fix errcheck warnings (#1739)

render/json.go

@@ -67,8 +67,8 @@ func WriteJSON(w http.ResponseWriter, obj interface{}) error {
 	if err != nil {
 		return err
 	}
-	w.Write(jsonBytes)
-	return nil
+	_, err = w.Write(jsonBytes)
+	return err
 }
 
 // Render (IndentedJSON) marshals the given interface object and writes it with custom ContentType.
@@ -78,8 +78,8 @@ func (r IndentedJSON) Render(w http.ResponseWriter) error {
 	if err != nil {
 		return err
 	}
-	w.Write(jsonBytes)
-	return nil
+	_, err = w.Write(jsonBytes)
+	return err
 }
 
 // WriteContentType (IndentedJSON) writes JSON ContentType.
@@ -96,10 +96,13 @@ func (r SecureJSON) Render(w http.ResponseWriter) error {
 	}
 	// if the jsonBytes is array values
 	if bytes.HasPrefix(jsonBytes, []byte("[")) && bytes.HasSuffix(jsonBytes, []byte("]")) {
-		w.Write([]byte(r.Prefix))
+		_, err = w.Write([]byte(r.Prefix))
+		if err != nil {
+			return err
+		}
 	}
-	w.Write(jsonBytes)
-	return nil
+	_, err = w.Write(jsonBytes)
+	return err
 }
 
 // WriteContentType (SecureJSON) writes JSON ContentType.
@@ -116,15 +119,27 @@ func (r JsonpJSON) Render(w http.ResponseWriter) (err error) {
 	}
 
 	if r.Callback == "" {
-		w.Write(ret)
-		return nil
+		_, err = w.Write(ret)
+		return err
 	}
 
 	callback := template.JSEscapeString(r.Callback)
-	w.Write([]byte(callback))
-	w.Write([]byte("("))
-	w.Write(ret)
-	w.Write([]byte(")"))
+	_, err = w.Write([]byte(callback))
+	if err != nil {
+		return err
+	}
+	_, err = w.Write([]byte("("))
+	if err != nil {
+		return err
+	}
+	_, err = w.Write(ret)
+	if err != nil {
+		return err
+	}
+	_, err = w.Write([]byte(")"))
+	if err != nil {
+		return err
+	}
 
 	return nil
 }
@@ -151,8 +166,8 @@ func (r AsciiJSON) Render(w http.ResponseWriter) (err error) {
 		buffer.WriteString(cvt)
 	}
 
-	w.Write(buffer.Bytes())
-	return nil
+	_, err = w.Write(buffer.Bytes())
+	return err
 }
 
 // WriteContentType (AsciiJSON) writes JSON ContentType.