为什么type('string')似乎在python cgi中返回null字符串

Question

我正在阅读Mark Lutz的Programming Python 3rd editon,我对一个问题很困惑:type('something')总是会产生一个空字符串.

有人可以解释一下吗？

上下文信息:

我在脚本中添加了一行 $CODEROOT\pp3e\Internet\Web\cgi-bin\tutor0.py

#!/usr/bin/python
#######################################################
# runs on the server, prints html to create a new page;
# url=http://localhost/cgi-bin/tutor0.py
#######################################################

print "Content-type: text/html\n"
print "<TITLE>CGI 101</TITLE>"
print "<H1>A First CGI script</H1>"
print '<p>[%s]'%type('apple') # ? I add this line
print "<P>Hello, CGI World!</P>"

对于添加的行,我希望在浏览器中看到[<type 'str'>],但我实际上看到了[].

启动HTTP服务器的python是 $CODEROOT\pp3e\Internet\Web\webserver.py

#########################################################################
# implement HTTP web server in Python which knows how to serve HTML
# pages and run server side CGI scripts;  serves files/scripts from
# the current working dir and port 80, unless command-line args;
# python scripts must be stored in webdir\cgi-bin or webdir\htbin;
# more than one of these may be running on the same machine to serve
# from different directories, as long as they listen on different ports;
#########################################################################

webdir = '.'   # where your html files and cgi-bin script directory live
port   = 80    # http://servername/ if 80, else use http://servername:xxxx/

import os, sys
from BaseHTTPServer import HTTPServer
from CGIHTTPServer  import CGIHTTPRequestHandler

if len(sys.argv) > 1: webdir = sys.argv[1]             # command-line args
if len(sys.argv) > 2: port   = int(sys.argv[2])        # else dafault ., 80
print 'webdir "%s", port %s' % (webdir, port)

# hack for Windows: os.environ not propogated
# to subprocess by os.popen2, force in-process
if sys.platform[:3] == 'win':
    CGIHTTPRequestHandler.have_popen2 = False
    CGIHTTPRequestHandler.have_popen3 = False          # emulate path after fork
    sys.path.append('cgi-bin')                         # else only adds my dir

os.chdir(webdir)                                       # run in html root dir
srvraddr = ("", port)                                  # my hostname, portnumber
srvrobj  = HTTPServer(srvraddr, CGIHTTPRequestHandler)
srvrobj.serve_forever()                                # serve clients till exit

我的环境:

• Python 2.7
• Windows 7 x64

Answer 1

可能是因为尖括号<type 'str'>导致输出被视为HTML.

尝试改变:

print '<p>[%s]'%type('apple') # ? I add this line

成:

hstr = "%s"%type('apple')
hstr = hstr.replace('<','&lt;').replace('>','&gt;')
print '<p>[%s]'%hstr