v2.0 Design

Main Concepts

• Channel: Import and export messages to and from a 3rd-party format, for example, phpBB, email, RSS feeds, etc. Modular system, so channels can be user-contributed.
• ‘Generic Message’: A generic (i.e. channel-agnostic) data structure that adapts to every channel. It is capable of integrating every channel’s special data in order to properly convert one format to another.
• Filters: Functions that change the data of the message in some way, for example, stripping html code from the body of the message, adding/removing subject field tags, etc.
• Routers: Conditional functions that can branch the processing of messages. For example, if the imported message subject contains the word “Forum 1″, export the message to phpBB3 forum 1; else export the message to phpBB3 forum 2.
• Chain: A sequence of channels, filters and routers which starts with the importing of messages and finishes with the exporting of messages. For example, you could build a chain like this: “phpBB -> Remove HTML -> smtp” in order to send phpBB posts to a mailserver after stripping any HTML.

So, m2f 2.0 works like this:

• The admin user builds two chains in order to bind to channels together. In this example, “phpBB3->smtp” and “pop3->phpBB3″.
• The first chain will be run every time a user posts a message on the forum.
• The second chain must be run manually or by the use of a cron script.
• m2f is designed to accept multiple import and export channels, so you could, for example, import mail from a POP mailbox, and export the message to both a phpBB2 forum and a phpBB3 forum.

You can learn more on the use cases page.

Directory structure

The following list refers to the root of a standard m2f download:

/application

the web User Interface for the administration control panel

/cache

um… the cache

/config

contains the configuration file for the Admin CP (N.B. this is different to the config file for running the tests)

/di

configuration files for Dependency Injection

/external

The files needed for 3rd-party software such as phpBB to communicate with m2f.

/includes

3rd-party library files used by m2f

/lib

the core m2f code

/models

database models, used by Doctrine ORM system

/test-suite

JavaScript-enabled test runner

/tests

contains all the test files

m2f Library Files

Let’s have a look at the contents of the /lib directory. We use ZEND-style naming conventions for all m2f library classes, so the class names directly map to files in the /lib directory:
M2f => /lib/M2f.php
M2f_Message => /lib/M2f/Message.php
M2f_Module_Channel_Phpbb2_Export => /lib/M2f/Module/Channel/Phpbb2/Export.php

I will now talk through the major areas of the m2f library, using class names as reference. (N.B. as of Jan 2009, this is a little out-of-date. Sorry - we’ll fix it soon!).

M2f

static helper function, such as autoload()

M2f_Cache

interface to Zend Framework’s Cache system. Stores cache files in /cache

M2f_Chain

the ‘guts’ of m2f. Like a Distribution List in v1.2. Add import and export channels to a chain, and everything happens when the chain is run.

M2f_Db

interface to Doctrine ORM system. Sets up a PDO object, passes it to Doctrine. Also responsible for installing the m2f tables

M2f_Di

interface to Crafty Dependency Injection system

M2f_Element

base class for objects which may be added to a chain (Channel, Filter, etc.)

M2f_Element_Config

configuration object for each instance of M2f_Element

M2f_Filter_Parser_Tokenizer

splits message text strings into tokens based on rules (such as BBCode)

M2f_Filter_Parser_Assembler

assemble tokenized string into M2f_Message style XML

M2f_Message

basic message class, passed between elements in a chain

M2f_Message_List

Container for instances of M2f_Message. Each Chain, Channel and Filter is passed a Message List

M2f_Model

base class for Doctrine Models (each model corresponds to a database table)

M2f_Persistable

base class for objects which need to be saved in the database

M2f_Receiver

receives and decodes cURL connections from 3rd-party software, such as phpBB

M2f_TransferObject

basic objects which hold an array of data

M2f_Transport

initiates cURL connections with 3rd-party software, such as phpBB

The directory I have missed out is the big one! Inside /modules you will find all the Channels, Filters (and more later!) which give m2f its functionality.