maubot/matrix/htmlutil.go

// maubot - A plugin-based Matrix bot system written in Go.
// Copyright (C) 2018 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package matrix

import (
	"strings"
	"gopkg.in/russross/blackfriday.v2"
	"maubot.xyz"
)

func RenderMarkdown(text string) maubot.Content {
	parser := blackfriday.New(
		blackfriday.WithExtensions(blackfriday.NoIntraEmphasis |
			blackfriday.Tables |
			blackfriday.FencedCode |
			blackfriday.Strikethrough |
			blackfriday.SpaceHeadings |
			blackfriday.DefinitionLists))
	ast := parser.Parse([]byte(text))

	renderer := blackfriday.NewHTMLRenderer(blackfriday.HTMLRendererParameters{
		Flags: blackfriday.UseXHTML,
	})

	var buf strings.Builder
	renderer.RenderHeader(&buf, ast)
	ast.Walk(func(node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
		return renderer.RenderNode(&buf, node, entering)
	})
	renderer.RenderFooter(&buf, ast)
	htmlBody := buf.String()

	return maubot.Content{
		FormattedBody: htmlBody,
		Format: maubot.FormatHTML,
		MsgType: maubot.MsgText,
		Body: HTMLToText(htmlBody),
	}
}