add api comments in file app.go

@@ -10,19 +10,22 @@ import (
 	"github.com/astaxie/beego/context"
 )
 
+// FitlerFunc defines filter function type.
 type FilterFunc func(*context.Context)
 
+// App defines beego application with a new PatternServeMux.
 type App struct {
 	Handlers *ControllerRegistor
 }
 
-// New returns a new PatternServeMux.
+// NewApp returns a new beego application.
 func NewApp() *App {
 	cr := NewControllerRegistor()
 	app := &App{Handlers: cr}
 	return app
 }
 
+// Run beego application.
 func (app *App) Run() {
 	addr := HttpAddr
 
@@ -84,39 +87,77 @@ func (app *App) Run() {
 	}
 }
 
+// Router adds a url-patterned controller handler.
+// The path argument supports regex rules and specific placeholders.
+// The c argument needs a controller handler implemented beego.ControllerInterface.
+// The mapping methods argument only need one string to define custom router rules.
+// usage:
+//	simple router
+// 	beego.Router("/admin", &admin.UserController{})
+//	beego.Router("/admin/index", &admin.ArticleController{})
+//
+// 	regex router
+//
+//	beego.Router(“/api/:id([0-9]+)“, &controllers.RController{})
+//
+//  custom rules
+//	beego.Router("/api/list",&RestController{},"*:ListFood")
+//	beego.Router("/api/create",&RestController{},"post:CreateFood")
+//	beego.Router("/api/update",&RestController{},"put:UpdateFood")
+//	beego.Router("/api/delete",&RestController{},"delete:DeleteFood")
 func (app *App) Router(path string, c ControllerInterface, mappingMethods ...string) *App {
 	app.Handlers.Add(path, c, mappingMethods...)
 	return app
 }
 
+// AutoRouter adds beego-defined controller handler.
+// if beego.AddAuto(&MainContorlller{}) and MainController has methods List and Page,
+// visit the url /main/list to exec List function or /main/page to exec Page function.
 func (app *App) AutoRouter(c ControllerInterface) *App {
 	app.Handlers.AddAuto(c)
 	return app
 }
 
+// UrlFor does another controller handler with params in current context.
+// The endpoint is formed as path.controller.name to defined the controller method which will run.
+// The values need key-pair data to assign into controller method.
 func (app *App) UrlFor(endpoint string, values ...string) string {
 	return app.Handlers.UrlFor(endpoint, values...)
 }
+
+// [Deprecated]
+// Filter adds a FilterFunc under pattern condition and named action.
+// The actions contains BeforeRouter,AfterStatic,BeforeExec,AfterExec and FinishRouter.
 func (app *App) Filter(pattern, action string, filter FilterFunc) *App {
 	app.Handlers.AddFilter(pattern, action, filter)
 	return app
 }
 
+// InsertFilter adds a FilterFunc with pattern condition and action constant.
+// The pos means action constant including
+// beego.BeforeRouter, beego.AfterStatic, beego.BeforeExec, beego.AfterExec and beego.FinishRouter.
 func (app *App) InsertFilter(pattern string, pos int, filter FilterFunc) *App {
 	app.Handlers.InsertFilter(pattern, pos, filter)
 	return app
 }
 
+// SetViewsPath sets view directory path in beego application.
+// it returns beego application self.
 func (app *App) SetViewsPath(path string) *App {
 	ViewsPath = path
 	return app
 }
 
+// SetStaticPath sets static directory path and proper url pattern in beego application.
+// if beego.SetStaticPath("static","public"), visit /static/* to load static file in folder "public".
+// it returns beego application self.
 func (app *App) SetStaticPath(url string, path string) *App {
 	StaticDir[url] = path
 	return app
 }
 
+// DelStaticPath removes the static folder setting in this url pattern in beego application.
+// it returns beego application self.
 func (app *App) DelStaticPath(url string) *App {
 	delete(StaticDir, url)
 	return app