How to call another program

[David Grey]

How do you call another program from within the perl script
and not loose control. When I try:

#!/usr/bin/perl

$Query_File = $ENV{QUERY_STRING};

print "Location: http://www.domain.com/cgi-bin/copyprog.pl\n\n";

it goes to domain.com and that is the last it is heard from, and
for some reason you have to put something like:
$Query_File = $ENV{QUERY_STRING};

in or all you get is an error. I am sure there is a command that
allows you to call another program from another domain then
come back and finish the job. Can you use LWP::UserAgent;
to execute a program and then have the rest of the program
finish what it is doing afterward?

 

[Tony Curtis]

How do you call another program from within the perl script
and not loose control. When I try:

#!/usr/bin/perl

use strict;
use warnings;

$Query_File = $ENV{QUERY_STRING};

"perldoc CGI" to handle submitted data cleanly.

print "Location: http://www.domain.com/cgi-bin/copyprog.pl\n\n";

it goes to domain.com and that is the last it is heard from,

That's correct behaviour.

and for some reason you have to put something like:
$Query_File = $ENV{QUERY_STRING}; in or all you get is an
error.

I'm afraid that is nonsense.

I am sure there is a command that allows you to call another
program from another domain then come back and finish the
job. Can you use LWP::UserAgent; to execute a program and
then have the rest of the program finish what it is doing
afterward?

You don't "call another program", you submit data to a URL.
(There might be a program of some kind implementing the
response to you from wherever the request is handled, but that
is irrelevant.)

"perldoc lwpcook" has various examples for LWP. Construct the
request and send it off. Parse the response for what you need
and carry on processing...

hth
t

 

[Jürgen Exner]

How do you call another program from within the perl script

perldoc -f system
perldoc -f exec
perldoc perlop and look for qx
....

and not loose control.

Well, not sure what you mean by "loose control" but I'm guessing mabye you
want to execute you script and the other program in parallel? Then use
fork() to spawn a new process and then exec() to the other program in the
child process. That way the parent process can still do whatever it wants to
do.

When I try:

#!/usr/bin/perl

$Query_File = $ENV{QUERY_STRING};

print "Location: http://www.domain.com/cgi-bin/copyprog.pl\n\n";

it goes to domain.com and that is the last it is heard from, and
for some reason you have to put something like:
$Query_File = $ENV{QUERY_STRING};

in or all you get is an error. I am sure there is a command that
allows you to call another program from another domain

What is "call another program from another domain" supposed to mean?
There are no domains in Perl programs.

then
come back and finish the job. Can you use LWP::UserAgent;
to execute a program and then have the rest of the program
finish what it is doing afterward?

What does all this have to do with executing program?

jue

 

[David Grey]

perldoc -f system
perldoc -f exec
perldoc perlop and look for qx
...


Well, not sure what you mean by "loose control" but I'm guessing mabye you
want to execute you script and the other program in parallel? Then use
fork() to spawn a new process and then exec() to the other program in the
child process. That way the parent process can still do whatever it wants to
do.

Would this be getting close:

while (-1) {

sleep 3;
forktest();
sleep 12;
}

# The rest of the program below

sub forktest {

FORK: {

$Query_File = $ENV{QUERY_STRING};

print "Location: http://www.domain.com/cgi-bin/copyprog.pl\n\n";

} return;
}

 

[gnari]

[snip discussion about execution and fork]

forget about fork here. that only came up because you
were talking about 'executing a script', when what
you want to do is to submit a HTTP request in the
middle of a cgi process.

read Tony's post in this thread.

gnari

 

[David Grey]

[snip discussion about execution and fork]

forget about fork here. that only came up because you
were talking about 'executing a script', when what
you want to do is to submit a HTTP request in the
middle of a cgi process.

read Tony's post in this thread.

gnari

It does no good to tell me to go off someplace and look something
up when I have not a clue what you are saying in the first place,
and don't have a clue what to look for. We are talking about a
language here, and it would help if people could show a bit of code
what you are saying. It is like a christian telling someone it is right
in Psalms go look it up, well there are 150 chapters in Psalms
where do you start. (Stating a fact not trying to be gruff.)

What I need to do is have a script that runs a script first on the
doman.com that performs a function that has to be done first, then
continue the script to copy a file produced on the domain.com .
I want a file from the A machine to the B machine every time a
html page come up so the data is current every time. I have finally
worked out everything but running the script on domain.com
and continuing, it will do one or the other, but not both. The
running of the script on domain.com must happen first.

Reading Tony's post in this thread is gibberish, it has no meaning
at this point, I don't know what he said. What I need is:

Run script on domain.com

Wait long enough for that to finish

continue script

That's it, the run script on domain.com must happen first.

 

[A. Sinan Unur]

It does no good to tell me to go off someplace and look something
up when I have not a clue what you are saying in the first place,
and don't have a clue what to look for. We are talking about a
language here, and it would help if people could show a bit of code
what you are saying. It is like a christian telling someone it is right
in Psalms go look it up, well there are 150 chapters in Psalms
where do you start. (Stating a fact not trying to be gruff.)

What I need to do is have a script that runs a script first on the
doman.com that performs a function that has to be done first, then
continue the script to copy a file produced on the domain.com .
I want a file from the A machine to the B machine every time a
html page come up so the data is current every time.

Then write it using the examples provided in the docs you have been
referred to. If you have problems once you actually try to do your own
work, then you can come back and ask.

I have finally worked out everything

Apparently not. You have a lot of reading to do to understand how HTTP
works.

Reading Tony's post in this thread is gibberish, it has no meaning
at this point, I don't know what he said.

Nice attitude. That'll get you a lot of help around here.

What I need is:

Run script on domain.com

Wait long enough for that to finish

continue script

That's it, the run script on domain.com must happen first.

Did you actually take a look at:

http://search.cpan.org/~gaas/libwww-perl-5.79/lib/LWP/Simple.pm

You should also be able to access it on your computer using

perldoc LWP::Simple

If you have made it this far, the following might help:

#! perl

use strict;
use warnings;

$| = 1;

use CGI qw/ :cgi /;
$CGI:OST_MAX = 1024;
$CGI:ISABLE_UPLOADS = 1;

use HTML::Entities;
use LWP::Simple;

use Regexp::Common qw/ URI /;

my $url = param('url');
$url = (defined $url ? $url : '');

if( $url =~ /^$RE{URI}{HTTP}{-keep}$/ ) {
my $content = get($1);
if(defined $content) {
show_results(HTML::Entities::encode($content));
} else {
show_form();
}
} else {
show_form();
}


sub show_form {
print header();
print<<END;
<html>
<head><title>Get Source</title></head>
<body>
<form>
<p>
URL:&nbsp;<input type="text" name="url" size="40">
<input type="submit">
</form>
</p>
</body>
</html>
END

}

sub show_results {
my ($content) = @_;

print header();
print<<END;
<html>
<head><title>Got Source!</title></head>
<form>
<p>
URL:&nbsp;<input type="text" name="url" size="40">
<input type="submit">
</form>
<h1>Results from previous request</h1>
<pre>
$content
</pre>
</body>
</html>
END

}
__END__

 

[David Grey]

Did you actually take a look at:

http://search.cpan.org/~gaas/libwww-perl-5.79/lib/LWP/Simple.pm

You should also be able to access it on your computer using

perldoc LWP::Simple

If you have made it this far, the following might help:

#! perl

use strict;
use warnings;

$| = 1;

use CGI qw/ :cgi /;
$CGI:OST_MAX = 1024;
$CGI:ISABLE_UPLOADS = 1;

use HTML::Entities;
use LWP::Simple;

use Regexp::Common qw/ URI /;

my $url = param('url');
$url = (defined $url ? $url : '');

if( $url =~ /^$RE{URI}{HTTP}{-keep}$/ ) {
my $content = get($1);
if(defined $content) {
show_results(HTML::Entities::encode($content));
} else {
show_form();
}
} else {
show_form();
}

sub show_form {
print header();
print<<END;
<html>
<head><title>Get Source</title></head>
<body>
<form>
<p>
URL:&nbsp;<input type="text" name="url" size="40">
<input type="submit">
</form>
</p>
</body>
</html>
END

}

sub show_results {
my ($content) = @_;

print header();
print<<END;
<html>
<head><title>Got Source!</title></head>
<form>
<p>
URL:&nbsp;<input type="text" name="url" size="40">
<input type="submit">
</form>
<h1>Results from previous request</h1>
<pre>
$content
</pre>
</body>
</html>
END

}
__END__

-

That is not what I want to do (from what I can tell) I want to :

print "Location: http://www.domain.com/cgi-bin/copyprog.pl\n\n";

run this script before running the rest of the script. When I run the
above it goes off and does not run the rest of the script that this
is in.

 

[A. Sinan Unur]

That is not what I want to do (from what I can tell) I want to :

print "Location: http://www.domain.com/cgi-bin/copyprog.pl\n\n";

Why this attachment to the redirect?

run this script before running the rest of the script. When I run the
above it goes off and does not run the rest of the script that this
is in.

I see no indication that you have read any of the responses.
By definition, that line will _redirect_ the request to

http://www.domain.com/cgi-bin/copyprog.pl

That's it. Basically, you can't have your cake and eat it too. You are
telling the user's browser to go fetch a different page than yours and
you are wondering why she has left you.

Do you live in an area with high lead concentration?

 

[David Grey]

Why this attachment to the redirect?

I want it to run the script above. Redirect does it, but it wont run
the rest of the script. I don't know of any other way, that is why
I am here.

I see no indication that you have read any of the responses.

Reading a post in german does little to know what they said, I
said I had not a clue what they were saying and you took that
as an insult. If you don't know that they are saying, you don't
what they are saying period.

By definition, that line will _redirect_ the request to

http://www.domain.com/cgi-bin/copyprog.pl

That's it. Basically, you can't have your cake and eat it too. You are
telling the user's browser to go fetch a different page than yours and
you are wondering why she has left you.

I want the the script to run the above script, I don know any other
way, so far everyone instead of telling me says go look it
up yourself. If I don't know what to look up I can't look it up.

Do you live in an area with high lead concentration?

No just an area where you expect me to run before I even know
how to walk. If you want to just be abusive and not help, I'm
sure you would be welcomed in any flame group. I don't see the
point of it here, if I knew what I was doing I would not be here.

 

[A. Sinan Unur]

I want it to run the script above. Redirect does it, but it wont run
the rest of the script. I don't know of any other way, that is why
I am here.

I just showed you another way. Did you actually try that script out with
the URL you are interested in?

if I knew what I was doing I would not be here.

You need to at least know something about what you are doing and be
willing to learn and do some work on your own.

 

[Tony Curtis]

A. Sinan Unur wrote:

I want it to run the script above. Redirect does it, but it
wont run the rest of the script. I don't know of any other
way, that is why I am here.

No, you want to GET (I assume) the URL above, and process the
response in some way.

Reading a post in german does little to know what they said,

Jeepers, I *do* speak German! That's spooky.

I want the the script to run the above script, I don know
any other way, so far everyone instead of telling me says go
look it up yourself. If I don't know what to look up I can't
look it up.

perldoc lwpcook, it has examples of building requests and
handling the responses.

LWP::Simple may be enough for what you're trying to do, but
it's difficult to tell.

To repeat: you are *not* running a script on another machine,
you are accessing a URL and processing its response. That
might be what is going on "under the hood" but it is
irrelevant. You really need to understand the difference
between running programs and processing URL responses, I have
the feeling this is tripping you up unnecessarily.

 

[David Grey]

No, you want to GET (I assume) the URL above, and process the
response in some way.

No, I just want it to run, period, then the rest of the script that
calls that script to run, that's it.

Jeepers, I *do* speak German! That's spooky.

I don't though, so posting in a language I don't know then
faulting me for not knowing the language is not fruitful.

perldoc lwpcook, it has examples of building requests and
handling the responses.

But it had nothing that shows how to run a script. I
do not want to copy a file, I want to run the script, then
finish the process.

LWP::Simple may be enough for what you're trying to do, but
it's difficult to tell.

To repeat: you are *not* running a script on another machine,
you are accessing a URL and processing its response.

There goes that german again. Care to give an example that
(I don't even know what to call it because you say I can't use the
word run so I call it dlksj) I want to dlksj the script on the
domain.com
and continue the process. Nothing more, nothing less.

That
might be what is going on "under the hood" but it is
irrelevant. You really need to understand the difference
between running programs and processing URL responses, I have
the feeling this is tripping you up unnecessarily.

I want to dlksj the script and continue on.

print "Location: http://www.domain.com/cgi-bin/copyprog.pl\n\n";

does it but never comes back.

 

[David Grey]

I just showed you another way. Did you actually try that script out with
the URL you are interested in?

I'm not going to try what will not do what I want, I want
to run a script in a script, I saw no evidence what you posted
would do that.

You need to at least know something about what you are doing and be
willing to learn and do some work on your own.

Oh please, you can't know about something before you know about
something, you just want to flame others, not help them.
I don't see why you are here other than to gloat I know more than
you idiots. You cannot look up what you have no clue what to
look up, and you cannot learn something that is not in your
existence yet. I have done my work, I just need a clue how
to run a script in a script, not get a file as it seems you posted.
I need to run a script at domain.com in a script, period.

 

[Tony Curtis]

no clue what to look up, and you cannot learn something that
is not in your existence yet. I have done my work, I just
need a clue how to run a script in a script,

You are *not* running a "script in a script".

not get a file as it seems you posted. I need to run a
script at domain.com in a script, period.

No, you want to process the response from accessing a URL via
some kind of HTTP request, probably GET.

This is your stumbling block. You are conflating accessing a
URL with the particular language in which you happened to code
the underlying implementation of that URL.

Or not in German, you want to connect to a webserver and
access something on that server. (The something happens to be
implemented as a perl program. That program outputs
something.) You want to collect what was output and then do
something else.

 

[Sherm Pendley]

No, I just want it to run, period

So what do you think is going to happen when you send a GET request, magic?
The server at the other end *runs* *the* *script* to service the request
you sent.

But it had nothing that shows how to run a script. I
do not want to copy a file, I want to run the script, then
finish the process.

Send a GET request to the URL - that's been explained several times now, so
I won't repeat it.

To handle that request, the remote server runs the script. If you don't care
about the output, fine - just ignore it or throw it away. The point is, by
fetching the URL yourself, instead of telling the browser to fetch it, your
script can wait for the other one to finish, and then send the browser
whatever output you want to send it.

There goes that german again. Care to give an example that
(I don't even know what to call it because you say I can't use the
word run so I call it dlksj)

Now who's being abusive? The people who have been advising you are not
spouting gibberish like "dlksj" just to confuse you. They're using clear,
concise technical terms that you happen to be unfamiliar with. They're
trying hard to help you, and you're being an ungrateful brat in return.
Nice.

I want to dlksj the script on the domain.com and continue the process.
Nothing more, nothing less.

Forget about the Location: then, and stop yelling at the kind people who
have been trying to help you. The biggest obstacle in your way right now is
your own stubborn refusal to learn.

sherm--

 

[John J. Trammell]

No, I just want it to run, period, then the rest of the script that
calls that script to run, that's it.


But it had nothing that shows how to run a script. I
do not want to copy a file, I want to run the script, then
finish the process.


There goes that german again. Care to give an example that (I don't
even know what to call it because you say I can't use the word run so
I call it dlksj) I want to dlksj the script on the domain.com and
continue the process. Nothing more, nothing less.


I want to dlksj the script and continue on.

print "Location: http://www.domain.com/cgi-bin/copyprog.pl\n\n";

does it but never comes back.

OK, I'll bite.

When you dlksj a script, what's happening? You're using a web browser
of some sort to request a file from a web server. The server realizes
that it isn't a .gif or an .html file, but a script, so it runs the
script, and the output is returned to you and displayed by your browser.

The trick is that that script can, in turn, act like its own little web
browser. The tools to have it do that are in Perl's LWP (libwww-perl).

Here's a script that retreives the front pages from Yahoo! and Google,
and prints the output:

#!/usr/bin/perl
use strict;
use warnings;
use LWP::Simple;
my $yahoo = get("http://www.yahoo.com/");
my $google = get("http://www.google.com/");
print $yahoo, $google;

That's how you can dlksj your script that's on some other server, but
not have your browser get stuck there.

 

[A. Sinan Unur]

A. Sinan Inner wrote:

This string is normally inserted by your newsreader. Why did you change my
last name?

I'm not going to try what will not do what I want, I want
to run a script in a script, I saw no evidence what you posted
would do that.
http://www.ext.nodak.edu/extpubs/alt-ag/ostrich.htm

Oh please, you can't know about something before you know about
something, you just want to flame others, not help them.

No, I do not. But I don't like it when Tony posts a nice explanation and
you call it 'gibberish'.

I don't see why you are here other than to gloat I know more than
you idiots.
Nice.

You cannot look up what you have no clue what to
look up, and you cannot learn something that is not in your
existence yet.

How do you find the courage to leave home everyday?

I have done my work, I just need a clue how to run a
script in a script, not get a file as it seems you posted.

HTTP does not work that way. What you have is a resource on another web
server. Requesting that resource results in a Perl CGI script being
executed on that server. When you do a redirect, you take your script out
of the picture. Kind of like setting up a blind date as opposed to going on
a double date.

If you are not interested in the actual content of the resource on the
other server, then you should be able to get away with using the head
function in LWP::Simple rather than get.

I need to run a script at domain.com in a script, period.

No you don't.

 

[Alan J. Flavell]

On Sun, 2 May 2004, David Grey wrote:

(in reply to A. Sinan Unur , and your carelessness with attributions
isn't helping your case:]

I'm not going to try what will not do what I want, I want
to run a script in a script, I saw no evidence what you posted
would do that.

Actually that's not as obvious as it seems. You obviously don't yet
understand what you are doing nor how to properly ask about what you
want - which is perfectly OK - we all have to start somewhere; it
would be to your advantage to explore all kinds of relevant building
blocks so that you could get a better feel for how they fit together,
after which, the answer to your problem will likely seem so obvious
that you won't need to ask about it.

Oh please, you can't know about something before you know about
something, you just want to flame others, not help them.
I don't see why you are here other than to gloat I know more than
you idiots.

You don't seem to have the remotest clue what kind of impression
you're making by this kind of public exhibition. As such, my own
interim reaction is that you probably can't be helped. But I'll give
you the benefit of the doubt before you go into the killfile, and the
answer might just be helpful to someone else.

I just need a clue how to run a script in a script, not get a file
as it seems you posted.

Not on the basis of your own evidence, no. You want to invoke a
remote URL which happens to have a script behind it, while retaining
control of the situation so that you can return the result. The
answer to that is LWP.

I need to run a script at domain.com in a script, period.

You don't know how to ask the question yet; that's OK - we all have to
make a start somewhere - but I'd say, on the basis of the most
plausible interpretation of what you want, is that the answer is LWP.

 

[A. Sinan Unur]

The trick is that that script can, in turn, act like its own little web
browser. The tools to have it do that are in Perl's LWP (libwww-perl).

Here's a script that retreives the front pages from Yahoo! and Google,
and prints the output:

#!/usr/bin/perl
use strict;
use warnings;
use LWP::Simple;
my $yahoo = get("http://www.yahoo.com/");
my $google = get("http://www.google.com/");
print $yahoo, $google;

That's how you can dlksj your script that's on some other server, but
not have your browser get stuck there.

Please don't do that.

[Sun May 02 18:15:47 2004] [error] [client 127.0.0.1] malformed header from
script. Bad header=<html><head>: t5.pl