Writing converters guide

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Writing converters guide

Post by Danielx64 » Sat Sep 20, 2014 1:07 pm

Does anyone know if there was ever a guide on how to write a converter for 3.0?

Or is the converter for phpbb 2 -> 3.0 is my best bet?

I am having some trouble getting my head around the table mapping.

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Re: Writing converters guide

Post by prototech » Sat Sep 20, 2014 4:18 pm

There is no guide that I'm aware of. The phpBB2 convertor contains some comments that will help you understand certain aspects of the convertor framework. For example, there's this whole chunk on table mapping:

Code: Select all

*	Description on how to use the convertor framework.
*	'schema' Syntax Description
*		-> 'target'			=> Target Table. If not specified the next table will be handled
*		-> 'primary'		=> Primary Key. If this is specified then this table is processed in batches
*		-> 'query_first'	=> array('target' or 'src', Query to execute before beginning the process
*								(if more than one then specified as array))
*		-> 'function_first'	=> Function to execute before beginning the process (if more than one then specified as array)
*								(This is mostly useful if variables need to be given to the converting process)
*		-> 'test_file'		=> This is not used at the moment but should be filled with a file from the old installation
*		// DB Functions
*		'distinct'	=> Add DISTINCT to the select query
*		'where'		=> Add WHERE to the select query
*		'group_by'	=> Add GROUP BY to the select query
*		'left_join'	=> Add LEFT JOIN to the select query (if more than one joins specified as array)
*		'having'	=> Add HAVING to the select query
*		// DB INSERT array
*		This one consist of three parameters
*		First Parameter:
*							The key need to be filled within the target table
*							If this is empty, the target table gets not assigned the source value
*		Second Parameter:
*							Source value. If the first parameter is specified, it will be assigned this value.
*							If the first parameter is empty, this only gets added to the select query
*		Third Parameter:
*							Custom Function. Function to execute while storing source value into target table.
*							The functions return value get stored.
*							The function parameter consist of the value of the second parameter.
*							types:
*								- empty string == execute nothing
*								- string == function to execute
*								- array == complex execution instructions
*		Complex execution instructions:
*		@todo test complex execution instructions - in theory they will work fine
*							By defining an array as the third parameter you are able to define some statements to be executed. The key
*							is defining what to execute, numbers can be appended...
*							'function' => execute function
*							'execute' => run code, whereby all occurrences of {VALUE} get replaced by the last returned value.
*										The result *must* be assigned/stored to {RESULT}.
*							'typecast'	=> typecast value
*							The returned variables will be made always available to the next function to continue to work with.
*							example (variable inputted is an integer of 1):
*							array(
*								'function1'		=> 'increment_by_one',		// returned variable is 2
*								'typecast'		=> 'string',				// typecast variable to be a string
*								'execute'		=> '{RESULT} = {VALUE} . ' is good';', // returned variable is '2 is good'
*								'function2'		=> 'replace_good_with_bad',				// returned variable is '2 is bad'
*							),
You can also poke me in #phpbb-coding or post any questions that you may have in the Convertors forum and direct my attention to it. :)

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Re: Writing converters guide

Post by Danielx64 » Sun Sep 21, 2014 1:46 am

Thank-you for that, I did take a look and I was like "surly there would be a guide somewhere". I'll take another look at it later and see if I can make any sense of it.

Mind you, it's the first time I even looked at it.... :)

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