Scrapy爬虫运行常见报错及解决
按照指南上搭建好了Scrapy的环境，该装的都装好了，参考教程是：
http://scrapy-chs.readthedocs.io/zh_CN/0.24/intro/tutorial.html
按照第一个Spider代码练习，保存在 tutorial/spiders 目录下的 dmoz_spider.py 文件中:
import scrapy
class DmozSpider(scrapy.Spider):
name = "dmoz"
allowed_domains = ["dmoz.org"]
start_urls = [
"http://www.dmoz.org/Computers/Programming/Languages/Python/Books/",
"http://www.dmoz.org/Computers/Programming/Languages/Python/Resources/"
]
def parse(self, response):
filename = response.url.split("/")[-2]
with open(filename, 'wb') as f:
f.write(response.body) terminal中运行：scrapy crawl dmoz，试图启动爬虫
报错提示一：
Scrapy 1.6.0 - no active project
Unknown command: crawl
alicedeMacBook-Pro:~ alice$ scrapy crawl dmoz
Scrapy 1.6.0 - no active project
Unknown command: crawl
Use "scrapy" to see available commands原因是：在使用命令行startproject的时候，会自动生成scrapy.cfg。而使用命令行cmd启动爬虫时，crawl会去搜索cmd当前目录下的scrapy.cfg文件，官方文档中也进行了说明。找不到scrapy.cfg文件则认为没有该project。
解决方案：因此cd进入该dmoz项目的根目录，即scrapy.cfg文件在的目录，执行命令scrapy crawl dmoz
正常情况下得到的输出应该是：
2014-01-23 18:13:07-0400 [scrapy] INFO: Scrapy started (bot: tutorial)
2014-01-23 18:13:07-0400 [scrapy] INFO: Optional features available: ...
2014-01-23 18:13:07-0400 [scrapy] INFO: Overridden settings: {}
2014-01-23 18:13:07-0400 [scrapy] INFO: Enabled extensions: ...
2014-01-23 18:13:07-0400 [scrapy] INFO: Enabled downloader middlewares: ...
2014-01-23 18:13:07-0400 [scrapy] INFO: Enabled spider middlewares: ...
2014-01-23 18:13:07-0400 [scrapy] INFO: Enabled item pipelines: ...
2014-01-23 18:13:07-0400 [dmoz] INFO: Spider opened
2014-01-23 18:13:08-0400 [dmoz] DEBUG: Crawled (200) 然而实际不是
报错提示二：
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/spiderloader.py", line 71, in load
raise KeyError("Spider not found: {}".format(spider_name))
KeyError: 'Spider not found: dmoz'
alicedeMacBook-Pro:tutorial alice$ scrapy crawl dmoz
2019-04-19 09:28:23 [scrapy.utils.log] INFO: Scrapy 1.6.0 started (bot: tutorial)
2019-04-19 09:28:23 [scrapy.utils.log] INFO: Versions: lxml 4.3.3.0, libxml2 2.9.9, cssselect 1.0.3, parsel 1.5.0, w3lib 1.19.0, Twisted 18.7.0, Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 16:39:00) - [GCC 4.2.1 (Apple Inc. build 5666) (dot 3)], pyOpenSSL 18.0.0 (OpenSSL 1.1.0i 14 Aug 2018), cryptography 2.3.1, Platform Darwin-17.3.0-x86_64-i386-64bit
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/spiderloader.py", line 69, in load
return self._spiders[spider_name]
KeyError: 'dmoz'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.7/bin/scrapy", line 10, in
sys.exit(execute())
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/cmdline.py", line 150, in execute
_run_print_help(parser, _run_command, cmd, args, opts)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/cmdline.py", line 90, in _run_print_help
func(*a, **kw)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/cmdline.py", line 157, in _run_command
cmd.run(args, opts)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/commands/crawl.py", line 57, in run
self.crawler_process.crawl(spname, **opts.spargs)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/crawler.py", line 171, in crawl
crawler = self.create_crawler(crawler_or_spidercls)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/crawler.py", line 200, in create_crawler
return self._create_crawler(crawler_or_spidercls)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/crawler.py", line 204, in _create_crawler
spidercls = self.spider_loader.load(spidercls)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/spiderloader.py", line 71, in load
raise KeyError("Spider not found: {}".format(spider_name))
KeyError: 'Spider not found: dmoz' 原因：定位的目录不正确，要进入到dmoz在的目录
解决方案：也比较简单，重新check目录进去即可
报错提示三：
File "/Library/Python/2.7/site-packages/twisted/internet/_sslverify.py", line 15, in
from OpenSSL._util import lib as pyOpenSSLlib
ImportError: No module named _util
alicedeMacBook-Pro:tutorial alice$ scrapy crawl dmoz
2018-08-06 22:25:23 [scrapy.utils.log] INFO: Scrapy 1.5.1 started (bot: tutorial)
2018-08-06 22:25:23 [scrapy.utils.log] INFO: Versions: lxml 4.2.4.0, libxml2 2.9.8, cssselect 1.0.3, parsel 1.5.0, w3lib 1.19.0, Twisted 18.7.0, Python 2.7.10 (default, Jul 15 2017, 17:16:57) - [GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.31)], pyOpenSSL 0.13.1 (LibreSSL 2.2.7), cryptography unknown, Platform Darwin-17.3.0-x86_64-i386-64bit
2018-08-06 22:25:23 [scrapy.crawler] INFO: Overridden settings: {'NEWSPIDER_MODULE': 'tutorial.spiders', 'SPIDER_MODULES': ['tutorial.spiders'], 'ROBOTSTXT_OBEY': True, 'BOT_NAME': 'tutorial'}
Traceback (most recent call last):
File "/usr/local/bin/scrapy", line 11, in
sys.exit(execute())
File "/Library/Python/2.7/site-packages/scrapy/cmdline.py", line 150, in execute
_run_print_help(parser, _run_command, cmd, args, opts)
File "/Library/Python/2.7/site-packages/scrapy/cmdline.py", line 90, in _run_print_help
func(*a, **kw)
File "/Library/Python/2.7/site-packages/scrapy/cmdline.py", line 157, in _run_command
cmd.run(args, opts)
File "/Library/Python/2.7/site-packages/scrapy/commands/crawl.py", line 57, in run
self.crawler_process.crawl(spname, **opts.spargs)
File "/Library/Python/2.7/site-packages/scrapy/crawler.py", line 170, in crawl
crawler = self.create_crawler(crawler_or_spidercls)
File "/Library/Python/2.7/site-packages/scrapy/crawler.py", line 198, in create_crawler
return self._create_crawler(crawler_or_spidercls)
File "/Library/Python/2.7/site-packages/scrapy/crawler.py", line 203, in _create_crawler
return Crawler(spidercls, self.settings)
File "/Library/Python/2.7/site-packages/scrapy/crawler.py", line 55, in __init__
self.extensions = ExtensionManager.from_crawler(self)
File "/Library/Python/2.7/site-packages/scrapy/middleware.py", line 58, in from_crawler
return cls.from_settings(crawler.settings, crawler)
File "/Library/Python/2.7/site-packages/scrapy/middleware.py", line 34, in from_settings
mwcls = load_object(clspath)
File "/Library/Python/2.7/site-packages/scrapy/utils/misc.py", line 44, in load_object
mod = import_module(module)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module
__import__(name)
File "/Library/Python/2.7/site-packages/scrapy/extensions/memusage.py", line 16, in
from scrapy.mail import MailSender
File "/Library/Python/2.7/site-packages/scrapy/mail.py", line 25, in
from twisted.internet import defer, reactor, ssl
File "/Library/Python/2.7/site-packages/twisted/internet/ssl.py", line 230, in
from twisted.internet._sslverify import (
File "/Library/Python/2.7/site-packages/twisted/internet/_sslverify.py", line 15, in
from OpenSSL._util import lib as pyOpenSSLlib
ImportError: No module named _util 网上查了很久的资料，仍然无解。部分博主说是pyOpenSSL或Scrapy的安装有问题，于是重新装了pyOpenSSL和Scrapy，但还是报同样错误，实在不知道怎么解决了。
后面重装了pyOpenSSL和Scrapy，貌似是解决了~
2019-04-19 09:46:37 [scrapy.core.engine] INFO: Spider opened
2019-04-19 09:46:37 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2019-04-19 09:46:39 [scrapy.core.engine] DEBUG: Crawled (403) (referer: None)
2019-04-19 09:46:39 [scrapy.core.engine] DEBUG: Crawled (403)