Allow registration of binary content types

Author: billrobertson42

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/model/ContainerConfig.java

@@ -4,6 +4,7 @@
 import com.amazonaws.serverless.proxy.internal.servlet.AwsProxyHttpServletRequest;
 
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
 
 
@@ -38,6 +39,7 @@ public static ContainerConfig defaultConfig() {
     private List<String> validFilePaths;
     private List<String> customDomainNames;
     private boolean queryStringCaseSensitive;
+    private final HashSet<String> binaryContentTypes = new HashSet<>();
 
     public ContainerConfig() {
         validFilePaths = new ArrayList<>();
@@ -219,4 +221,22 @@ public boolean isQueryStringCaseSensitive() {
     public void setQueryStringCaseSensitive(boolean queryStringCaseSensitive) {
         this.queryStringCaseSensitive = queryStringCaseSensitive;
     }
+
+    /**
+     * Configure specified content type as binary
+     */
+    public void addBinaryContentType(String type) {
+        if(type != null) {
+            binaryContentTypes.add(type);
+        }
+    }
+
+    /**
+     * Determine if specified content type has been configured as binary
+     * @param type
+     * @return
+     */
+    public boolean isBinaryContentType(String type) {
+        return binaryContentTypes.contains(type);
+    }
 }