drive/backend/handlers/onlyoffice.go

package handlers

import (
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"

	"git.elijahkuntz.com/Elijah/drive/config"
	"git.elijahkuntz.com/Elijah/drive/middleware"
	"github.com/gofiber/fiber/v2"
	"github.com/golang-jwt/jwt/v5"
)

type OnlyOfficeHandler struct {
	Config *config.Config
}

type CallbackRequest struct {
	Status int    `json:"status"`
	Url    string `json:"url"`
	Key    string `json:"key"`
}

func (h *OnlyOfficeHandler) Callback(c *fiber.Ctx) error {
	path := c.Query("path")
	token := c.Query("token")

	if path == "" {
		return c.Status(400).SendString("path required")
	}

	// Validate the token to ensure the callback is authorized
	if err := middleware.ValidateDownloadToken(token, h.Config.JWTSecret, ""); err != nil {
		return c.Status(401).SendString("unauthorized")
	}

	var req CallbackRequest
	if err := c.BodyParser(&req); err != nil {
		return c.Status(400).JSON(fiber.Map{"error": "invalid json"})
	}

	// Status 2: Document is ready for saving
	// Status 6: Document is being edited, force save was triggered
	if req.Status == 2 || req.Status == 6 {
		if req.Url == "" {
			return c.Status(400).JSON(fiber.Map{"error": "url required"})
		}

		// If the server cannot resolve the public URL due to hairpin NAT,
		// we can rewrite it to use the internal Docker IP
		downloadUrl := req.Url

		// Download modified file from Document Server
		resp, err := http.Get(downloadUrl)
		if err != nil {
			return c.Status(500).JSON(fiber.Map{"error": "failed to download file"})
		}
		defer resp.Body.Close()

		targetPath := filepath.Join(h.Config.StorageDir, path)
		
		// Save file
		out, err := os.Create(targetPath)
		if err != nil {
			return c.Status(500).JSON(fiber.Map{"error": "failed to open file for writing"})
		}
		defer out.Close()

		if _, err := io.Copy(out, resp.Body); err != nil {
			return c.Status(500).JSON(fiber.Map{"error": "failed to write file"})
		}
	}

	// Send successful response according to OnlyOffice API
	return c.JSON(fiber.Map{"error": 0})
}

// CreateBlank creates an empty document for Docs or Slides mode
func (h *OnlyOfficeHandler) CreateBlank(c *fiber.Ctx) error {
	req := new(struct {
		Type string `json:"type"`
		Name string `json:"name"`
	})

	if err := c.BodyParser(req); err != nil {
		return c.Status(400).JSON(fiber.Map{"error": "invalid request"})
	}

	if req.Name == "" {
		req.Name = "Untitled Document"
		if req.Type == "slide" {
			req.Name = "Untitled Presentation"
		}
	}

	ext := ".docx"
	if req.Type == "slide" {
		ext = ".pptx"
	}
	
	// Add extension if missing
	if filepath.Ext(req.Name) != ext {
		req.Name += ext
	}

	// Make sure the file name doesn't collide
	basePath := filepath.Join(h.Config.StorageDir, req.Name)
	finalPath := basePath
	counter := 1
	for {
		if _, err := os.Stat(finalPath); os.IsNotExist(err) {
			break
		}
		finalPath = filepath.Join(h.Config.StorageDir, fmt.Sprintf("%s (%d)%s", req.Name[:len(req.Name)-len(ext)], counter, ext))
		counter++
	}

	// Create an empty file. OnlyOffice will initialize it when opened.
	f, err := os.Create(finalPath)
	if err != nil {
		return c.Status(500).JSON(fiber.Map{"error": "failed to create file"})
	}
	f.Close()

	// Return the relative path
	relativePath, _ := filepath.Rel(h.Config.StorageDir, finalPath)
	
	return c.JSON(fiber.Map{
		"path": filepath.ToSlash(relativePath),
		"name": filepath.Base(finalPath),
	})
}

// SignConfig takes the OnlyOffice configuration payload and signs it with the JWT secret
func (h *OnlyOfficeHandler) SignConfig(c *fiber.Ctx) error {
	if h.Config.OnlyOfficeJWT == "" {
		return c.Status(500).JSON(fiber.Map{"error": "JWT secret is not configured on the server"})
	}

	var payload map[string]interface{}
	if err := c.BodyParser(&payload); err != nil {
		return c.Status(400).JSON(fiber.Map{"error": "invalid json payload"})
	}

	// Create a new JWT token using the HS256 algorithm
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims(payload))

	// Sign the token with our secret
	signedToken, err := token.SignedString([]byte(h.Config.OnlyOfficeJWT))
	if err != nil {
		return c.Status(500).JSON(fiber.Map{"error": "failed to sign token"})
	}

	return c.JSON(fiber.Map{
		"token": signedToken,
	})
}