Applications Messaging Standard

[Noel Winstanley]

  On 7 Feb 2007, at 16:38, Tony Linde wrote:

> Quick(ish) question re PLASTIC: is the plastic hub something like a  
> message
> broker?

Its a little like a message broker, but specialized and simplified to  
the task of inter-application messaging - so not a general messaging  
solution.

Unlike a messaging system like MSeries or ActiveMQ, Plastic hub  
implementations don't queue messages, and makes no guarantees about  
delivery of messages (whilst MSeries guarantee once and once only for  
every message), or, I believe, ordering of messages.

Plastic has a lot less support for security, transactions, and other  
things that typically concern enterprise software. If a plastic  
message is dropped, or even spoofed or intercepted, it's assumed that  
this isn't the end of the world.

Similar to a messaging system, a plastic hub doesn't really care  
about the content of the messages - the definition and format of  
mesages are left to the message producer and consumer to agree,  
whilst the hub just takes care of routing them.

> And if so, how does it relate to existing ones such as ActiveMQ
> (http://activemq.apache.org/home.html)?
>

PLASTIC is a specification that uses open-standard transports and has  
multiple implementations.

  Most message brokers use a closed communication protocol and don't  
interoperate well with each other. Although there's , eg, a Java API  
to messaging systems (JMS), it makes no guarantee that any JMS client  
can connect to any messsaging system - specific drivers are required  
(as with JDBC). This is not the case with PLASTIC.

Plastic has been out in the wild for about a year, ActiveMQ only left  
the apache incubator today.

Plastic is good for quickly exchanging control info between desktop  
apps. Message Brokers are good for, eg,  processing banking  
transactions.

cheers
noel.

> T.
>
>> -----Original Message-----
>> From: owner-apps at eso.org [mailto:owner-apps at eso.org] On
>> Behalf Of Alasdair Allan
>> Sent: 06 February 2007 17:12
>> To: Paul Harrison
>> Cc: Noel Winstanley; apps at ivoa.net; John Taylor; Mark Allen
>> Subject: Re: Applications Messaging Standard (was Re: )
>>
>>
>> Paul Harrison wrote:
>>> Alasdair Allan wrote:
>>>> JSON has mind share and is viewed as being "sexier" than XML-RPC
>>>> for some reason.
>>>
>>> I have to say this is another case of web 2.0 hype...
>>>
>>> JSON invented because it directly evaled into javascript data
>>> object, but as every Perl programmer from the earliest CGI days
>>> knows that is a security nightmare...
>>
>> As a Perl programmer, err, yup! However I do make extensive use of
>> Data::Dumper and Storable (et al.) to serialise, transmit or store,
>> and then eval() Perl objects. I just don't send them over the wire
>> (or accept them) from/to un-trusted sources. That way lies madness.
>>
>>> so you need to use a JSON parser - so what is the point?
>>
>> It's as good as anything? It's compact and fairly simple, there are
>> lots of libraries to parse and create it, and people seem to
>> like it.
>> It'll be around for a while. We could have worse reasons.
>>
>> Al.
>>
>>
>