I can't change spider settings in parse method. But it is definitely must be a way.

For example:

class SomeSpider(BaseSpider):name = 'mySpider'allowed_domains = ['example.com']start_urls = ['http://example.com']settings.overrides['ITEM_PIPELINES'] = ['myproject.pipelines.FirstPipeline']print settings['ITEM_PIPELINES'][0]#printed 'myproject.pipelines.FirstPipeline'def parse(self, response):#...some codesettings.overrides['ITEM_PIPELINES'] = ['myproject.pipelines.SecondPipeline']print settings['ITEM_PIPELINES'][0]# printed 'myproject.pipelines.SecondPipeline'item = Myitem()item['mame'] = 'Name for SecondPipeline'  

But! Item will be processed by FirstPipeline. New ITEM_PIPELINES param don't work. How can I change settings after start crawling? Thanks in advance!

If you want that different spiders to have different pipelines you can set for a spider a pipelines list attribute which defines the pipelines for that spider. Than in pipelines check for existence:

class MyPipeline(object):def process_item(self, item, spider):if self.__class__.__name__ not in getattr(spider, 'pipelines',[]):return item...return itemclass MySpider(CrawlSpider):pipelines = set(['MyPipeline','MyPipeline3',])

If you want that different items to be proceesed by different pipelines you can do this:

    class MyPipeline2(object):def process_item(self, item, spider):if isinstance(item, MyItem):...return itemreturn item