爬虫-request和BeautifulSoup模块

requests简介

Python标准库中提供了：urllib、urllib2、httplib等模块以供Http请求，但是，它的 API 太渣了。它是为另一个时代、另一个互联网所创建的。它需要巨量的工作，甚至包括各种方法覆盖，来完成最简单的任务。

Requests 是使用 Apache2 Licensed 许可证的基于Python开发的HTTP 库，其在Python内置模块的基础上进行了高度的封装，从而使得Pythoner进行网络请求时，变得美好了许多，使用Requests可以轻而易举的完成浏览器可有的任何操作。

1.GET请求

# 1、无参数实例import requestsret = requests.get('https://github.com/timeline.json')print ret.url
print ret.text# 2、有参数实例import requestspayload = {'key1': 'value1', 'key2': 'value2'}
ret = requests.get("http://httpbin.org/get", params=payload)print ret.url
print ret.text

2.POST请求

# 1、基本POST实例import requestspayload = {'key1': 'value1', 'key2': 'value2'}
ret = requests.post("http://httpbin.org/post", data=payload)print ret.text# 2、发送请求头和数据实例import requests
import jsonurl = 'https://api.github.com/some/endpoint'
payload = {'some': 'data'}
headers = {'content-type': 'application/json'}ret = requests.post(url, data=json.dumps(payload), headers=headers)print ret.text
print ret.cookies

3、其他请求

requests.get(url, params=None, **kwargs)
requests.post(url, data=None, json=None, **kwargs)
requests.put(url, data=None, **kwargs)
requests.head(url, **kwargs)
requests.delete(url, **kwargs)
requests.patch(url, data=None, **kwargs)
requests.options(url, **kwargs)# 以上方法均是在此方法的基础上构建
requests.request(method, url, **kwargs)

4、更多参数

def request(method, url, **kwargs):"""Constructs and sends a :class:`Request <Request>`.:param method: method for the new :class:`Request` object.:param url: URL for the new :class:`Request` object.:param params: (optional) Dictionary or bytes to be sent in the query string for the :class:`Request`.:param data: (optional) Dictionary, bytes, or file-like object to send in the body of the :class:`Request`.:param json: (optional) json data to send in the body of the :class:`Request`.:param headers: (optional) Dictionary of HTTP Headers to send with the :class:`Request`.:param cookies: (optional) Dict or CookieJar object to send with the :class:`Request`.:param files: (optional) Dictionary of ``'name': file-like-objects`` (or ``{'name': file-tuple}``) for multipart encoding upload.``file-tuple`` can be a 2-tuple ``('filename', fileobj)``, 3-tuple ``('filename', fileobj, 'content_type')``or a 4-tuple ``('filename', fileobj, 'content_type', custom_headers)``, where ``'content-type'`` is a stringdefining the content type of the given file and ``custom_headers`` a dict-like object containing additional headersto add for the file.:param auth: (optional) Auth tuple to enable Basic/Digest/Custom HTTP Auth.:param timeout: (optional) How long to wait for the server to send databefore giving up, as a float, or a :ref:`(connect timeout, readtimeout) <timeouts>` tuple.:type timeout: float or tuple:param allow_redirects: (optional) Boolean. Set to True if POST/PUT/DELETE redirect following is allowed.:type allow_redirects: bool:param proxies: (optional) Dictionary mapping protocol to the URL of the proxy.:param verify: (optional) whether the SSL cert will be verified. A CA_BUNDLE path can also be provided. Defaults to ``True``.:param stream: (optional) if ``False``, the response content will be immediately downloaded.:param cert: (optional) if String, path to ssl client cert file (.pem). If Tuple, ('cert', 'key') pair.:return: :class:`Response <Response>` object:rtype: requests.ResponseUsage::>>> import requests>>> req = requests.request('GET', 'http://httpbin.org/get')<Response [200]>"""

参数列表

def param_method_url():# requests.request(method='get', url='http://127.0.0.1:8000/test/')# requests.request(method='post', url='http://127.0.0.1:8000/test/')passdef param_param():# - 可以是字典# - 可以是字符串# - 可以是字节（ascii编码以内）# requests.request(method='get',# url='http://127.0.0.1:8000/test/',# params={'k1': 'v1', 'k2': '水电费'})# requests.request(method='get',# url='http://127.0.0.1:8000/test/',# params="k1=v1&k2=水电费&k3=v3&k3=vv3")# requests.request(method='get',# url='http://127.0.0.1:8000/test/',# params=bytes("k1=v1&k2=k2&k3=v3&k3=vv3", encoding='utf8'))# 错误# requests.request(method='get',# url='http://127.0.0.1:8000/test/',# params=bytes("k1=v1&k2=水电费&k3=v3&k3=vv3", encoding='utf8'))passdef param_data():# 可以是字典# 可以是字符串# 可以是字节# 可以是文件对象# requests.request(method='POST',# url='http://127.0.0.1:8000/test/',# data={'k1': 'v1', 'k2': '水电费'})# requests.request(method='POST',# url='http://127.0.0.1:8000/test/',# data="k1=v1; k2=v2; k3=v3; k3=v4"# )# requests.request(method='POST',# url='http://127.0.0.1:8000/test/',# data="k1=v1;k2=v2;k3=v3;k3=v4",# headers={'Content-Type': 'application/x-www-form-urlencoded'}# )# requests.request(method='POST',# url='http://127.0.0.1:8000/test/',# data=open('data_file.py', mode='r', encoding='utf-8'), # 文件内容是：k1=v1;k2=v2;k3=v3;k3=v4# headers={'Content-Type': 'application/x-www-form-urlencoded'}# )passdef param_json():# 将json中对应的数据进行序列化成一个字符串，json.dumps(...)# 然后发送到服务器端的body中，并且Content-Type是 {'Content-Type': 'application/json'}requests.request(method='POST',url='http://127.0.0.1:8000/test/',json={'k1': 'v1', 'k2': '水电费'})def param_headers():# 发送请求头到服务器端requests.request(method='POST',url='http://127.0.0.1:8000/test/',json={'k1': 'v1', 'k2': '水电费'},headers={'Content-Type': 'application/x-www-form-urlencoded'})def param_cookies():# 发送Cookie到服务器端requests.request(method='POST',url='http://127.0.0.1:8000/test/',data={'k1': 'v1', 'k2': 'v2'},cookies={'cook1': 'value1'},)# 也可以使用CookieJar（字典形式就是在此基础上封装）from http.cookiejar import CookieJarfrom http.cookiejar import Cookieobj = CookieJar()obj.set_cookie(Cookie(version=0, name='c1', value='v1', port=None, domain='', path='/', secure=False, expires=None,discard=True, comment=None, comment_url=None, rest={'HttpOnly': None}, rfc2109=False,port_specified=False, domain_specified=False, domain_initial_dot=False, path_specified=False))requests.request(method='POST',url='http://127.0.0.1:8000/test/',data={'k1': 'v1', 'k2': 'v2'},cookies=obj)def param_files():# 发送文件# file_dict = {# 'f1': open('readme', 'rb')# }# requests.request(method='POST',# url='http://127.0.0.1:8000/test/',# files=file_dict)# 发送文件，定制文件名# file_dict = {# 'f1': ('test.txt', open('readme', 'rb'))# }# requests.request(method='POST',# url='http://127.0.0.1:8000/test/',# files=file_dict)# 发送文件，定制文件名# file_dict = {# 'f1': ('test.txt', "hahsfaksfa9kasdjflaksdjf")# }# requests.request(method='POST',# url='http://127.0.0.1:8000/test/',# files=file_dict)# 发送文件，定制文件名# file_dict = {#     'f1': ('test.txt', "hahsfaksfa9kasdjflaksdjf", 'application/text', {'k1': '0'})# }# requests.request(method='POST',#                  url='http://127.0.0.1:8000/test/',#                  files=file_dict)passdef param_auth():from requests.auth import HTTPBasicAuth, HTTPDigestAuthret = requests.get('https://api.github.com/user', auth=HTTPBasicAuth('wupeiqi', 'sdfasdfasdf'))print(ret.text)# ret = requests.get('http://192.168.1.1',# auth=HTTPBasicAuth('admin', 'admin'))# ret.encoding = 'gbk'# print(ret.text)# ret = requests.get('http://httpbin.org/digest-auth/auth/user/pass', auth=HTTPDigestAuth('user', 'pass'))# print(ret)#def param_timeout():# ret = requests.get('http://google.com/', timeout=1)# print(ret)# ret = requests.get('http://google.com/', timeout=(5, 1))# print(ret)passdef param_allow_redirects():ret = requests.get('http://127.0.0.1:8000/test/', allow_redirects=False)print(ret.text)def param_proxies():# proxies = {# "http": "61.172.249.96:80",# "https": "http://61.185.219.126:3128",# }# proxies = {'http://10.20.1.128': 'http://10.10.1.10:5323'}# ret = requests.get("http://www.proxy360.cn/Proxy", proxies=proxies)# print(ret.headers)# from requests.auth import HTTPProxyAuth## proxyDict = {# 'http': '77.75.105.165',# 'https': '77.75.105.165'# }# auth = HTTPProxyAuth('username', 'mypassword')## r = requests.get("http://www.google.com", proxies=proxyDict, auth=auth)# print(r.text)passdef param_stream():ret = requests.get('http://127.0.0.1:8000/test/', stream=True)print(ret.content)ret.close()# from contextlib import closing# with closing(requests.get('http://httpbin.org/get', stream=True)) as r:# # 在此处理响应。# for i in r.iter_content():# print(i)def requests_session():import requestssession = requests.Session()### 1、首先登陆任何页面，获取cookiei1 = session.get(url="http://dig.chouti.com/help/service")### 2、用户登陆，携带上一次的cookie，后台对cookie中的 gpsd 进行授权i2 = session.post(url="http://dig.chouti.com/login",data={'phone': "8615131255089",'password': "xxxxxx",'oneMonth': ""})i3 = session.post(url="http://dig.chouti.com/link/vote?linksId=8589623",)print(i3.text)

官方文档：http://cn.python-requests.org/zh_CN/latest/user/quickstart.html#id4

BeautifulSoup

BeautifulSoup是一个模块，该模块用于接收一个HTML或XML字符串，然后将其进行格式化，之后遍可以使用他提供的方法进行快速查找指定元素，从而使得在HTML或XML中查找指定元素变得简单。

from bs4 import BeautifulSouphtml_doc = """
<html><head><title>The Dormouse's story</title></head>
<body>
asdf<div class="title"><b>The Dormouse's story总共</b><h1>f</h1></div>
<div class="story">Once upon a time there were three little sisters; and their names were<a  class="sister0" id="link1">Els<span>f</span>ie</a>,<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.</div>
ad<br/>sf
<p class="story">...</p>
</body>
</html>
"""soup = BeautifulSoup(html_doc, features="lxml")
# 找到第一个a标签
tag1 = soup.find(name='a')
# 找到所有的a标签
tag2 = soup.find_all(name='a')
# 找到id＝link2的标签
tag3 = soup.select('#link2')

安装：

pip3 install beautifulsoup4

使用示例：

from bs4 import BeautifulSouphtml_doc = """
<html><head><title>The Dormouse's story</title></head>
<body>...
</body>
</html>
"""soup = BeautifulSoup(html_doc, features="lxml")

1. name，标签名称

# tag = soup.find('a')
# name = tag.name  # 获取
# print(name)
# tag.name = 'span' # 设置
# print(soup)

2. attr，标签属性

# tag = soup.find('a')
# attrs = tag.attrs # 获取属性
# print(attrs)
# tag.attrs = {'ik': 123}  # 设置
# tag.attrs['id'] = 'v'  # 设置
# print(soup)

3. children,所有子标签

# body = soup.find('body')
# v = body.children

4. children,所有子子孙孙标签

# body = soup.find('body')
# v = body.descendants

5. clear,将标签的所有子标签全部清空（保留标签名）

# body = soup.find('body')
# body.clear()
# print(soup)

6. decompose,递归的删除所有的标签

# body = soup.find('body')
# body.decompose()
# print(soup)

7. extract,递归的删除所有的标签，并获取删除的标签

# body = soup.find('body')
# v = body.extract()
# print(soup)

8. decode,转换为字符串（含当前标签）；decode_contents（不含当前标签）

# body = soup.find('body')
# v = body.decode()
# v = body.decode_contents()
# print(v)

9. encode,转换为字节（含当前标签）；encode_contents（不含当前标签）

# body = soup.find('body')
# v = body.encode()
# v = body.encode_contents()
# print(v)

10. find,获取匹配的第一个标签

# tag = soup.find('a')
# print(tag)
# tag = soup.find(name='a', attrs={'class': 'sister'}, recursive=True, text='Lacie')
# tag = soup.find(name='a', class_='sister', recursive=True, text='Lacie')
# print(tag)
# 使用class进行寻找的时候避免关键字，使用'class_'

11. find_all,获取匹配的所有标签

# tag = soup.find_all('a')
# print(tag)# tags = soup.find_all('a', limit=1)  # 匹配到的第一个a标签
# print(tags)# tags = soup.find_all(name='a', attrs={'class': 'sister'}, recursive=True, text='Lacie')
# # tags = soup.find(name='a', class_='sister', recursive=True, text='Lacie')
# print(tags)  # recursive 递归查找# ##### 列表 #####
# v = soup.find_all(name=['a', 'div'])
# print(v)# v = soup.find_all(class_=['sister0', 'sister'])
# print(v)# v = soup.find_all(text=['tillie'])
# print(v, type(v[0]))# v = soup.find_all(id=['link1','link2'])
# print(v)# v = soup.find_all(href=['link1','link2'])
# print(v)# #### 正则 ####
import re
# rep = re.compile('p')
# rep = re.compile('^p')
# v = soup.find_all(name=rep)
# print(v)# rep = re.compile('sister.*')
# v = soup.find_all(class_=rep)
# print(v)# rep = re.compile('http://www.oldboy.com/static/.*')
# v = soup.find_all(href=rep)
# print(v)# ####### 方法筛选 #######
# def func(tag):
# return tag.has_attr('class') and tag.has_attr('id')
# v = soup.find_all(name=func)
# print(v)# ## get,获取标签属性
# tag = soup.find('a')
# v = tag.get('id')
# print(v)

12. has_attr,检查标签是否具有该属性

# tag = soup.find('a')
# v = tag.has_attr('id')
# print(v)

13. get_text,获取标签内部文本内容　　

# tag = soup.find('a')
# v = tag.get_text('id')
# print(v)

14. index,检查标签在某标签中的索引位置

# tag = soup.find('body')
# v = tag.index(tag.find('div'))
# print(v)# tag = soup.find('body')
# for i,v in enumerate(tag):
# print(i,v)

15. is_empty_element,是否是空标签(是否可以是空)或者自闭合标签，

判断是否是如下标签：'br' , 'hr', 'input', 'img', 'meta','spacer', 'link', 'frame', 'base'

# tag = soup.find('br')
# v = tag.is_empty_element
# print(v)

16. 当前的关联标签

# soup.next
# soup.next_element
# soup.next_elements
# soup.next_sibling
# soup.next_siblings#
# tag.previous
# tag.previous_element
# tag.previous_elements
# tag.previous_sibling
# tag.previous_siblings#
# tag.parent
# tag.parents

17. 查找某标签的关联标签

# tag.find_next(...)
# tag.find_all_next(...)
# tag.find_next_sibling(...)
# tag.find_next_siblings(...)# tag.find_previous(...)
# tag.find_all_previous(...)
# tag.find_previous_sibling(...)
# tag.find_previous_siblings(...)# tag.find_parent(...)
# tag.find_parents(...)# 参数同find_all

18. select,select_one, CSS选择器

soup.select("title")soup.select("p nth-of-type(3)")soup.select("body a")soup.select("html head title")tag = soup.select("span,a")soup.select("head > title")soup.select("p > a")soup.select("p > a:nth-of-type(2)")soup.select("p > #link1")soup.select("body > a")soup.select("#link1 ~ .sister")soup.select("#link1 + .sister")soup.select(".sister")soup.select("[class~=sister]")soup.select("#link1")soup.select("a#link2")soup.select('a[href]')soup.select('a[href="http://example.com/elsie"]')soup.select('a[href^="http://example.com/"]')soup.select('a[href$="tillie"]')soup.select('a[href*=".com/el"]')from bs4.element import Tagdef default_candidate_generator(tag):for child in tag.descendants:if not isinstance(child, Tag):continueif not child.has_attr('href'):continueyield childtags = soup.find('body').select("a", _candidate_generator=default_candidate_generator)
print(type(tags), tags)from bs4.element import Tag
def default_candidate_generator(tag):for child in tag.descendants:if not isinstance(child, Tag):continueif not child.has_attr('href'):continueyield childtags = soup.find('body').select("a", _candidate_generator=default_candidate_generator, limit=1)
print(type(tags), tags)

19. 标签的内容

# tag = soup.find('span')
# print(tag.string)          # 获取
# tag.string = 'new content' # 设置
# print(soup)# tag = soup.find('body')
# print(tag.string)
# tag.string = 'xxx'
# print(soup)# tag = soup.find('body')
# v = tag.stripped_strings  # 递归内部获取所有标签的文本
# print(v)

20.append在当前标签内部追加一个标签

# tag = soup.find('body')
# tag.append(soup.find('a'))
# print(soup)
#
# from bs4.element import Tag
# obj = Tag(name='i',attrs={'id': 'it'})
# obj.string = '我是一个新来的'
# tag = soup.find('body')
# tag.append(obj)
# print(soup)

21.insert在当前标签内部指定位置插入一个标签

# from bs4.element import Tag
# obj = Tag(name='i', attrs={'id': 'it'})
# obj.string = '我是一个新来的'
# tag = soup.find('body')
# tag.insert(2, obj)
# print(soup)

22. insert_after,insert_before 在当前标签后面或前面插入

# from bs4.element import Tag
# obj = Tag(name='i', attrs={'id': 'it'})
# obj.string = '我是一个新来的'
# tag = soup.find('body')
# # tag.insert_before(obj)
# tag.insert_after(obj)
# print(soup)

23. replace_with 在当前标签替换为指定标签

# from bs4.element import Tag
# obj = Tag(name='i', attrs={'id': 'it'})
# obj.string = '我是一个新来的'
# tag = soup.find('div')
# tag.replace_with(obj)
# print(soup)

24. 创建标签之间的关系

# tag = soup.find('div')
# a = soup.find('a')
# tag.setup(previous_sibling=a)
# print(tag.previous_sibling)

25. wrap，将指定标签把当前标签包裹起来

# from bs4.element import Tag
# obj1 = Tag(name='div', attrs={'id': 'it'})
# obj1.string = '我是一个新来的'
#
# tag = soup.find('a')
# v = tag.wrap(obj1)
# print(soup)# tag = soup.find('a')
# v = tag.wrap(soup.find('p'))
# print(soup)

26. unwrap，去掉当前标签，将保留其包裹的标签

# tag = soup.find('a')
# v = tag.unwrap()
# print(soup)

转载于:https://www.cnblogs.com/sxzwj/p/6387069.html