gitea/modules/markup/internal/renderinternal.go

83 lines
2.2 KiB
Go

// Copyright 2024 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package internal
import (
"crypto/rand"
"encoding/base64"
"html/template"
"io"
"regexp"
"strings"
"sync"
"code.gitea.io/gitea/modules/htmlutil"
"golang.org/x/net/html"
)
var reAttrClass = sync.OnceValue[*regexp.Regexp](func() *regexp.Regexp {
// TODO: it isn't a problem at the moment because our HTML contents are always well constructed
return regexp.MustCompile(`(<[^>]+)\s+class="([^"]+)"([^>]*>)`)
})
// RenderInternal also works without initialization
// If no initialization (no secureID), it will not protect any attributes and return the original name&value
type RenderInternal struct {
secureID string
secureIDPrefix string
}
func (r *RenderInternal) Init(output io.Writer) io.WriteCloser {
buf := make([]byte, 12)
_, err := rand.Read(buf)
if err != nil {
panic("unable to generate secure id")
}
return r.init(base64.URLEncoding.EncodeToString(buf), output)
}
func (r *RenderInternal) init(secID string, output io.Writer) io.WriteCloser {
r.secureID = secID
r.secureIDPrefix = r.secureID + ":"
return &finalProcessor{renderInternal: r, output: output}
}
func (r *RenderInternal) RecoverProtectedValue(v string) (string, bool) {
if !strings.HasPrefix(v, r.secureIDPrefix) {
return "", false
}
return v[len(r.secureIDPrefix):], true
}
func (r *RenderInternal) SafeAttr(name string) string {
if r.secureID == "" {
return name
}
return "data-attr-" + name
}
func (r *RenderInternal) SafeValue(val string) string {
if r.secureID == "" {
return val
}
return r.secureID + ":" + val
}
func (r *RenderInternal) NodeSafeAttr(attr, val string) html.Attribute {
return html.Attribute{Key: r.SafeAttr(attr), Val: r.SafeValue(val)}
}
func (r *RenderInternal) ProtectSafeAttrs(content template.HTML) template.HTML {
if r.secureID == "" {
return content
}
return template.HTML(reAttrClass().ReplaceAllString(string(content), `$1 data-attr-class="`+r.secureIDPrefix+`$2"$3`))
}
func (r *RenderInternal) FormatWithSafeAttrs(w io.Writer, fmt string, a ...any) error {
_, err := w.Write([]byte(r.ProtectSafeAttrs(htmlutil.HTMLFormat(fmt, a...))))
return err
}