http://qs1969.pair.com?node_id=1076425


in reply to Simultaneously reading from a file and serving data

I'm no expert but: can't you just use a fork? I haven't used it for a while but IIRC it's actually not very hard to use and there are several nice examples in perlipc.

Something like: 

if (my $pid = fork()) {
    # network stuff
} else {
    # file stuff
}

[download]

Replies are listed 'Best First'.
Re^2: Simultaneously reading from a file and serving data
by wazoox (Prior) on Feb 27, 2014 at 19:50 UTC
    The problem with a fork is that the %data won't be shared between processes...
[reply]

      WARNING: I'm afraid this message is actually irrelevant. See EDIT note at the end.

      Well, you can have your two processes communicate with yet another named pipe. I really think you should (re-)read perlipc. There are lots of examples for this kind of stuff. Check out the open() command for instance. You can use it to fork and create a named pipe in the same time. See the "Safe Pipe Opens" section.

      Maybe something like this:

      if (my $pid = open(JSON, '|-') {
    # database stuff
    print JSON $json;
} else {
    # this is the child fork.
    # STDIN here is actually JSON in the other fork.
    # network stuff
    my $json = <>;
    # some more network stuff I guess
}

      [download]

      EDIT I've just realized this wont solve your issue since the child process would block waiting for data from the parent process. It can't do that *AND* act as a network server at the same time. It only moves the blocking problem from one place to an other. So I'm sorry, I don't know.

[reply]
[d/l]

In Section Seekers of Perl Wisdom