Extension:Page Schemas

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Page Schemas

Release status: stable

Implementation Special page
Description Defines a tag, <PageSchema>, that can be used to define page schemas.
Author(s) Yaron Koren and Ankit Garg
Latest version 0.4.3 (May 2014)
MediaWiki 1.18.* or greater
Database changes No
License GPL
Download See below
Tags
<PageSchema>
Added rights

generatepages

Hooks used
ParserFirstCallInit

Translate the Page Schemas extension if it is available at translatewiki.net

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Page Schemas is a MediaWiki extension that allows for defining all the schema information about a "class", or data type - for naming, display, data input, and browsing - within a single piece of XML contained within a category page. This XML then is used to generate all the necessary additional pages needed to put the schema into effect, such as template pages and, for instance, if Semantic Forms is installed, form pages. The XML can be created and edited via a helper form, preventing users from having to generate or modify it manually.

Page Schemas allows other extensions to define their own fields to add to the XML, using hooks. Currently, the following extensions hook into Page Schemas:

Special pages[edit | edit source]

The "edit schema" page, when Semantic MediaWiki, Semantic Forms and Semantic Drilldown are installed

Page Schemas defines two pages that can show up as tabs on category pages: "Edit schema" (which appears as "Create schema" if no schema exists yet) and "Generate pages". "Edit schema" allows for creating or editing the XML via the helper form, while "Generate pages" provides a button that lets the administrator create the template(s), semantic properties, form etc. automatically from the XML definition. "Generate pages" also includes checkboxes for each of the pages to be generated, to let administrators choose not to override certain wiki pages that already exist.

Any user who is allowed to edit a certain category page will see the "Edit schema/Create schema" tab for that category, and will be allowed to use that page to modify the schema.

In order to generate pages, a user must have the 'generatepages' permission. By default, this permission is given only to members of the 'sysop' user group. You can add to or modify the set of allowed users, though, by modifying the $wgGroupPermissions array in LocalSettings.php. To enable all registered users to generate pages from the schema, for instance, you would add the following:

$wgGroupPermissions['user']['generatepages'] = true;

Code and download[edit | edit source]

You can download the Page Schemas code, in .zip format, here.

You can also download the code via Git from the MediaWiki source code repository. From a command line, you can call the following:

git clone https://gerrit.wikimedia.org/r/p/mediawiki/extensions/PageSchemas.git

To view the code online, including version history for each file, go here.

Installation[edit | edit source]

After you've obtained a 'PageSchemas' directory, place this directory within the main MediaWiki 'extensions' directory. Then, in the file 'LocalSettings.php' in the main MediaWiki directory, add the following line:

include_once( "$IP/extensions/PageSchemas/PageSchemas.php" );

Tutorial video[edit | edit source]

You can see a screencast video for Page Schemas created by Yury Katkov, explaining how it's used and why it can be useful, here.

Sample XML structure[edit | edit source]

Here is some sample XML, to be contained within a page called "Category:Cities", used to define the schema for pages within that category. This section defines the name of the form, and information for a single field of that class, "Population".

<PageSchema>
	<semanticforms_Form name="City">
	<standardInputs/>
	</semanticforms_Form>
	<Template name="City" format="standard">
		<Field name="Population">
			<Label>Pop.</Label>
			<semanticmediawiki_Property name="Has population">
				<Type>Number</Type>
			</semanticmediawiki_Property>	
			<semanticforms_FormInput>
				<InputType>text</InputType>
				<Parameter name="size">20</Parameter>
				<Parameter name="mandatory"/>
			</semanticforms_FormInput>
		</Field>
		...
	</Template>
	...
	<Section name="History" level="2">
		<semanticforms_PageSection>
			<Parameter name="rows">10</Parameter>
			<Parameter name="mandatory"/>
		</semanticforms_PageSection>
	</Section>
	...
</PageSchema>

Importing into Page Schemas[edit | edit source]

The following utilities can import data structures (both MediaWiki-based and external) into the Page Schemas format:

  • db-to-smw-page-schemas, a script in Node.js that queries a database's schema and generates corresponding category pages with Page Schemas XML.
  • A shell script that creates Page Schemas XML from a Semantic Forms form definition.

Common problems[edit | edit source]

  • If you are using MediaWiki 1.22, there is a good chance that trying to generate pages automatically will not work, because of a bug in MW 1.22 in which jobs that modify pages simply do not get run. If that is happening for you, it is recommended to add this call in LocalSettings.php, which should restore the correct behavior:
$wgPhpCli = false;
  • If you see duplicate entries of the Semantic MediaWiki fields, most likely there are two different calls to enableSemantics() - possibly one in LocalSettings.php and one in the settings file for Semantic Bundle, if you have that installed. You should remove one of them.

Authors[edit | edit source]

Page Schemas was created by Ankit Garg as part of the 2011 Google Summer of Code, and was mentored by Yaron Koren. It was later modified significantly, and is currently maintained, by Yaron Koren. Parts of it are based on the TemplateInfo extension, by Yaron Koren and Roan Kattouw.

Significant code contributions were also made by Himeshi De Silva and Vedmaka.

Version history[edit | edit source]

Page Schemas is currently at version 0.4.3.

The version history for Page Schemas is:

  • 0.1 - August 23, 2011 - initial version
  • 0.2 - October 13, 2011 - overhaul; many changes to display and code structure
  • 0.3 - October 25, 2011 - extensions hook into Page Schemas via a single hook and a subclass, instead of a variety of hooks; various other changes
  • 0.3.1 - August 24, 2012 - template display format can be selected; various small fixes and improvements
  • 0.4 - October 7, 2013 - handling added for page sections; "Generate pages" UI improved; handling added for MW 1.21
  • 0.4.1 - December 9, 2013 - template-specific attributes appear only for multiple-instance templates; handling removed for MW 1.16
  • 0.4.2 - February 11, 2014 - "namespace" attribute added for fields; handling removed for MW 1.17
  • 0.4.3 - May 8, 2014 - fix for <PageSchema> tag when called from within a script; i18n changed to use JSON files

Roadmap[edit | edit source]

Features and improvements that it would be great to add to Page Schemas in the future include:

  • Allowing Semantic Forms to use the Page Schemas XML directly when generating a form, instead of requiring a separate form definition.
  • More tools to export/import data structure files in formats such as UML and SQL to/from the Page Schemas XML format.
  • Making use of the proposed ContentHandler for storing XML natively, instead of in a wiki page, if/when it gets added to MediaWiki.