference.
These mechanisms are described in more detail below.
1. Command line options¶
Arguments provided by the command line are the ones that take most precedence,
overriding any other options. You can explicitly override one (or more)
settings using the -s
(or --set
) command line option.
Example:
scrapy crawl myspider -s LOG_FILE=scrapy.log
2. Settings per-spider¶
Spiders (See the Spiders chapter for reference) can define their
own settings that will take precedence and override the project ones. They can
do so by setting their scrapy.spiders.Spider.custom_settings
attribute.
3. Project settings module¶
The project settings module is the standard configuration file for your Scrapy
project. It’s where most of your custom settings will be populated. For
example:: myproject.settings
.
4. Default settings per-command¶
Each Scrapy tool command can have its own default
settings, which override the global default settings. Those custom command
settings are specified in the default_settings
attribute of the command
class.
5. Default global settings¶
The global defaults are located in the scrapy.settings.default_settings
module and documented in the Built-in settings reference section.
How to access settings¶
Settings can be accessed through the scrapy.crawler.Crawler.settings
attribute of the Crawler that is passed to from_crawler
method in
extensions and middlewares:
class MyExtension(object):
@classmethod
def from_crawler(cls, crawler):
settings = crawler.settings
if settings['LOG_ENABLED']:
print "log is enabled!"
In other words, settings can be accessed 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 methods provided the
Settings
API.
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.
AWS_ACCESS_KEY_ID¶
Default: None
The AWS access key used by code that requires access to Amazon Web services, such as the S3 feed storage backend.
AWS_SECRET_ACCESS_KEY¶
Default: None
The AWS secret key used by code that requires access to Amazon Web services, such as the S3 feed storage backend.
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 startproject
command.
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¶
Default: 16
The maximum number of concurrent (ie. simultaneous) requests that will be performed by the Scrapy downloader.
CONCURRENT_REQUESTS_PER_DOMAIN¶
Default: 8
The maximum number of concurrent (ie. simultaneous) requests that will be performed to any single domain.
CONCURRENT_REQUESTS_PER_IP¶
Default: 0
The maximum number of concurrent (ie. simultaneous) requests that will be
performed to any single IP. If non-zero, the
CONCURRENT_REQUESTS_PER_DOMAIN
setting is ignored, and this one is
used instead. In other words, concurrency limits will be applied per IP, not
per domain.
This setting also affects DOWNLOAD_DELAY
:
if CONCURRENT_REQUESTS_PER_IP
is non-zero, download delay is
enforced per IP, not per domain.
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
.
DEPTH_LIMIT¶
Default: 0
The maximum depth that will be allowed to crawl for any site. If zero, no limit will be imposed.
DEPTH_PRIORITY¶
Default: 0
An integer that is used to adjust the request priority based on its depth.
If zero, no priority adjustment is made from depth.
DEPTH_STATS_VERBOSE¶
Default: False
Whether to collect verbose depth stats. If this is enabled, the number of requests for each depth is collected in the stats.
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.downloadermiddlewares.robotstxt.RobotsTxtMiddleware': 100,
'scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware': 300,
'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware': 350,
'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware': 400,
'scrapy.downloadermiddlewares.retry.RetryMiddleware': 500,
'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware': 550,
'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.chunked.ChunkedTransferMiddleware': 830,
'scrapy.downloadermiddlewares.stats.DownloaderStats': 850,
'scrapy.downloadermiddlewares.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.
DOWNLOAD_DELAY¶
Default: 0
The amount of time (in secs) that the downloader should wait before downloading consecutive pages from the same website. 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
.
When CONCURRENT_REQUESTS_PER_IP
is non-zero, delays are enforced
per ip address instead of per domain.
You can also change this setting per spider by setting download_delay
spider attribute.
DOWNLOAD_HANDLERS¶
Default: {}
A dict containing the request downloader handlers enabled in your project. See DOWNLOAD_HANDLERS_BASE for example format.
DOWNLOAD_HANDLERS_BASE¶
Default:
{
'file': 'scrapy.core.downloader.handlers.file.FileDownloadHandler',
'http': 'scrapy.core.downloader.handlers.http.HttpDownloadHandler',
'https': 'scrapy.core.downloader.handlers.http.HttpDownloadHandler',
's3': 'scrapy.core.downloader.handlers.s3.S3DownloadHandler',
}
A dict containing the request download handlers enabled by default in Scrapy.
You should never modify this setting in your project, modify
DOWNLOAD_HANDLERS
instead.
If you want to disable any of the above download handlers you must define them
in your project’s DOWNLOAD_HANDLERS
setting and assign None
as their value. For example, if you want to disable the file download
handler:
DOWNLOAD_HANDLERS = {
'file': None,
}
DOWNLOAD_TIMEOUT¶
Default: 180
The amount of time (in secs) that the downloader will wait before timing out.
Note
This timeout can be set per spider using download_timeout
spider attribute and per-request using download_timeout
Request.meta key.
DOWNLOAD_MAXSIZE¶
Default: 1073741824 (1024MB)
The maximum response size (in bytes) that downloader will download.
If you want to disable it set to 0.
Note
This size can be set per spider using download_maxsize
spider attribute and per-request using download_maxsize
Request.meta key.
This feature needs Twisted >= 11.1.
DOWNLOAD_WARNSIZE¶
Default: 33554432 (32MB)
The response size (in bytes) that downloader will start to warn.
If you want to disable it set to 0.
Note
This size can be set per spider using download_warnsize
spider attribute and per-request using download_warnsize
Request.meta key.
This feature needs Twisted >= 11.1.
DUPEFILTER_CLASS¶
Default: 'scrapy.dupefilters.RFPDupeFilter'
The class used to detect and filter duplicate requests.
The default (RFPDupeFilter
) filters based on request fingerprint using
the scrapy.utils.request.request_fingerprint
function. In order to change
the way duplicates are checked you could subclass RFPDupeFilter
and
override its request_fingerprint
method. This method should accept
scrapy Request
object and return its fingerprint
(a string).
DUPEFILTER_DEBUG¶
Default: False
By default, RFPDupeFilter
only logs the first duplicate request.
Setting DUPEFILTER_DEBUG
to True
will make it log all duplicate requests.
EDITOR¶
Default: depends on the environment
The editor to use for editing spiders with the edit
command. It
defaults to the EDITOR
environment variable, if set. Otherwise, it defaults
to vi
(on Unix systems) or the IDLE editor (on Windows).
EXTENSIONS¶
Default:: {}
A dict containing the extensions enabled in your project, and their orders.
EXTENSIONS_BASE¶
Default:
{
'scrapy.extensions.corestats.CoreStats': 0,
'scrapy.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,
}
The list of available extensions. Keep in mind that some of them 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.
ITEM_PIPELINES¶
Default: {}
A dict containing the item pipelines to use, and their orders. The dict is empty by default order values are arbitrary but it’s customary to define them in the 0-1000 range.
Lists are supported in ITEM_PIPELINES
for backwards compatibility,
but they are deprecated.
Example:
ITEM_PIPELINES = {
'mybot.pipelines.validate.ValidateMyItem': 300,
'mybot.pipelines.validate.StoreMyItem': 800,
}
ITEM_PIPELINES_BASE¶
Default: {}
A dict containing the pipelines enabled by default in Scrapy. You should never
modify this setting in your project, modify ITEM_PIPELINES
instead.
LOG_FORMAT¶
Default: '%(asctime)s [%(name)s] %(levelname)s: %(message)s'
String for formatting log messsages. Refer to the Python logging documentation for the whole list of available placeholders.
LOG_DATEFORMAT¶
Default: '%Y-%m-%d %H:%M:%S'
String for formatting date/time, expansion of the %(asctime)s
placeholder
in LOG_FORMAT
. Refer to the Python datetime documentation for the whole list of available
directives.
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_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.extensions.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.
MEMUSAGE_LIMIT_MB¶
Default: 0
Scope: scrapy.extensions.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.
MEMUSAGE_NOTIFY_MAIL¶
Default: False
Scope: scrapy.extensions.memusage
A list of emails to notify if the memory limit has been reached.
Example:
MEMUSAGE_NOTIFY_MAIL = ['[email protected]']
MEMUSAGE_REPORT¶
Default: False
Scope: scrapy.extensions.memusage
Whether to send a memory usage report after each spider has been closed.
MEMUSAGE_WARNING_MB¶
Default: 0
Scope: scrapy.extensions.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
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 DOWNLOAD_DELAY
is zero (default) this option has no effect.
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.
REDIRECT_MAX_TIMES¶
Default: 20
Defines the maximum times a request can be redirected. After this maximum 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.
ROBOTSTXT_OBEY¶
Default: False
Scope: scrapy.downloadermiddlewares.robotstxt
If enabled, Scrapy will respect robots.txt policies. For more information see RobotsTxtMiddleware
SPIDER_CONTRACTS¶
Default:: {}
A dict containing the scrapy contracts enabled in your project, used for testing spiders. For more info see Spiders Contracts.
SPIDER_CONTRACTS_BASE¶
Default:
{
'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 SPIDER_CONTRACTS
instead. For more info see Spiders Contracts.
SPIDER_LOADER_CLASS¶
Default: 'scrapy.spiderloader.SpiderLoader'
The class that will be used for loading spiders, which must implement the SpiderLoader API.
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.spidermiddlewares.httperror.HttpErrorMiddleware': 50,
'scrapy.spidermiddlewares.offsite.OffsiteMiddleware': 500,
'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. 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.statscollectors.MemoryStatsCollector'
The class to use for collecting stats, who must implement the Stats Collector API.
STATS_DUMP¶
Default: True
Dump the Scrapy stats (to the Scrapy log) once the spider finishes.
For more info see: Stats Collection.
STATSMAILER_RCPTS¶
Default: []
(empty list)
Send Scrapy stats after spiders finish scraping. See
StatsMailer
for more info.
TELNETCONSOLE_ENABLED¶
Default: True
A boolean which specifies if the telnet console will be enabled (provided its extension is also enabled).
TELNETCONSOLE_PORT¶
Default: [6023, 6073]
The port range 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 templates when creating new projects with
startproject
command.
URLLENGTH_LIMIT¶
Default: 2083
Scope: spidermiddlewares.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: "Scrapy/VERSION (+http://scrapy.org)"
The default User-Agent to use when crawling, unless overridden.
Settings documented elsewhere:¶
The following settings are documented elsewhere, please check each specific case to see how to enable and use them.
- AJAXCRAWL_ENABLED
- AUTOTHROTTLE_DEBUG
- AUTOTHROTTLE_ENABLED
- AUTOTHROTTLE_MAX_DELAY
- AUTOTHROTTLE_START_DELAY
- CLOSESPIDER_ERRORCOUNT
- CLOSESPIDER_ITEMCOUNT
- CLOSESPIDER_PAGECOUNT
- CLOSESPIDER_TIMEOUT
- COMMANDS_MODULE
- COMPRESSION_ENABLED
- COOKIES_DEBUG
- COOKIES_ENABLED
- FEED_EXPORTERS
- FEED_EXPORTERS_BASE
- FEED_EXPORT_FIELDS
- FEED_FORMAT
- FEED_STORAGES
- FEED_STORAGES_BASE
- FEED_STORE_EMPTY
- FEED_URI
- FILES_EXPIRES
- FILES_STORE
- HTTPCACHE_DBM_MODULE
- HTTPCACHE_DIR
- HTTPCACHE_ENABLED
- HTTPCACHE_EXPIRATION_SECS
- HTTPCACHE_GZIP
- HTTPCACHE_IGNORE_HTTP_CODES
- HTTPCACHE_IGNORE_MISSING
- HTTPCACHE_IGNORE_SCHEMES
- HTTPCACHE_POLICY
- HTTPCACHE_STORAGE
- HTTPERROR_ALLOWED_CODES
- HTTPERROR_ALLOW_ALL
- IMAGES_EXPIRES
- IMAGES_MIN_HEIGHT
- IMAGES_MIN_WIDTH
- IMAGES_STORE
- IMAGES_THUMBS
- MAIL_FROM
- MAIL_HOST
- MAIL_PASS
- MAIL_PORT
- MAIL_SSL
- MAIL_TLS
- MAIL_USER
- METAREFRESH_ENABLED
- REDIRECT_ENABLED
- REDIRECT_MAX_METAREFRESH_DELAY
- REDIRECT_MAX_TIMES
- REFERER_ENABLED
- RETRY_ENABLED
- RETRY_HTTP_CODES
- RETRY_TIMES
- TELNETCONSOLE_HOST
- TELNETCONSOLE_PORT