How to control input of an external program?

klactose has asked for the wisdom of the Perl Monks concerning the following question:

Hello monks,

Although I've used the site for tips for about a year, this is my first posting, so excuse me if I am not following correct protocol.

I have a problem that I can't figure out. I am programming in a windows environment, and I am trying to write a simple script that will run several curl commands.

My problem occurs when I run a curl command that needs a response (example "Enter host password for user 'username':").

I can't figure out how to actually send the password to curl.

I've tried several different methods but none have worked for me. Here is a snippet from my latest attempt:

my ($pid, $writeme);
for(0..4){
    $pid = open $writeme, "|-",
        "c:\\apps\\curl\\curl -u user$_ -X DELETE http://localhost:300
+0/site/users/user$_";
    sleep 2;
    print $writeme "password$_\r"; #curl isn't receiving this input
    close $writeme; #perl hangs here
    sleep 1;
}
[download]

The password that I send by printing to $writeme isn't being seen by curl for some reason, which leaves curl in a "waiting for input state".

If anyone could show me how I can fix this, I would be immensely grateful.

Thanks!

Comment on How to control input of an external program? Download Code

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Re: How to control input of an external program? by gmargo (Hermit) on Nov 09, 2009 at 19:34 UTC
What's wrong with specifying the user/password on the command line? Save yourself the pain. From the man page: `-u/--user <user:password>` [download]	[reply] [d/l]
Re^2: How to control input of an external program? by klactose (Initiate) on Nov 09, 2009 at 19:47 UTC
that will work for this specific instance, but what about in general?	[reply]
Re^3: How to control input of an external program? by ikegami (Patriarch) on Nov 09, 2009 at 20:06 UTC
You already have the general solution. (Send the input to the program's STDIN.) You're asking for a specific solution. (For some reason, `curl` reads the password from the tty, not STDIN.)	[reply] [d/l]
Re: How to control input of an external program? by ikegami (Patriarch) on Nov 09, 2009 at 19:43 UTC
The curl library can be accessed from Perl more directly via WWW::Curl, WWW::Curl::Simple and LWP::Curl. You should check if any of those fulfill your needs. There's also LWP available to you, the standard Perl web module.	[reply]
Re^2: How to control input of an external program? by klactose (Initiate) on Nov 09, 2009 at 19:52 UTC
Thanks, I will look into the Curl modules, didn't realize that Perl had any. I did look into LWP but I couldn't find info about support for the full range of HTTP methods, only for POST/GET. Perhaps I didn't look long enough!	[reply]
Re^3: How to control input of an external program? by ikegami (Patriarch) on Nov 09, 2009 at 20:03 UTC
I don't know what you made you think that some methods aren't accepted, but testing shows DELETE is accepted `$ perl -MHTTP::Request -e' print HTTP::Request->new( DELETE => "http://..." )->as_string ' DELETE http://...` [download]	[reply] [d/l]
Re^4: How to control input of an external program? by klactose (Initiate) on Nov 09, 2009 at 20:35 UTC
Re: How to control input of an external program? by ikegami (Patriarch) on Nov 09, 2009 at 20:10 UTC
I just noticed you're sending \r instead of \n as you should. That could cause curl to hang.	[reply]
Re^2: How to control input of an external program? by klactose (Initiate) on Nov 09, 2009 at 20:26 UTC
I tried \n first, but had the same result, \r was just the latest attempt at the time... haha... As I mentioned I was running into a dead end =)	[reply]
Re: How to control input of an external program? by Khen1950fx (Canon) on Nov 09, 2009 at 22:10 UTC
If you use WWW::Curl, you'll want to read the tutorial for libcurl. I just looked over the tutorial, and I see three easy ways to do passwords: `protocol://user:password@example.com/path/` This appears to be the standard method for giving the password. You could also do: `curl_easy_setopt(easyhandle, CURLOPT_USERPWD, "myname:thesecret");` or `curl_easy_setopt(easyhandle, CURLOPT_PROXYUSERPWD, "myname:thesecret");`	[reply] [d/l] [select]