最近学习了Fiddler抓包工具的简单使用，通过抓包，我们可以抓取到HTTP请求，并对其进行分析。现在我准备尝试着结合Python来模拟GitHub登录。
Fiddler抓包分析
首先，我们想要模拟一个网站的登录，我们必须要简单了解其大致过程。
在这里，我通过Fiddler来抓取GitHub登录的请求，从网页上登录的URL为： https://github.com/login ，抓包结果如下：
<tt-image data-tteditor-tag="tteditorTag" contenteditable="false" class="syl1563086356110" data-render-status="finished" data-syl-blot="image" style="box-sizing: border-box; cursor: text; color: rgb(34, 34, 34); font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", "Helvetica Neue", Arial, sans-serif; font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: pre-wrap; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial; display: block;">
image
<input class="pgc-img-caption-ipt" placeholder="图片描述(最多50字)" value="" style="box-sizing: border-box; outline: 0px; color: rgb(102, 102, 102); position: absolute; left: 187.5px; transform: translateX(-50%); padding: 6px 7px; max-width: 100%; width: 375px; text-align: center; cursor: text; font-size: 12px; line-height: 1.5; background-color: rgb(255, 255, 255); background-image: none; border: 0px solid rgb(217, 217, 217); border-radius: 4px; transition: all 0.2s cubic-bezier(0.645, 0.045, 0.355, 1) 0s;"></tt-image>
左边的是会话列表，右边的是请求和响应的数据。一般情况下，登录都是用POST请求，因为我在左边的会话列表中设置了显示RequestMethod一列，因此能够很方便的找到POST请求。当然，Fiddler默认不显示RequestMethod，如果没有设置，还可以通过命令“=post”来快速过滤POST请求。
<tt-image data-tteditor-tag="tteditorTag" contenteditable="false" class="syl1563086356113" data-render-status="finished" data-syl-blot="image" style="box-sizing: border-box; cursor: text; color: rgb(34, 34, 34); font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", "Helvetica Neue", Arial, sans-serif; font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: pre-wrap; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial; display: block;">
image
<input class="pgc-img-caption-ipt" placeholder="图片描述(最多50字)" value="" style="box-sizing: border-box; outline: 0px; color: rgb(102, 102, 102); position: absolute; left: 187.5px; transform: translateX(-50%); padding: 6px 7px; max-width: 100%; width: 375px; text-align: center; cursor: text; font-size: 12px; line-height: 1.5; background-color: rgb(255, 255, 255); background-image: none; border: 0px solid rgb(217, 217, 217); border-radius: 4px; transition: all 0.2s cubic-bezier(0.645, 0.045, 0.355, 1) 0s;"></tt-image>
在GitHub登录时，我们通过抓包发现，GitHub登录的URL虽然时https://github.com/login，但发生了302重定向，其真正提交POST表单数据的URL是 https://github.com/session ，当登录成功时，则会跳转到 https://github.com/ 首页。
打开WebForm，我们可以看到POST表单数据提交的值，可以发现，只有authenticity_token、login、password三个字段是会变化的，其余的每次登录都是固定的值。而login、password分别是我们登录的用户和密码，因此我们只需要分析出 authenticity_token 从何而来，便可以实现模拟登录了。
至于如何确定 authenticity_token 从哪个页面返回的，我们直接在响应数据中搜索就行了，或者把数据复制出来再进行搜索。最后我们会发现，authenticity_token 是在 https://github.com/login 这个请求中返回的，只不过用 hidden 隐藏起来了。
<tt-image data-tteditor-tag="tteditorTag" contenteditable="false" class="syl1563086356115" data-render-status="finished" data-syl-blot="image" style="box-sizing: border-box; cursor: text; color: rgb(34, 34, 34); font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", "Helvetica Neue", Arial, sans-serif; font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: pre-wrap; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial; display: block;">
image
<input class="pgc-img-caption-ipt" placeholder="图片描述(最多50字)" value="" style="box-sizing: border-box; outline: 0px; color: rgb(102, 102, 102); position: absolute; left: 187.5px; transform: translateX(-50%); padding: 6px 7px; max-width: 100%; width: 375px; text-align: center; cursor: text; font-size: 12px; line-height: 1.5; background-color: rgb(255, 255, 255); background-image: none; border: 0px solid rgb(217, 217, 217); border-radius: 4px; transition: all 0.2s cubic-bezier(0.645, 0.045, 0.355, 1) 0s;"></tt-image>
好了，到目前大致流程我们已经梳理清楚了，接下来我们便通过Python来实现模拟GitHub登录。
代码实现
本人环境：PyCharm 2018.2.4、Python3.7.0
1. 设置请求头和Session
<pre spellcheck="false" style="box-sizing: border-box; margin: 5px 0px; padding: 5px 10px; border: 0px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-weight: 400; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: inherit; vertical-align: baseline; cursor: text; counter-reset: list-1 0 list-2 0 list-3 0 list-4 0 list-5 0 list-6 0 list-7 0 list-8 0 list-9 0; background-color: rgb(240, 240, 240); border-radius: 3px; white-space: pre-wrap; color: rgb(34, 34, 34); letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;"># 设置Session
self.s = requests.session()
# 设置请求头
self.headers = {
"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:44.0) Gecko/20100101 Firefox/44.0"
}
# 在使用Fiddler时进行请求，通过该代码忽略SSLError错误
self.s.verify = False
</pre>
在这里，我们设置了Session会话对象，Session相当于1个微型浏览器，能够自动帮我们保持请求中的某些参数（如cookies），有了它，我们一般不需要额外去处理cookies、header等。
假如我们是在Fiddler打开的状态下，通过代码进行请求，那么将会遇到SSLError的错误，而当加上 self.s.verify = False 这行代码后，我们便可以忽略该错误。
<pre spellcheck="false" style="box-sizing: border-box; margin: 5px 0px; padding: 5px 10px; border: 0px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-weight: 400; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: inherit; vertical-align: baseline; cursor: text; counter-reset: list-1 0 list-2 0 list-3 0 list-4 0 list-5 0 list-6 0 list-7 0 list-8 0 list-9 0; background-color: rgb(240, 240, 240); border-radius: 3px; white-space: pre-wrap; color: rgb(34, 34, 34); letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">requests.exceptions.SSLError: HTTPSConnectionPool(host='github.com', port=443): Max retries exceeded with url: /login (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1045)')))
</pre>
注意：
我们通过上面的代码忽略了SSLError的错误后，再次运行，这时仍然会出现2行警告，这2个警告并不影响我们的登录，可以不管它。
<pre spellcheck="false" style="box-sizing: border-box; margin: 5px 0px; padding: 5px 10px; border: 0px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-weight: 400; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: inherit; vertical-align: baseline; cursor: text; counter-reset: list-1 0 list-2 0 list-3 0 list-4 0 list-5 0 list-6 0 list-7 0 list-8 0 list-9 0; background-color: rgb(240, 240, 240); border-radius: 3px; white-space: pre-wrap; color: rgb(34, 34, 34); letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">D:\Python\installation\lib\site-packages\urllib3\connectionpool.py:847: InsecureRequestWarning: Unverified HTTPS request is being made. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#ssl-warnings
InsecureRequestWarning)
D:\Python\installation\lib\site-packages\urllib3\connectionpool.py:847: InsecureRequestWarning: Unverified HTTPS request is being made. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#ssl-warnings
InsecureRequestWarning)
</pre>
如果我们想去掉这2行警告，也可以通过如下代码来解决（针对Python3）：
<pre spellcheck="false" style="box-sizing: border-box; margin: 5px 0px; padding: 5px 10px; border: 0px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-weight: 400; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: inherit; vertical-align: baseline; cursor: text; counter-reset: list-1 0 list-2 0 list-3 0 list-4 0 list-5 0 list-6 0 list-7 0 list-8 0 list-9 0; background-color: rgb(240, 240, 240); border-radius: 3px; white-space: pre-wrap; color: rgb(34, 34, 34); letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">import urllib3
urllib3.disable_warnings()
</pre>
2. 获取authenticity_token
<pre spellcheck="false" style="box-sizing: border-box; margin: 5px 0px; padding: 5px 10px; border: 0px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-weight: 400; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: inherit; vertical-align: baseline; cursor: text; counter-reset: list-1 0 list-2 0 list-3 0 list-4 0 list-5 0 list-6 0 list-7 0 list-8 0 list-9 0; background-color: rgb(240, 240, 240); border-radius: 3px; white-space: pre-wrap; color: rgb(34, 34, 34); letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">login_url = "https://github.com/login"
r = self.s.get(login_url, headers = self.headers)
authenticity_token = re.findall('<input type="hidden" name="authenticity_token" value="(.+?)" />', r.text)
print("authenticity_token：{}".format(authenticity_token))
return authenticity_token[1]
</pre>
当我们访问 https://github.com/login 时，登录界面会生成隐藏参数authenticity_token，而这恰是我们在登录提交表单时需要用到的参数。我们可通过正则表达式 re.findall 来获取authenticity_token。另外，我们还会发现，HTML界面中存在2个authenticity_token，因此通过正则返回的是一个长度为2的列表，经过分析，GitHub在登录时用到的是列表中的第二个元素，即authenticity_token[1]。
3. 模拟登录
<pre spellcheck="false" style="box-sizing: border-box; margin: 5px 0px; padding: 5px 10px; border: 0px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-weight: 400; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: inherit; vertical-align: baseline; cursor: text; counter-reset: list-1 0 list-2 0 list-3 0 list-4 0 list-5 0 list-6 0 list-7 0 list-8 0 list-9 0; background-color: rgb(240, 240, 240); border-radius: 3px; white-space: pre-wrap; color: rgb(34, 34, 34); letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">def github_login(self, authenticity_token, username, password):
session_url = "https://github.com/session"
body = {
"authenticity_token":authenticity_token,
"commit":"Sign in",
"login":username,
"password":password,
"utf8":"✓",
"webauthn-support":"unknown"
}
r = self.s.post(session_url, headers = self.headers, data = body)
title = re.findall('<title>(.+?)</title>',r.text)
print("title：%s" %title[0])
return title[0]
</pre>
我们在上面得到authenticity_token后，便可以来实现登录了。通过POST请求提交表单后，我们需要判断是否登录成功。在这里，我是通过页面的标题来判断GitHub是否登录成功，当然，还有许多方法可以用于判断。
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4. 通过 title 判断是否登录成功
<pre spellcheck="false" style="box-sizing: border-box; margin: 5px 0px; padding: 5px 10px; border: 0px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-weight: 400; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: inherit; vertical-align: baseline; cursor: text; counter-reset: list-1 0 list-2 0 list-3 0 list-4 0 list-5 0 list-6 0 list-7 0 list-8 0 list-9 0; background-color: rgb(240, 240, 240); border-radius: 3px; white-space: pre-wrap; color: rgb(34, 34, 34); letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">def is_login_success(self, title):
if "GitHub" == title:
return True
else:
return False
</pre>
GitHub登录成功后，界面的标题会显示"GitHub"，而登录失败时，一般显示的标题则是"Sign in to GitHub · GitHub"。
OK，以上就是通过Python模拟GitHub登录的过程，难度不大，相信大多数人阅读后都应该可以进行实践。
附源码：
<pre spellcheck="false" style="box-sizing: border-box; margin: 5px 0px; padding: 5px 10px; border: 0px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-weight: 400; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: inherit; vertical-align: baseline; cursor: text; counter-reset: list-1 0 list-2 0 list-3 0 list-4 0 list-5 0 list-6 0 list-7 0 list-8 0 list-9 0; background-color: rgb(240, 240, 240); border-radius: 3px; white-space: pre-wrap; color: rgb(34, 34, 34); letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">import requests
import re
import urllib3
urllib3.disable_warnings()
class Github_Login():
def init(self):
# 设置Session
self.s = requests.session()
# 设置请求头
self.headers = {
"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:44.0) Gecko/20100101 Firefox/44.0"
}
# 在使用Fiddler时进行请求，通过该代码忽略SSLError错误
self.s.verify = False
# 获取 authenticity_token
def get_authenticity_token(self):
login_url = "https://github.com/login"
r = self.s.get(login_url, headers = self.headers)
authenticity_token = re.findall('<input type="hidden" name="authenticity_token" value="(.+?)" />', r.text)
print("authenticity_token：{}".format(authenticity_token))
return authenticity_token[1]
# 模拟登录，并返回 title
def github_login(self, authenticity_token, username, password):
session_url = "https://github.com/session"
body = {
"authenticity_token":authenticity_token,
"commit":"Sign in",
"login":username,
"password":password,
"utf8":"✓",
"webauthn-support":"unknown"
}
r = self.s.post(session_url, headers = self.headers, data = body)
title = re.findall('<title>(.+?)</title>',r.text)
print("title：%s" %title[0])
return title[0]
# 通过 title 判断是否登录成功
def is_login_success(self, title):
if "GitHub" == title:
return True
else:
return False
if name == 'main':
github = Github_Login()
authenticity_token = github.get_authenticity_token()
title = github.github_login(authenticity_token, username = "用户名", password = "密码")
login_result = github.is_login_success(title)
print(login_result)
</pre>
如有错误，欢迎指出！
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