OPENIG-246 OpenIG in reverse proxy configuration fails half the time …

…with http code 501

* Request.getEntity() never returns null, so it can't be used to determine if the request had a content or not
* Added an isEmpty() method for this purpose
* Updated HttpClient to use Entity.isEmpty()

openig-core/src/main/java/org/forgerock/openig/http/Entity.java

@@ -96,6 +96,19 @@ public final class Entity implements Closeable {
         setRawInputStream(EMPTY_STREAM);
     }
 
+    /**
+     * Returns {@literal true} if the entity is empty.
+     * This method does not read any actual content from the InputStream.
+     * @return {@literal true} if the entity is empty.
+     */
+    public boolean isEmpty() {
+        try {
+            return trunk.available() == 0;
+        } catch (IOException e) {
+            return true;
+        }
+    }
+
     /**
      * Closes all resources associated with this entity. Any open streams will
      * be closed, and the underlying content reset back to a zero length.

openig-core/src/main/java/org/forgerock/openig/http/HttpClient.java

@@ -399,7 +399,7 @@ public void execute(final Exchange exchange) throws IOException {
      */
     public Response execute(final Request request) throws IOException {
         final HttpRequestBase clientRequest =
-                request.getEntity() != null ? new EntityRequest(request) : new NonEntityRequest(request);
+                request.getEntity().isEmpty() ? new NonEntityRequest(request) : new EntityRequest(request);
         clientRequest.setURI(request.getUri().asURI());
         // connection headers to suppress
         final CaseInsensitiveSet suppressConnection = new CaseInsensitiveSet();

openig-core/src/test/java/org/forgerock/openig/http/EntityTest.java

@@ -66,6 +66,7 @@ public void entityIsEmptyByDefault() throws Exception {
         assertThat(entity.getBytes()).isEmpty();
         assertThat(entity.getString()).isEmpty();
         assertThat(entity.toString()).isEmpty();
+        assertThat(entity.isEmpty()).isTrue();
         entity.push();
         assertThat(entity.getRawInputStream().available()).isEqualTo(0);
         entity.pop();
@@ -77,20 +78,23 @@ public void getBytes() throws Exception {
         entity.setRawInputStream(mockJsonContent1);
         assertThat(entity.getBytes()).isEqualTo(bytes(JSON_CONTENT1));
         assertThat(mockJsonContent1.available()).isEqualTo(JSON_CONTENT1.length());
+        assertThat(entity.isEmpty()).isFalse();
         verify(mockJsonContent1, never()).close();
     }
 
     @Test
     public void getJson() throws Exception {
         entity.setRawInputStream(mockJsonContent1);
         assertThat(entity.getJson()).isEqualTo(JSON_VALUE1);
+        assertThat(entity.isEmpty()).isFalse();
         verify(mockJsonContent1, never()).close();
     }
 
     @Test(expectedExceptions = ParseException.class)
     public void getJsonWhenEntityContainsInvalidJsonThrowsParseException() throws Exception {
         mockJsonContent1 = mockContent(INVALID_JSON);
         entity.setRawInputStream(mockJsonContent1);
+        assertThat(entity.isEmpty()).isFalse();
         try {
             entity.getJson();
         } finally {
@@ -127,6 +131,7 @@ public void getRawInputStream() throws Exception {
         entity.setRawInputStream(mockJsonContent1);
         assertThat(entity.getRawInputStream()).isSameAs(mockJsonContent1);
         assertThat(mockJsonContent1.available()).isEqualTo(JSON_CONTENT1.length());
+        assertThat(entity.isEmpty()).isFalse();
         verify(mockJsonContent1, never()).close();
     }
 
@@ -135,6 +140,7 @@ public void getString() throws Exception {
         entity.setRawInputStream(mockJsonContent1);
         assertThat(entity.getString()).isEqualTo(JSON_CONTENT1);
         assertThat(mockJsonContent1.available()).isEqualTo(JSON_CONTENT1.length());
+        assertThat(entity.isEmpty()).isFalse();
         verify(mockJsonContent1, never()).close();
     }