创建scrapy项目
(主要在命令行操作)
scrapy startproject 项目名
例：
C:\Users\董贺贺>scrapy startproject hongyanhuoshui
New Scrapy project 'hongyanhuoshui', using template directory 'D:\anaconda\lib\site-packages\scrapy\templates\project', created in:
C:\Users\董贺贺\hongyanhuoshui
You can start your first spider with:
cd hongyanhuoshui
scrapy genspider example example.com
C:\Users\董贺贺>
这时候crawl的结构目录已经基本生成：
C:\Users\董贺贺>cd hongyanhuoshui
C:\Users\董贺贺\hongyanhuoshui>tree /f
卷 Windows-SSD 的文件夹 PATH 列表
卷序列号为 0026-9AA2
C:.
│ scrapy.cfg
│
└─hongyanhuoshui
│ items.py
│ middlewares.py
│ pipelines.py
│ settings.py
│ __init__.py
│
├─spiders
│ │ __init__.py
│ │
│ └─__pycache__
└─__pycache__
C:\Users\董贺贺\hongyanhuoshui>
根据第一段代码的提示，我们还可以创建spider.py文件，故我们创建了spider文件，并命名为hongyan.py，然后我们查看创建spider后的结构：
C:\Users\董贺贺\hongyanhuoshui> scrapy genspider hongyan https://www.baidu.com
Created spider 'hongyan' using template 'basic' in module:
hongyanhuoshui.spiders.hongyan
C:\Users\董贺贺\hongyanhuoshui>tree /f
卷 Windows-SSD 的文件夹 PATH 列表
卷序列号为 0026-9AA2
C:.
│ scrapy.cfg
│
└─hongyanhuoshui
│ items.py
│ middlewares.py
│ pipelines.py
│ settings.py
│ __init__.py
│
├─spiders
│ │ hongyan.py
│ │ __init__.py
│ │
│ └─__pycache__
│ __init__.cpython-37.pyc
│
└─__pycache__
settings.cpython-37.pyc
__init__.cpython-37.pyc
C:\Users\董贺贺\hongyanhuoshui>
对比上一段代码，显然spiders文件中多了hongyan.py，此文件对于我们执行爬虫文件必不可少。
关于命令行的详细使用
命令的使用范围
这里的命令分为全局的命令和项目的命令，全局的命令表示可以在任何地方使用，而项目的命令只能在项目目录下使用
可用的工具命令
C:\Users\董贺贺\hongyanhuoshui>scrapy -h
Scrapy 1.6.0 - project: hongyanhuoshui
Usage:
scrapy [options] [args]
Available commands:
bench Run quick benchmark test
check Check spider contracts
crawl Run a spider
edit Edit spider
fetch Fetch a URL using the Scrapy downloader
genspider Generate new spider using pre-defined templates
list List available spiders
parse Parse URL (using its spider) and print the results
runspider Run a self-contained spider (without creating a project)
settings Get settings values
shell Interactive scraping console
startproject Create new project
version Print Scrapy version
view Open URL in browser, as seen by Scrapy
Use "scrapy -h" to see more info about a command
还可以通过crapy
全局命令有：
- startproject
- genspider
- settings
- runspider
- shell
- fetch
- view
- version
项目命令有：
- crawl
- check
- list
- edit
- parse
- bench
startproject
这个东西没啥好说的，就是创建项目。scrapy startproject 项目名
genspider
用于生成爬虫，这里scrapy提供给我们不同的几种模板生成spider,默认用的是basic,我们可以通过命令查看所有的模板，默认情况下是先进入项目，即：
cd 项目名
scrapy genspider 文件名 目标网站
如果我们想更改默认怎么办，我么先看看主要有哪几种形式：
C:\Users\董贺贺\hongyanhuoshui>scrapy genspider -l
Available templates:
basic
crawl
csvfeed
xmlfeed
主要有四种形式，比如我们想使用crawl模式怎么更改呢(我重新完整的创建了新项目)：
C:\Users\董贺贺>scrapy startproject myproject
New Scrapy project 'myproject', using template directory 'D:\anaconda\lib\site-packages\scrapy\templates\project', created in:
C:\Users\董贺贺\myproject
You can start your first spider with:
cd myproject
scrapy genspider example example.com
C:\Users\董贺贺>cd myproject
C:\Users\董贺贺\myproject>scrapy genspider -t crawl baidu https://www.baidu.com
Created spider 'baidu' using template 'crawl' in module:
myproject.spiders.baidu
scrapy genspider -t 模板名 名称 网址
crawl
这个是用去启动spider爬虫格式为：
scrapy crawl 爬虫名字
C:\Users\董贺贺\myproject>scrapy crawl baidu
2019-07-17 15:02:17 [scrapy.utils.log] INFO: Scrapy 1.6.0 started (bot: myproject)
2019-07-17 15:02:17 [scrapy.utils.log] INFO: Versions: lxml 4.3.0.0, libxml2 2.9.8, cssselect 1.0.3, parsel 1.5.1, w3lib 1.20.0, Twisted 19.2.0, Python 3.7.0 (default, Jun 28 2018, 08:04:48) [MSC v.1912 64 bit (AMD64)], pyOpenSSL 18.0.0 (OpenSSL 1.1.1c 28 May 2019), cryptography 2.7, Platform Windows-10-10.0.17763-SP0
2019-07-17 15:02:17 [scrapy.crawler] INFO: Overridden settings: {'BOT_NAME': 'myproject', 'NEWSPIDER_MODULE': 'myproject.spiders', 'ROBOTSTXT_OBEY': True, 'SPIDER_MODULES': ['myproject.spiders']}
2019-07-17 15:02:17 [scrapy.extensions.telnet] INFO: Telnet Password: b57cecfc4210fb6c
2019-07-17 15:02:18 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
'scrapy.extensions.telnet.TelnetConsole',
'scrapy.extensions.logstats.LogStats']
2019-07-17 15:02:18 [scrapy.middleware] INFO: Enabled downloader middlewares:
['scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware',
'scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
'scrapy.downloadermiddlewares.retry.RetryMiddleware',
'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',
'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',
'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',
'scrapy.downloadermiddlewares.cookies.CookiesMiddleware',
'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware',
'scrapy.downloadermiddlewares.stats.DownloaderStats']
2019-07-17 15:02:18 [scrapy.middleware] INFO: Enabled spider middlewares:
['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',
'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',
'scrapy.spidermiddlewares.referer.RefererMiddleware',
'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',
'scrapy.spidermiddlewares.depth.DepthMiddleware']
2019-07-17 15:02:18 [scrapy.middleware] INFO: Enabled item pipelines:
[]
2019-07-17 15:02:18 [scrapy.core.engine] INFO: Spider opened
2019-07-17 15:02:18 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2019-07-17 15:02:18 [py.warnings] WARNING: D:\anaconda\lib\site-packages\scrapy\spidermiddlewares\offsite.py:61: URLWarning: allowed_domains accepts only domains, not URLs. Ignoring URL entry https://www.baidu.com in allowed_domains.
warnings.warn(message, URLWarning)
2019-07-17 15:02:18 [scrapy.extensions.telnet] INFO: Telnet console listening on 127.0.0.1:6023
2019-07-17 15:02:20 [scrapy.downloadermiddlewares.retry] DEBUG: Retrying (failed 1 times): DNS lookup failed: no results for hostname lookup: https.
2019-07-17 15:02:22 [scrapy.downloadermiddlewares.retry] DEBUG: Retrying (failed 2 times): DNS lookup failed: no results for hostname lookup: https.
2019-07-17 15:02:25 [scrapy.downloadermiddlewares.retry] DEBUG: Gave up retrying (failed 3 times): DNS lookup failed: no results for hostname lookup: https.
2019-07-17 15:02:39 [scrapy.downloadermiddlewares.robotstxt] ERROR: Error downloading : DNS lookup failed: no results for hostname lookup: https.
Traceback (most recent call last):
File "D:\anaconda\lib\site-packages\twisted\internet\defer.py", line 1416, in _inlineCallbacks
result = result.throwExceptionIntoGenerator(g)
File "D:\anaconda\lib\site-packages\twisted\python\failure.py", line 512, in throwExceptionIntoGenerator
return g.throw(self.type, self.value, self.tb)
File "D:\anaconda\lib\site-packages\scrapy\core\downloader\middleware.py", line 43, in process_request
defer.returnValue((yield download_func(request=request,spider=spider)))
File "D:\anaconda\lib\site-packages\twisted\internet\defer.py", line 654, in _runCallbacks
current.result = callback(current.result, *args, **kw)
File "D:\anaconda\lib\site-packages\twisted\internet\endpoints.py", line 975, in startConnectionAttempts
"no results for hostname lookup: {}".format(self._hostStr)
twisted.internet.error.DNSLookupError: DNS lookup failed: no results for hostname lookup: https.
2019-07-17 15:02:41 [scrapy.downloadermiddlewares.retry] DEBUG: Retrying ": 1,
'robotstxt/request_count': 1,
'scheduler/dequeued': 3,
'scheduler/dequeued/memory': 3,
'scheduler/enqueued': 3,
'scheduler/enqueued/memory': 3,
'start_time': datetime.datetime(2019, 7, 17, 7, 2, 18, 354765)}
2019-07-17 15:02:46 [scrapy.core.engine] INFO: Spider closed (finished)
这里需要注意这里的爬虫名字和通过scrapy genspider 生成爬虫的名字是一致的
check
用于检查代码是否有错误，scrapy check
C:\Users\董贺贺\myproject>scrapy check
----------------------------------------------------------------------
Ran 0 contracts in 0.000s
OK
显然我们这段代码是没问题的
list
输出所有可用的爬虫文件
C:\Users\董贺贺\myproject>scrapy list
baidu
edit
edit 在命令行下编辑spider 不建议运行
scrapy edit myspider
fetch
scrapy fetch url地址
该命令会通过scrapy downloader 讲网页的源代码下载下来并显示出来
这里有一些参数：
--nolog 不打印日志
--headers 打印响应头信息
--no-redirect 不做跳转
# fetch 输出日志及网页源代码
scrapy fetch http://www.baidu.com
# fetch --nolog 只输出源代码
scrapy fetch --nolog http://www.baidu.com
# fetch --nolog --headers 输出响应头
scrapy fetch --nolog --headers http://www.baidu.com
# --nolog --no-redirect 禁止重定向
scrapy fetch --nolog --no-redirect http://www.baidu.com
scrapy
scrapy view url地址
该命令会讲网页document内容下载下来，并且在浏览器显示出来
例：scrapy view http://news.163.com
shell
这是一个命令行交互模式
通过scrapy shell url地址进入交互模式
这里我么可以通过css选择器以及xpath选择器获取我们想要的内容
C:\Users\董贺贺\myproject>scrapy shell www.baidu.com// --nolog
[s] Available Scrapy objects:
[s] scrapy scrapy module (contains scrapy.Request, scrapy.Selector, etc)
[s] crawler
[s] item {}
[s] request
[s] Useful shortcuts:
[s] fetch(url[, redirect=True]) Fetch URL and update local objects (by default, redirects are followed)
[s] fetch(req) Fetch a scrapy.Request and update local objects
[s] shelp() Shell help (print this help)
[s] view(response) View response in a browser
In [1]:
exit退出交互模式
settings
获取当前的配置信息
通过scrapy settings -h可以获取这个命令的所有帮助信息
C:\Users\董贺贺\myproject>scrapy settings -h
Usage
=====
scrapy settings [options]
Get settings values
Options
=======
--help, -h show this help message and exit
--get=SETTING print raw setting value
--getbool=SETTING print setting value, interpreted as a boolean
--getint=SETTING print setting value, interpreted as an integer
--getfloat=SETTING print setting value, interpreted as a float
--getlist=SETTING print setting value, interpreted as a list
Global Options
--------------
--logfile=FILE log file. if omitted stderr will be used
--loglevel=LEVEL, -L LEVEL
log level (default: DEBUG)
--nolog disable logging completely
--profile=FILE write python cProfile stats to FILE
--pidfile=FILE write process ID to FILE
--set=NAME=VALUE, -s NAME=VALUE
set/override setting (may be repeated)
--pdb enable pdb on failure
runspider
这个和通过crawl启动爬虫不同，这里是scrapy runspider 爬虫文件名称
所有的爬虫文件都是在项目目录下的spiders文件夹中
version
查看版本信息，并查看依赖库的信息
C:\Users\董贺贺\myproject>scrapy version
Scrapy 1.6.0
C:\Users\董贺贺\myproject>scrapy version -v
Scrapy : 1.6.0
lxml : 4.3.0.0
libxml2 : 2.9.8
cssselect : 1.0.3
parsel : 1.5.1
w3lib : 1.20.0
Twisted : 19.2.0
Python : 3.7.0 (default, Jun 28 2018, 08:04:48) [MSC v.1912 64 bit (AMD64)]
pyOpenSSL : 18.0.0 (OpenSSL 1.1.1c 28 May 2019)
cryptography : 2.7
Platform : Windows-10-10.0.17763-SP0
shell是重点