running command line executable and capturing stdout

Forum|Forum|14 years ago
August 3, 2011
6 replies
1940 views

Hey everybody,

Is there a way from either ACL or Javascript to run a command line executable and capture the output from stdout? The ACL function system() just returns a success or failure status code. (I'm running Windows.)

For a broader picture, I want to do some HTTP PUT and DELETEs using curl, and capture the resulting status code that is output to stdout. So if there's a reasonably sane way to do low-level HTTP stuff more natively in Arbortext, I'm open to that too.

Thanks,

James

C

ClayHelberg

18-Opal

Hi James-

The basic pattern for doing this is to redirect stdout to a file when
you run the command, and then read in the resulting text file and parse
it as needed. I developed a utility function to do this a while back,
here's the gist of it:

function windows_command(command) {

# executes the given command and returns any text sent to stdout

result = system("cmd /C " . command . " > $home\epicoutput.txt",1);

if (result != 0) { return "*** command failed ***" }

else {

$output = ";

$outputfile = open("$home\epicoutput.txt");

while (getline($outputfile,$line)!=0) {

$output = $output . " " . $line;

}

close($outputfile);

system("cmd /C del $home\epicoutput.txt",1);

return $output;

}

}

HTH

--Clay

Clay Helberg

Senior Consultant

TerraXML

J

jsulak

Author

1-Visitor

Thanks, everyone. I was hoping to avoid the write to a file / read from a file loop, but I guess that's the only way to do it.

-James

C

ClayHelberg

18-Opal

If you *really* object to writing/reading a file, you might be able to
set something up using Java where you redirect System.out to a
java.io.StringWriter or something similar and use Runtime.exec(). But to
be honest that seems like a lot more trouble than it's worth, unless
there's some kind of high cost involved with writing and reading from
the file system.

--Clay

Clay Helberg

Senior Consultant

TerraXML

C

ClayHelberg

18-Opal

OK, so it was more trouble than it was worth, except that my curiosity
got the better of me. Here's some JavaScript code that uses Java objects
to get the job done without writing to/reading from any disk files:

var rt = Packages.java.lang.Runtime.getRuntime();

var pid = rt.exec("cmd /C dir C:\\Temp");

var is = pid.getInputStream();

var isr = Packages.java.io.InputStreamReader(is);

var br = Packages.java.io.BufferedReader(isr);

var line = br.readLine();

var output = ";

while (line != null) {

output += line + "\n";

line = br.readLine();

}

Application.print(output);

This is just static code to run a test case, but it works. Conversion to
a general function is left as an exercise.

Of course, you could also write it in pure Java if you prefer that, or
maybe even ACL using the various java_*() functions.

--Clay

Clay Helberg

Senior Consultant

TerraXML

G

GarethOakes