Page Content Service

The Page Content Service (PCS) is a set of Node.js-based services in Wikimedia production designed to deliver Wikimedia project page content and metadata for modern reading clients. It delivers:

1. Optimized page content for modern clients to provide a full article reading experience
2. A standard structured representation for pages that can be used for display within lists and previews
3. Aggregated common CSS used for styling and theming articles
4. Client logic for page interactions such as changing reading themes, handling references, lazy loading images, and more are provided as a JavaScript interface that clients can execute locally

PCS delivers content in both HTML and JSON formats. It consolidates data from the Wikipedia, Commons and Wikidata MediaWiki APIs as well as the Parsoid and ORES API. It will supersede the mobile-sections endpoint of the Mobile Content Service (MCS).

PCS is maintained by the Wikimedia Product Infrastructure team.

Endpoints

HTML endpoints

/page/mobile-html

Stability: experimental

Provides Parsoid HTML with a few key differences:

• Additions:
  • Theming support (default, sepia, dark, black) + dimming of images
  • Setting of body margins based on native client guidelines
  • Edit icons for sections + page description
  • Page header
    • Title
    • Pronunciation link (if present on page)
    • Description (from Wikidata or from local wiki) or link to add a new description
  • Page footer
    • Menu items ("last edited on" with link to page history, page issues, disambiguations, link to talk page, geo coordinates if found on page, ...)
    • Read more (makes an XHR to get a configurable number of related pages)
• Removals:
  • Navboxes
• Transformations:
  • Infoboxes are collapsible.
  • Reference list sections are collapsible.
  • Images of at least a certain size are lazy loaded.
  • The lead content paragraph is moved above the first infobox.

More detail about the JavaScript interface can be found on the pcs.md page.

Examples: Prod | Beta cluster | Labs | Local RB | Local MCS

JSON endpoints

/page/summary

Stability: stable

The Summary serves two very important purposes:

1. It provides the data necessary for the representation of a page within a page/link preview, search results, other lists, etc…
2. It provides basic metadata necessary for clients to make business logic and navigation decisions before displaying a page.

To accomplish number 1, it contains some basic metadata: an image/thumbnail, a description, the first paragraph of the page plain text and HTML form (extract and extract_html), and article language and directionality (RTL or LTR). It's preferable to use the extract_html over extract since some complex formulas are better handled with HTML than plain text.

To accomplish number 2, it contains some semantic information on the page, its name space, and various URLs in order for clients to understand the content of the page prior to deciding how to display it.

Additionally, the Summary structure is provided in other APIs (like the feed) that return lists of pages.

Page_Previews/API_Specification

Example URLs: Prod | Beta cluster | Labs | Local RB | Local MCS

For comparison, here is the action=query request this endpoint replaces: Prod. In the current version TextExtract is not used anymore, though. Instead PCS gets more of the information from the respective Parsoid HTML output and does some transformations on that.

/page/media-list

Stability: experimental

Lists media items shown on a page: images, videos, and audio. This is useful for clients wishing to build a gallery interface for content within a page or for downloading images for offline reading.

Example URLs: Prod | Beta cluster | Labs | Local RB | Local MCS

/page/mobile-html-offline-resources

Stability: experimental

List of the CSS and JS schemeless URLs for offline resourcing for mobile consumption. The motivation for this endpoint is to let native clients know what other files they would have to download when saving a page for offline without having to parse the page.

Example URLs: Prod | Beta cluster | Labs | Local RB | Local MCS

Example output:

[
  "//meta.wikimedia.org/api/rest_v1/data/css/mobile/base",
  "//meta.wikimedia.org/api/rest_v1/data/css/mobile/pcs",
  "//meta.wikimedia.org/api/rest_v1/data/javascript/mobile/pcs",
  "//en.wikipedia.org/api/rest_v1/data/css/mobile/site"
]

Example URLs: Prod | Beta cluster | Labs | Local RB | Local MCS

Clients

PCS can be used by any WMF or 3rd party client that wants to display page content for reading contexts. As mentioned above the /page/summary endpoint is heavily used in other places and already use by the native apps and the web PagePreview feature. /page/mobile-html has some coupling to the wikimedia-page-library and is somewhat tied to design decisions for the native WMF apps. If needed there could be another HTML endpoint that sits somewhere between Parsoid HTML and /page/mobile-html.

Within the WMF, the following clients are expected to integrate use of /page/mobile-html in 2020:

1. Wikipedia Android App
2. Wikipedia iOS App

External links

• Usage documentation can be found at the API spec