Inline feature (labstack#637)

context.go

@@ -3,6 +3,7 @@ package echo
 import (
 	"encoding/json"
 	"encoding/xml"
+	"fmt"
 	"io"
 	"mime"
 	"mime/multipart"
@@ -140,6 +141,10 @@ type (
 		// client to save the file.
 		Attachment(io.ReadSeeker, string) error
 
+		// Inline sends a response from `io.ReaderSeeker` as inline, opening
+		// the file in the browser.
+		Inline(io.ReadSeeker, string) error
+
 		// NoContent sends a response with no body and a status code.
 		NoContent(int) error
 
@@ -417,8 +422,16 @@ func (c *echoContext) File(file string) error {
 }
 
 func (c *echoContext) Attachment(r io.ReadSeeker, name string) (err error) {
+	return c.contentDisposition(r, name, "attachment")
+}
+
+func (c *echoContext) Inline(r io.ReadSeeker, name string) (err error) {
+	return c.contentDisposition(r, name, "inline")
+}
+
+func (c *echoContext) contentDisposition(r io.ReadSeeker, name, dispositionType string) (err error) {
 	c.response.Header().Set(HeaderContentType, ContentTypeByExtension(name))
-	c.response.Header().Set(HeaderContentDisposition, "attachment; filename="+name)
+	c.response.Header().Set(HeaderContentDisposition, fmt.Sprintf("%s; filename=%s", dispositionType, name))
 	c.response.WriteHeader(http.StatusOK)
 	_, err = io.Copy(c.response, r)
 	return

context_test.go

@@ -145,6 +145,19 @@ func TestContext(t *testing.T) {
 		}
 	}
 
+	// Inline
+	rec = test.NewResponseRecorder()
+	c = e.NewContext(req, rec).(*echoContext)
+	file, err = os.Open("_fixture/images/walle.png")
+	if assert.NoError(t, err) {
+		err = c.Inline(file, "walle.png")
+		if assert.NoError(t, err) {
+			assert.Equal(t, http.StatusOK, rec.Status())
+			assert.Equal(t, "inline; filename=walle.png", rec.Header().Get(HeaderContentDisposition))
+			assert.Equal(t, 219885, rec.Body.Len())
+		}
+	}
+
 	// NoContent
 	rec = test.NewResponseRecorder()
 	c = e.NewContext(req, rec).(*echoContext)