How to disable features(html tags)?

[ivanjaros]

I want to have multiple filters per user roles so certain users can use links, images or bold text, for example, but others can not. Is there a way to configure goldmark this way or do I have to run it through something like bluemonday afterwards(which seems like not an ideal solution)? The way goldmark works is it gives option to add features but not remove them(it lacks configuration for core features and extensions).

[tulir]

You can override the parser used by goldmark to remove the defaults. Here's an example with a bunch of the defaults disabled:

package main

import (
	"fmt"
	"strings"

	"github.com/yuin/goldmark"
	"github.com/yuin/goldmark/parser"
	"github.com/yuin/goldmark/util"
)

func main() {
	parserWithoutFeatures := parser.NewParser(
		parser.WithBlockParsers(
			//util.Prioritized(parser.NewSetextHeadingParser(), 100),
			util.Prioritized(parser.NewThematicBreakParser(), 200),
			//util.Prioritized(parser.NewListParser(), 300),
			//util.Prioritized(parser.NewListItemParser(), 400),
			//util.Prioritized(parser.NewCodeBlockParser(), 500),
			//util.Prioritized(parser.NewATXHeadingParser(), 600),
			//util.Prioritized(parser.NewFencedCodeBlockParser(), 700),
			//util.Prioritized(parser.NewBlockquoteParser(), 800),
			//util.Prioritized(parser.NewHTMLBlockParser(), 900),
			util.Prioritized(parser.NewParagraphParser(), 1000),
		),
		parser.WithInlineParsers(
			//util.Prioritized(parser.NewCodeSpanParser(), 100),
			util.Prioritized(parser.NewLinkParser(), 200),
			util.Prioritized(parser.NewAutoLinkParser(), 300),
			//util.Prioritized(parser.NewRawHTMLParser(), 400),
			util.Prioritized(parser.NewEmphasisParser(), 500),
		),
		parser.WithParagraphTransformers(
			util.Prioritized(parser.LinkReferenceParagraphTransformer, 100),
		),
	)
	markdown := goldmark.New(goldmark.WithParser(parserWithoutFeatures))
	var buf strings.Builder
	markdown.Convert([]byte(`# Hello world (no headings)

* No lists `+"`or code`"+`

**Yes bold *and italic***, [also links](https://example.com)
`), &buf)
	fmt.Println(buf.String())
}

Output:

<p># Hello world (no headings)</p>
<p>* No lists `or code`</p>
<p><strong>Yes bold <em>and italic</em></strong>, <a href="https://example.com">also links</a></p>

The list of defaults is in parser/parser.go: https://github.com/yuin/goldmark/blob/v1.5.3/parser/parser.go#L567-L621