NAME

AnyEvent::Handle::Writer - Extended version of AnyEvent::Handle with additional write options

SYNOPSIS

   use AnyEvent;
   use AnyEvent::Handle::Writer;

   my $hdl; $hdl = AnyEvent::Handle::Writer->new(
      fh => $fh,
      on_error => sub {
         my ($hdl, $fatal, $msg) = @_;
         warn "got error $msg\n";
         $hdl->destroy;
      }
   );

   # Custom writer
   $hdl->push_write(sub {
      my $h = shift;
      if ($have_data) {
         $h->unshift_write($data);
         return 1; # Work done
      } else {
         return 0; # Work not done, call me again
      }
   });

   # sendfile
   $hdl->push_sendfile('/path/to/file', 1024);

RATIONALE

We have great l<AnyEvent::Handle>. But it have only raw write queue. This module extends it with callbacks in write queue and adds a push_sendfile() call, which would be processed at correct time

METHODS

push_write($data)

"WRITE_QUEUE" in AnyEvent::Handle

push_write(type => @args)

"WRITE_QUEUE" in AnyEvent::Handle

push_write($cb->($handle))

This version of call allow to push a callback, which will be invoked when the write queue before it became empty.

   Callback should return:
      true  - when there is no work to be done with this callback.
              it will be removed from queue and continue
      false - when it want to be called again (i.e. not all work was done)
              it will be kept in queue and called on next drain

This call allow us to implement such a thing:

   $handle->push_write("HTTP/1.1 200 OK\012\015\012\015");
   $handle->push_write(sub {
      # Manual work on handle
      my $h = shift;
      my $len = syswrite($h->{fh}, $data); # Here may be also sendfile work
      if (defined $len) {
         diag "written $len";
         substr $data, 0, $len, "";
         if (length $data) {
            return 0; # want be called again
         } else {
            return 1; # all done
         }
      } elsif (!$!{EAGAIN} and !$!{EINTR} and !$!{WSAEWOULDBLOCK}) {
         $h->_error ($!, 1);
         return 1; # No more requests to me, got an error
      }
      else { return 0; }
   });
   $handle->push_write("HTTP/1.1 200 OK\012\015\012\015");
   $handle->push_write("Common response");

unshift_write($data) =head2 unshift_write(type => @args) =head2 unshift_write($cb->($handle))

Analogically to unshift_read, it unshift write data at the beginngin of queue. The only recommended usage is from write callback

   $handle->push_write("1")
   $handle->push_write(sub {
      my $h = shift;
      $h->unshift_write("2");
      return 1;
   });
   $handle->push_write("3");
   
   # The output will be "123"

push_sendfile($filename, [$size, [$offset]]);

Push sendfile operation into write queue. If sendfile cannot be found (Sys::Sendfile) or if it fails with one of ENOSYS, ENOTSUP, EOPNOTSUPP, EAFNOSUPPORT, EPROTOTYPE or ENOTSOCK, it will be emulated with chunked read/write

   $handle->push_write("HTTP/1.0 200 OK\nContent-length: $size\n...\n\n");
   $handle->push_sendfile($file, $size, $offset);

ACKNOWLEDGEMENTS

AUTHOR

Mons Anderson, <mons at cpan.org>

LICENSE

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.