資料爬蟲(三):python中requests庫使用方法詳解
一、什麼是Requests
Requests 是⽤Python語⾔編寫,基於urllib,採⽤Apache2 Licensed開源協議的 HTTP 庫。它⽐ urllib 更加⽅便,可以節約我們⼤量的⼯作,完全滿⾜HTTP測試需求。
⼀句話——Python實現的簡單易⽤的HTTP庫
二、安裝Requests庫
進入命令列win+R執行
命令:pip install requests
專案匯入:import requests
三、各種請求方式
直接上程式碼,不明白可以檢視我的urllib的基本使用方法
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')
這麼多請求方式,都有什麼含義,所以問下度娘:
- GET: 請求指定的頁面資訊,並返回實體主體。
- HEAD: 只請求頁面的首部。
- POST: 請求伺服器接受所指定的文件作為對所標識的URI的新的從屬實體。
- PUT: 從客戶端向伺服器傳送的資料取代指定的文件的內容。
- DELETE: 請求伺服器刪除指定的頁面。
- get 和 post比較常見 GET請求將提交的資料放置在HTTP請求協議頭中
- POST提交的資料則放在實體資料中
(1)、基本的GET請求
import requests response = requests.get('http://httpbin.org/get') print(response.text)
返回值:
{ "args": {}, "headers": { "Accept": "*/*", "Accept-Encoding": "gzip, deflate", "Connection": "close", "Host": "httpbin.org", "User-Agent": "python-requests/2.18.4" }, "origin": "183.64.61.29", "url": "http://httpbin.org/get" }
(2)、帶引數的GET請求
將name和age傳進去
import requests response = requests.get("http://httpbin.org/get?name=germey&age=22") print(response.text)
{ "args": { "age": "22", "name": "germey" }, "headers": { "Accept": "*/*", "Accept-Encoding": "gzip, deflate", "Connection": "close", "Host": "httpbin.org", "User-Agent": "python-requests/2.18.4" }, "origin": "183.64.61.29", "url": "http://httpbin.org/get?name=germey&age=22" }
或者使用params的方法:
import requests data = { 'name': 'germey', 'age': 22 } response = requests.get("http://httpbin.org/get", params=data) print(response.text)
返回值一樣
(3)、解析json
將返回值已json的形式展示:
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()))
返回值:
<class 'str'> {'args': {}, 'headers': {'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate', 'Connection': 'close', 'Host': 'httpbin.org', 'User-Agent': 'python-requests/2.18.4'}, 'origin': '183.64.61.29', 'url': 'http://httpbin.org/get'} {'args': {}, 'headers': {'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate', 'Connection': 'close', 'Host': 'httpbin.org', 'User-Agent': 'python-requests/2.18.4'}, 'origin': '183.64.61.29', 'url': 'http://httpbin.org/get'} <class 'dict'>
(4)、獲取二進位制資料
記住返回值.content就ok了
import requests response = requests.get("https://github.com/favicon.ico") print(type(response.text), type(response.content)) print(response.text) print(response.content)
返回值為二進位制不必再進行展示,
(5)、新增headers
有些網站訪問時必須帶有瀏覽器等資訊,如果不傳入headers就會報錯,如下
import requests response = requests.get("https://www.zhihu.com/explore") print(response.text)
返回值:
<html><body><h1>500 Server Error</h1> An internal server error occured. </body></html>
當傳入headers時:
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)
成功返回網頁原始碼不做展示
(6)、基本POST請求
不明白見我博文urllib的使用方法
import requests data = {'name': 'germey', 'age': '22'} response = requests.post("http://httpbin.org/post", data=data) print(response.text)
返回:
{ "args": {}, "data": "", "files": {}, "form": { "age": "22", "name": "germey" }, "headers": { "Accept": "*/*", "Accept-Encoding": "gzip, deflate", "Connection": "close", "Content-Length": "18", "Content-Type": "application/x-www-form-urlencoded", "Host": "httpbin.org", "User-Agent": "python-requests/2.18.4" }, "json": null, "origin": "183.64.61.29", "url": "http://httpbin.org/post" }
三、響應
response屬性
import requests response = requests.get('http://www.jianshu.com') print(type(response.status_code), response.status_code) print(type(response.headers), response.headers) print(type(response.cookies), response.cookies) print(type(response.url), response.url) print(type(response.history), response.history)
return:
<class 'int'> 200 <class 'requests.structures.CaseInsensitiveDict'> {'Date': 'Thu, 01 Feb 2018 20:47:08 GMT', 'Server': 'Tengine', 'Content-Type': 'text/html; charset=utf-8', 'Transfer-Encoding': 'chunked', 'X-Frame-Options': 'DENY', 'X-XSS-Protection': '1; mode=block', 'X-Content-Type-Options': 'nosniff', 'ETag': 'W/"9f70e869e7cce214b6e9d90f4ceaa53d"', 'Cache-Control': 'max-age=0, private, must-revalidate', 'Set-Cookie': 'locale=zh-CN; path=/', 'X-Request-Id': '366f4cba-8414-4841-bfe2-792aeb8cf302', 'X-Runtime': '0.008350', 'Content-Encoding': 'gzip', 'X-Via': '1.1 gjf22:8 (Cdn Cache Server V2.0), 1.1 PSzqstdx2ps251:10 (Cdn Cache Server V2.0)', 'Connection': 'keep-alive'} <class 'requests.cookies.RequestsCookieJar'> <RequestsCookieJar[<Cookie locale=zh-CN for www.jianshu.com/>]> <class 'str'> https://www.jianshu.com/ <class 'list'> [<Response [301]>]
狀態碼判斷:常見的網頁狀態碼:
100: ('continue',), 101: ('switching_protocols',), 102: ('processing',), 103: ('checkpoint',), 122: ('uri_too_long', 'request_uri_too_long'), 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. 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. 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. 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'),
四、高階操作
(1)、檔案上傳
使用 Requests 模組,上傳檔案也是如此簡單的,檔案的型別會自動進行處理:
例項:
import requests files = {'file': open('cookie.txt', 'rb')} response = requests.post("http://httpbin.org/post", files=files) print(response.text)
這是通過測試網站做的一個測試,返回值如下:
{ "args": {}, "data": "", "files": { "file": "#LWP-Cookies-2.0\r\nSet-Cookie3: BAIDUID=\"D2B4E137DE67E271D87F03A8A15DC459:FG=1\"; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; expires=\"2086-02-13 11:15:12Z\"; version=0\r\nSet-Cookie3: BIDUPSID=D2B4E137DE67E271D87F03A8A15DC459; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; expires=\"2086-02-13 11:15:12Z\"; version=0\r\nSet-Cookie3: H_PS_PSSID=25641_1465_21087_17001_22159; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; discard; version=0\r\nSet-Cookie3: PSTM=1516953672; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; expires=\"2086-02-13 11:15:12Z\"; version=0\r\nSet-Cookie3: BDSVRTM=0; path=\"/\"; domain=\"www.baidu.com\"; path_spec; discard; version=0\r\nSet-Cookie3: BD_HOME=0; path=\"/\"; domain=\"www.baidu.com\"; path_spec; discard; version=0\r\n" }, "form": {}, "headers": { "Accept": "*/*", "Accept-Encoding": "gzip, deflate", "Connection": "close", "Content-Length": "909", "Content-Type": "multipart/form-data; boundary=84835f570cfa44da8f4a062b097cad49", "Host": "httpbin.org", "User-Agent": "python-requests/2.18.4" }, "json": null, "origin": "183.64.61.29", "url": "http://httpbin.org/post" }
(2)、獲取cookie
當需要cookie時,直接呼叫response.cookie:(response為請求後的返回值)
import requests response = requests.get("https://www.baidu.com") print(response.cookies) for key, value in response.cookies.items(): print(key + '=' + value)
輸出結果:
<RequestsCookieJar[<Cookie BDORZ=27315 for .baidu.com/>]> BDORZ=27315
(3)、會話維持、模擬登陸
如果某個響應中包含一些Cookie,你可以快速訪問它們:
import requests r = requests.get('http://www.google.com.hk/') print(r.cookies['NID']) print(tuple(r.cookies))
要想傳送你的cookies到伺服器,可以使用 cookies 引數:
import requests url = 'http://httpbin.org/cookies' cookies = {'testCookies_1': 'Hello_Python3', 'testCookies_2': 'Hello_Requests'} # 在Cookie Version 0中規定空格、方括號、圓括號、等於號、逗號、雙引號、斜槓、問號、@,冒號,分號等特殊符號都不能作為Cookie的內容。 r = requests.get(url, cookies=cookies) print(r.json())
(4)、證書驗證
因為12306有一個錯誤證書,我們那它的網站做測試會出現下面的情況,證書不是官方證書,瀏覽器會識別出一個錯誤
import requests response = requests.get('https://www.12306.cn') print(response.status_code)
返回值:
怎麼正常進入這樣的網站了,程式碼如下:
import requests from requests.packages import urllib3 urllib3.disable_warnings() response = requests.get('https://www.12306.cn', verify=False) print(response.status_code)
將verify設定位False即可,返回的狀態碼為200
urllib3.disable_warnings()這條命令主要用於消除警告資訊
(5)、代理設定
在進行爬蟲爬取時,有時候爬蟲會被伺服器給遮蔽掉,這時採用的方法主要有降低訪問時間,通過代理ip訪問,如下:
import requests proxies = { "http": "http://127.0.0.1:9743", "https": "https://127.0.0.1:9743", } response = requests.get("https://www.taobao.com", proxies=proxies) print(response.status_code)
ip可以從網上抓取,或者某寶購買
如果代理需要設定賬戶名和密碼,只需要將字典更改為如下: proxies = { "http":"http://user:[email protected]:9999" } 如果你的代理是通過sokces這種方式則需要pip install "requests[socks]" proxies= { "http":"socks5://127.0.0.1:9999", "https":"sockes5://127.0.0.1:8888" }
(6)、超時設定
訪問有些網站時可能會超時,這時設定好timeout就可以解決這個問題
import requests from requests.exceptions import ReadTimeout try: response = requests.get("http://httpbin.org/get", timeout = 0.5) print(response.status_code) except ReadTimeout: print('Timeout')
正常訪問,狀態嗎返回200
(7)、認證設定
如果碰到需要認證的網站可以通過requests.auth模組實現
import requests from requests.auth import HTTPBasicAuth response = requests.get("http://120.27.34.24:9001/",auth=HTTPBasicAuth("user","123")) print(response.status_code)
當然這裡還有一種方式
import requests response = requests.get("http://120.27.34.24:9001/",auth=("user","123")) print(response.status_code)
(8)、異常處理
遇到網路問題(如:DNS查詢失敗、拒絕連線等)時,Requests會丟擲一個ConnectionError 異常。
遇到罕見的無效HTTP響應時,Requests則會丟擲一個 HTTPError 異常。
若請求超時,則丟擲一個 Timeout 異常。
若請求超過了設定的最大重定向次數,則會丟擲一個 TooManyRedirects 異常。
所有Requests顯式丟擲的異常都繼承自 requests.exceptions.RequestException 。