.. _topics-settings: ======== Settings ======== .. module:: scrapy.conf :synopsis: Settings manager 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`. 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`_. .. _import search path: http://diveintopython.org/getting_to_know_python/everything_is_an_object.html 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. Project settings module 3. Default settings per-command 4. Default global settings (less precedence) These mechanisms are described in more detail below. 1. Global overrides ------------------- Global overrides are the ones that take 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. .. highlight:: sh Example:: scrapy crawl domain.com --set LOG_FILE=scrapy.log 2. 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``. 3. Default settings per-command ------------------------------- Each :doc:`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. 4. Default global settings -------------------------- The global defaults are located in the ``scrapy.settings.default_settings`` module and documented in the :ref:`topics-settings-ref` section. How to access settings ====================== .. highlight:: python 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:: Settings() There is a (singleton) Settings object automatically instantiated when the :mod:`scrapy.conf` module is loaded, and it's usually accessed like this:: >>> from scrapy.conf import settings .. method:: get(name, default=None) Get a setting value without affecting its original type. :param name: the setting name :type name: string :param default: the value to return if no setting is found :type default: any .. method:: getbool(name, default=False) Get a setting value as a boolean. For example, both ``1`` and ``'1'``, and ``True`` return ``True``, while ``0``, ``'0'``, ``False`` and ``None`` return ``False```` For example, settings populated through environment variables set to ``'0'`` will return ``False`` when using this method. :param name: the setting name :type name: string :param default: the value to return if no setting is found :type default: any .. method:: getint(name, default=0) Get a setting value as an int :param name: the setting name :type name: string :param default: the value to return if no setting is found :type default: any .. method:: getfloat(name, default=0.0) Get a setting value as a float :param name: the setting name :type name: string :param default: the value to return if no setting is found :type default: any .. method:: 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 split by ",". For example, settings populated through environment variables set to ``'one,two'`` will return a list ['one', 'two'] when using this method. :param name: the setting name :type name: string :param default: the value to return if no setting is found :type default: any 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. .. _topics-settings-ref: 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. .. setting:: AWS_ACCESS_KEY_ID 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 `. .. setting:: AWS_SECRET_ACCESS_KEY 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 `. .. setting:: BOT_NAME 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 :command:`startproject` command. .. setting:: BOT_VERSION 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. .. setting:: CONCURRENT_ITEMS CONCURRENT_ITEMS ---------------- Default: ``100`` Maximum number of concurrent items (per response) to process in parallel in the Item Processor (also known as the :ref:`Item Pipeline `). .. setting:: CONCURRENT_REQUESTS CONCURRENT_REQUESTS ------------------- Default: ``16`` The maximum number of concurrent (ie. simultaneous) requests that will be performed by the Scrapy downloader. .. setting:: CONCURRENT_REQUESTS_PER_DOMAIN CONCURRENT_REQUESTS_PER_DOMAIN ------------------------------ Default: ``8`` The maximum number of concurrent (ie. simultaneous) requests that will be performed to any single domain. .. setting:: CONCURRENT_REQUESTS_PER_IP 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 :setting:`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. .. setting:: CONCURRENT_SPIDERS CONCURRENT_SPIDERS ------------------ Default: ``8`` Maximum number of spiders to scrape in parallel. .. setting:: DEFAULT_ITEM_CLASS DEFAULT_ITEM_CLASS ------------------ Default: ``'scrapy.item.Item'`` The default class that will be used for instantiating items in the :ref:`the Scrapy shell `. .. setting:: DEFAULT_REQUEST_HEADERS 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 :class:`~scrapy.contrib.downloadermiddleware.defaultheaders.DefaultHeadersMiddleware`. .. setting:: DEFAULT_RESPONSE_ENCODING DEFAULT_RESPONSE_ENCODING ------------------------- Default: ``'ascii'`` The default encoding to use for :class:`~scrapy.http.TextResponse` objects (and subclasses) when no encoding is declared and no encoding could be inferred from the body. .. setting:: DEPTH_LIMIT DEPTH_LIMIT ----------- Default: ``0`` The maximum depth that will be allowed to crawl for any site. If zero, no limit will be imposed. .. setting:: DEPTH_PRIORITY DEPTH_PRIORITY -------------- Default: ``1`` An integer that is used to set the request priority based on request depth. To crawl in `breadth-first order`_, set :setting:`DEPTH_PRIORITY` to ``1``. To crawl in `depth-first order`_, set :setting:`DEPTH_PRIORITY` to ``-1``. To disable any priority adjustment based on depth, set :setting:`DEPTH_PRIORITY` to ``0``. .. setting:: DEPTH_STATS DEPTH_STATS ----------- Default: ``True`` Whether to collect maximum depth stats. .. setting:: DEPTH_STATS_VERBOSE 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. .. setting:: DNSCACHE_ENABLED DNSCACHE_ENABLED ---------------- Default: ``True`` Whether to enable DNS in-memory cache. .. setting:: DOWNLOADER_DEBUG DOWNLOADER_DEBUG ---------------- Default: ``False`` Whether to enable the Downloader debugging mode. .. setting:: DOWNLOADER_MIDDLEWARES 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 DOWNLOADER_MIDDLEWARES_BASE --------------------------- Default:: { 'scrapy.contrib.downloadermiddleware.robotstxt.RobotsTxtMiddleware': 100, 'scrapy.contrib.downloadermiddleware.httpauth.HttpAuthMiddleware': 300, 'scrapy.contrib.downloadermiddleware.downloadtimeout.DownloadTimeoutMiddleware': 350, '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.chunked.ChunkedTransferMiddleware': 830, '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 :setting:`DOWNLOADER_MIDDLEWARES` instead. For more info see :ref:`topics-downloader-middleware-setting`. .. setting:: DOWNLOADER_STATS DOWNLOADER_STATS ---------------- Default: ``True`` Whether to enable downloader stats collection. .. setting:: DOWNLOAD_DELAY 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 :setting:`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 * :setting:`DOWNLOAD_DELAY`. You can also change this setting per spider. .. setting:: DOWNLOAD_HANDLERS DOWNLOAD_HANDLERS ----------------- Default: ``{}`` A dict containing the request downloader handlers enabled in your project. See `DOWNLOAD_HANDLERS_BASE` for example format. .. setting:: DOWNLOAD_HANDLERS_BASE 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 :setting:`DOWNLOAD_HANDLERS` instead. .. setting:: DOWNLOAD_TIMEOUT DOWNLOAD_TIMEOUT ---------------- Default: ``180`` The amount of time (in secs) that the downloader will wait before timing out. .. setting:: DUPEFILTER_CLASS DUPEFILTER_CLASS ---------------- Default: ``'scrapy.dupefilter.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. .. setting:: EDITOR EDITOR ------ The editor to use for editing spiders with the :command:`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). .. setting:: ENCODING_ALIASES 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 :setting:`ENCODING_ALIASES_BASE` setting which contains some default mappings. .. setting:: ENCODING_ALIASES_BASE 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 :setting:`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`_. .. _ISO-8859-1: http://en.wikipedia.org/wiki/ISO/IEC_8859-1 .. _CP1252: http://en.wikipedia.org/wiki/Windows-1252 .. _Character encodings in HTML: http://en.wikipedia.org/wiki/Character_encodings_in_HTML .. setting:: EXTENSIONS EXTENSIONS ---------- Default:: ``{}`` A dict containing the extensions enabled in your project, and their orders. .. setting:: EXTENSIONS_BASE 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.closespider.CloseSpider': 0, 'scrapy.contrib.feedexport.FeedExporter': 0, 'scrapy.contrib.spidercontext.SpiderContext': 0, 'scrapy.contrib.logstats.LogStats': 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 :ref:`extensions user guide ` and the :ref:`list of available extensions `. .. setting:: ITEM_PIPELINES ITEM_PIPELINES -------------- Default: ``[]`` The item pipelines to use (a list of classes). Example:: ITEM_PIPELINES = [ 'mybot.pipeline.validate.ValidateMyItem', 'mybot.pipeline.validate.StoreMyItem' ] .. setting:: LOG_ENABLED LOG_ENABLED ----------- Default: ``True`` Whether to enable logging. .. setting:: LOG_ENCODING LOG_ENCODING ------------ Default: ``'utf-8'`` The encoding to use for logging. .. setting:: LOG_FILE LOG_FILE -------- Default: ``None`` File name to use for logging output. If None, standard error will be used. .. setting:: LOG_LEVEL 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 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:: MEMDEBUG_ENABLED MEMDEBUG_ENABLED ---------------- Default: ``False`` Whether to enable memory debugging. .. setting:: MEMDEBUG_NOTIFY 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 = ['user@example.com'] .. setting:: MEMUSAGE_ENABLED 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 :ref:`topics-extensions-ref-memusage`. .. setting:: MEMUSAGE_LIMIT_MB 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 :ref:`topics-extensions-ref-memusage`. .. setting:: MEMUSAGE_NOTIFY_MAIL 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 = ['user@example.com'] See :ref:`topics-extensions-ref-memusage`. .. setting:: MEMUSAGE_REPORT MEMUSAGE_REPORT --------------- Default: ``False`` Scope: ``scrapy.contrib.memusage`` Whether to send a memory usage report after each spider has been closed. See :ref:`topics-extensions-ref-memusage`. .. setting:: MEMUSAGE_WARNING_MB 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. .. setting:: NEWSPIDER_MODULE NEWSPIDER_MODULE ---------------- Default: ``''`` Module where to create new spiders using the :command:`genspider` command. Example:: NEWSPIDER_MODULE = 'mybot.spiders_dev' .. setting:: RANDOMIZE_DOWNLOAD_DELAY RANDOMIZE_DOWNLOAD_DELAY ------------------------ Default: ``True`` If enabled, Scrapy will wait a random amount of time (between 0.5 and 1.5 * :setting:`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 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: http://www.gnu.org/software/wget/manual/wget.html .. setting:: REDIRECT_MAX_TIMES 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. .. setting:: REDIRECT_MAX_METAREFRESH_DELAY 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) .. setting:: REDIRECT_PRIORITY_ADJUST REDIRECT_PRIORITY_ADJUST ------------------------ Default: ``+2`` Adjust redirect request priority relative to original request. A negative priority adjust means more priority. .. setting:: ROBOTSTXT_OBEY ROBOTSTXT_OBEY -------------- Default: ``False`` Scope: ``scrapy.contrib.downloadermiddleware.robotstxt`` If enabled, Scrapy will respect robots.txt policies. For more information see :ref:`topics-dlmw-robots` .. setting:: SCHEDULER SCHEDULER --------- Default: ``'scrapy.core.scheduler.Scheduler'`` The scheduler to use for crawling. .. setting:: SPIDER_MIDDLEWARES 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 SPIDER_MIDDLEWARES_BASE ----------------------- Default:: { 'scrapy.contrib.spidermiddleware.httperror.HttpErrorMiddleware': 50, '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 :setting:`SPIDER_MIDDLEWARES` instead. For more info see :ref:`topics-spider-middleware-setting`. .. setting:: SPIDER_MODULES SPIDER_MODULES -------------- Default: ``[]`` A list of modules where Scrapy will look for spiders. Example:: SPIDER_MODULES = ['mybot.spiders_prod', 'mybot.spiders_dev'] .. setting:: SQLITE_DB SQLITE_DB --------- Default: ``'scrapy.db'`` The location of the project SQLite database, used for storing the spider queue and other persistent data of the project. If a relative path is given, is taken relative to the project data dir. For more info see: :ref:`topics-project-structure`. .. setting:: STATS_CLASS STATS_CLASS ----------- Default: ``'scrapy.statscol.MemoryStatsCollector'`` The class to use for collecting stats (must implement the Stats Collector API, or subclass the StatsCollector class). .. setting:: STATS_DUMP STATS_DUMP ---------- Default: ``True`` Dump (to the Scrapy log) the :ref:`Scrapy stats ` collected during the crawl. The spider-specific stats are logged when the spider is closed, while the global stats are dumped when the Scrapy process finishes. For more info see: :ref:`topics-stats`. .. setting:: STATS_ENABLED STATS_ENABLED ------------- Default: ``True`` Enable stats collection. .. setting:: STATSMAILER_RCPTS STATSMAILER_RCPTS ----------------- Default: ``[]`` (empty list) Send Scrapy stats after spiders finish scraping. See :class:`~scrapy.contrib.statsmailer.StatsMailer` for more info. .. setting:: TELNETCONSOLE_ENABLED TELNETCONSOLE_ENABLED --------------------- Default: ``True`` A boolean which specifies if the :ref:`telnet console ` will be enabled (provided its extension is also enabled). .. setting:: TELNETCONSOLE_PORT 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 :ref:`topics-telnetconsole`. .. setting:: TEMPLATES_DIR TEMPLATES_DIR ------------- Default: ``templates`` dir inside scrapy module The directory where to look for templates when creating new projects with :command:`startproject` command. .. setting:: URLLENGTH_LIMIT 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 .. setting:: USER_AGENT USER_AGENT ---------- Default: ``"%s/%s" % (BOT_NAME, BOT_VERSION)`` The default User-Agent to use when crawling, unless overridden. .. _Amazon web services: http://aws.amazon.com/ .. _breadth-first order: http://en.wikipedia.org/wiki/Breadth-first_search .. _depth-first order: http://en.wikipedia.org/wiki/Depth-first_search