// Copyright 2026 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package external
import (
"encoding/base64"
"io"
"unicode/utf8"
"code.gitea.io/gitea/modules/htmlutil"
"code.gitea.io/gitea/modules/markup"
"code.gitea.io/gitea/modules/public"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/util"
)
type frontendRenderer struct {
name string
patterns []string
}
var (
_ markup.PostProcessRenderer = (*frontendRenderer)(nil)
_ markup.ExternalRenderer = (*frontendRenderer)(nil)
)
func (p *frontendRenderer) Name() string {
return p.name
}
func (p *frontendRenderer) NeedPostProcess() bool {
return false
}
func (p *frontendRenderer) FileNamePatterns() []string {
// TODO: the file extensions are ambiguous, even if the file name matches, it doesn't mean that the file is a 3D model
// There are some approaches to make it more accurate, but they are all complicated:
// A. Make backend know everything (detect a file is a 3D model or not)
// B. Let frontend renders to try render one by one
//
// If there would be more frontend renders in the future, we need to implement the "frontend" approach:
// 1. Make backend or parent window collect the supported extensions of frontend renders (done: backend external render framework)
// 2. If the current file matches any extension, start the general iframe embedded render (done: this renderer)
// 3. The iframe window calls the frontend renders one by one (done: frontend external render)
// 4. Report the render result to parent by postMessage (TODO: when needed)
return p.patterns
}
func (p *frontendRenderer) SanitizerRules() []setting.MarkupSanitizerRule {
return nil
}
func (p *frontendRenderer) GetExternalRendererOptions() (ret markup.ExternalRendererOptions) {
ret.SanitizerDisabled = true
ret.DisplayInIframe = true
ret.ContentSandbox = "allow-scripts allow-forms allow-modals allow-popups allow-downloads"
return ret
}
func (p *frontendRenderer) Render(ctx *markup.RenderContext, input io.Reader, output io.Writer) error {
if ctx.RenderOptions.StandalonePageOptions == nil {
opts := p.GetExternalRendererOptions()
return markup.RenderIFrame(ctx, &opts, output)
}
content, err := util.ReadWithLimit(input, int(setting.UI.MaxDisplayFileSize))
if err != nil {
return err
}
contentEncoding, contentString := "text", util.UnsafeBytesToString(content)
if !utf8.Valid(content) {
contentEncoding = "base64"
contentString = base64.StdEncoding.EncodeToString(content)
}
_, err = htmlutil.HTMLPrintf(output,
`
`,
p.name, ctx.RenderOptions.RelativePath,
contentEncoding, contentString,
public.AssetURI("js/external-render-frontend.js"))
return err
}