Distributed MVC Application model

Planet implements a distributed version of the Model-View-Controller Pattern (MVC). In this pattern, a web request starts in a Controller, which calls one more Services fetching Models (usually stored in databases), which is used by Templates (View) to render the web response.

http://www.planetframework.com/documentation/1.8/D...ributed-MVC-Application-model/


Distributed Command Pattern - an extension of command pattern for connected systems


The problem of distributed systems

While designing the architecture of connected systems, the design needs to consider how commands are executed not only in the application where it originated, but also on all other connected systems. For example, in a chat application which is connected to a chat room, if one user writes a message, the message needs to be shown on the user’s screen and also simultaneously on screens of all other users who are present on the chat room. This raises an architectural design issue where a command needs to be invoked on the originating application and necessary data be sent to the server in order to broadcast the message to all other connected users. Each connected user needs to receive the data from server, translate it, and then show it on the screen.

This situation results in extra architectural design and coding for the communication performed for each action. First of all, following the command pattern, we can only perform action on the same application, more specifically, on the same process. Then we need to prepare for a network transmission. So, there is some specific protocol developed to maintain communication with the server and the client. Both the server and the client maintain a code base to understand this protocol. When a message is received from the network, the message needs to be processed and then some specific code needs to be written in order to perform actions based on the message.

Here is a design which shows how a typical chat application is developed:


http://www.codeproject.com/Articles/9415/Distribut...Pattern-an-extension-of-comman