How to make fread blocking and read until the end? - php

Question

I am executing a TCL script from PHP using proc_open.
I first open the TCL shell
2) Send a command using fwrite
3) What I need is fread to wait/block until the
command sent by fwrite is complete
and get all the contents .The command may take some time to complete.
(I am able to read just 2 lines and then it is going off to the next loop)
Can someone guide me.
The present code is
<?php
$app = 'tclsh84';
$descriptorspec = array(
0 => array("pipe","r"),
1 => array("pipe","w"),
2 => array("file","C:/wamp/www/tcl/bin/g.txt","w")
) ;
$process = proc_open($app, $descriptorspec, $pipes);
if (is_resource($process))
{
for($i=0;$i<4;$i++)
{
fwrite($pipes[0], 'source c:/wamp/www/tcl/bin/test.tcl'."\n");
$content= fread($pipes[1],8192)
print "$content";
}
fclose($pipes[0]);
fclose($pipes[1]);
proc_close($process);
}
?>

Answer 1

I'm thinking about a combination of
stream_select and/or feof()
fread() and concatenation of the partial results ($result .= fread())
and maybe proc_get_status() to determine the end of the process
You want to wait until the tcl application doesn't write something to its stdout for a certain amount of time (presuming that this means the end of the last command) and then send the next command/line to its stdin?
edit:
Seems like you can send all commands to the tcl shell at once and they are processed one by one, i.e. the shell reads the next input line/command when it's done with the previous one. I've tested this with the script.
incr a 1
after 1000
puts [concat [clock seconds] $a]
and
<?php
$app = 'c:/programme/tcl/bin/tclsh85.exe';
$descriptorspec = array(
0 => array("pipe","r"),
1 => array("pipe","w"),
2 => array("file","C:/god.txt","w")
) ;
$process = proc_open($app, $descriptorspec, $pipes);
if (is_resource($process)) {
fwrite($pipes[0], "set a 1\n");
for($i=0;$i<4;$i++) {
fwrite($pipes[0], "source c:/helloworld.tcl\n");
}
// when all scripts are done the shell shall exit
fwrite($pipes[0], "exit\n");
fclose($pipes[0]);
do {
$read=array($pipes[1]); $write=array(); $except=array($pipes[1]);
// wait up to 1 second for new output of the tcl process
$ready = stream_select($read, $write, $except, 1, 0);
if ( $ready && $read /* is not empty */) {
// get the partial output
$r = fread($pipes[1], 2048);
echo $r;
}
// is the process still running?
$status = proc_get_status($process);
} while($status['running']);
fclose($pipes[1]);
proc_close($process);
}
?>
You probably want to add some more error handling. E.g. if stream_select() returns x times with an timeout something might have gone wrong.
edit2:
Let the shell print something you can scan for after each script.
<?php
// something that's not in the "normal" output of the scripts
$id = 'done'. time();
$app = 'c:/programme/tcl/bin/tclsh85.exe';
$descriptorspec = array(
0 => array("pipe","r"),
1 => array("pipe","w"),
2 => array("file","C:/god.txt","w")
) ;
$process = proc_open($app, $descriptorspec, $pipes);
if (is_resource($process)) {
fwrite($pipes[0], "set a 1\n");
for($i=0;$i<4;$i++) {
$output = '';
$continue = true;
$cTimeout = 0;
echo 'loop ', $i, "\n";
fwrite($pipes[0], "source c:/helloworld.tcl\n");
fwrite($pipes[0], "puts $id\n");
echo "waiting for idle\n";
do {
$read=array($pipes[1]);
$write=array();
$except=array($pipes[1]);
$ready = stream_select($read, $write, $except, 1, 0);
if ( $ready && $read ) {
$output .= fread($pipes[1], 2048);
// if the delimiter id shows up in $output
if ( false!==strpos($output, $id) ) {
// the script is done
$continue = false;
}
}
} while($continue);
echo 'loop ', $i, " finished\n";
}
proc_close($process);
}
?>

Answer 2

Try:
$content = '';
while(!feof($pipes[1]))
{
$content .= fread($pipes[1],8192);
}
Does that wait?