简单扩展 PocketBase 功能

package main

import (
	"log"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/pocketbase/pocketbase"
	"github.com/pocketbase/pocketbase/apis"
	"github.com/pocketbase/pocketbase/core"
	"github.com/pocketbase/pocketbase/plugins/ghupdate"
	"github.com/pocketbase/pocketbase/plugins/jsvm"
	"github.com/pocketbase/pocketbase/plugins/migratecmd"
)

func main() {
	app := pocketbase.New()

	// ---------------------------------------------------------------
	// 可选的插件标志
	// ---------------------------------------------------------------

	var hooksDir string  // 使用 JavaScript 扩展 Pocketbase 时 js 代码存放的目录
	app.RootCmd.PersistentFlags().StringVar(
		&hooksDir,
		"hooksDir",
		"",
		"the directory with the JS app hooks",
	)

	var hooksWatch bool  // 热重启：当修改 js 代码后时候重新启动应用
	app.RootCmd.PersistentFlags().BoolVar(
		&hooksWatch,
		"hooksWatch",
		true,
		"auto restart the app on pb_hooks file change",
	)

	var hooksPool int  // 启动的 js 运行时池数量，增加池大小可能会在高并发场景中提高性能，但也会增加内存使用量
	app.RootCmd.PersistentFlags().IntVar(
		&hooksPool,
		"hooksPool",
		25,
		"the total prewarm goja.Runtime instances for the JS app hooks execution",
	)

	var migrationsDir string  // 数据库迁移目录
	app.RootCmd.PersistentFlags().StringVar(
		&migrationsDir,
		"migrationsDir",
		"",
		"the directory with the user defined migrations",
	)

	var automigrate bool  // 时候启用数据库自动迁移功能
	app.RootCmd.PersistentFlags().BoolVar(
		&automigrate,
		"automigrate",
		true,
		"enable/disable auto migrations",
	)

	var publicDir string  // 静态文件存放目录
	app.RootCmd.PersistentFlags().StringVar(
		&publicDir,
		"publicDir",
		defaultPublicDir(),
		"the directory to serve static files",
	)

	var indexFallback bool // 主要针对单页应用（SPA）程序路由启用 history 模式时的空路由回滚至 `index.html`
	app.RootCmd.PersistentFlags().BoolVar(
		&indexFallback,
		"indexFallback",
		true,
		"fallback the request to index.html on missing static path (eg. when pretty urls are used with SPA)",
	)

	var queryTimeout int  // 数据库查询超时时间
	app.RootCmd.PersistentFlags().IntVar(
		&queryTimeout,
		"queryTimeout",
		30,
		"the default SELECT queries timeout in seconds",
	)

	app.RootCmd.ParseFlags(os.Args[1:])

	// ---------------------------------------------------------------
	// 插件和钩子
	// ---------------------------------------------------------------

	// 加载 jsvm （js 虚拟机）
	jsvm.MustRegister(app, jsvm.Config{
		MigrationsDir: migrationsDir,
		HooksDir:      hooksDir,
		HooksWatch:    hooksWatch,
		HooksPoolSize: hooksPool,
	})

	// 注册数据库迁移指令
	migratecmd.MustRegister(app, app.RootCmd, migratecmd.Config{
		TemplateLang: migratecmd.TemplateLangJS,
		Automigrate:  automigrate,
		Dir:          migrationsDir,
	})

	// 从 github 检查更新 PocketBase 版本
	ghupdate.MustRegister(app, app.RootCmd, ghupdate.Config{})

	app.OnAfterBootstrap().PreAdd(func(e *core.BootstrapEvent) error {
		app.Dao().ModelQueryTimeout = time.Duration(queryTimeout) * time.Second
		return nil
	})

	app.OnBeforeServe().Add(func(e *core.ServeEvent) error {
		// 部署静态资源
		e.Router.GET("/*", apis.StaticDirectoryHandler(os.DirFS(publicDir), indexFallback))
		return nil
	})

	if err := app.Start(); err != nil {
		log.Fatal(err)
	}
}

// 设置默认 `pb_public` 目录相对于可执行文件的位置
func defaultPublicDir() string {
	if strings.HasPrefix(os.Args[0], os.TempDir()) {
		// most likely ran with go run
		return "./pb_public"
	}

	return filepath.Join(os.Args[0], "../pb_public")
}