src/main/java/eu/mulk/mulkcms2/common/markdown/MarkdownConverter.java

package eu.mulk.mulkcms2.common.markdown;

import com.vladsch.flexmark.ext.abbreviation.AbbreviationExtension;
import com.vladsch.flexmark.ext.autolink.AutolinkExtension;
import com.vladsch.flexmark.ext.definition.DefinitionExtension;
import com.vladsch.flexmark.ext.footnotes.FootnoteExtension;
import com.vladsch.flexmark.ext.gfm.strikethrough.StrikethroughExtension;
import com.vladsch.flexmark.ext.tables.TablesExtension;
import com.vladsch.flexmark.ext.typographic.TypographicExtension;
import com.vladsch.flexmark.html.HtmlRenderer;
import com.vladsch.flexmark.parser.Parser;
import com.vladsch.flexmark.util.data.MutableDataSet;
import java.util.Arrays;
import javax.enterprise.context.ApplicationScoped;
import org.jsoup.Jsoup;
import org.jsoup.safety.Safelist;

@ApplicationScoped
public class MarkdownConverter {

  private final Parser parser;
  private final HtmlRenderer renderer;

  public MarkdownConverter() {
    var options = new MutableDataSet();
    options.set(
        Parser.EXTENSIONS,
        Arrays.asList(
            TablesExtension.create(),
            StrikethroughExtension.create(),
            AbbreviationExtension.create(),
            AutolinkExtension.create(),
            DefinitionExtension.create(),
            TypographicExtension.create(),
            FootnoteExtension.create()));
    options.set(Parser.FENCED_CODE_BLOCK_PARSER, true);
    options.set(HtmlRenderer.SOFT_BREAK, "\n");
    options.set(HtmlRenderer.HARD_BREAK, "<br />\n");
    options.set(TypographicExtension.ENABLE_SMARTS, true);
    options.set(TypographicExtension.ENABLE_QUOTES, true);
    options.set(FootnoteExtension.FOOTNOTE_BACK_REF_STRING, "");

    this.parser = Parser.builder(options).build();
    this.renderer = HtmlRenderer.builder(options).build();
  }

  public String htmlify(String markdown) {
    var parsedDocument = parser.parse(markdown);
    var unsanitizedHtml = renderer.render(parsedDocument);
    return Jsoup.clean(unsanitizedHtml, Safelist.relaxed());
  }
}