Python Challenge[17]

[Level 17]

Title: eat?

图片就是提示了。饼干是cookies，cookie不仅仅是饼干。浏览器查看网页cookie，显示you+should+have+followed+busynothing...。busynothing，nothing，且左下角的图是第四关的图。从busynothing=12345开始，收集cookie中的info值。

import httplib2,re
h = httplib2.Http('.Cache')
url, num = 'http://www.pythonchallenge.com/pc/def/linkedlist.php?busynothing=', '12345'
pattern = re.compile('info=(.*)')
info = ''
while num.isdigit():
  resp,content=h.request(url+num)
  info += pattern.search(resp['set-cookie'].split(';')[0]).groups()[0]
  num = content.decode('utf-8').split(' ')[-1]
print(info)

info最终是一段以BZh91AY开头的字符串，使用bz2解压，异常终止，显示OSError: Invalid data stream。搜了下，这段字符需要转换：

import bz2,urllib.parse
info = urllib.parse.unquote_to_bytes(info.replace('+','%20'))
print(bz2.decompress(info).decode('utf-8'))#ascii

得到这么一段信息：

is it the 26th already? call his father and inform him that "the flowers are on their way". he'll understand.

his father指的是十五关莫扎特的父亲Leopold Mozart，call？phone，十三关的phone：

import xmlrpc.client
xmlrpc = xmlrpc.client.ServerProxy('http://www.pythonchallenge.com/pc/phonebook.php')
print(xmlrpc.phone('Leopold'))

得到555-VIOLIN。然而VIOLIN.html不存在，violin.html显示no! i mean yes! but ../stuff/violin.php.。violin.php显示一张照片，标题是it's me. what do you want?。前面提示inform him that "the flowers are on their way"，怎样inform？卡了下，是要把网页cookie中的info值设置为the flowers are on their way。

url = 'http://www.pythonchallenge.com/pc/stuff/violin.php'
headers = {'Cookie':'info=the flowers are on their way'}
print(h.request(url,headers=headers)[1].decode('utf-8'))

得到oh well, don't you dare to forget the balloons.，嗯，[Level 18]

小结

1. 使用httplib2库，cookie信息包含在httplib2.Http().request()返回的Response实例中。
2. 直接遍历得到的最终info值需要转义，使用urllib.parse.unquote()或urllib.parse.unquote_plus()方法返回的二进制对象均不能正常使用bz2解压。若要使用该方法，需要额外的参数：urllib.parse.unquote_plus(info,'latin1').encode('latin1')
3. 经urllib.parse.unquote_to_bytes(string)方法转换返回的对象可以正常解压，该方法功能是将%xx转义替换为其等效的single-octet字符（unquote_plus()和unquote()是单个字符），以字节对象返回。不像unquote_plus()能将+转为空格，unquote_to_bytes()需要手动替换。urllib库中文文档可参考Urllib库
4. 使用Http.request()设置cookie，cookie包含在headers中。headers={'Cookie': 'cookie_value'}

Python Challenge Wiki

1. 使用urllib库获取cookie信息。

import urllib.request
h = urllib.request.urlopen(url)
cookie = h.getheader('Set-Cookie')

或直接获取info值：

from urllib.request import build_opener,HTTPCookieProcessor,HTTPHandler
import http.cookiejar
cj = http.cookiejar.CookieJar()
opener = build_opener(HTTPCookieProcessor(cj),HTTPHandler)
f = opener.open(url)
for cookie in cj:
  print(cookie.value)

2. 设置cookie。

from urllib.request import Request, urlopen
from urllib.parse import quote_plus
req = Request(url, headers = { "Cookie": "info=" + quote_plus(msg)})
#print(urlopen(req).read().decode())

或者这样：

import urllib.request, urllib.parse
o = urllib.request.build_opener()
o.addheaders.append(('Cookie', 'info='+urllib.parse.quote_plus(msg)))
res = o.open(url)
#print(res.read().decode())

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