4.爬虫 requests库讲解 GET请求 POST请求 响应
requests库相比于urllib库更好用！！！
0.各种请求方式
import requests requests.post('http://httpbin.org/post') requests.put('http://httpbin.org/put') requests.delete('http://httpbin.org/delete') requests.head('http://httpbin.org/get') requests.options('http://httpbin.org/get')
*http://httpbin.org是一个http请求验证网站！
1.GET请求
- 带参数的get请求（两种方式是等效的）
import requests response = requests.get("http://httpbin.org/get?name=germey&age=22") print(response.text) ######################## import requests data = { 'name': 'germey', 'age': 22 } response = requests.get("http://httpbin.org/get", params=data) print(response.text)
输出结果如下：
{
"args": {
"age": "22",
"name": "germey"
},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Host": "httpbin.org",
"User-Agent": "python-requests/2.18.4"
},
"origin": "182.148.156.45, 182.148.156.45",
"url": "https://httpbin.org/get?name=germey&age=22"
}
* params=data 对于get请求 添加附加的格外的信息，这个信息一般用字典来存储，可见返回的结果中args字段.
- 解析json
import requests import json response = requests.get("http://httpbin.org/get") print(type(response.text)) print(response.json()) print(json.loads(response.text)) print(type(response.json()))
输出结果如下：
<class 'str'>
{'args': {}, 'headers': {'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate', 'Host': 'httpbin.org', 'User-Agent': 'python-requests/2.18.4'}, 'origin': '182.148.156.45, 182.148.156.45', 'url': 'https://httpbin.org/get'}
{'args': {}, 'headers': {'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate', 'Host': 'httpbin.org', 'User-Agent': 'python-requests/2.18.4'}, 'origin': '182.148.156.45, 182.148.156.45', 'url': 'https://httpbin.org/get'}
<class 'dict'>
*网页返回的类型是str类型，但是有的很特殊，返回的是JSON格式的字符串.json()将JSON格式的字符串转换为字典。
*可以看到response.json()和json.loads(response.text)打印出来的结果是一样的！
*倘若网页返回的结果不是JSON格式的，便会出现解析错误，抛出json.decoder.JSONDecodeError的异常。
- 获取二进制数据
import requests response = requests.get("https://github.com/favicon.ico") print(type(response.text), type(response.content)) print(response.text) print(response.content)
"""
#抓取并保存二进制数据(图片、视频、音频等文件)
with open('文件名称','wb') as f:
f.write(r.content)
"""
*图标地址一般都放在网络根目录下，名称为favicon.ico
*获取文本数据：response.text
*获取图片等二进制数据：response.content
- 添加headers
import requests headers = { 'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36' } response = requests.get("https://www.zhihu.com/explore", headers=headers) print(response.text)
2.POST请求
- 带参数POST请求
import requests data = {'name': 'germey', 'age': '22'} response = requests.post("http://httpbin.org/post", params=data)print(response.text)
- 添加headers
import requests data = {'name': 'germey', 'age': '22'} headers = { 'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36' } response = requests.post("http://httpbin.org/post", params=data, headers=headers)
print(response.text) print(response.json())
输出结果如下：
{
"args": {
"age": "22",
"name": "germey"
},
"data": "",
"files": {},
"form": {},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Content-Length": "0",
"Host": "httpbin.org",
"User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36"
},
"json": null,
"origin": "101.206.170.234, 101.206.170.234",
"url": "https://httpbin.org/post?name=germey&age=22"
}
{'args': {'age': '22', 'name': 'germey'}, 'data': '', 'files': {}, 'form': {}, 'headers': {'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate', 'Content-Length': '0', 'Host': 'httpbin.org', 'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36'}, 'json': None, 'origin': '101.206.170.234, 101.206.170.234', 'url': 'https://httpbin.org/post?name=germey&age=22'}
*可以看到GET和POST方式的带参数的请求和添加headers的方式差不多！
3.响应
- reponse属性
import requests response = requests.get('http://www.jianshu.com') print(type(response.status_code), response.status_code) #状态码 print(type(response.headers), response.headers) #响应头 print(type(response.cookies), response.cookies) #cookies值 print(type(response.url), response.url) #url print(type(response.history), response.history) #请求历史
输出结果如下：
<class 'int'> 403
<class 'requests.structures.CaseInsensitiveDict'> {'Server': 'Tengine', 'Content-Type': 'text/html', 'Transfer-Encoding': 'chunked', 'Connection': 'keep-alive', 'Date': 'Tue, 09 Apr 2019 13:14:23 GMT', 'Vary': 'Accept-Encoding', 'Strict-Transport-Security': 'max-age=31536000; includeSubDomains; preload', 'Content-Encoding': 'gzip', 'x-alicdn-da-ups-status': 'endOs,0,403', 'Via': 'cache29.l2cm12-6[17,0], cache8.cn389[77,0]', 'Timing-Allow-Origin': '*', 'EagleId': '7d412b4815548156634056180e'}
<class 'requests.cookies.RequestsCookieJar'> <RequestsCookieJar[]>
<class 'str'> https://www.jianshu.com/
<class 'list'> [<Response [301]>]
- 状态码判断
下面列出反悔码和相应的查询条件：
# 信息性状态码
100: ('continue',),
101: ('switching_protocols',),
102: ('processing',),
103: ('checkpoint',),
122: ('uri_too_long', 'request_uri_too_long'),
# 成功状态码
200: ('ok', 'okay', 'all_ok', 'all_okay', 'all_good', '\\o/', '✓'),
201: ('created',),
202: ('accepted',),
203: ('non_authoritative_info', 'non_authoritative_information'),
204: ('no_content',),
205: ('reset_content', 'reset'),
206: ('partial_content', 'partial'),
207: ('multi_status', 'multiple_status', 'multi_stati', 'multiple_stati'),
208: ('already_reported',),
226: ('im_used',),
# Redirection.重定向
300: ('multiple_choices',),
301: ('moved_permanently', 'moved', '\\o-'),
302: ('found',),
303: ('see_other', 'other'),
304: ('not_modified',),
305: ('use_proxy',),
306: ('switch_proxy',),
307: ('temporary_redirect', 'temporary_moved', 'temporary'),
308: ('permanent_redirect',
'resume_incomplete', 'resume',), # These 2 to be removed in 3.0
# Client Error.客户端错误
400: ('bad_request', 'bad'),
401: ('unauthorized',),
402: ('payment_required', 'payment'),
403: ('forbidden',),
404: ('not_found', '-o-'),
405: ('method_not_allowed', 'not_allowed'),
406: ('not_acceptable',),
407: ('proxy_authentication_required', 'proxy_auth', 'proxy_authentication'),
408: ('request_timeout', 'timeout'),
409: ('conflict',),
410: ('gone',),
411: ('length_required',),
412: ('precondition_failed', 'precondition'),
413: ('request_entity_too_large',),
414: ('request_uri_too_large',),
415: ('unsupported_media_type', 'unsupported_media', 'media_type'),
416: ('requested_range_not_satisfiable', 'requested_range', 'range_not_satisfiable'),
417: ('expectation_failed',),
418: ('im_a_teapot', 'teapot', 'i_am_a_teapot'),
421: ('misdirected_request',),
422: ('unprocessable_entity', 'unprocessable'),
423: ('locked',),
424: ('failed_dependency', 'dependency'),
425: ('unordered_collection', 'unordered'),
426: ('upgrade_required', 'upgrade'),
428: ('precondition_required', 'precondition'),
429: ('too_many_requests', 'too_many'),
431: ('header_fields_too_large', 'fields_too_large'),
444: ('no_response', 'none'),
449: ('retry_with', 'retry'),
450: ('blocked_by_windows_parental_controls', 'parental_controls'),
451: ('unavailable_for_legal_reasons', 'legal_reasons'),
499: ('client_closed_request',),
# Server Error.服务端错误
500: ('internal_server_error', 'server_error', '/o\\', '✗'),
501: ('not_implemented',),
502: ('bad_gateway',),
503: ('service_unavailable', 'unavailable'),
504: ('gateway_timeout',),
505: ('http_version_not_supported', 'http_version'),
506: ('variant_also_negotiates',),
507: ('insufficient_storage',),
509: ('bandwidth_limit_exceeded', 'bandwidth'),
510: ('not_extended',),
511: ('network_authentication_required', 'network_auth', 'network_authentication'),
状态码用于判断请求是否成功，requests还提供了一个内置的状态码查询对象requests.codes。（两种写法都可以）
import requests response = requests.get('http://www.jianshu.com') exit() if not response.status_code == requests.codes.ok else print('Request Successfully') ################################### import requests response = requests.get('http://www.jianshu.com') exit() if not response.status_code == 200 else print('Request Successfully')
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