For registered binary content types, skip the

utf-8 scan

Author: billrobertson42

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsProxyHttpServletResponseWriter.java

@@ -15,6 +15,7 @@
 
 import com.amazonaws.serverless.exceptions.InvalidResponseObjectException;
 import com.amazonaws.serverless.proxy.ResponseWriter;
+import com.amazonaws.serverless.proxy.internal.LambdaContainerHandler;
 import com.amazonaws.serverless.proxy.internal.testutils.Timer;
 import com.amazonaws.serverless.proxy.model.AwsProxyResponse;
 import com.amazonaws.services.lambda.runtime.Context;
@@ -39,7 +40,7 @@ public AwsProxyResponse writeResponse(AwsHttpServletResponse containerResponse,
         if (containerResponse.getAwsResponseBodyString() != null) {
             String responseString;
 
-            if (isValidUtf8(containerResponse.getAwsResponseBodyBytes())) {
+            if (!isBinary(containerResponse.getContentType()) && isValidUtf8(containerResponse.getAwsResponseBodyBytes())) {
                 responseString = containerResponse.getAwsResponseBodyString();
             } else {
                 responseString = Base64.getMimeEncoder().encodeToString(containerResponse.getAwsResponseBodyBytes());
@@ -55,4 +56,8 @@ public AwsProxyResponse writeResponse(AwsHttpServletResponse containerResponse,
         Timer.stop("SERVLET_RESPONSE_WRITE");
         return awsProxyResponse;
     }
+
+    private boolean isBinary(String contentType) {
+        return contentType == null ? false : LambdaContainerHandler.getContainerConfig().isBinaryContentType(contentType);
+    }
 }