Python CGI: How to redirect to another page after processing POST data

问题

I'm trying to write a Python script, in pyscripts/find_match.py that will process data received from a POST in an upload.php page, send it to connect.php and then redirect to another PHP page, response.php that will display information based on my processed data and that has an

<?php include '/connect_database.php';?>

line.

Up till now, I am able to get the POST info, process it and send it through a JSON to connect.php, but I am not able to make find_match.py redirect to response.php. My code looks like this:

In pyscripts/find_match.py:

print "Content-type: text/html"
print
print "<html><head>"
print "</head><body>"
import cgi
import cgitb
cgitb.enable()

try:
    form = cgi.FieldStorage()
    fn = form.getvalue('picture_name')
    cat_id = form.getvalue('selected')
except KeyError:
    print 'error'
else:
    # code to process data here

    data_to_be_displayed = # data to be used in connect.php; it's an array of ids

    import httplib, json, urllib2
    headers = {'Content-type': 'application/json', 'Accept': 'text/plain'}
    conn = httplib.HTTPConnection('192.168.56.101:80')
    #converting list to a json stream
    data_to_be_displayed = json.dumps(data_to_be_displayed, ensure_ascii = 'False')
    conn.request("POST", "/connect_database.php", data_to_be_displayed, headers)
    response = conn.getresponse()
    text = response.read()
    # print response.status, text
    conn.close()

    # WHAT I WANT TOT DO HERE
    if response.status == 200:
        redirect('/response.php')
print "</body></html>"

In response.php:

<!DOCTYPE html>
<html>

<head>
    <title>Response Page</title>
</head>
<body>
        <div id="main">
            <?php include '/connect_database.php';?>
        </div>
</body>
</html>

I have found some info about the urllib.HTTPRequestHandler class and the Location header, but I don't know how to use them. Tried using

<meta http-equiv="refresh" content="0;url=%s" />

in the HEAD tag, but it doesn't work. Please help.

回答1:

I wish people didn't keep trying to write CGI in 2014.

To redirect in a plain CGI application, you just need to output the destination next to a "Location:" header. However, you have already closed the headers and printed a blank HTML document at the top of your script. Don't do that: it's not only wrong for the redirection, it's also wrong for your alternative path, the form error, since you have already closed the HTML tags.

Instead, start your script like this:

# No printing at the start!
import cgi
...

try:
    form = cgi.FieldStorage()
    fn = form.getvalue('picture_name')
    cat_id = form.getvalue('selected')
except KeyError:
    print "Content-type: text/html"
    print
    print "<html><body>error</body></html>"
else:
    ...
    if response.status == 200:
        print "Location: response.php"

回答2:

1) Where is the shebang? (#!/usr/bin/env python)

2) print 'error' is a problem. cgi scripts stdout is the browser, the word 'error' will be problematic.

3) chmod 755 the script

I throw more redirects than webpages, here is the function I use.

def togo(location):
    print "HTTP/1.1 302 Found"
    print "Location: ",location,"\r\n"
    print "Connection: close \r\n"
    print ""

I don't know if that last print statement is needed, and the Connection close header seems to be optional to most clients, but I leave it because it is supposed to be in there, I think. RFC reading tends to put me right to sleep.

When I first write cgi scripts, I don't use cgi.FieldStorage, I hardcode the values so I can test it on the command line, after I get that working, I try it in a browser with the hard coded values, when that's working I add in the cgi.FieldStorage.

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