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|
package functions
import (
"bufio"
"bytes"
"errors"
"fmt"
"html"
"io"
"net/url"
"strings"
"text/template"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
"github.com/caddyserver/caddy/v2/modules/caddyhttp/templates"
)
func init() {
caddy.RegisterModule(Gemtext{})
httpcaddyfile.RegisterDirective(
"gemtext",
func(h httpcaddyfile.Helper) ([]httpcaddyfile.ConfigValue, error) {
var f Gemtext
err := f.UnmarshalCaddyfile(h.Dispenser)
return []httpcaddyfile.ConfigValue{{
Class: "template_function", Value: f,
}}, err
},
)
}
type Gemtext struct {
// If given then any `gemini://` URLs encountered as links within the
// document will be appended to this URL, having their `gemini://` scheme
// stripped off first.
//
// e.g. if `gateway_url` is `https://some.gateway/x/` then the following
// line:
//
// => gemini://geminiprotocol.net Check it out!
//
// becomes
//
// <a href="https://some.gateway/x/geminiprotocol.net">Check it out!</a>
GatewayURL string `json:"gateway_url,omitempty"`
}
var _ templates.CustomFunctions = (*Gemtext)(nil)
func (f *Gemtext) CustomTemplateFunctions() template.FuncMap {
return template.FuncMap{
"gemtext": f.funcGemtext,
}
}
func (Gemtext) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "http.handlers.templates.functions.gemtext",
New: func() caddy.Module { return new(Gemtext) },
}
}
func sanitizeText(str string) string {
return html.EscapeString(strings.TrimSpace(str))
}
type gemtextResult struct {
Title string
Body string
}
func (g *Gemtext) funcGemtext(input any) (gemtextResult, error) {
var (
r = bufio.NewReader(strings.NewReader(caddy.ToString(input)))
w = new(bytes.Buffer)
title string
pft, list bool
writeErr error
)
write := func(fmtStr string, args ...any) {
if writeErr != nil {
return
}
fmt.Fprintf(w, fmtStr, args...)
}
loop:
for {
if writeErr != nil {
return gemtextResult{}, fmt.Errorf("writing line: %w", writeErr)
}
line, err := r.ReadString('\n')
switch {
case errors.Is(err, io.EOF):
break loop
case err != nil:
return gemtextResult{}, fmt.Errorf("reading next line: %w", err)
case strings.HasPrefix(line, "```"):
if !pft {
write("<pre>\n")
pft = true
} else {
write("</pre>\n")
pft = false
}
continue
case pft:
write(line)
continue
case len(strings.TrimSpace(line)) == 0:
continue
}
// list case is special, because it requires a prefix and suffix tag
if strings.HasPrefix(line, "*") {
if !list {
write("<ul>\n")
}
write("<li>%s</li>\n", sanitizeText(line[1:]))
list = true
continue
} else if list {
write("</ul>\n")
list = false
}
switch {
case strings.HasPrefix(line, "=>"):
// TODO convert gemini:// links ?
var (
line = strings.TrimSpace(line[2:])
urlStr = line
label = urlStr
)
if i := strings.IndexAny(urlStr, " \t"); i > -1 {
urlStr, label = urlStr[:i], sanitizeText(urlStr[i:])
}
if g.GatewayURL != "" {
if u, err := url.Parse(urlStr); err == nil && u.Scheme == "gemini" {
urlStr = g.GatewayURL + u.Host + u.Path
}
}
write("<p><a href=\"%s\">%s</a></p>\n", urlStr, label)
case strings.HasPrefix(line, "###"):
write("<h3>%s</h3>\n", sanitizeText(line[3:]))
case strings.HasPrefix(line, "##"):
write("<h2>%s</h2>\n", sanitizeText(line[2:]))
case strings.HasPrefix(line, "#"):
line = sanitizeText(line[1:])
if title == "" {
title = line
}
write("<h1>%s</h1>\n", line)
case strings.HasPrefix(line, ">"):
write("<blockquote>%s</blockquote>\n", sanitizeText(line[1:]))
default:
line = strings.TrimSpace(line)
write("<p>%s</p>\n", line)
}
}
return gemtextResult{
Title: title,
Body: w.String(),
}, nil
}
// UnmarshalCaddyfile implements caddyfile.Unmarshaler.
func (g *Gemtext) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
d.Next() // consume directive name
for nesting := d.Nesting(); d.NextBlock(nesting); {
v := d.Val()
switch v {
case "gateway_url":
if !d.Args(&g.GatewayURL) {
return d.ArgErr()
} else if _, err := url.Parse(g.GatewayURL); err != nil {
return fmt.Errorf("invalid gateway url: %w", err)
}
default:
return fmt.Errorf("unknown directive %q", v)
}
}
return nil
}
|
