gnu-social/vendor/zetacomponents/document/design/design_2.txt

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eZ Component: Document, Design
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:Author: $Author$
:Revision: $Revision$
:Date: $Date$
Design description
==================
ezcDocument class (abstract)
----------------------------
This class is the base class for each implemented markup format. The extending
classes are named like 'ezcDocumentHtmlDocument'.
The extending classes implement the required actions to load a file or string
in the respective markup and return an arbitrary structure describing the
document and containing all available markup information. For each document
there will be at least a conversion to the DocBook__ format.
The document classes may implement additional interfaces for direct access to
some converted format, if there are shortcut implementations available, like
the following example shows::
<?php
class ezcDocumentRstDocument extends ezcDocument implements
ezcDocumentHtmlConversion
{
// Required by ezcDocumentHtmlConversion interface
public function getAsHtml()
{
// Use direct conversion using `rst2html.py`
}
}
?>
Beside loading a document all document classes need to implement save()
method, which returns the document serialized as a string.
ezcDocumentWikiBase class
^^^^^^^^^^^^^^^^^^^^^^^^^
There may be extensions, like a basic wiki syntax parser, from the document
class, which implement a set of parse helper functions for some set of markup
languages.
ezcDocumentConversion interface
-------------------------------
Interface that defines an abstract conversion class. Real conversion classes
will implement conversion of the given document from one format to another.
The names of that classes follow the pattern:
'ezcDocumentRstToHtmlConversion'.
The main method of this abstract class, convert(), takes a document of the
first format and returns a document in the other format. Both objects extend
the ezcDocument class::
<?php
abstract class ezcDocumentConversion
{
/**
* @return ezcDocument
*/
abstract public function convert( ezcDocument $source );
}
?>
ezcDocumentXsltConversion
^^^^^^^^^^^^^^^^^^^^^^^^^
There are a lot of conversions which may just work on the base of an XSLT. For
all those conversions an abstract ezcDocumentXsltConversion class is provided,
which just takes a set of XSLT files to apply to the XML of the source
document and handles the selection of a proper XSLT engine.
ezcDocumentManager
------------------
The document manager knows about the document parsers to use for each format
and offers a set of static convenient methods to change the used parser for a
document type, or directly create a document from a string or file. The Syntax
for accessing the document manager could look like::
<?php
ezcDocumentManager::setFormat( 'rst', 'myCustomRstDocument' );
$doc = ezcDocumentManager::loadFile( 'rst', '/path/to/my.rst' );
?>
The document manager initiall knows about all internal formats and has them
registered.
ezcDocumentConversionManager
----------------------------
This won't be implemented in the first release.
While you may call the conversion directly, the conversion manager has a set
of registered conversion routes and offers you direct access to the document
conversions, like::
<?php
$result = ezcDocumentConversionManager::convert(
'rst', 'xhtml', '/path/to/my.rst'
);
?>
There will be an interface to overwrite default conversion routes and add or
change the classes used for some conversion.
Multiple conversions
^^^^^^^^^^^^^^^^^^^^
There may be multiple conversion implementations for a set of formats. A
conversion from ezp4xml to HTML may not only be done by using an XSLT, but also
using a simple templating enging, based on string replacements, or a
ezcDocumentTemplateTieIn which uses ezcTemplate to convert between the
documents.
ezcDocumentValidation interface
-------------------------------
The document classes may implement the ezcDocumentValidation, which provides
the method validate( $file ), which can be used to validate an input file
before trying to load it.
The XML based formats will usually implement this by checking against a
RelaxNG based document definition.
Algorithms
==========
Transforming XML
----------------
XML documents are transformed using XSLT stylesheets and XSL extension for
PHP. Transformations are done with ezcDocXSLTTransformer class. Optionally
the transformations may be done by the xsltrans CLI utility.
Examples
========
Examples for the usage of the ezcDocument API.
Loading a document
------------------
::
$doc = new ezcDocumentRstDocument();
$doc->loadFile( '/path/to/my.rst' );
Validating a set of documents
-----------------------------
::
$doc = new ezcDocumentXhtmlDocument();
$result_1 = $doc->validate( '/path/to/first.htm' );
$result_2 = $doc->validate( '/path/to/second.htm' );
foreach ( $result_1 as $error )
{
echo "- {$error->msg} in {$error->line} in {$error->file}.\n";
}
Convert between documents
-------------------------
::
$doc = new ezcDocumentRstDocument();
$doc->loadFile( '/path/to/my.rst' );
$converter = new ezcDocumentRstToHtmlConversion();
$converter->option->literalTag = 'code';
$html = $converter->convert( $doc );
// __toString() will of course be implemented, too.
echo $doc->save();
Using the document manager
--------------------------
::
ezcDocumentManager::setFormat( 'rst', 'myCustomRstHandler' );
$doc = ezcDocumentManager::loadFile( 'rst', '/path/to/my.rst' );
// All errors in the RST syntax should now be magically fixed.
echo $doc;
..
Local Variables:
mode: rst
fill-column: 79
End:
vim: et syn=rst tw=79