python scrapy项目下spiders内多个爬虫同时运行的实现

133 阅读 0 评论 88 点赞

我是靠谱客的博主酷酷小笼包，最近开发中收集的这篇文章主要介绍python scrapy项目下spiders内多个爬虫同时运行的实现，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

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