--- loncom/lonmaxima	2006/03/04 06:56:10	1.10
+++ loncom/lonmaxima	2006/05/10 02:12:17	1.19
@@ -3,7 +3,7 @@
 # The LearningOnline Network with CAPA
 # Connect to MAXIMA CAS
 #
-# $Id: lonmaxima,v 1.10 2006/03/04 06:56:10 albertel Exp $
+# $Id: lonmaxima,v 1.19 2006/05/10 02:12:17 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -30,7 +30,7 @@
 # http://www.lon-capa.org/
 #
 
- 
+use Expect; 
 use IPC::Open3;
 use IO::Select;
 use IO::Socket;
@@ -44,7 +44,7 @@ use strict;
 
 # global variables
 my $PREFORK                = 5;        # number of children to maintain
-my $MAX_CLIENTS_PER_CHILD  = 5;        # number of clients each child should process
+my $MAX_CLIENTS_PER_CHILD  = 50;       # number of clients each child should process
 my %children               = ();       # keys are current child process IDs
 my $children               = 0;        # current number of children
 my $status;                            # string for current status
@@ -52,58 +52,10 @@ my $pidfile;                           #
 my $port;                              # path to UNIX socket file
 my %perlvar;                           # configuration file info
 my $lastlog;                           # last string that was logged
+
 use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children $status
 	    $pidfile $port %perlvar $lastlog);
  
-sub maximareply {
-    my ($cmd) = @_;
-    my $reply='';
-    my $error='';
-    my $exitstatus='';
-
-    unless ($cmd=~/\;\n$/) { $cmd.=";\n"; }
-
-    my ($cmd_in, $cmd_out, $cmd_err);
-    my $maximapid = open3($cmd_in, $cmd_out, $cmd_err, 'maxima');
-    $children{$maximapid} = 1;
-    
-    print $cmd_in $cmd;
-    close($cmd_in);
-
-    &status("Command sent");
-
-    $SIG{ALRM} = sub { kill 9 => $maximapid; }; 
-    alarm(5);
-
-    my $selector = IO::Select->new();
-
-    $selector->add($cmd_err, $cmd_out);
-    
-    while (my @ready = $selector->can_read()) {
-	foreach my $fh (@ready) {
-	    if (ref($fh) 
-		&& ref($cmd_err)
-		&& fileno($fh) == fileno($cmd_err)) {
-		$error.=<$cmd_err>;
-	    } else {
-		my $line = scalar(<$cmd_out>);
-                if ($line=~/^(\(\%o|\s)/) {
-		    $line=~s/^\(.*\)/     /; 
-		    $reply.=$line; 
-		}
-	    }
-	    $selector->remove($fh) if eof($fh);
-	}
-    }
-    alarm(0);
-    $SIG{ALRM} = 'DEFAULT';
-    if (ref($cmd_out)) { close($cmd_out); }
-    if (ref($cmd_err)) { close($cmd_err); }
-
-    &status("Command processed");
-    return ($reply,$error,$exitstatus);
-}
- 
 # ------------------------------------------------------------ Service routines 
 sub REAPER {                        # takes care of dead children 
                                     # and MAXIMA processes
@@ -292,10 +244,38 @@ sub make_new_child {
         sigprocmask(SIG_UNBLOCK, $sigset)
             or die("Can't unblock SIGINT for fork: $!\n");
 
-	&process_requests($server);
+        &logthis('New process started');
+
+        my $command=Expect->spawn('maxima');
+        $command->log_stdout(0);
+
+        &getmaximaoutput($command);
+
+        for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
+           &status('Accepting connections');
+           my $client = $server->accept()     or last;
+           print $command "kill(all);reset();\n";
+           &sync($command);
+           while (my $cmd=<$client>) {
+              &status('Processing command');
+              print $command &unescape($cmd);
+              my $reply=&getmaximaoutput($command);
+              print $client &escape($reply)."\n";
+              if ($reply=~/^Error\:/) {
+                 &logthis('Died through '.$reply);
+                 $client->close();
+                 $command->hard_close();     
+                 exit;
+              }	      
+	      &sync($command);
+              &status('Waiting for commands');
+           }
+        }
 
         # tidy up gracefully and finish
 
+        $command->soft_close();
+
         # this exit is VERY important, otherwise the child will become
         # a producer of more and more children, forking yourself into
         # process death.
@@ -303,15 +283,39 @@ sub make_new_child {
     }
 }
 
-sub process_requests {
-    my ($server) = @_;
-    # handle connections until we've reached $MAX_CLIENTS_PER_CHILD
-    for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
-	&status('Accepting connections');     
-	my $client = $server->accept()     or last;
-	while (my $cmd=<$client>) {
-	    &status('Processing command');
-	    print $client &escape((&maximareply(&unescape($cmd)))[0])."\n";
+{
+    my $counter;
+    sub sync {
+	my ($command)=@_;
+	$counter++;
+	my $expect=$counter.time;
+	print $command "$expect;\n";
+	while (1) {
+	    my $output=&getmaximaoutput($command);
+	    if (($output=~/\Q$expect\E/) || ($output=~/^Error\:/)) {
+		return;
+	    }
 	}
-    }    
+    }
+}
+
+sub getmaximaoutput {
+    my ($command)=@_;
+    my (undef,$error,undef,$output)=$command->expect(20, -re => '\(\%i\d+\)');
+    if ($error) {
+       return 'Error: '.$error;
+    }
+    my $foundoutput=0;
+    my $realoutput='';
+    foreach my $line (split(/\n/,$output)) {
+       if ($line=~/\;/) { $foundoutput=1; next; }
+       if (!$foundoutput) { next; }
+       my ($label)=($line=~s/^(\(\%o\d+\))//);
+       if ($label) {
+          $label=~s/\S/ /g;
+          $line=$label.$line;
+       }
+       $realoutput.=$line."\n";
+    }
+    return $realoutput;
 }
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>500 Internal Server Error</title>
</head><body>
<h1>Internal Server Error</h1>
<p>The server encountered an internal error or
misconfiguration and was unable to complete
your request.</p>
<p>Please contact the server administrator at 
 root@localhost to inform them of the time this error occurred,
 and the actions you performed just before this error.</p>
<p>More information about this error may be available
in the server error log.</p>
</body></html>