Request

Bind Data

To bind request body into a Go type use Context#Bind(i interface{}).The default binder supports decoding application/json, application/xml andapplication/x-www-form-urlencoded data based on the Content-Type header.

Example below binds the request payload into User struct based on tags:

  1. // User
  2. type User struct {
  3.   Name  string `json:"name" form:"name" query:"name"`
  4.   Email string `json:"email" form:"email" query:"email"`
  5. }
  1. // Handler
  2. func(c echo.Context) (err error) {
  3.   u := new(User)
  4.   if err = c.Bind(u); err != nil {
  5.     return
  6.   }
  7.   return c.JSON(http.StatusOK, u)
  8. }

JSON Data

  1. curl \
  2.   -X POST \
  3.   http://localhost:1323/users \
  4.   -H 'Content-Type: application/json' \
  5.   -d '{"name":"Joe","email":"[email protected]"}'

Form Data

  1. curl \
  2.   -X POST \
  3.   http://localhost:1323/users \
  4.   -d 'name=Joe' \
  5.   -d '[email protected]'

Query Parameters

  1. curl \
  2.   -X GET \
  3.   http://localhost:1323/users\?name\=Joe\&email\[email protected]

Custom Binder

Custom binder can be registered using Echo#Binder.

Example

  1. type CustomBinder struct {}
  3. func (cb *CustomBinder) Bind(i interface{}, c echo.Context) (err error) {
  4.     // You may use default binder
  5.     db := new(echo.DefaultBinder)
  6.     if err = db.Bind(i, c); err != echo.ErrUnsupportedMediaType {
  7.         return
  8.     }
  10.     // Define your custom implementation
  12.     return
  13. }

Retrieve Data

Form Data

Form data can be retrieved by name using Context#FormValue(name string).

Example

  1. // Handler
  2. func(c echo.Context) error {
  3.     name := c.FormValue("name")
  4.     return c.String(http.StatusOK, name)
  5. }
  1. curl \
  2.   -X POST \
  3.   http://localhost:1323 \
  4.   -d 'name=Joe'

To bind a custom data type, you can implement Echo#BindUnmarshaler interface.

Example

  1. type Timestamp time.Time
  3. func (t *Timestamp) UnmarshalParam(src string) error {
  4.     ts, err := time.Parse(time.RFC3339, src)
  5.     *t = Timestamp(ts)
  6.     return err
  7. }

Query Parameters

Query parameters can be retrieved by name using Context#QueryParam(name string).

Example

  1. // Handler
  2. func(c echo.Context) error {
  3.     name := c.QueryParam("name")
  4.     return c.String(http.StatusOK, name)
  5. })
  1. curl \
  2.   -X GET \
  3.   http://localhost:1323\?name\=Joe

Similar to form data, custom data type can be bind using Context#QueryParam(name string).

Path Parameters

Registered path parameters can be retrieved by name using Context#Param(name string) string.

Example

  1. e.GET("/users/:name", func(c echo.Context) error {
  2.     name := c.Param("name")
  3.     return c.String(http.StatusOK, name)
  4. })
  1. $ curl http://localhost:1323/users/Joe

Validate Data

Echo doesn’t have built-in data validation capabilities, however, you can registera custom validator using Echo#Validator and leverage third-party libraries.

Example below uses https://github.com/go-playground/validator framework for validation:

  1. type (
  2.     User struct {
  3.         Name  string `json:"name" validate:"required"`
  4.         Email string `json:"email" validate:"required,email"`
  5.     }
  7.     CustomValidator struct {
  8.         validator *validator.Validate
  9.     }
  10. )
  12. func (cv *CustomValidator) Validate(i interface{}) error {
  13.     return cv.validator.Struct(i)
  14. }
  16. func main() {
  17.     e := echo.New()
  18.     e.Validator = &CustomValidator{validator: validator.New()}
  19.     e.POST("/users", func(c echo.Context) (err error) {
  20.         u := new(User)
  21.         if err = c.Bind(u); err != nil {
  22.             return
  23.         }
  24.         if err = c.Validate(u); err != nil {
  25.             return
  26.         }
  27.         return c.JSON(http.StatusOK, u)
  28.     })
  29.     e.Logger.Fatal(e.Start(":1323"))
  30. }
  1. curl \
  2.   -X POST \
  3.   http://localhost:1323/users \
  4.   -H 'Content-Type: application/json' \
  5.   -d '{"name":"Joe","email":"[email protected]"}'
  6. {"message":"Key: 'User.Email' Error:Field validation for 'Email' failed on the 'email' tag"}