18.22.1 Problem
You want to pass
input to an external program run from inside a PHP script. You might, for
example, use a database that requires you to run an external program to index
text and want to pass text to that program.
18.22.2 Solution
Open a pipe to the program with popen( ) , write to the pipe with fputs(
) or
fwrite( ), then close the pipe with pclose( ):
$ph = popen('program arg1 arg2','w') or die($php_errormsg);
if (-1 == fputs($ph,"first line of input\n")) { die($php_errormsg); }
if (-1 == fputs($ph,"second line of input\n")) { die($php_errormsg); }
pclose($ph) or die($php_errormsg);
18.22.3 Discussion
This example uses popen( ) to
call the nsupdate command,
which submits Dynamic DNS Update requests to name servers:
$ph = popen('/usr/bin/nsupdate -k keyfile') or die($php_errormsg);
if (-1 == fputs($ph,"update delete test.example.com A\n")) { die($php_errormsg); }
if (-1 == fputs($ph,"update add test.example.com 5 A 192.168.1.1\n"))
{ die($php_errormsg); }
pclose($ph) or die($php_errormsg);
Two commands are sent to nsupdate via popen( ). The first deletes the
test.example.com A record, and the second adds a
new A record for test.example.com with the
address 192.168.1.1.
