echo/website/content/guide/migrating.md

+++ title = "Migrating" description = "Migrating from Echo v1 to v2" [menu.side] name = "Migrating" parent = "guide" weight = 2 +++

Migrating from v1

Change Log

• Good news, 85% of the API remains the same.
• Engine interface to abstract HTTP server implementation, allowing us to use HTTP servers beyond Go standard library. It currently supports standard and fasthttp server.
• Context, Request and Response are converted to interfaces. More...
• Handler signature is changed to func (c echo.Context) error.
• Dropped auto wrapping of handler and middleware to enforce compile time check.
• APIs to run middleware before or after the router, which doesn't require Echo#Hook API now.
• Ability to define middleware at route level.
• Echo#HTTPError exposed it's fields Code and Message.
• Option to specify log format in logger middleware and default logger.

API

v1	v2
Context#Query()	Context#QueryParam()
Context#Form()	Context#FormValue()

FAQ

Q. How to access original objects from interfaces?

A. Only if you need to...

// `*http.Request`
c.Request().(*standard.Request).Request

// `*http.URL`
c.Request().URL().(*standard.URL).URL

// Request `http.Header`
c.Request().Header().(*standard.Header).Header

// `http.ResponseWriter`
c.Response().(*standard.Response).ResponseWriter

// Response `http.Header`
c.Response().Header().(*standard.Header).Header

Q. How to use standard handler and middleware?

A.

package main

import (
	"net/http"

	"github.com/labstack/echo"
	"github.com/labstack/echo/engine/standard"
)

// Standard middleware
func middleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		println("standard middleware")
		next.ServeHTTP(w, r)
	})
}

// Standard handler
func handler(w http.ResponseWriter, r *http.Request) {
	println("standard handler")
}

func main() {
	e := echo.New()
	e.Use(standard.WrapMiddleware(middleware))
	e.GET("/", standard.WrapHandler(http.HandlerFunc(handler)))
	e.Run(standard.New(":1323"))
}

Next?

• Browse through recipes freshly converted to v2.
• Read documentation and dig into test cases.