echo/website/content/guide.md

+++ title = "Guide" description = "Guide" type = "guide" +++

Quick Start

Installation

$ go get -u github.com/labstack/echo

Hello, World!

Create server.go

package main

import (
	"net/http"
	
	"github.com/labstack/echo"
)

func main() {
	e := echo.New()
	e.GET("/", func(c echo.Context) error {
		return c.String(http.StatusOK, "Hello, World!")
	})
	e.Logger.Fatal(e.Start(":1323"))
}

Start server

$ go run server.go

Browse to http://localhost:1323 and you should see Hello, World! on the page.

Routing

e.POST("/users", saveUser)
e.GET("/users/:id", getUser)
e.PUT("/users/:id", updateUser)
e.DELETE("/users/:id", deleteUser)

Path Parameters

// e.GET("/users/:id", getUser)
func getUser(c echo.Context) error {
  	// User ID from path `users/:id`
  	id := c.Param("id")
	return c.String(http.StatusOK, id)
}

Browse to http://localhost:1323/users/Joe and you should see 'Joe' on the page.

Query Parameters

/show?team=x-men&member=wolverine

//e.GET("/show", show)
func show(c echo.Context) error {
	// Get team and member from the query string
	team := c.QueryParam("team")
	member := c.QueryParam("member")
	return c.String(http.StatusOK, "team:" + team + ", member:" + member)
}

Browse to http://localhost:1323/show?team=x-men&member=wolverine and you should see 'team:x-men, member:wolverine' on the page.

Form application/x-www-form-urlencoded

POST /save

name	value
name	Joe Smith
email	joe@labstack.com

// e.POST("/save", save)
func save(c echo.Context) error {
	// Get name and email
	name := c.FormValue("name")
	email := c.FormValue("email")
	return c.String(http.StatusOK, "name:" + name + ", email:" + email)
}

Run the following command:

$ curl -F "name=Joe Smith" -F "email=joe@labstack.com" http://localhost:1323/save
// => name:Joe Smith, email:joe@labstack.com

Form multipart/form-data

POST /save

name	value
name	Joe Smith
avatar	avatar

func save(c echo.Context) error {
	// Get name
	name := c.FormValue("name")
	// Get avatar
  	avatar, err := c.FormFile("avatar")
  	if err != nil {
 		return err
 	}
 
 	// Source
 	src, err := avatar.Open()
 	if err != nil {
 		return err
 	}
 	defer src.Close()
 
 	// Destination
 	dst, err := os.Create(avatar.Filename)
 	if err != nil {
 		return err
 	}
 	defer dst.Close()
 
 	// Copy
 	if _, err = io.Copy(dst, src); err != nil {
  		return err
  	}

	return c.HTML(http.StatusOK, "<b>Thank you! " + name + "</b>")
}

Run the following command.

$ curl -F "name=Joe Smith" -F "avatar=@/path/to/your/avatar.png" http://localhost:1323/save
// => <b>Thank you! Joe Smith</b>

For checking uploaded image, run the following command.

cd <project directory>
ls avatar.png
// => avatar.png

Handling Request

• Bind JSON or XML or form payload into Go struct based on Content-Type request header.
• Render response as JSON or XML with status code.

type User struct {
	Name  string `json:"name" xml:"name" form:"name"`
	Email string `json:"email" xml:"email" form:"email"`
}

e.POST("/users", func(c echo.Context) error {
	u := new(User)
	if err := c.Bind(u); err != nil {
		return err
	}
	return c.JSON(http.StatusCreated, u)
	// or
	// return c.XML(http.StatusCreated, u)
})

Static Content

Server any file from static directory for path /static/*.

e.Static("/static", "static")

Learn More

Template Rendering

Middleware

// Root level middleware
e.Use(middleware.Logger())
e.Use(middleware.Recover())

// Group level middleware
g := e.Group("/admin")
g.Use(middleware.BasicAuth(func(username, password string) bool {
	if username == "joe" && password == "secret" {
		return true
	}
	return false
}))

// Route level middleware
track := func(next echo.HandlerFunc) echo.HandlerFunc {
	return func(c echo.Context) error {
		println("request to /users")
		return next(c)
	}
}
e.GET("/users", func(c echo.Context) error {
	return c.String(http.StatusOK, "/users")
}, track)