Add support for rendering terminal output with colors (#19497)

modules/markup/renderer.go

@@ -5,6 +5,7 @@
 package markup
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -93,6 +94,12 @@ type Renderer interface {
 	Render(ctx *RenderContext, input io.Reader, output io.Writer) error
 }
 
+// RendererContentDetector detects if the content can be rendered
+// by specified renderer
+type RendererContentDetector interface {
+	CanRender(filename string, input io.Reader) bool
+}
+
 var (
 	extRenderers = make(map[string]Renderer)
 	renderers    = make(map[string]Renderer)
@@ -117,6 +124,20 @@ func GetRendererByType(tp string) Renderer {
 	return renderers[tp]
 }
 
+// DetectRendererType detects the markup type of the content
+func DetectRendererType(filename string, input io.Reader) string {
+	buf, err := io.ReadAll(input)
+	if err != nil {
+		return ""
+	}
+	for _, renderer := range renderers {
+		if detector, ok := renderer.(RendererContentDetector); ok && detector.CanRender(filename, bytes.NewReader(buf)) {
+			return renderer.Name()
+		}
+	}
+	return ""
+}
+
 // Render renders markup file to HTML with all specific handling stuff.
 func Render(ctx *RenderContext, input io.Reader, output io.Writer) error {
 	if ctx.Type != "" {