117 lines
3.3 KiB
Go
117 lines
3.3 KiB
Go
/*
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GoToSocial
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Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package text
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import (
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"context"
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"fmt"
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"net/url"
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"mvdan.cc/xurls/v2"
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)
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// schemes is the regex for schemes we accept when looking for links.
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// Basically, we accept https or http.
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var schemes = `(((http|https))://)`
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// FindLinks parses the given string looking for recognizable URLs (including scheme).
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// It returns a list of those URLs, without changing the string, or an error if something goes wrong.
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// If no URLs are found within the given string, an empty slice and nil will be returned.
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func FindLinks(in string) ([]*url.URL, error) {
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rxStrict, err := xurls.StrictMatchingScheme(schemes)
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if err != nil {
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return nil, err
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}
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urls := []*url.URL{}
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// bail already if we don't find anything
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found := rxStrict.FindAllString(in, -1)
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if len(found) == 0 {
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return urls, nil
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}
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// for each string we find, we want to parse it into a URL if we can
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// if we fail to parse it, just ignore this match and continue
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for _, f := range found {
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u, err := url.Parse(f)
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if err != nil {
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continue
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}
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urls = append(urls, u)
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}
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// deduplicate the URLs
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urlsDeduped := []*url.URL{}
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for _, u := range urls {
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if !contains(urlsDeduped, u) {
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urlsDeduped = append(urlsDeduped, u)
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}
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}
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return urlsDeduped, nil
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}
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// contains checks if the given url is already within a slice of URLs
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func contains(urls []*url.URL, url *url.URL) bool {
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for _, u := range urls {
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if u.String() == url.String() {
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return true
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}
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}
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return false
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}
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// ReplaceLinks replaces all detected links in a piece of text with their HTML (href) equivalents.
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// Note: because Go doesn't allow negative lookbehinds in regex, it's possible that an already-formatted
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// href will end up double-formatted, if the text you pass here contains one or more hrefs already.
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// To avoid this, you should sanitize any HTML out of text before you pass it into this function.
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func (f *formatter) ReplaceLinks(ctx context.Context, in string) string {
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rxStrict, err := xurls.StrictMatchingScheme(schemes)
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if err != nil {
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panic(err)
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}
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replaced := rxStrict.ReplaceAllStringFunc(in, func(urlString string) string {
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thisURL, err := url.Parse(urlString)
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if err != nil {
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return urlString // we can't parse it as a URL so don't replace it
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}
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shortString := thisURL.Hostname()
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if thisURL.Path != "" {
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shortString = shortString + thisURL.Path
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}
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if thisURL.Fragment != "" {
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shortString = shortString + "#" + thisURL.Fragment
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}
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if thisURL.RawQuery != "" {
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shortString = shortString + "?" + thisURL.RawQuery
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}
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replacement := fmt.Sprintf(`<a href="%s" rel="noopener">%s</a>`, urlString, shortString)
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return replacement
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})
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return replaced
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}
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