Extension:TemplateData

The TemplateData extension introduces a  tag and an API which together allow editors to specify how templates should be invoked. This information is available as a nicely-formatted table for end-users, and as a JSON API, which enables other systems (e.g. VisualEditor) to build interfaces for working with templates and their parameters.

Defining a TemplateData block
The TemplateData extension works through having a  tag defined in the wikitext of a template page (optionally it can be transcluded into the template page as well). This is designed to be compatible with the common layout many wikis have of transcluding template documentation from a separate page (but is not required). This content of the  tag is parsed as JSON using the format described below; note that all descriptions must be in plain text (no wikitext is accepted inside the JSON).

The below is a visualised version of the JSON data as defined on the template page enclosed by   tags. The formal specification is available in the TemplateData repository. Please refer to spec.templatedata.json for the latest version.

Example of how TemplateData is displayed on the template page
{	"description": "Label unsigned comments in a conversation.", "params": { "user": { "label": "Username", "type": "wiki-user-name", "required": true, "description": "User name of person who forgot to sign their comment.", "aliases": ["1"] },		"date": { "label": "Date", "description": { "en": "Timestamp of when the comment was posted, in YYYY-MM-DD format." },			"aliases": ["2"] },		"year": { "label": "Year", "type": "number" },		"month": { "label": "Month", "inherits": "year" },		"day": { "label": "Day", "inherits": "year" },		"comment": { "required": false }	},	"sets": [ {			"label": "Date", "params": ["year", "month", "day"] }	] }

Using the TemplateData API
See the automatically formatted help at https://en.wikipedia.org/w/api.php?action=help&modules=templatedata. An example of a working call is https://en.wikipedia.org/w/api.php?action=templatedata&titles=Template:Cite%20web (for Template:Cite web). You can also see a formatted version to better understand the structure.

Additions and changes to JSON as received from the API
The JSON structure provided in response to an API HTTP get request is significantly different than that which is defined in the. In response to the API request, the MediaWiki software makes the following changes to the JSON object:
 * Adds two wrapping objects:
 * An overall Pages Object containing one or more Page Objects
 * An object with a numeric key: a Page Object


 * Additions/changes to the actual TemplateData Object
 * Add the  key
 * Add the  key
 * Add the  key
 * Change all TemplateText occurrences that are just strings to objects with a single key for the current wiki's Wikipedia language code

Live example: Template:Cite web: source template page,  is transcluded from the  template documentation page, [//en.wikipedia.org/w/api.php?action=templatedata&titles=Template:Cite%20web&format=jsonfm API response in HTML format], [//en.wikipedia.org/w/api.php?action=templatedata&titles=Template:cite%20web actual API response].