# Lumberjack::Message::JSON
JSON representation of a Lumberjack::Message
## Synopsis
use Lumberjack;
use Lumberjack::Message::JSON;
my $message = Lumberjack::Message.new(message => 'this is a message');
$message does Lumberjack::Message::JSON;
my $str = $message.to-json;
...
my $new-message = (Lumberjack::Message but Lumberjack::Message::JSON).from-json($str);
# Alternatively the derived type can be provided as a constant:
constant JSONMessage = (Lumberjack::Message but Lumberjack::Message::JSON);
...
## Description
This is used by [Lumberjack::Dispatcher::EventSource](Lumberjack::Dispatcher::EventSource), [Lumberjack::Dispatcher::Proxy](Lumberjack::Dispatcher::Proxy), [Lumberjack::Application::PSGI](Lumberjack::Application::PSGI) and [Lumberjack::Application::WebSocket](Lumberjack::Application::WebSocket) to serialise and deserialise the [Lumberjack::Message](Lumberjack::Message) to/from JSON for transport over HTTP or websockets.
It is implemented as role that can be mixed at run-time to existing Message objects and to create a derived type to un-marshal to (see the Synopsis.)
Itself it uses `JSON::Class` to provide `to-json` and `from-json` and provides custom marshallers and un-marshallers to ensure that the data is rendered meaningfully in JSON.
The JSON will be something like:
{
"backtrace" : [
{
"file" : "-e",
"line" : 1,
"subname" : "<unit>",
"code" : {}
}
],
"message" : "this is a test",
"class" : {
"log-level" : 2,
"is-logger" : false,
"name" : "Any"
},
"level" : 2,
"when" : "2016-04-12T00:18:34.435650+01:00"
}
Which reflects the [Lumberjack::Message](Lumberjack::Message) fairly closely. There may of course be more backtrace frames.
The 'class' object in the JSON when de-serialised may cause a temporary type to be created with the name provided if the type is not available on the target system, if "is-logger" is true then it will have the `Lumberjack::Logger` applied and the log-level set. This is done so that the message will appear the same as one created on the local system for a message received from a remote logger.
## Installation
Assuming you have a working Rakudo installation you should be able to install this with *zef*:
zef install Lumberjack::Message::JSON
## Support
I originally made this as an internal class to `Lumberjack::Application` but found another use for it, so it may not do everything that your application may need.
Any suggestions/patches/bugs can be reported at
https://github.com/jonathanstowe/Lumberjack-Message-JSON/issues
## Copyright and Licence
This is free software, please see the [LICENCE](LICENCE) for further details.
© Jonathan Stowe 2021 -
