Closed #170

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

context.go

@@ -3,12 +3,15 @@ package echo
 import (
 	"encoding/json"
 	"encoding/xml"
+	"io"
 	"net/http"
 
 	"fmt"
 
 	"net/url"
 
+	"os"
+
 	"golang.org/x/net/websocket"
 )
 
@@ -163,6 +166,21 @@ func (c *Context) XML(code int, i interface{}) error {
 	return xml.NewEncoder(c.response).Encode(i)
 }
 
+// File sends a file as attachment.
+func (c *Context) File(name string) error {
+	file, err := os.Open(name)
+	if err != nil {
+		return err
+	}
+	fi, err := file.Stat()
+	if err != nil {
+		return err
+	}
+	c.response.Header().Set(ContentDisposition, "attachment; filename="+fi.Name())
+	_, err = io.Copy(c.response, file)
+	return err
+}
+
 // NoContent sends a response with no body and a status code.
 func (c *Context) NoContent(code int) error {
 	c.response.WriteHeader(code)

context_test.go

@@ -88,7 +88,6 @@ func TestContext(t *testing.T) {
 	assert.Error(t, err)
 
 	// JSON
-	req.Header.Set(Accept, ApplicationJSON)
 	rec = httptest.NewRecorder()
 	c = NewContext(req, NewResponse(rec), New())
 	err = c.JSON(http.StatusOK, user{"1", "Joe"})
@@ -99,7 +98,6 @@ func TestContext(t *testing.T) {
 	}
 
 	// JSONP
-	req.Header.Set(Accept, ApplicationJavaScript)
 	rec = httptest.NewRecorder()
 	c = NewContext(req, NewResponse(rec), New())
 	callback := "callback"
@@ -111,7 +109,6 @@ func TestContext(t *testing.T) {
 	}
 
 	// XML
-	req.Header.Set(Accept, ApplicationXML)
 	rec = httptest.NewRecorder()
 	c = NewContext(req, NewResponse(rec), New())
 	err = c.XML(http.StatusOK, user{"1", "Joe"})
@@ -122,7 +119,6 @@ func TestContext(t *testing.T) {
 	}
 
 	// String
-	req.Header.Set(Accept, TextPlain)
 	rec = httptest.NewRecorder()
 	c = NewContext(req, NewResponse(rec), New())
 	err = c.String(http.StatusOK, "Hello, World!")
@@ -133,7 +129,6 @@ func TestContext(t *testing.T) {
 	}
 
 	// HTML
-	req.Header.Set(Accept, TextHTML)
 	rec = httptest.NewRecorder()
 	c = NewContext(req, NewResponse(rec), New())
 	err = c.HTML(http.StatusOK, "Hello, <strong>World!</strong>")
@@ -143,6 +138,15 @@ func TestContext(t *testing.T) {
 		assert.Equal(t, "Hello, <strong>World!</strong>", rec.Body.String())
 	}
 
+	// File
+	rec = httptest.NewRecorder()
+	c = NewContext(req, NewResponse(rec), New())
+	err = c.File("test/fixture/walle.png")
+	if assert.NoError(t, err) {
+		assert.Equal(t, http.StatusOK, rec.Code)
+		assert.Equal(t, 219885, rec.Body.Len())
+	}
+
 	// NoContent
 	rec = httptest.NewRecorder()
 	c = NewContext(req, NewResponse(rec), New())

echo.go

@@ -64,6 +64,11 @@ type (
 	binder struct {
 	}
 
+	// Validator is the interface that wraps the Validate method.
+	Validator interface {
+		Validate() error
+	}
+
 	// Renderer is the interface that wraps the Render method.
 	Renderer interface {
 		Render(w io.Writer, name string, data interface{}) error
@@ -119,7 +124,6 @@ const (
 	// Headers
 	//---------
 
-	Accept             = "Accept"
 	AcceptEncoding     = "Accept-Encoding"
 	Authorization      = "Authorization"
 	ContentDisposition = "Content-Disposition"
@@ -587,7 +591,7 @@ func wrapHandler(h Handler) HandlerFunc {
 	}
 }
 
-func (*binder) Bind(r *http.Request, i interface{}) (err error) {
+func (binder) Bind(r *http.Request, i interface{}) (err error) {
 	ct := r.Header.Get(ContentType)
 	err = UnsupportedMediaType
 	if strings.HasPrefix(ct, ApplicationJSON) {