Sorry for the way OT post, but this list seems to have the smartest, most
experienced, most friendly perl programmers around -- and this question on
other perl lists failed to get any bites.
Would someone be willing to offer a bit of help off list?
I'm trying to get two programs talking in an HTTP-like protocol through a
unix pipe. I'm first trying to get it to work between two perl programs
(below), but in the end, the "client" will be a C program (and that's a
different nut to crack).
The goal is to add a "filter" feature to the C program, where you register
some external program (called a server, in this example, since it will be
answering requests) and the C program starts the server, and then feeds
requests over and over leaving the server in memory.
A simple filter might be something that converts to lower case, or converts
text dates to a timestamp. The C program (client) sends headers and some
content, and the filter (server) returns headers and some content. But
it's a "Keep Alive" connection, so another request can be sent without
closing the pipe.
This approach seems simple -- at least for someone writing the filter
program. Just read and print (non-buffered). It's probably not very
portable -- I'd expect to fail on Windows. (Are there better methods?)
Anyway, this is the sample code I was trying, but was not getting anywhere.
Seems like IO::Select::can_read() returns true and then I can read back the
first header, but then can_read() never returns true again.
I really need to be able to read and parse the headers, then read
Content-Length: bytes since the content can be of varying length.
> cat client.pl
#!/usr/local/bin/perl -w
use strict;
use IPC::Open2;
use IO::Select;
use IO::Handle;
my ( $rh, $wh );
my $pid = open2($rh, $wh, './server.pl');
$pid || die "Failed to open";
my $read = IO::Select->new( $rh );
$rh->autoflush;
$wh->autoflush;
for (1..2) {
print "\n>>$0: Sending Headers:$_\n";
print $wh "Header-number: $_\n",
"Content-type: perl/test\n",
"Header: test\n\n";
# Now read the response
while ( 1 ) {
my $fh;
if ( ($fh) = $read->can_read(0) ) {
print "Can read!\n";
my $buffer = <$rh>;
#$fh->read( $buffer, 1024 );
last unless $buffer;
print "<<$0: Read $buffer";
} else {
print "Can't read sleeping...\n";
sleep 1;
}
}
print "$0: All done!\n";
}
lii@mardy:~ > cat server.pl
#!/usr/local/bin/perl -w
use strict;
$|=1;
warn "In $0 pid=$$\n";
while (1) {
my @headers = ();
while ( <> ) {
chomp;
if ( $_ ) {
warn "$0: Read '$_'\n";
push @headers, $_;
} else {
for ( @headers ) {
warn "$0: Sending $_\n";
print $_,"\n";
}
print "\n";
last;
}
}
}
Bill Moseley
mailto:[EMAIL PROTECTED]
