Package com.ericbouchut.learndev.course

Class MarkdownRenderer

java.lang.Object

com.ericbouchut.learndev.course.MarkdownRenderer

@Service
public class MarkdownRenderer
extends Object

Converts lesson Markdown to HTML that is safe to serve.

Lesson content is instructor input and CommonMark passes raw HTML through, so the rendered output is sanitized against an allowlist: no script, event handler, or frame survives, whatever the Markdown contains. Results are cached by the SHA-256 of the source, so a lesson is rendered once per content version (see ADR-0013 in docs/adr/).

Markdown headings are demoted one level (# becomes h2, capped at h6): the lesson page already provides the single h1 (the lesson title), and one h1 per page with no skipped level is an RGAA 9.1 commitment (see ADR-0014 and docs/rgaa.md).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	MarkdownRenderer.RenderedMarkdown	Sanitized lesson HTML plus its table of contents (ADR-0018).
static final record	MarkdownRenderer.TocEntry	One TOC entry: minted anchor id, heading text, rendered level.

Constructor Summary

Constructors

Constructor	Description
MarkdownRenderer()

Method Summary

Modifier and Type	Method	Description
static String	cacheKey(String markdown)	Cache key: SHA-256 of the source.
MarkdownRenderer.RenderedMarkdown	render(String markdown)
static String	stripLeadingTitleHeading(String markdown, String title)	Drops a leading level-1 heading whose text repeats the lesson title, so the common habit of starting a document with its title does not render as an h2 duplicating the page h1 (see ADR-0014).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

MarkdownRenderer

public MarkdownRenderer()

Method Details

render

@Cacheable(cacheNames="renderedMarkdown",
           key="T(com.ericbouchut.learndev.course.MarkdownRenderer).cacheKey(#markdown)")
public MarkdownRenderer.RenderedMarkdown render(String markdown)

stripLeadingTitleHeading

public static String stripLeadingTitleHeading(String markdown,
 String title)

Drops a leading level-1 heading whose text repeats the lesson title, so the common habit of starting a document with its title does not render as an h2 duplicating the page h1 (see ADR-0014). Handles the ATX form (# Title, closing #s tolerated) and the setext form (Title underlined with =); the match is trimmed and case-insensitive. Callers apply this BEFORE render(String) so the render cache stays keyed by the exact rendered input; the stored Markdown is never modified.

cacheKey

public static String cacheKey(String markdown)

Cache key: SHA-256 of the source. Content-addressed, so edited content is a new key and stale entries cannot exist; the fixed-size key also avoids holding whole lesson sources in the cache's key set.