gmitohtml/pkg/gmitohtml/convert.go

112 lines
2.6 KiB
Go

package gmitohtml
import (
"bufio"
"bytes"
"errors"
"fmt"
"net/url"
"path"
"strings"
"sync"
)
// ErrInvalidURL is the error returned when the URL is invalid.
var ErrInvalidURL = errors.New("invalid URL")
var daemonAddress string
var assetLock sync.Mutex
func rewriteURL(u string, loc *url.URL) string {
if daemonAddress != "" {
if strings.HasPrefix(u, "gemini://") {
return "http://" + daemonAddress + "/gemini/" + u[9:]
} else if strings.Contains(u, "://") {
return u
} else if loc != nil && len(u) > 0 && !strings.HasPrefix(u, "//") {
newPath := u
if u[0] != '/' {
newPath = path.Join(loc.Path, u)
}
return "http://" + daemonAddress + "/gemini/" + loc.Host + newPath
}
return "http://" + daemonAddress + "/gemini/" + u
}
return u
}
// Convert converts text/gemini to text/html.
func Convert(page []byte, u string) []byte {
var result []byte
var preformatted bool
parsedURL, err := url.Parse(u)
if err != nil {
parsedURL = nil
err = nil
}
scanner := bufio.NewScanner(bytes.NewReader(page))
for scanner.Scan() {
line := scanner.Bytes()
l := len(line)
if l >= 3 && string(line[0:3]) == "```" {
preformatted = !preformatted
if preformatted {
result = append(result, []byte("<pre>\n")...)
} else {
result = append(result, []byte("</pre>\n")...)
}
continue
}
if preformatted {
result = append(result, line...)
result = append(result, []byte("\n")...)
continue
}
if l >= 7 && bytes.HasPrefix(line, []byte("=> ")) {
split := bytes.SplitN(line[3:], []byte(" "), 2)
if len(split) != 2 {
split = bytes.SplitN(line[3:], []byte("\t"), 2)
}
if len(split) == 2 {
link := append([]byte(`<a href="`), rewriteURL(string(split[0]), parsedURL)...)
link = append(link, []byte(`">`)...)
link = append(link, split[1]...)
link = append(link, []byte(`</a>`)...)
result = append(result, link...)
result = append(result, []byte("<br>")...)
continue
}
}
heading := 0
for i := 0; i < l; i++ {
if line[i] == '#' {
heading++
} else {
break
}
}
if heading > 0 {
result = append(result, []byte(fmt.Sprintf("<h%d>%s</h%d>", heading, line[heading:], heading))...)
continue
}
result = append(result, line...)
result = append(result, []byte("<br>")...)
}
if preformatted {
result = append(result, []byte("</pre>\n")...)
}
result = append([]byte("<!DOCTYPE html>\n<html>\n<head>\n<meta name=\"viewport\" content=\"width=device-width,initial-scale=1\">\n<link rel=\"stylesheet\" href=\"/assets/style.css\"></link>\n</head>\n<body>\n"), result...)
result = append(result, []byte("\n</body>\n</html>")...)
return result
}