1 files changed, 146 insertions, 0 deletions
diff --git a/modules/markup/external/external.go b/modules/markup/external/external.go
new file mode 100644
index 0000000..122517e
--- /dev/null
+++ b/modules/markup/external/external.go
@@ -0,0 +1,146 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package external
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"runtime"
+	"strings"
+
+	"code.gitea.io/gitea/modules/graceful"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/process"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
+)
+
+// RegisterRenderers registers all supported third part renderers according settings
+func RegisterRenderers() {
+	for _, renderer := range setting.ExternalMarkupRenderers {
+		if renderer.Enabled && renderer.Command != "" && len(renderer.FileExtensions) > 0 {
+			markup.RegisterRenderer(&Renderer{renderer})
+		}
+	}
+}
+
+// Renderer implements markup.Renderer for external tools
+type Renderer struct {
+	*setting.MarkupRenderer
+}
+
+var (
+	_ markup.PostProcessRenderer = (*Renderer)(nil)
+	_ markup.ExternalRenderer    = (*Renderer)(nil)
+)
+
+// Name returns the external tool name
+func (p *Renderer) Name() string {
+	return p.MarkupName
+}
+
+// NeedPostProcess implements markup.Renderer
+func (p *Renderer) NeedPostProcess() bool {
+	return p.MarkupRenderer.NeedPostProcess
+}
+
+// Extensions returns the supported extensions of the tool
+func (p *Renderer) Extensions() []string {
+	return p.FileExtensions
+}
+
+// SanitizerRules implements markup.Renderer
+func (p *Renderer) SanitizerRules() []setting.MarkupSanitizerRule {
+	return p.MarkupSanitizerRules
+}
+
+// SanitizerDisabled disabled sanitize if return true
+func (p *Renderer) SanitizerDisabled() bool {
+	return p.RenderContentMode == setting.RenderContentModeNoSanitizer || p.RenderContentMode == setting.RenderContentModeIframe
+}
+
+// DisplayInIFrame represents whether render the content with an iframe
+func (p *Renderer) DisplayInIFrame() bool {
+	return p.RenderContentMode == setting.RenderContentModeIframe
+}
+
+func envMark(envName string) string {
+	if runtime.GOOS == "windows" {
+		return "%" + envName + "%"
+	}
+	return "$" + envName
+}
+
+// Render renders the data of the document to HTML via the external tool.
+func (p *Renderer) Render(ctx *markup.RenderContext, input io.Reader, output io.Writer) error {
+	var (
+		command = strings.NewReplacer(
+			envMark("GITEA_PREFIX_SRC"), ctx.Links.SrcLink(),
+			envMark("GITEA_PREFIX_RAW"), ctx.Links.RawLink(),
+		).Replace(p.Command)
+		commands = strings.Fields(command)
+		args     = commands[1:]
+	)
+
+	if p.IsInputFile {
+		// write to temp file
+		f, err := os.CreateTemp("", "gitea_input")
+		if err != nil {
+			return fmt.Errorf("%s create temp file when rendering %s failed: %w", p.Name(), p.Command, err)
+		}
+		tmpPath := f.Name()
+		defer func() {
+			if err := util.Remove(tmpPath); err != nil {
+				log.Warn("Unable to remove temporary file: %s: Error: %v", tmpPath, err)
+			}
+		}()
+
+		_, err = io.Copy(f, input)
+		if err != nil {
+			f.Close()
+			return fmt.Errorf("%s write data to temp file when rendering %s failed: %w", p.Name(), p.Command, err)
+		}
+
+		err = f.Close()
+		if err != nil {
+			return fmt.Errorf("%s close temp file when rendering %s failed: %w", p.Name(), p.Command, err)
+		}
+		args = append(args, f.Name())
+	}
+
+	if ctx == nil || ctx.Ctx == nil {
+		if ctx == nil {
+			log.Warn("RenderContext not provided defaulting to empty ctx")
+			ctx = &markup.RenderContext{}
+		}
+		log.Warn("RenderContext did not provide context, defaulting to Shutdown context")
+		ctx.Ctx = graceful.GetManager().ShutdownContext()
+	}
+
+	processCtx, _, finished := process.GetManager().AddContext(ctx.Ctx, fmt.Sprintf("Render [%s] for %s", commands[0], ctx.Links.SrcLink()))
+	defer finished()
+
+	cmd := exec.CommandContext(processCtx, commands[0], args...)
+	cmd.Env = append(
+		os.Environ(),
+		"GITEA_PREFIX_SRC="+ctx.Links.SrcLink(),
+		"GITEA_PREFIX_RAW="+ctx.Links.RawLink(),
+	)
+	if !p.IsInputFile {
+		cmd.Stdin = input
+	}
+	var stderr bytes.Buffer
+	cmd.Stdout = output
+	cmd.Stderr = &stderr
+	process.SetSysProcAttribute(cmd)
+
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("%s render run command %s %v failed: %w\nStderr: %s", p.Name(), commands[0], args, err, stderr.String())
+	}
+	return nil
+}