Changeset 0.22.4 (#146)

server/handlers/export.go

@@ -0,0 +1,110 @@
+package handlers
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+)
+
+// ExportHandler converts markdown content to PDF or DOCX via pandoc.
+type ExportHandler struct{}
+
+func NewExportHandler() *ExportHandler { return &ExportHandler{} }
+
+type exportRequest struct {
+	Content  string `json:"content" binding:"required"`
+	Format   string `json:"format" binding:"required"` // "pdf" or "docx"
+	Filename string `json:"filename"`                  // optional base name
+}
+
+// Convert handles POST /api/v1/export.
+// Converts markdown content to the requested format and returns the file.
+func (h *ExportHandler) Convert(c *gin.Context) {
+	var req exportRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Validate format
+	switch req.Format {
+	case "pdf", "docx":
+		// ok
+	default:
+		c.JSON(http.StatusBadRequest, gin.H{"error": "format must be pdf or docx"})
+		return
+	}
+
+	// Check pandoc availability
+	if _, err := exec.LookPath("pandoc"); err != nil {
+		c.JSON(http.StatusServiceUnavailable, gin.H{"error": "pandoc is not installed on the server"})
+		return
+	}
+
+	// Create temp dir for conversion
+	tmpDir, err := os.MkdirTemp("", "export-*")
+	if err != nil {
+		log.Printf("export: failed to create temp dir: %v", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "export failed"})
+		return
+	}
+	defer os.RemoveAll(tmpDir)
+
+	// Write markdown to temp file
+	inputPath := filepath.Join(tmpDir, "input.md")
+	if err := os.WriteFile(inputPath, []byte(req.Content), 0644); err != nil {
+		log.Printf("export: failed to write input: %v", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "export failed"})
+		return
+	}
+
+	// Determine output filename
+	baseName := "document"
+	if req.Filename != "" {
+		baseName = strings.TrimSuffix(req.Filename, filepath.Ext(req.Filename))
+	}
+	outputFile := baseName + "." + req.Format
+	outputPath := filepath.Join(tmpDir, outputFile)
+
+	// Build pandoc command
+	args := []string{inputPath, "-o", outputPath, "--standalone"}
+	if req.Format == "pdf" {
+		// Try to use a lightweight PDF engine
+		for _, engine := range []string{"weasyprint", "wkhtmltopdf", "pdflatex"} {
+			if _, err := exec.LookPath(engine); err == nil {
+				args = append(args, "--pdf-engine="+engine)
+				break
+			}
+		}
+	}
+
+	cmd := exec.CommandContext(c.Request.Context(), "pandoc", args...)
+	cmd.Dir = tmpDir
+	if output, err := cmd.CombinedOutput(); err != nil {
+		log.Printf("export: pandoc failed: %v\n%s", err, string(output))
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"error":   "pandoc conversion failed",
+			"details": string(output),
+		})
+		return
+	}
+
+	// Serve the file
+	contentType := "application/octet-stream"
+	switch req.Format {
+	case "pdf":
+		contentType = "application/pdf"
+	case "docx":
+		contentType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
+	}
+
+	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=%q", outputFile))
+	c.File(outputPath)
+	c.Header("Content-Type", contentType)
+}