CSC/ECE 517 Fall 2017/M1752 Implement the Microdata API

M1752 : Implement the Microdata API

Introduction

Scope

The scope of this project is to implement initial support for Microdata API specification by allowing the Servo engine to read Microdata API tags from web pages and interpret them in the DOM. This should lay a groundwork for future improvements to implement features to created vCard and JSON data from Microdata on the ServoShell.

Specification

The WHATWG Microdata HTML specification allows web data to be enriched in that it allows machines to learn more about the data in a web page. A typical example of an HTML file with Microdata is shown below -

<img src="avatar.jpg" itemprop="photo">
 My name is John Cox, and I am a writer for
 <a href="http://net.tutsplus.com" itemprop="affliation">Nettuts+</a>.
 I live in
 
   Louisville,
   KY
 

https://github.com/servo/servo/wiki/Microdata-project

Some popular websites like - use the Microdata.

This specification consists of the following HTML attributes. Out of which ‘itemtype’ and ‘itemprop’ are currently in scope.

For more information about the specification, please refer - The number of websites that use Microdata is growing; currently about 13% of websites use Microdata (statistics courtesy Alexa) , an % increase since 2014

Design

As for the initial stage of this project, the scope did not require any major changes to the engine design. We implemented a DOM method to handle appropriate attributes in the Microdata API. The below diagram shows an overview of components involved in the design.

Implementation

The implementation involved updates to the Web Interface Definition Language (webidl) files and its Rust implementation.

parse_plain_attributes ->

propertyNames ->

The method

HTMLElement.webidl ->

Configuration

The preference [Pref="dom.microdata.testing.enabled"] was added to toggle the experimental microdata methods during development.

Testing

testharness is used as the testing framework.

Dependencies

Html5ever - HTML attribute names are fetched in Servo from a lookup file in the html5ever module. The html5ever module was augmented with the 'itemprop' and 'itemtype' attributes for use in Servo.

Htmlelement.rs ->

Pull Request

References

http://html5doctor.com/microdata/