Make Go plugin handlers take a *Context

Take a *Context instead of a echo.Context. This saves a type assertion
in each handler.

plugin_go.go

@@ -34,7 +34,10 @@ func (p *goPlugin) LoadTemplate(t *template.Template) error {
 
 func (p *goPlugin) SetRoutes(group *echo.Group) {
 	for _, r := range p.p.routes {
-		group.Add(r.Method, r.Path, r.Handler)
+		h := r.Handler
+		group.Add(r.Method, r.Path, func(ectx echo.Context) error {
+			return h(ectx.(*Context))
+		})
 	}
 
 	group.Static("/plugins/"+p.p.Name+"/assets", pluginDir+"/"+p.p.Name+"/public/assets")
@@ -59,7 +62,7 @@ func (p *goPlugin) Close() error {
 type goPluginRoute struct {
 	Method  string
 	Path    string
-	Handler echo.HandlerFunc
+	Handler HandlerFunc
 }
 
 // GoPlugin is a helper to create Go plugins.
@@ -75,30 +78,30 @@ type GoPlugin struct {
 	routes []goPluginRoute
 
 	templateFuncs template.FuncMap
-	injectFuncs map[string]InjectFunc
+	injectFuncs   map[string]InjectFunc
 }
 
+// HandlerFunc is a function serving HTTP requests.
+type HandlerFunc func(*Context) error
+
 // AddRoute registers a new HTTP route.
-//
-// The echo.Context passed to the HTTP handler can be type-asserted to
-// *koushin.Context.
-func (p *GoPlugin) AddRoute(method, path string, handler echo.HandlerFunc) {
+func (p *GoPlugin) AddRoute(method, path string, handler HandlerFunc) {
 	p.routes = append(p.routes, goPluginRoute{method, path, handler})
 }
 
-func (p *GoPlugin) DELETE(path string, handler echo.HandlerFunc) {
+func (p *GoPlugin) DELETE(path string, handler HandlerFunc) {
 	p.AddRoute(http.MethodDelete, path, handler)
 }
 
-func (p *GoPlugin) GET(path string, handler echo.HandlerFunc) {
+func (p *GoPlugin) GET(path string, handler HandlerFunc) {
 	p.AddRoute(http.MethodGet, path, handler)
 }
 
-func (p *GoPlugin) POST(path string, handler echo.HandlerFunc) {
+func (p *GoPlugin) POST(path string, handler HandlerFunc) {
 	p.AddRoute(http.MethodPost, path, handler)
 }
 
-func (p *GoPlugin) PUT(path string, handler echo.HandlerFunc) {
+func (p *GoPlugin) PUT(path string, handler HandlerFunc) {
 	p.AddRoute(http.MethodPut, path, handler)
 }
 

plugins/base/routes.go

@@ -19,19 +19,17 @@ import (
 )
 
 func registerRoutes(p *koushin.GoPlugin) {
-	p.GET("/", func(ectx echo.Context) error {
-		return ectx.Redirect(http.StatusFound, "/mailbox/INBOX")
+	p.GET("/", func(ctx *koushin.Context) error {
+		return ctx.Redirect(http.StatusFound, "/mailbox/INBOX")
 	})
 
 	p.GET("/mailbox/:mbox", handleGetMailbox)
 	p.POST("/mailbox/:mbox", handleGetMailbox)
 
-	p.GET("/message/:mbox/:uid", func(ectx echo.Context) error {
-		ctx := ectx.(*koushin.Context)
+	p.GET("/message/:mbox/:uid", func(ctx *koushin.Context) error {
 		return handleGetPart(ctx, false)
 	})
-	p.GET("/message/:mbox/:uid/raw", func(ectx echo.Context) error {
-		ctx := ectx.(*koushin.Context)
+	p.GET("/message/:mbox/:uid/raw", func(ctx *koushin.Context) error {
 		return handleGetPart(ctx, true)
 	})
 
@@ -62,9 +60,7 @@ type MailboxRenderData struct {
 	Query              string
 }
 
-func handleGetMailbox(ectx echo.Context) error {
-	ctx := ectx.(*koushin.Context)
-
+func handleGetMailbox(ctx *koushin.Context) error {
 	mboxName, err := url.PathUnescape(ctx.Param("mbox"))
 	if err != nil {
 		return echo.NewHTTPError(http.StatusBadRequest, err)
@@ -125,9 +121,7 @@ func handleGetMailbox(ectx echo.Context) error {
 	})
 }
 
-func handleLogin(ectx echo.Context) error {
-	ctx := ectx.(*koushin.Context)
-
+func handleLogin(ctx *koushin.Context) error {
 	username := ctx.FormValue("username")
 	password := ctx.FormValue("password")
 	if username != "" && password != "" {
@@ -146,9 +140,7 @@ func handleLogin(ectx echo.Context) error {
 	return ctx.Render(http.StatusOK, "login.html", koushin.NewBaseRenderData(ctx))
 }
 
-func handleLogout(ectx echo.Context) error {
-	ctx := ectx.(*koushin.Context)
-
+func handleLogout(ctx *koushin.Context) error {
 	ctx.Session.Close()
 	ctx.SetSession(nil)
 	return ctx.Redirect(http.StatusFound, "/login")
@@ -255,9 +247,7 @@ type ComposeRenderData struct {
 	Message *OutgoingMessage
 }
 
-func handleCompose(ectx echo.Context) error {
-	ctx := ectx.(*koushin.Context)
-
+func handleCompose(ctx *koushin.Context) error {
 	var msg OutgoingMessage
 	if strings.ContainsRune(ctx.Session.Username(), '@') {
 		msg.From = ctx.Session.Username()
@@ -358,9 +348,7 @@ func handleCompose(ectx echo.Context) error {
 	})
 }
 
-func handleMove(ectx echo.Context) error {
-	ctx := ectx.(*koushin.Context)
-
+func handleMove(ctx *koushin.Context) error {
 	mboxName, uid, err := parseMboxAndUid(ctx.Param("mbox"), ctx.Param("uid"))
 	if err != nil {
 		return echo.NewHTTPError(http.StatusBadRequest, err)
@@ -391,9 +379,7 @@ func handleMove(ectx echo.Context) error {
 	return ctx.Redirect(http.StatusFound, fmt.Sprintf("/mailbox/%v", url.PathEscape(to)))
 }
 
-func handleDelete(ectx echo.Context) error {
-	ctx := ectx.(*koushin.Context)
-
+func handleDelete(ctx *koushin.Context) error {
 	mboxName, uid, err := parseMboxAndUid(ctx.Param("mbox"), ctx.Param("uid"))
 	if err != nil {
 		return echo.NewHTTPError(http.StatusBadRequest, err)
@@ -432,9 +418,7 @@ func handleDelete(ectx echo.Context) error {
 	return ctx.Redirect(http.StatusFound, fmt.Sprintf("/mailbox/%v", url.PathEscape(mboxName)))
 }
 
-func handleSetFlags(ectx echo.Context) error {
-	ctx := ectx.(*koushin.Context)
-
+func handleSetFlags(ctx *koushin.Context) error {
 	mboxName, uid, err := parseMboxAndUid(ctx.Param("mbox"), ctx.Param("uid"))
 	if err != nil {
 		return echo.NewHTTPError(http.StatusBadRequest, err)