NAME

       Feersum::Connection::Handle - PSGI-style reader/writer objects.

SYNOPSIS

       For read handles:

           my $buf;
           my $r = delete $env{'psgi.input'};
           $r->read($buf, 1, 1); # read the second byte of input without moving offset
           $r->read($buf, $env{CONTENT_LENGTH}); # append the whole input
           $r->close(); # discards any un-read() data

           # assuming the handle is "open":
           $r->seek(2,SEEK_CUR); # returns 1, discards skipped bytes
           $r->seek(-1,SEEK_CUR); # returns 0, can't seek back

           # not yet supported, throws exception:
           # $r->poll_cb(sub { .... });

       For write handles:

           $w->write("scalar");
           $w->write(\"scalar ref");
           $w->write_array(\@some_stuff);
           $w->poll_cb(sub {
               # use $_[0] instead of $w to avoid a closure
               $_[0]->write(\"some data");
               # can close() or unregister the poll_cb in here
               $_[0]->close();
           });

       For both:

           $h->response_guard(guard { response_is_complete() });

DESCRIPTION

       See the PSGI spec for more information on how read/write handles are used (The Delayed Response and
       Streaming Body section has details on the writer).

METHODS

   Reader methods
       The reader is obtained via "$env->{'psgi.input'}".

       "$r->read($buf, $len)"
           Read the first $len bytes of the request body into the buffer specified by $buf (similar to how
           sysread works).

           The calls to "$r->read()" will never block.  Currently, the entire body is read into memory (or
           perhaps to a temp file) before the Feersum request handler is even called.  This behaviour MAY
           change. Regardless, Feersum will be doing some buffering so "psgix.input.buffered" is set in the PSGI
           env hash.

       "$r->seek(...)"
           Seeking is partially supported.  Feersum discards skipped-over bytes to conserve memory.

               $r->seek(0,SEEK_CUR);  # returns 1
               $r->seek(-1,SEEK_CUR); # returns 0
               $r->seek(-1,SEEK_SET); # returns 0
               $r->seek(2,SEEK_CUR); # returns 1, discards skipped bytes
               $r->seek(42,SEEK_SET); # returns 1 if room, discards skipped bytes
               $r->seek(-8,SEEK_END); # returns 1 if room, discards skipped bytes

       "$r->close()"
           Discards the remainder of the input buffer.

       "$r->poll_cb(sub { .... })"
           NOT YET SUPPORTED.  PSGI only defined poll_cb for the Writer object.

   Writer methods.
       The writer is obtained under PSGI by sending a code/headers pair to the "starter" callback.  Under
       Feersum, calls to "$req->start_streaming" return one.

       "$w->write("scalar")"
           Send the scalar as a "T-E: chunked" chunk.

           The calls to "$w->write()" will never block and data is buffered until transmitted.  This behaviour
           is indicated by "psgix.output.buffered" in the PSGI env hash (Twiggy supports this too, for example).

       "$w->write(\"scalar ref")"
           Works just like write("scalar") above.  This extension is indicated by "psgix.body.scalar_refs" in
           the PSGI env hash.

       "$w->write_array(\@array)"
           Pass in an array-ref and it works much like the two write() calls above, except it's way more
           efficient than calling write() over and over.  Undefined elements of the array are ignored.

       "$w->close()"
           Close the HTTP response (which triggers the "T-E: chunked" terminating chunk to be sent).  This
           method is implicitly called when the last reference to the writer is dropped.

       "$w->poll_cb(sub { .... })"
           Register a callback to be called when the write buffer is empty.  Pass in "undef" to unset.  The sub
           can call close().

           A reference to the writer is passed in as the first and only argument to the sub.  It's recommended
           that you use $_[0] rather than closing-over on $w to prevent a circular reference.

   Common methods.
       Methods in common to both types of handles.

       "$h->response_guard($guard)"
           Register a guard to be triggered when the response is completely sent and the socket is closed.  A
           "guard" in this context is some object that will do something interesting in its DESTROY/DEMOLISH
           method. For example, Guard.

           The guard is *not* attached to this handle object; the guard is attached to the response.

           "psgix.output.guard" is the PSGI-env extension that indicates this method.

       "$h->fileno"
           Returns the file descriptor number for this connection.

AUTHOR

       Jeremy Stashewsky, "stash@cpan.org"

COPYRIGHT AND LICENSE

       Copyright (C) 2010 by Jeremy Stashewsky & Socialtext Inc.

       This library is free software; you can redistribute it and/or modify it under the same terms as Perl
       itself, either Perl version 5.8.7 or, at your option, any later version of Perl 5 you may have available.