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基于公司最近的业务，需要分析网络舆情，得到较为准确的信息，需要开发一款通用式爬虫，支持贴吧、微信、百度、域名、指定贴吧、指定关键字等抓取。本人故开发此项爬虫代码。
1.开发依赖环境 scrapy_redis+chrome+selenium(phantomjs也可以)
2.开发环境安装（详情见我的上一篇文章）
3.架构流程详解
获取需要抓取的关键字、域名、指定贴吧名字等建立一个mysql初始任务数据表，然后将这些数据插入到mysql中。详情见下图：
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可以根据自己的需求进行配置。
2.爬虫启动过程中会去mysql拿下发任务进行抓取，crawled=0表示未抓取的任务，爬虫成功启动后会将crawled字段置为1表示任务开始抓取。当此任务结束时，爬虫在调用close_spider函数时，会将crawled状态更新为2，表示此项任务抓取结束。
st_status表示动静态开关切换，0表示静态、1表示动态。
crawltasktime：任务下发时间。
engine：1.表示微信搜狗引擎、2.表示百度引擎、3.表示贴吧 0.表示抓取域名。
keyword：表示抓取指定关键字。
domain: 表示抓取的指定域名。
depth：爬虫抓取深度限制。
width：爬虫抓取宽度限制。
accesspoint：CMWAP、CMNET爬取模式，多种模式中用“,”分隔，默认为CMNET。
totalpages：爬虫抓取页面数量限制。
CrawlFrequency：对任务爬取的频率 0表示爬取一次，1表示无线循环抓取。
cycletime：爬虫爬取时间限制，单位秒
repeattimes：爬虫请求失败重复请求次数设置。
interval：爬虫重复拨测时间间隔。
company：任务所属公司设置。
3.将抓取的文本、图片的数据存入mongodb或者mysql数据库。
4.进行数据分析提取相关数据。
4.scheduler 代码开发详解
因为我们所有的任务都是使用的同一款爬虫，所以爬虫在没有请求的时候，我们不让他继续等待。故修改scrapy_redis源码，让爬虫在没有请求的情况下，自动等待15秒后关闭爬虫。避免浪费内存资源，节省空间！首先找到scrapy_redis的scheduler.py这个文件夹。这个文件里面的代码主要作用就是收集指纹和处理请求，保证一个请求按一定（settings配置中的规则）的规则去消耗。
/usr/local/lib/python2.7/dist- packages/scrapy_redis/scheduler.py这是源代码的路径。多的不说，直接上图。
# coding=utf-8import redis
import importlib
import six
import datetime
import time
from scrapy.utils.misc import load_object
import os
from . import connection, defaults# TODO: add SCRAPY_JOB support.class Scheduler(object):
"""Redis-based scheduler
Settings
--------
SCHEDULER_PERSIST : bool (default: False)
Whether to persist or clear redis queue.
SCHEDULER_FLUSH_ON_START : bool (default: False)
Whether to flush redis queue on start.
SCHEDULER_IDLE_BEFORE_CLOSE : int (default: 0)
How many seconds to wait before closing if no message is received.
SCHEDULER_QUEUE_KEY : str
Scheduler redis key.
SCHEDULER_QUEUE_CLASS : str
Scheduler queue class.
SCHEDULER_DUPEFILTER_KEY : str
Scheduler dupefilter redis key.
SCHEDULER_DUPEFILTER_CLASS : str
Scheduler dupefilter class.
SCHEDULER_SERIALIZER : str
Scheduler serializer.
"""
#++++
lostGetRequest = 0
def __init__(self, server,
persist=False,
flush_on_start=False,
queue_key=defaults.SCHEDULER_QUEUE_KEY,
queue_cls=defaults.SCHEDULER_QUEUE_CLASS,
dupefilter_key=defaults.SCHEDULER_DUPEFILTER_KEY,
dupefilter_cls=defaults.SCHEDULER_DUPEFILTER_CLASS,
idle_before_close=0,
serializer=None): """Initialize scheduler.
Parameters
----------
server : Redis
The redis server instance.
persist : bool
Whether to flush requests when closing. Default is False.
flush_on_start : bool
Whether to flush requests on start. Default is False.
queue_key : str
Requests queue key.
queue_cls : str
Importable path to the queue class.
dupefilter_key : str
Duplicates filter key.
dupefilter_cls : str
Importable path to the dupefilter class.
idle_before_close : int
Timeout before giving up.
"""
if idle_before_close < 0:
raise TypeError("idle_before_close cannot be negative") self.server = server self.persist = persist self.flush_on_start = flush_on_start self.queue_key = queue_key self.queue_cls = queue_cls self.dupefilter_cls = dupefilter_cls self.dupefilter_key = dupefilter_key self.idle_before_close = idle_before_close self.serializer = serializer self.stats = None def __len__(self): return len(self.queue)
@classmethod def from_settings(cls, settings):
kwargs = { 'persist': settings.getbool('SCHEDULER_PERSIST'), 'flush_on_start': settings.getbool('SCHEDULER_FLUSH_ON_START'), 'idle_before_close': settings.getint('SCHEDULER_IDLE_BEFORE_CLOSE'),
} # If these values are missing, it means we want to use the defaults.
optional = { # TODO: Use custom prefixes for this settings to note that are
# specific to scrapy-redis.
'queue_key': 'SCHEDULER_QUEUE_KEY', 'queue_cls': 'SCHEDULER_QUEUE_CLASS', 'dupefilter_key': 'SCHEDULER_DUPEFILTER_KEY', # We use the default setting name to keep compatibility.
'dupefilter_cls': 'DUPEFILTER_CLASS', 'serializer': 'SCHEDULER_SERIALIZER',
} for name, setting_name in optional.items():
val = settings.get(setting_name) if val:
kwargs[name] = val # Support serializer as a path to a module.
if isinstance(kwargs.get('serializer'), six.string_types):
kwargs['serializer'] = importlib.import_module(kwargs['serializer'])
server = connection.from_settings(settings) # Ensure the connection is working.
server.ping() return cls(server=server, **kwargs)
@classmethod def from_crawler(cls, crawler):
instance = cls.from_settings(crawler.settings) # FIXME: for now, stats are only supported from this constructor
instance.stats = crawler.stats return instance def open(self, spider): self.spider = spider
print 'spider.name is %s' %(spider.redis_key)
try:
self.queue = load_object(self.queue_cls)(
server=self.server,
spider=spider, #key=self.queue_key % {'spider': spider.name},
key=self.queue_key % {'spider': spider.host},
serializer=self.serializer,
)
except TypeError as e:
raise ValueError("Failed to instantiate queue class '%s': %s", self.queue_cls, e) try:
self.df = load_object(self.dupefilter_cls)(
server=self.server, #key=self.dupefilter_key % {'spider': spider.name},
key=self.dupefilter_key % {'spider': spider.host},
debug=spider.settings.getbool('DUPEFILTER_DEBUG'),
)
except TypeError as e:
raise ValueError("Failed to instantiate dupefilter class '%s': %s", self.dupefilter_cls, e) if self.flush_on_start:
self.flush() # notice if there are requests already in the queue to resume the crawl
if len(self.queue):
spider.log("Resuming crawl (%d requests scheduled)" % len(self.queue)) def close(self, reason): if not self.persist:
self.flush() def flush(self): self.df.clear() self.queue.clear() def enqueue_request(self, request): if not request.dont_filter and self.df.request_seen(request): self.df.log(request, self.spider) return False if self.stats:
self.stats.inc_value('scheduler/enqueued/redis', spider=self.spider) self.queue.push(request) return True def next_request(self):
block_pop_timeout = self.idle_before_close
request = self.queue.pop(block_pop_timeout) if request and self.stats:
self.lostGetRequest = 0
self.stats.inc_value('scheduler/dequeued/redis', spider=self.spider) if request is None:
self.lostGetRequest += 1
print "request is None, lostGetRequest = {%s}, time = {%s}" %(self.lostGetRequest,datetime.datetime.now()) if self.lostGetRequest >= 15:
print "request is None, close spider."
self.spider.crawler.engine.close_spider(self.spider, 'queue is empty') return request def has_pending_requests(self): return len(self) > 0代码很简单，当spider被初始化时，同时会初始化一个对应的scheduler对象，这个调度器对象通过读取settings，配置好自己的调度容器queue和判重工具dupefilter。爬虫在运行过程过，会源源不断的通过引擎来和调度器协调工作，调度器将引擎分发的请求经过一系列的入队列、指纹收集等处理后，按settings中设置的爬取策略分发给下载中间件去下载。而这份代码我们主要设置了一个类变量用来进行计时。当next_request这个函数处理的请求不为空，我们就会重置他的状态为0，当请求为空，我们就要进行一个15秒的计时。当计时结束，引发异常调用close_spider将爬虫进行关闭。此代码还修改了scrapy_redis默认的dupfilter和request 两个key。
5.spider开发代码详解
# -*- coding: utf-8 -*-import scrapyfrom scrapy.http import Request, HtmlResponsefrom bs4 import BeautifulSoupimport timefrom urllib import urlencodeimport reimport sys
reload(sys)
sys.setdefaultencoding('utf-8')import redisfrom redistest.settings import REDIS_PORT, REDIS_HOSTimport hashlibimport randomimport osimport urllibdef soup_text(body):
try:
soup = BeautifulSoup(body, 'lxml') for script in soup(["script", "style"]):
script.extract()
line = re.compile(r'\s+')
line = line.sub(r'', soup.body.getText()) #p2 = re.compile(u'[^\u4e00-\u9fa5]') # 中GDAC\u4e00\u9fa5
#str2 = p2.sub(r'', line)
outStr = line.strip(',') except:
outStr = ''
return outStrdef rand5():
randnum = ""
for i in range(0, 5):
randnum += str(random.randint(0, 9)) return randnumclass BaiduSpider(scrapy.Spider):
name = 'redistest'
params = ''
keyword = ''
allowed_domains = []
sousu = ''
start_urls = []
datadupefilter = ''
filepath = ''
def __init__(self, param=None, *args, **kwargs):
super(BaiduSpider, self).__init__(*args, **kwargs)
self.data_conn = redis.Redis(host=REDIS_HOST, port=REDIS_PORT, db=8)
self.yuqing = self.name+':item'
self.datadupefilter = 'datadupefilter'
self.params = eval(param) if self.params['keyword'] != '0':
self.keyword = self.params['keyword'].decode('utf-8') print self.params
self.sousu = self.params['engine']
self.filepath = "/home/YuQing/scrapy_yuqing/content"
if not os.path.exists(self.filepath):
os.mkdir(self.filepath) if self.sousu == 1:
self.start_urls = ['http://weixin.sogou.com']
self.params['redis_key'] = None
elif self.sousu == 2:
self.start_urls = ['https://www.baidu.com']
self.params['redis_key'] = None
elif self.sousu == 0:
self.params['redis_key'] = None
self.start_urls = ['https://tieba.baidu.com/f?ie=utf-8&kw=%s&fr=search&' % self.params['keyword']] else: if self.params['redis_key']:
self.start_urls = [self.params['redis_key']] if self.params['crosssitecrawl'] == 0 and self.params['redis_key']:
proto, rest = urllib.splittype(self.params['redis_key'])
host, rest = urllib.splithost(rest)
self.allowed_domains = [host.replace('www.','')] print self.start_urls,self.sousu,self.params['redis_key'],self.allowed_domains def make_requests_from_url(self, url):
if self.params['st_status'] == 1: return Request(url, meta={'keyword': self.keyword, 'engine':self.sousu, 'phantomjs':True}) else: return Request(url) def parse(self, response):
# 判断页面的返回状态
if int(response.status) >= 200 and int(response.status) < 400: if not self.params['redis_key'] and self.sousu:
a_list = response.xpath('//h3/a/@href').extract() for url in a_list: if url.startswith('http://') != True and url.startswith('https://') !=True:
url = response.urljoin(url) yield scrapy.Request(url=url, meta={'url':response.url}, callback=self.parse_url) if response.meta.has_key('page') != True and self.sousu == 2:
flag = 1
for next_url in response.xpath('//div[@id="page"]/a/@href').extract(): if next_url.startswith('http://') != True and next_url.startswith('https://') !=True:
nextUrl = self.start_urls[0] + next_url
regex = 'pn=(\d+)'
page_number = re.compile(regex).search(nextUrl).group(1) if page_number and flag:
flag = 0
# 抓取前50页
for page in range(10,500,10):
next_page = 'pn=' + str(page)
old_page = re.compile(regex).search(nextUrl).group()
nextUrl = nextUrl.replace(old_page, next_page) yield scrapy.Request(url=nextUrl, meta={'page':page}, callback=self.parse) if response.meta.has_key('page') != True and self.sousu == 1:
flag = 1
for next_url in response.xpath('//div[@class="p-fy"]/a/@href').extract(): if next_url.startswith('http://') != True and next_url.startswith('https://') !=True:
nextUrl = self.start_urls[0] + '/weixin' + next_url
regex = 'page=(\d+)'
page_number = re.compile(regex).search(nextUrl).group(1) if page_number and flag:
flag = 0
for page in range(2,3):
next_page = 'page=' + str(page)
old_page = re.compile(regex).search(nextUrl).group()
nextUrl = nextUrl.replace(old_page, next_page) yield scrapy.Request(url=nextUrl, meta={'page':page}, callback=self.parse) # 支持贴吧抓取
elif not self.params['redis_key'] and not self.sousu: for page in range(0, 200, 50):
pn = urlencode({'pn':page})
next_page = response.url + pn yield scrapy.Request(next_page, callback=self.parse_tieba)
else:
self.parse_url(response) print response.url
a_list = response.xpath('//a/@href').extract() for linkstr in a_list: if linkstr.startswith('http://') != True and linkstr.startswith('https://') !=True:
linkstr = response.urljoin(linkstr) if 'about:blank' != linkstr and linkstr.lower().endswith('.rar') != True and linkstr.lower().endswith('.apk') != True and linkstr.startswith('tel') != True and linkstr.lower().endswith('.css') != True and linkstr.lower().endswith('.js') != True: yield scrapy.Request(url=linkstr, meta={'url':response.url}, callback=self.parse) def parse_tieba(self, response):
with open('aa', 'a') as f:
f.write(response.url+'\n')
regex = 'href="(.*?)"'
a_list = re.compile(regex).findall(response.body) for url in a_list: if len(url) >= 5 and 'javascript' not in url and 'css' not in url and url.startswith('/p'): if url.startswith('http:') != True and url.startswith('https:') != True:
url = response.urljoin(url) yield scrapy.Request(url, meta={'url':response.url}, callback=self.parse_url) def parse_dupefilter(self, response):
try:
a_list = response.xpath("//a/@href").extract()
data = soup_text(response)
data = data + str(a_list) except Exception, e:
data = str(e) print data if data:
m = hashlib.md5()
m.update(data)
data_md5 = m.hexdigest() return data_md5 else: return ''
def parse_text(self, response):
item = {} try:
father_url = response.meta["url"] except:
father_url = "''"
try:
item['title'] = response.xpath('//title/text()').extract_first().replace('\r\n','').replace('\n','') except:
item['title'] = "''"
item['url'] = response.url
item['domain'] = ''
item['crawl_time'] = time.strftime('%Y%m%d%H%M%S')
item['keyword'] = ''
item['Type_result'] = ''
item['type'] = 'html'
item['filename'] = 'yq_' + str(int(time.time())) + '_0' + str(rand5())+'.txt'
item['referver'] = father_url
item['like'] = ''
item['transpond'] = ''
item['comment'] = ''
item['publish_time'] = ''
return item def parse_url(self, response):
# 以内容做指纹
data_md5 = self.parse_dupefilter(response) if self.data_conn.sadd(self.datadupefilter, data_md5):
content = soup_text(response.body) print content
item = self.parse_text(response)
self.data_conn.lpush(self.yuqing, item)
yuqing_file = os.path.join(self.filepath, item['filename']) with open(yuqing_file, 'w') as b:
b.write(content) def pang_bo(self, response):
# 过略掉百度网页
if 'baidu.com' not in response.url:
item = self.parse_text(response)
content = soup_text(response.body) if len(content) > 3000:
content = content[:3000]
body = item['url']+','+item['crawl_time']+','+item['title'].replace(',','') +','+content+'\n'
filename = time.strftime('%Y%m%d%H')+'.csv'
with open(filename, 'a') as f:
f.write(body)启动爬虫的时候我们会以 scrapy crawl spider -a="{}" 的形式，给他传递一个json字符串，在spider 的init中，我们继承了BaiduSpider原有的初始化，并重写我们需要的东西。在init方法中，我们提取到我们从外面传入的数据，并进行处理。连接数据库、引擎选择、跨域开关设置、redis_key配置等。
修改make_request_from_url这个函数，此函数会传递一个url参数给Request对象。在这个过程过，我们会根据传递的动静态开关，给Request对象添加一个meta字典。这样我们在middlewares中间件中，通过process_request方法，提取到该请求携带的参数，来启动selenium+chrome来进行抓取。process_request函数是一个类方法，它默认携带request和spider两个对象。我们可以通过request.meta来获取刚刚传递的数据，详情如下图：
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作者：可爱的小虫虫
链接：https://www.jianshu.com/p/8a1a1802fa92
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