机械化 Python 和授权，而不会首先出现 401 错误

Question

我正在尝试使用 Mechanize 来自动与非常挑剔的遗留系统进行交互。特别是，在第一个登录页面之后，必须随每个请求发送授权，这会将您从系统中剔除。不幸的是，Mechanize 似乎只满足于在第一次收到 401 未经授权错误后才发送授权。有什么办法让它每次都发送授权吗？

下面是一些示例代码：

br.add_password("http://example.com/securepage", "USERNAME", "PASSWORD", "/MYREALM")
br.follow_link(link_to_secure_page) # where the url is the previous URL

这是我从调试 Mechanize 中得到的响应：

send: 'GET /securepage HTTP/1.1\r\nAccept-Encoding: identity\r\nHost: example.com\r\nReferer: http://example.com/home\r\nConnection: close\r\nUser-Agent: Python-urllib/2.7\r\n\r\n'
reply: 'HTTP/1.1 401 Unauthorized\r\n'
header: Server: Tandy1000Web
header: Date: Thu, 08 Dec 2011 03:08:04 GMT
header: Connection: close
header: Expires: Tue, 01 Jan 1980 06:00:00 GMT
header: Content-Type: text/html; charset=US-ASCII
header: Content-Length: 210
header: WWW-Authenticate: Basic realm="/MYREALM"
header: Cache-control: no-cache
send: 'GET /securepage HTTP/1.1\r\nAccept-Encoding: identity\r\nHost: example.com\r\nReferer: http://example.com/home\r\nConnection: close\r\nAuthorization: Basic VVNFUk5BTUU6UEFTU1dPUkQ=\r\nUser-Agent: Python-urllib/2.7\r\n\r\n'
reply: 'HTTP/1.1 200 OK\r\n'
header: Server: Tandy1000Web
header: Date: Thu, 08 Dec 2011 03:08:07 GMT
header: Connection: close
header: Last-Modified: Thu, 08 Dec 2011 03:08:06 GMT
header: Expires: Tue, 01 Jan 1980 06:00:00 GMT
header: Content-Type: text/html; charset=UTF-8
header: Content-Length: 33333
header: Cache-control: no-cache

问题是，与使用 GET 请求在现代 Web 应用程序中发生的情况相反，首先遇到 401 错误，我得到了错误的页面。我已经通过 CURL 和 urllib2 确认，如果我通过在第一个请求中传递 auth 标头来直接点击 URL，我会得到正确的页面。

关于如何告诉 mechanize 始终发送 auth 标头并避免第一个 401 错误的任何提示？这需要在客户端修复。我无法修改服务器。

Answer 1

from base64 import b64encode
import mechanize

url = 'http://192.168.3.5/table.js'
username = 'admin'
password = 'password'

# I have had to add a carriage return ('%s:%s\n'), but
# you may not have to.
b64login = b64encode('%s:%s' % (username, password))

br = mechanize.Browser()

# # I needed to change to Mozilla for mine, but most do not
# br.addheaders= [('User-agent', 'Mozilla/5.0')]

br.addheaders.append( 
  ('Authorization', 'Basic %s' % b64login )
)

br.open(url)
r = br.response()
data = r.read()

print data