从Python脚本运行Scrapy

Question

我一直在尝试通过一个Python脚本来运行scrapy，因为我需要获取数据并把它保存到我的数据库里。但是当我用scrapy命令运行时，

scrapy crawl argos

脚本运行得很好，但当我尝试按照这个链接用脚本运行时，

http://doc.scrapy.org/en/latest/topics/practices.html#run-scrapy-from-a-script

我遇到了这个错误。

$ python pricewatch/pricewatch.py update
Traceback (most recent call last):
  File "pricewatch/pricewatch.py", line 39, in <module>
    main()
  File "pricewatch/pricewatch.py", line 31, in main
    update()
  File "pricewatch/pricewatch.py", line 24, in update
    setup_crawler("argos.co.uk")
  File "pricewatch/pricewatch.py", line 13, in setup_crawler
    settings = get_project_settings()
  File "/Library/Python/2.7/site-packages/Scrapy-0.22.2-py2.7.egg/scrapy/utils/project.py", line 58, in get_project_settings
    settings_module = import_module(settings_module_path)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
ImportError: No module named settings

我不明白为什么它找不到get_project_setting()，而用scrapy命令在终端上运行却没问题。

这是我项目的截图。

这是pricewatch.py的代码：

import commands
import sys
from database import DBInstance
from twisted.internet import reactor
from scrapy.crawler import Crawler
from scrapy import log
from spiders.argosspider import ArgosSpider
from scrapy.utils.project import get_project_settings
import settings

def setup_crawler(domain):
    spider = ArgosSpider(domain=domain)
    settings = get_project_settings()
    crawler = Crawler(settings)
    crawler.configure()
    crawler.crawl(spider)
    crawler.start()

def update():
    #print "Enter a product to update:"
    #product = raw_input()
    #print product
    #db = DBInstance()
    setup_crawler("argos.co.uk")
    log.start()
    reactor.run()

def main():
    try:
        if sys.argv[1] == "update":
            update()
        elif sys.argv[1] == "database":
            #db = DBInstance()
    except IndexError:
        print "You must select a command from Update, Search, History"


if  __name__ =='__main__':
    main()

Answer 1

这个回答大部分是从这个回答复制过来的，我觉得它能解答你的问题，并且提供了一个不错的例子。

考虑一个项目，结构如下。

my_project/
    main.py                 # Where we are running scrapy from
    scraper/
        run_scraper.py               #Call from main goes here
        scrapy.cfg                   # deploy configuration file
        scraper/                     # project's Python module, you'll import your code from here
            __init__.py
            items.py                 # project items definition file
            pipelines.py             # project pipelines file
            settings.py              # project settings file
            spiders/                 # a directory where you'll later put your spiders
                __init__.py
                quotes_spider.py     # Contains the QuotesSpider class

基本上，命令scrapy startproject scraper是在我的项目文件夹（my_project）中执行的。我在外层的scraper文件夹里添加了一个run_scraper.py文件，在根文件夹里添加了一个main.py文件，并在spiders文件夹里添加了一个quotes_spider.py文件。

我的主文件是：

from scraper.run_scraper import Scraper
scraper = Scraper()
scraper.run_spiders()

我的run_scraper.py文件是：

from scraper.scraper.spiders.quotes_spider import QuotesSpider
from scrapy.crawler import CrawlerProcess
from scrapy.utils.project import get_project_settings
import os


class Scraper:
    def __init__(self):
        settings_file_path = 'scraper.scraper.settings' # The path seen from root, ie. from main.py
        os.environ.setdefault('SCRAPY_SETTINGS_MODULE', settings_file_path)
        self.process = CrawlerProcess(get_project_settings())
        self.spiders = QuotesSpider # The spider you want to crawl

    def run_spiders(self):
        self.process.crawl(self.spider)
        self.process.start()  # the script will block here until the crawling is finished

另外，要注意设置可能需要检查一下，因为路径需要根据根文件夹来设置（是my_project，而不是scraper）。所以在我的情况下：

SPIDER_MODULES = ['scraper.scraper.spiders']
NEWSPIDER_MODULE = 'scraper.scraper.spiders'

等等...

Answer 2

我已经解决了这个问题。只需要把 pricewatch.py 文件放到项目的最上层目录，然后运行它，就可以了。