1 files changed, 64 insertions, 0 deletions
diff --git a/modules/markup/asciicast/asciicast.go b/modules/markup/asciicast/asciicast.go
new file mode 100644
index 00000000..06780623
--- /dev/null
+++ b/modules/markup/asciicast/asciicast.go
@@ -0,0 +1,64 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package asciicast
+
+import (
+	"fmt"
+	"io"
+	"net/url"
+	"regexp"
+
+	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+func init() {
+	markup.RegisterRenderer(Renderer{})
+}
+
+// Renderer implements markup.Renderer for asciicast files.
+// See https://github.com/asciinema/asciinema/blob/develop/doc/asciicast-v2.md
+type Renderer struct{}
+
+// Name implements markup.Renderer
+func (Renderer) Name() string {
+	return "asciicast"
+}
+
+// Extensions implements markup.Renderer
+func (Renderer) Extensions() []string {
+	return []string{".cast"}
+}
+
+const (
+	playerClassName = "asciinema-player-container"
+	playerSrcAttr   = "data-asciinema-player-src"
+)
+
+// SanitizerRules implements markup.Renderer
+func (Renderer) SanitizerRules() []setting.MarkupSanitizerRule {
+	return []setting.MarkupSanitizerRule{
+		{Element: "div", AllowAttr: "class", Regexp: regexp.MustCompile(playerClassName)},
+		{Element: "div", AllowAttr: playerSrcAttr},
+	}
+}
+
+// Render implements markup.Renderer
+func (Renderer) Render(ctx *markup.RenderContext, _ io.Reader, output io.Writer) error {
+	rawURL := fmt.Sprintf("%s/%s/%s/raw/%s/%s",
+		setting.AppSubURL,
+		url.PathEscape(ctx.Metas["user"]),
+		url.PathEscape(ctx.Metas["repo"]),
+		ctx.Metas["BranchNameSubURL"],
+		url.PathEscape(ctx.RelativePath),
+	)
+
+	_, err := io.WriteString(output, fmt.Sprintf(
+		`<div class="%s" %s="%s"></div>`,
+		playerClassName,
+		playerSrcAttr,
+		rawURL,
+	))
+	return err
+}