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88 lines
1.7 KiB
88 lines
1.7 KiB
package gmi
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import (
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"bufio"
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"errors"
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"fmt"
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"io"
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"net/url"
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"path"
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"path/filepath"
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"regexp"
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"strings"
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)
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func hasImgExt(p string) bool {
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switch path.Ext(strings.ToLower(p)) {
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case ".jpg", ".jpeg", ".png", ".gif", ".svg":
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return true
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default:
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return false
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}
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}
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// matches `=> dstURL [optional description]`
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var linkRegexp = regexp.MustCompile(`^=>\s+(\S+)\s*(.*?)\s*$`)
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// GemtextToMarkdown reads a gemtext formatted body from the Reader and writes
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// the markdown version of that body to the Writer.
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//
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// gmiGateway, if given, is used for all `gemini://` links. The `gemini://`
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// prefix will be stripped, and replaced with the given URL.
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func GemtextToMarkdown(dst io.Writer, src io.Reader, gmiGateway *url.URL) error {
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bufSrc := bufio.NewReader(src)
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for {
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line, err := bufSrc.ReadString('\n')
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if err != nil && !errors.Is(err, io.EOF) {
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return fmt.Errorf("reading: %w", err)
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}
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last := err == io.EOF
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if match := linkRegexp.FindStringSubmatch(line); len(match) > 0 {
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u, err := url.Parse(match[1])
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if err != nil {
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return fmt.Errorf("link to invalid url %q: %w", match[1], err)
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}
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if u.Scheme == "gemini" && gmiGateway != nil {
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newU := *gmiGateway
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newU.Path = filepath.Join(newU.Path, u.Host, u.Path)
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newU.RawQuery = u.RawQuery
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u = &newU
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}
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isImg := hasImgExt(u.Path)
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descr := match[2]
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if descr != "" {
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// ok
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} else if isImg {
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descr = "Image"
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} else {
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descr = "Link"
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}
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line = fmt.Sprintf("[%s](%s)\n", descr, u.String())
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if isImg {
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line = "!" + line
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}
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}
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if _, err := dst.Write([]byte(line)); err != nil {
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return fmt.Errorf("writing: %w", err)
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}
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if last {
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return nil
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}
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}
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}
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