RawJSON added to allow writing JSON from bytes

context.go

@@ -5,6 +5,7 @@
 package gin
 
 import (
+	"bytes"
 	"errors"
 	"io"
 	"math"
@@ -358,6 +359,14 @@ func (c *Context) JSON(code int, obj interface{}) {
 	}
 }
 
+// RawJSON give a buffer of bytes representing JSON just write it out
+// this habdles cases where you get back JSON as bytes from redis or ffjson
+// and you do not want the extra marshall/demarshal overhead
+// It also sets the Content-Type as "application/json".
+func (c *Context) RawJSON(code int, obj interface{}) {
+	c.Render(code, render.RawJSON{Data: obj.(*bytes.Buffer)})
+}
+
 // XML serializes the given struct as XML into the response body.
 // It also sets the Content-Type as "application/xml".
 func (c *Context) XML(code int, obj interface{}) {

context_test.go

@@ -257,6 +257,21 @@ func TestContextRenderJSON(t *testing.T) {
 	assert.Equal(t, w.HeaderMap.Get("Content-Type"), "application/json; charset=utf-8")
 }
 
+// Tests that the response is JSON writen out from bytes
+// and Content-Type is set to application/json
+func TestContextRenderRawJSON(t *testing.T) {
+	c, w, _ := createTestContext()
+
+	var buffer bytes.Buffer
+	buffer.WriteString("{\"foo\": \"bar\"}")
+
+	c.RawJSON(201, &buffer)
+
+	assert.Equal(t, w.Code, 201)
+	assert.Equal(t, w.Body.String(), "{\"foo\": \"bar\"}")
+	assert.Equal(t, w.HeaderMap.Get("Content-Type"), "application/json; charset=utf-8")
+}
+
 // Tests that the response is serialized as JSON
 // we change the content-type before
 func TestContextRenderAPIJSON(t *testing.T) {

render/json.go

@@ -5,6 +5,7 @@
 package render
 
 import (
+	"bytes"
 	"encoding/json"
 	"net/http"
 )
@@ -17,6 +18,9 @@ type (
 	IndentedJSON struct {
 		Data interface{}
 	}
+	RawJSON struct {
+		Data *bytes.Buffer
+	}
 )
 
 var jsonContentType = []string{"application/json; charset=utf-8"}
@@ -39,3 +43,9 @@ func WriteJSON(w http.ResponseWriter, obj interface{}) error {
 	writeContentType(w, jsonContentType)
 	return json.NewEncoder(w).Encode(obj)
 }
+
+func (r RawJSON) Render(w http.ResponseWriter) error {
+	writeContentType(w, jsonContentType)
+	w.Write(r.Data.Bytes())
+	return nil
+}

render/render.go

@@ -13,6 +13,7 @@ type Render interface {
 var (
 	_ Render     = JSON{}
 	_ Render     = IndentedJSON{}
+	_ Render     = RawJSON{}
 	_ Render     = XML{}
 	_ Render     = String{}
 	_ Render     = Redirect{}