How do I read HTTP POST XML sent to CGI?

Ruby
1

Hello Ruby Masters,

I am a ruby newbie and tried to use a http client to send the XML HTTP
POST request to my cgi,
I thought I can get the text I input in the HTTP POST directly from the
$stdin as a string in cgi and extract the data out. but it didn’t seem
to work.

I tried to do $stdin.realines to parse every line of the $stdin but I
got nothing out of it.

Could anyone please advise ?

Thanks,
Erick

2

You don’t read from $stdin. Read this cgi tutorial:

Note that there is no distinction between POST and GET data when using
cgi: you read them the same way with your ruby script.

3

On Fri, Apr 29, 2011 at 10:46 PM, Ting C. [email protected] wrote:

Could anyone please advise ?

Are you using the cgi library from the stdlib?
If so, it reads the params from $stdin and gives you access to them
as a hash. Take a look at this example:

[Ruby Web Applications - CGI Programming]

#!/usr/bin/ruby

require ‘cgi’
cgi = CGI.new
h = cgi.params # => {“FirstName”=>[“Zara”],“LastName”=>[“Ali”]}
h[‘FirstName’] # => [“Zara”]
h[‘LastName’] # => [“Ali”]

It takes care of GET and POST parsing either the query string or the
POST body for you.

Hope this helps,

Jesus.

4

Thanks all, does that mean if I POST

apple
ipad

in the HTTP Client then I can read it in my cgi as:

#!/usr/bin/ruby

require ‘cgi’
cgi = CGI.new
h = cgi.params # => {“customer”=>[“apple”],“product”=>[“ipad”]}
h[‘customer’] # => [“apple”]
h[‘product’] # => [“ipad”]

Thanks!

5

On Sat, Apr 30, 2011 at 05:46:50AM +0900, Ting C. wrote:

Could anyone please advise ?

Use the CGI library.

require 'cgi'
cgi = CGI.new
cgi['parameter_name']

Note: This is from memory. I have not tested it.

6

I am using this tool:

and simply post Text input with the Method and URL specified only.
And the text content I input is:.

www.xxxurl.com DATA_TYPE IMAGE

I wish in the cgi code to extract the URL and the option values out but
by following the reference above I cannot get it work.

7

Ting C. wrote in post #995885:

I am using this tool:
soft-net.net
and simply post Text input with the Method and URL specified only.
And the text content I input is:.

www.xxxurl.com DATA_TYPE IMAGE

I wish in the cgi code to extract the URL and the option values out but
by following the reference above I cannot get it work.

Post your ruby code.

8

well… i only followed the instruction. trying to see if those
parameters came in

#!/usr/local/bin/ruby
require “cgi”

cgi = CGI.new

h = cgi.params
puts h[‘URL’]
puts h[‘VALUE’]

puts cgi[‘PARAMETER’]

9

Ting C. wrote in post #995889:

well… i only followed the instruction. trying to see if those
parameters came in

Nobody on the ruby forum has any idea what your software does with this:

www.xxxurl.com DATA_TYPE IMAGE

A request containing post data is sent to the server with name/value
pairs in the body of the request. Maybe your
software interprets that xml as an instruction to send a request to
www.xxxurl.com, with the name/value pairs DATA_TYPE=IMAGE.

By the way, you can also get the individual parameters like this:

puts cgi[“DATA_TYPE”]

And you might want to do a:

p cgi.params

to see if you get any post data.

10

Sorry about misleading, I think my problem is that I cannot get any POST
data in my CGI, I tried your suggestion above and looks like the POST
data did not come through.

do you know what’s possibly the reason?
or do you have any format recommend in the POST data? the only thing
that matter to me is to get the url data so my cgi script can take that
url to do the rest of the work.

Thanks!

11

On Sat, 30 Apr 2011, Ting C. wrote:

Sorry about misleading, I think my problem is that I cannot get any POST
data in my CGI, I tried your suggestion above and looks like the POST
data did not come through.

do you know what’s possibly the reason?
or do you have any format recommend in the POST data? the only thing
that matter to me is to get the url data so my cgi script can take that
url to do the rest of the work.

Did you read this:

12

On Sat, Apr 30, 2011 at 09:21:55AM +0900, Ting C. wrote:

Sorry about misleading, I think my problem is that I cannot get any POST
data in my CGI, I tried your suggestion above and looks like the POST
data did not come through.

do you know what’s possibly the reason?
or do you have any format recommend in the POST data? the only thing
that matter to me is to get the url data so my cgi script can take that
url to do the rest of the work.

Try this as a way to diagnose the issue:

require 'cgi'
cgi = CGI.new
cgi.params.each_pair {|k,v| puts k + ' => ' + v }

That should tell you exactly what parameter keys and values are being
sent to your Ruby script. If you’re actually viewing the output in the
browser, you might want to try adding some markup:

require 'cgi'
cgi = CGI.new
puts "<ul>"
cgi.params.each_pair {|k,v| puts "<li>#{k} => #{v}</li>" }
puts "</ul>"
13

On Sat, Apr 30, 2011 at 06:54:36AM +0900, Ting C. wrote:

cgi = CGI.new
h = cgi.params # => {“customer”=>[“apple”],“product”=>[“ipad”]}
h[‘customer’] # => [“apple”]
h[‘product’] # => [“ipad”]

Show us an example of how you’re posting the data.

14

Ting C. wrote in post #995897:

Sorry about misleading, I think my problem is that I cannot get any POST
data in my CGI, I tried your suggestion above and looks like the POST
data did not come through.

do you know what’s possibly the reason?

Do you have to use that request software? You can easily test whether
your server’s cgi gateway is working by using a ruby script to send the
post request:

require ‘net/http’
require ‘uri’

url = URI.parse(‘http://www.somehost.com/some_page’)
#That should be the url to your cgi script

data = {
‘my_url’ => ‘http://www.some_site.com’
}
#That hash should include all name/value pairs you
#want to send to the server

response = Net::HTTP.post_form(url, data)

puts response.body

That will also work if both scripts are on localhost–just start up your
server script, then in a different terminal window execute your request
script.

You should start by writing a cgi script that just echos back the info
it received, like Chad P. showed you. Once you know that everything
is working correctly with the cgi gateway, then you can figure out why
your original script isn’t working.