enabled validator, updated docs, fixed #298, fixed #438, fixed #305

Signed-off-by: Vishal Rana <vr@labstack.com>

context.go

@@ -99,8 +99,12 @@ type (
 		// does it based on Content-Type header.
 		Bind(i interface{}) error
 
+		// Validate validates provided `i`. It is usually called after `Context#Bind()`.
+		// Validator must be registered using `Echo#Validator`.
+		Validate(i interface{}) error
+
 		// Render renders a template with data and sends a text/html response with status
-		// code. Templates can be registered using `Echo.Renderer`.
+		// code. Renderer must be registered using `Echo.Renderer`.
 		Render(code int, name string, data interface{}) error
 
 		// HTML sends an HTTP response with status code.
@@ -350,6 +354,13 @@ func (c *context) Bind(i interface{}) error {
 	return c.echo.Binder.Bind(i, c)
 }
 
+func (c *context) Validate(i interface{}) error {
+	if c.echo.Validator == nil {
+		return ErrValidatorNotRegistered
+	}
+	return c.echo.Validator.Validate(i)
+}
+
 func (c *context) Render(code int, name string, data interface{}) (err error) {
 	if c.echo.Renderer == nil {
 		return ErrRendererNotRegistered

echo.go

@@ -63,6 +63,7 @@ type (
 		Debug            bool
 		HTTPErrorHandler HTTPErrorHandler
 		Binder           Binder
+		Validator        Validator
 		Renderer         Renderer
 		AutoTLSManager   autocert.Manager
 		ShutdownTimeout  time.Duration
@@ -102,7 +103,7 @@ type (
 
 	// Validator is the interface that wraps the Validate function.
 	Validator interface {
-		Validate() error
+		Validate(i interface{}) error
 	}
 
 	// Renderer is the interface that wraps the Render function.
@@ -217,6 +218,7 @@ var (
 	ErrUnauthorized                = NewHTTPError(http.StatusUnauthorized)
 	ErrMethodNotAllowed            = NewHTTPError(http.StatusMethodNotAllowed)
 	ErrStatusRequestEntityTooLarge = NewHTTPError(http.StatusRequestEntityTooLarge)
+	ErrValidatorNotRegistered      = errors.New("validator not registered")
 	ErrRendererNotRegistered       = errors.New("renderer not registered")
 	ErrInvalidRedirectCode         = errors.New("invalid redirect status code")
 	ErrCookieNotFound              = errors.New("cookie not found")

website/content/guide/customization.md

@@ -21,7 +21,7 @@ You can set a custom HTTP error handler using `Echo#HTTPErrorHandler`.
 
 ## Debugging
 
-`Echo#Debug` enables/disables debug mode.
+`Echo#Debug` enable / disable debug mode.
 
 ## Logging
 

website/content/guide/request.md

@@ -7,88 +7,188 @@ description = "Handling HTTP request in Echo"
   weight = 6
 +++
 
-## Bind Request Body
+## Bind Data
 
-To bind request body into a provided Go type use `Context#Bind(interface{})`.
+To bind request body into a Go type use `Context#Bind(i interface{})`.
 The default binder supports decoding application/json, application/xml and
-application/x-www-form-urlencoded payload based on Context-Type header.
+application/x-www-form-urlencoded data based on the Context-Type header.
 
-*Example*
+Example below binds the request payload into `User` struct based on tags:
 
-TODO
+```go
+// User
+User struct {
+  Name  string `json:"name" form:"name" query:"name"`
+  Email string `json:"email" form:"email" query:"email"`
+}
+```
 
-> Custom binder can be registered via `Echo#SetBinder(Binder)`
+```go
+// Handler
+func(c echo.Context) (err error) {
+  u := new(User)
+  if err = c.Bind(u); err != nil {
+    return
+  }
+  return c.JSON(http.StatusOK, u)
+}
+```
 
-## Query Parameter
+### JSON Data
 
-Query parameter can be retrieved by name using `Context#QueryParam(name string)`.
+```sh
+curl \
+  -X POST \
+  http://localhost:1323/users \
+  -H 'Content-Type: application/json' \
+  -d '{"name":"Joe","email":"joe@labstack"}'
+```
+
+### Form Data
+
+```sh
+curl \
+  -X POST \
+  http://localhost:1323/users \
+  -d 'name=Joe' \
+  -d 'email=joe@labstack.com'
+```
+
+### Query Parameters
+
+```sh
+curl \
+  -X GET \
+  http://localhost:1323/users\?name\=Joe\&email\=joe@labstack.com
+```
+
+## Custom Binder
+
+Custom binder can be registered using `Echo#Binder`.
 
 *Example*
 
 ```go
-e.GET("/users", func(c echo.Context) error {
+type CustomBinder struct {}
+
+func (cb *CustomBinder) Bind(i interface{}, c echo.Context) (err error) {
+	// You may use default binder
+	db := new(echo.DefaultBinder)
+	if err = db.Bind(i, c); err != echo.ErrUnsupportedMediaType {
+		return
+	}
+
+	// Define your custom implementation
+	
+	return
+}
+```
+
+## Retrieve Data
+
+### Form Data
+
+Form data can be retrieved by name using `Context#FormValue(name string)`.
+
+*Example*
+
+```go
+// Handler
+func(c echo.Context) error {
+	name := c.FormValue("name")
+	return c.String(http.StatusOK, name)
+}
+```
+
+```sh
+curl \
+  -X POST \
+  http://localhost:1323 \
+  -d 'name=Joe'
+```
+
+### Query Parameters
+
+Query parameters can be retrieved by name using `Context#QueryParam(name string)`.
+
+*Example*
+
+```go
+// Handler
+func(c echo.Context) error {
 	name := c.QueryParam("name")
 	return c.String(http.StatusOK, name)
 })
 ```
 
 ```sh
-$ curl -G -d "name=joe" http://localhost:1323/users
+curl \
+  -X GET \
+  http://localhost:1323\?name\=Joe
 ```
 
-## Form Parameter
+### Path Parameters
 
-Form parameter can be retrieved by name using `Context#FormValue(name string)`.
+Registered path parameters can be retrieved by name using `Context#Param(name string) string`.
-
-*Example*
-
-```go
-e.POST("/users", func(c echo.Context) error {
-	name := c.FormValue("name")
-	return c.String(http.StatusOK, name)
-})
-```
-
-```sh
-$ curl -d "name=joe" http://localhost:1323/users
-```
-
-## Path Parameter
-
-Registered path parameter can be retrieved by name `Context#Param(name string) string`.
 
 *Example*
 
 ```go
 e.GET("/users/:name", func(c echo.Context) error {
-	// By name
 	name := c.Param("name")
-
 	return c.String(http.StatusOK, name)
 })
 ```
 
 ```sh
-$ curl http://localhost:1323/users/joe
+$ curl http://localhost:1323/users/Joe
 ```
 
+## Validate Data
 
-## Handler Path
+Echo doesn't have built-in data validation capabilities, however you can set a
+custom validator using `Echo#Validator` and leverage third-party [libraries](https://github.com/avelino/awesome-go#validation).
 
-`Context#Path()` returns the registered path for the handler, it can be used in the
+Example below uses https://github.com/go-playground/validator framework for validation:
-middleware for logging purpose.
-
-*Example*
 
 ```go
-e.Use(func(handler echo.HandlerFunc) echo.HandlerFunc {
+type (
-	return func(c echo.Context) error {
+	User struct {
-		println(c.Path())
+		Name  string `json:"name" validate:"required"`
-		return handler(c)
+		Email string `json:"email" validate:"required,email"`
 	}
-})
 
-e.GET("/users/:name", func(c echo.Context) error) {
+	CustomValidator struct {
-    return c.String(http.StatusOK, name)
+		validator *validator.Validate
-})
+	}
+)
+
+func (cv *CustomValidator) Validate(i interface{}) error {
+	return cv.validator.Struct(i)
+}
+
+func main() {
+	e := echo.New()
+	e.Validator = &CustomValidator{validator: validator.New()}
+	e.POST("/users", func(c echo.Context) (err error) {
+		u := new(User)
+		if err = c.Bind(u); err != nil {
+			return
+		}
+		if err = c.Validate(u); err != nil {
+			return
+		}
+		return c.JSON(http.StatusOK, u)
+	})
+	e.Logger.Fatal(e.Start(":1323"))
+}
+```
+
+```sh
+curl \
+  -X POST \
+  http://localhost:1323/users \
+  -H 'Content-Type: application/json' \
+  -d '{"name":"Joe","email":"joe@invalid-domain"}'
+{"message":"Key: 'User.Email' Error:Field validation for 'Email' failed on the 'email' tag"}
 ```