一般创建了scrapy文件夹后,可能需要写多个爬虫,如果想让它们同时运行而不是顺次运行的话,得怎么做?
a、在spiders目录的同级目录下创建一个commands目录,并在该目录中创建一个crawlall.py,将scrapy源代码里的commands文件夹里的crawl.py源码复制过来,只修改run()方法即可!
- import os
- from scrapy.commands import ScrapyCommand
- from scrapy.utils.conf import arglist_to_dict
- from scrapy.utils.python import without_none_values
- from scrapy.exceptions import UsageError
- class Command(ScrapyCommand):
- requires_project = True
- def syntax(self):
- return "[options] <spider>"
- def short_desc(self):
- return "Run all spider"
- def add_options(self, parser):
- ScrapyCommand.add_options(self, parser)
- parser.add_option("-a", dest="spargs", action="append", default=[], metavar="NAME=VALUE",
- help="set spider argument (may be repeated)")
- parser.add_option("-o", "--output", metavar="FILE",
- help="dump scraped items into FILE (use - for stdout)")
- parser.add_option("-t", "--output-format", metavar="FORMAT",
- help="format to use for dumping items with -o")
- def process_options(self, args, opts):
- ScrapyCommand.process_options(self, args, opts)
- try:
- opts.spargs = arglist_to_dict(opts.spargs)
- except ValueError:
- raise UsageError("Invalid -a value, use -a NAME=VALUE", print_help=False)
- if opts.output:
- if opts.output == '-':
- self.settings.set('FEED_URI', 'stdout:', priority='cmdline')
- else:
- self.settings.set('FEED_URI', opts.output, priority='cmdline')
- feed_exporters = without_none_values(
- self.settings.getwithbase('FEED_EXPORTERS'))
- valid_output_formats = feed_exporters.keys()
- if not opts.output_format:
- opts.output_format = os.path.splitext(opts.output)[1].replace(".", "")
- if opts.output_format not in valid_output_formats:
- raise UsageError("Unrecognized output format '%s', set one"
- " using the '-t' switch or as a file extension"
- " from the supported list %s" % (opts.output_format,
- tuple(valid_output_formats)))
- self.settings.set('FEED_FORMAT', opts.output_format, priority='cmdline')
- def run(self, args, opts):
- #获取爬虫列表
- spd_loader_list=self.crawler_process.spider_loader.list()#获取所有的爬虫文件。
- print(spd_loader_list)
- #遍历各爬虫
- for spname in spd_loader_list or args:
- self.crawler_process.crawl(spname, **opts.spargs)
- print ('此时启动的爬虫为:'+spname)
- self.crawler_process.start()
b、还得在里面加个_init_.py文件
c、到这里还没完,settings.py配置文件还需要加一条。
COMMANDS_MODULE = ‘项目名称.目录名称’
COMMANDS_MODULE = 'ds1.commands'
d、最后启动crawlall即可!
当然,安全起见,可以先在命令行中进入该项目所在目录,并输入scrapy -h,可以查看是否有命令crawlall 。如果有,那就成功了,可以启动了
我是写了个启动文件,放在第一级即可
要不直接在命令台cmd里输入 scrapy crawlall 就行了
##注意的是,爬虫好像是2个同时运行,而且运行时是交叉的?
还有settings里的文件,只针对其中一个?