A Go script to install Notion RTL (on macOS only for now) for the desktop app. Sadly Notion recreates the HTML file this script modifies on whenever the app is relaunched, so the changes need to keep being reapplied.

install_notion_rtl.go

package main

import (
  "errors"
  "fmt"
  "io/ioutil"
  "os"
  "os/user"
  "path/filepath"
  "runtime"
  "strings"
)

var rtlScriptTag string = "<script type=\"text/javascript\" src=\"https://cdn.jsdelivr.net/gh/obahareth/notion-rtl@master/index.js\"></script>"

func getHomeDirectory() string {
  usr, err := user.Current()

  if err != nil {
    panic(err)
  }

  return usr.HomeDir
}

func getNotionAssetCacheDirectory() (string, error) {
  homeDir := getHomeDirectory()

  if strings.Contains(runtime.GOOS, "darwin") {
    return fmt.Sprintf("%s/Library/Application Support/Notion/assetCache/", homeDir), nil
  }

  // TODO: Handle Windows
  return "", errors.New("Unable to find Notion's assets directory")
}

// Get all index-*.html files for all versions inside the asset cache directory
func getAllIndexHTMLFiles() []string {
  assetCacheDirectory, err := getNotionAssetCacheDirectory()

  if err != nil {
    panic(err)
  }

  globPattern := fmt.Sprintf("%s**%cindex*.html", assetCacheDirectory, os.PathSeparator)
  files, err := filepath.Glob(globPattern)

  if err != nil {
    panic(err)
  }

  return files
}

func isRTLScriptAlreadyIncluded(fileContents string) bool {
  return strings.Contains(fileContents, rtlScriptTag)
}

func includeRTLScriptInHTMLFile(path string) bool {
  fileContents, err := ioutil.ReadFile(path)

  if err != nil {
    panic(err)
  }

  if isRTLScriptAlreadyIncluded(string(fileContents)) {
    return true
  }

  closingBodyTag := "</body>"
  closingBodyTagWithRTLScriptTag := fmt.Sprintf("%s%s", rtlScriptTag, closingBodyTag)

  newFileContents := strings.Replace(string(fileContents), closingBodyTag, closingBodyTagWithRTLScriptTag, -1)

  err = ioutil.WriteFile(path, []byte(newFileContents), 0)

  if err != nil {
    panic(err)
  }

  return true
}

func includeRTLScriptTagInAllHTMLFiles() bool {
  files := getAllIndexHTMLFiles()

  if files == nil {
    return false
  }

  for _, file := range files {
    if !includeRTLScriptInHTMLFile(file) {
      return false
    }
  }

  return true
}

func main() {
  fmt.Print("Including script in Notion's HTML files...\n\n")

  if includeRTLScriptTagInAllHTMLFiles() {
    fmt.Println("✅ Done! Please reload or restart Notion")
  } else {
    fmt.Println("❌ Unable to include scripts, please open an issue at https://github.com/obahareth/notion-rtl/issues")
  }
}