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// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// 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 <http://www.gnu.org/licenses/>.
package text
import (
"bytes"
"context"
"regexp"
"strings"
"code.superseriousbusiness.org/gotosocial/internal/gtsmodel"
"code.superseriousbusiness.org/gotosocial/internal/log"
"code.superseriousbusiness.org/gotosocial/internal/regexes"
"codeberg.org/gruf/go-byteutil"
"github.com/yuin/goldmark"
"github.com/yuin/goldmark/extension"
"github.com/yuin/goldmark/renderer"
"github.com/yuin/goldmark/renderer/html"
)
// FromMarkdown fulfils FormatFunc by parsing
// the given markdown input into a FormatResult.
//
// Inline (aka unsafe) HTML elements are allowed,
// as they should be sanitized afterwards anyway.
func (f *Formatter) FromMarkdown(
ctx context.Context,
parseMention gtsmodel.ParseMentionFunc,
authorID string,
statusID string,
input string,
) *FormatResult {
return f.fromMarkdown(
ctx,
false, // basic = false
parseMention,
authorID,
statusID,
input,
)
}
// FromMarkdownBasic fulfils FormatFunc by parsing
// the given markdown input into a FormatResult.
//
// Unlike FromMarkdown, it will only parse emojis with
// the custom renderer, leaving aside mentions and tags.
//
// Inline (aka unsafe) HTML elements are not allowed.
//
// If the result is a single paragraph,
// it will not be wrapped in <p> tags.
func (f *Formatter) FromMarkdownBasic(
ctx context.Context,
parseMention gtsmodel.ParseMentionFunc,
authorID string,
statusID string,
input string,
) *FormatResult {
res := f.fromMarkdown(
ctx,
true, // basic = true
parseMention,
authorID,
statusID,
input,
)
res.HTML = unwrapParagraph(res.HTML)
return res
}
// fromMarkdown parses the given input text either
// with or without emojis, and returns the result.
func (f *Formatter) fromMarkdown(
ctx context.Context,
basic bool,
parseMention gtsmodel.ParseMentionFunc,
authorID string,
statusID string,
input string,
) *FormatResult {
var (
result = new(FormatResult)
opts []renderer.Option
)
if basic {
// Don't allow raw HTML tags,
// markdown syntax only.
opts = []renderer.Option{
html.WithXHTML(),
html.WithHardWraps(),
}
} else {
opts = []renderer.Option{
html.WithXHTML(),
html.WithHardWraps(),
// Allow raw HTML tags, we
// sanitize at the end anyway.
html.WithUnsafe(),
}
}
// Instantiate goldmark parser for
// markdown, using custom renderer
// to add hashtag/mention links.
md := goldmark.New(
goldmark.WithRendererOptions(
opts...,
),
goldmark.WithExtensions(
&customRenderer{
ctx,
f.db,
parseMention,
authorID,
statusID,
// If basic, pass
// emojiOnly = true.
basic,
result,
},
// Turns URLs into links.
extension.NewLinkify(
extension.WithLinkifyURLRegexp(regexes.URLLike),
),
extension.Footnote,
extension.Strikethrough,
),
)
// Convert input string to bytes
// without performing any allocs.
bInput := byteutil.S2B(input)
// Parse input into HTML.
var htmlBytes bytes.Buffer
if err := md.Convert(
bInput,
&htmlBytes,
); err != nil {
log.Errorf(ctx, "error formatting markdown input to HTML: %s", err)
}
// Clean and shrink HTML.
result.HTML = byteutil.B2S(htmlBytes.Bytes())
result.HTML = SanitizeHTML(result.HTML)
result.HTML = MinifyHTML(result.HTML)
return result
}
var parasRegexp = regexp.MustCompile(`</?p>`)
// unwrapParagraph removes opening and closing paragraph tags
// of input HTML, if input html is a single paragraph only.
func unwrapParagraph(html string) string {
if !strings.HasPrefix(html, "<p>") {
return html
}
if !strings.HasSuffix(html, "</p>") {
return html
}
// Make a substring excluding the
// opening and closing paragraph tags.
sub := html[3 : len(html)-4]
// If there are still other paragraph tags left
// inside the substring, return html unchanged.
containsOtherParas := parasRegexp.MatchString(sub)
if containsOtherParas {
return html
}
// Return the substring.
return sub
}
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