// 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
tags. plainTextParser := parser.NewParser( parser.WithBlockParsers( util.Prioritized(newPlaintextParser(), 500), ), ) return f.fromPlain( ctx, plainTextParser, false, // basic = false parseMention, authorID, statusID, input, ) } // FromPlainNoParagraph fulfils FormatFunc by parsing // the given plaintext input into a FormatResult. // // Unlike FromPlain, it will not wrap the resulting // HTML in
tags, making it useful for parsing // short fragments of text that oughtn't be formally // wrapped as a paragraph. func (f *Formatter) FromPlainNoParagraph( ctx context.Context, parseMention gtsmodel.ParseMentionFunc, authorID string, statusID string, input string, ) *FormatResult { // Initialize block parser that // doesn't wrap result in
tags. plainTextParser := parser.NewParser( parser.WithBlockParsers( util.Prioritized(newPlaintextParserNoParagraph(), 500), ), ) return f.fromPlain( ctx, plainTextParser, false, // basic = false parseMention, authorID, statusID, input, ) } // FromPlainBasic fulfils FormatFunc by parsing // the given plaintext input into a FormatResult. // // Unlike FromPlain, it will only parse emojis with // the custom renderer, leaving aside mentions and tags. // // Resulting HTML will also NOT be wrapped in
tags. func (f *Formatter) FromPlainBasic( ctx context.Context, parseMention gtsmodel.ParseMentionFunc, authorID string, statusID string, input string, ) *FormatResult { // Initialize block parser that // doesn't wrap result in
tags.
plainTextParser := parser.NewParser(
parser.WithBlockParsers(
util.Prioritized(newPlaintextParserNoParagraph(), 500),
),
)
return f.fromPlain(
ctx,
plainTextParser,
true, // basic = true
parseMention,
authorID,
statusID,
input,
)
}
// fromPlain parses the given input text
// using the given plainTextParser, and
// returns the result.
func (f *Formatter) fromPlain(
ctx context.Context,
plainTextParser parser.Parser,
basic bool,
parseMention gtsmodel.ParseMentionFunc,
authorID string,
statusID string,
input string,
) *FormatResult {
result := new(FormatResult)
// Instantiate goldmark parser for
// plaintext, using custom renderer
// to add hashtag/mention links.
md := goldmark.New(
goldmark.WithRendererOptions(
html.WithXHTML(),
html.WithHardWraps(),
),
// Use whichever plaintext
// parser we were passed.
goldmark.WithParser(plainTextParser),
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.LinkScheme),
),
),
)
// 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 plaintext 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
}
// ParseHTMLToPlain parses the given HTML string, then
// outputs it to equivalent plaintext while trying to
// keep as much of the smenantic intent of the input
// HTML as possible, ie., titles are placed on separate
// lines, `
`s are converted to newlines, text inside
// `` and `` tags is retained, but without
// emphasis, `` links are unnested and the URL they
// link to is placed in angle brackets next to them,
// lists are replaced with newline-separated indented
// items, etc.
//
// This function is useful when you need to filter on
// HTML and want to avoid catching tags in the filter,
// or when you want to serve something in a plaintext
// format that may contain HTML tags (eg., CWs).
func ParseHTMLToPlain(html string) string {
plain := html2text.HTML2TextWithOptions(
html,
html2text.WithLinksInnerText(),
html2text.WithUnixLineBreaks(),
html2text.WithListSupport(),
)
return strings.TrimSpace(plain)
}
// StripHTMLFromText runs text through strict sanitization
// to completely remove any HTML from the input without
// trying to preserve the semantic intent of any HTML tags.
//
// This is useful in cases where the input was not allowed
// to contain HTML at all, and the output isn't either.
func StripHTMLFromText(text string) string {
// Unescape first to catch any tricky critters.
content := gohtml.UnescapeString(text)
// Remove all detected HTML.
content = strict.Sanitize(content)
// Unescape again to return plaintext.
content = gohtml.UnescapeString(content)
return strings.TrimSpace(content)
}