NAME

IO::Async::JSONStream - send or receive lines of JSON data in IO::Async

SYNOPSIS

 use IO::Async::JSONStream;

 use IO::Async::Loop;
 my $loop = IO::Async::Loop->new;

 my $jsonstream = IO::Async::JSONStream->new;
 $loop->add( $jsonstream );

 $jsonstream->connect(
    host    => "my.server",
    service => 12345,
 )->then( sub {
    $jsonstream->write_json( [ data => { goes => "here" } ] );
    $jsonstream->read_json
 })->on_done( sub {
    my ( $data ) = @_;

    print "Received the data $data\n";
 })->get;

DESCRIPTION

This subclass of IO::Async::Stream implements a simple JSON-encoded data stream, sending and receiving Perl data structures by JSON-encoded lines of text.

EVENTS

The following events are invoked, either using subclass methods or CODE references in parameters:

on_json $data

Invoked when a line of JSON-encoded data is received. It is passed the decoded data as a regular Perl data structure.

on_json_error $error, $line

Invoked when a line is received but JSON decoding fails. It is passed the failure exception from the JSON decoder and the line on which decoding failed.

PARAMETERS

The following named parameters may be passed to new or configure:

on_json => CODE

on_json_error => CODE

CODE references for event handlers.

eol => STRING

Optional. Sets the string used for the line ending on the stream. Defaults to \n if not given.

METHODS

$jsonstream->write_json( $data, %args )

Writes a new line of JSON-encoded data from the given Perl data structure.

Other arguments are passed to the write method. Returns a Future which will complete when the line is flushed.

$jsonstream->read_json ==> $data

Returns a Future that will yield the next line of JSON-encoded data to be read from the stream. This takes place instead of the on_json event.

If a JSON decoding error occurs it will result in a failed Future with the operation name json and the line on which decoding failed as its argument.

TODO

• Consider a true streaming mode, using JSON's incremental parsing ability.

AUTHOR

Paul Evans <leonerd@leonerd.org.uk>