scrapy.exceptions
Here's a list of all exceptions included in Scrapy and their usage.
CloseSpider(reason='cancelled')
This exception can be raised from a spider callback to request the spider to be closed/stopped. Supported arguments:
- param reason
the reason for closing
- type reason
str
For example:
def parse_page(self, response):
if 'Bandwidth exceeded' in response.body:
raise CloseSpider('bandwidth_exceeded')
DontCloseSpider
This exception can be raised in a spider_idle
signal handler to prevent the spider from being closed.
DropItem
The exception that must be raised by item pipeline stages to stop processing an Item. For more information see topics-item-pipeline
.
IgnoreRequest
This exception can be raised by the Scheduler or any downloader middleware to indicate that the request should be ignored.
NotConfigured
This exception can be raised by some components to indicate that they will remain disabled. Those components include:
- Extensions
- Item pipelines
- Downloader middlewares
- Spider middlewares
The exception must be raised in the component's __init__
method.
NotSupported
This exception is raised to indicate an unsupported feature.
2.2
StopDownload(fail=True)
Raised from a ~scrapy.signals.bytes_received
or ~scrapy.signals.headers_received
signal handler to indicate that no further bytes should be downloaded for a response.
The fail
boolean parameter controls which method will handle the resulting response:
- If
fail=True
(default), the request errback is called. The response object is available as theresponse
attribute of theStopDownload
exception, which is in turn stored as thevalue
attribute of the received~twisted.python.failure.Failure
object. This means that in an errback defined asdef errback(self, failure)
, the response can be accessed thoughfailure.value.response
. - If
fail=False
, the request callback is called instead.
In both cases, the response could have its body truncated: the body contains all bytes received up until the exception is raised, including the bytes received in the signal handler that raises the exception. Also, the response object is marked with "download_stopped"
in its Response.flags
attribute.
Note
fail
is a keyword-only parameter, i.e. raising StopDownload(False)
or StopDownload(True)
will raise a TypeError
.
See the documentation for the ~scrapy.signals.bytes_received
and ~scrapy.signals.headers_received
signals and the topics-stop-response-download
topic for additional information and examples.