https://miro.com/app/board/uXjVOi-LVy0=/ - an overview of the data flow in the parsoid endpoints, when and how we do stashing and caching, and what we are changing
ParsoidOutputAccess - Service for getting parsoid outputs and warms the cache with pregenerated outputs.
ParserCache - Cache for ParserOutput objects corresponding to the latest page revisions. The ParserCache is a two-tiered cache backed by BagOStuff which supports varying the stored content on the values of ParserOptions used during a page parse.
ParsoidOutputStash - Parsoid HTML and Parsoid metadata from storage. Add stash option to /page/html & /revision/html endpoints. When this option is set, the PageBundle returned by Parsoid is stashed and an etag is returned that can later be used to make use of the stashed PageBundle.
PageBundle (PB): Returned by the ParsoidOutputStash. Represents a parsed page from Parsoid. PageBundle is equivalent to the given ParserOutput.
WikitextContentHandler - Content handler for wiki text pages. ContentHandler instances are stateless singletons that serve, among other things, as a factory for Content objects. Generally, there is one subclass of ContentHandler and one subclass of Content for every type of content model.
RevisionRenderer - The RevisionRenderer service provides access to rendered output for revisions. It does so by acting as a factory for RenderedRevision instances, which in turn provide lazy access to ParserOutput objects.
RenderedRevision - RenderedRevision represents the rendered representation of a revision. It acts as a lazy provider of ParserOutput objects for the revision's individual slots, as well as a combined ParserOutput of all slots.
ParserOptions - The parsing of wikitext is based on the applied ParserOptions. ParserOptions are initialized from the RequestContext where the Language and User are the two important parameters.
ParserOutput - The result of parsing is stored as the ParserOutput object. The main attribute here is mText, that holds the whole HTML representation of the article content. Besides that ParserOutput holds separately categories, links, images, sections, templates and other "parts" of the article as variables. Moreover, it holds information relevant for caching – cache time, expiry and revision. After the ParserOutput is produced, the values of its attributes are set to the OutputPage object.
PoolWorkArticleView - After the wikitext is parsed and ParserOutput is created (in PoolWorkArticleView::doWork()), the output will be cached if cache expiry > 0 and we are dealing with the latest revision of the article.
ParsoidClient - Client to convert wikitext to html and html to wikitext using the Parsoid. Different implementations of this exist, such as VRSParsoidClient and DirectParsoidClient.
ParsoidHandler - Base class for Parsoid handlers.
TransformHandler - REST API Handler for transforming content given in the requests: /v1/transform/{from}/to/{format}, /v1/transform/{from}/to/{format}/{title}, /v1/transform/{from}/to/{format}/{title}/{revision}. Extends the ParsoidHandler.
VRSParsoidClient - A ParsoidClient that does transformation using the REST API. See patch.
DirectParsoidClient - Previously the VisualEditorParsoidClient. Uses the Parsoid directly for transformation, and not the REST interface. See patch.
WTTransform - Logic to transform wikitext to HTML.
HTMLTransform - Logic to transform HTML to wikitext. See patch.
HtmlOutputRendererHelper - Helper for getting output of a given wikitext page rendered by Parsoid.
