fix an issue on accesslog when response and request recorder and minifier were enabled

Author: kataras

HISTORY.md

@@ -21,7 +21,9 @@ Developers are not forced to upgrade if they don't really need it. Upgrade whene
 
 # Next
 
-Change applies to `master` branch.
+Changes apply to `master` branch.
+
+- Fix [iris-premium#17](https://github.com/kataras/iris-premium/issues/17).
 
 - Replace [russross/blackfriday](github.com/russross/blackfriday/v2) with [gomarkdown](https://github.com/gomarkdown/markdown) as requested at [#2098](https://github.com/kataras/iris/issues/2098).
 

middleware/accesslog/accesslog.go

@@ -836,20 +836,27 @@ func (ac *AccessLog) after(ctx *context.Context, lat time.Duration, method, path
 	}
 
 	if ac.shouldReadResponseBody() {
-		responseData := ctx.Recorder().Body()
-		responseBodyLength := len(responseData)
+		actualResponseData := ctx.Recorder().Body()
+		responseBodyLength := len(actualResponseData)
+
 		if ac.BytesSentBody {
 			bytesSent = responseBodyLength
 		}
 		if ac.ResponseBody && responseBodyLength > 0 {
 			if ac.BodyMinify {
+				// Copy response data as minifier now can change the back slice,
+				// fixes: https://github.com/kataras/iris-premium/issues/17.
+				responseData := make([]byte, len(actualResponseData))
+				copy(responseData, actualResponseData)
+
 				if minified, err := ctx.Application().Minifier().Bytes(ctx.GetContentType(), responseData); err == nil {
 					responseBody = string(minified)
+					responseBodyLength = len(responseBody)
 				}
 			}
 
 			if responseBody == "" {
-				responseBody = string(responseData)
+				responseBody = string(actualResponseData)
 			}
 		}