fix: inconsistent behavior when buffer http entity content with org.a…

arex-instrumentation/httpclient/arex-httpclient-apache-v4/src/main/java/io/arex/inst/httpclient/apache/common/ApacheHttpClientAdapter.java

@@ -140,9 +140,9 @@ public static void bufferRequestEntity(HttpEntityEnclosingRequest enclosingReque
             return;
         }
         try {
-            enclosingRequest.setEntity(new BufferedHttpEntity(enclosingRequest.getEntity()));
+            enclosingRequest.setEntity(new ArexBufferedHttpEntity(enclosingRequest.getEntity()));
         } catch (Exception ignore) {
-            // ignore exception
+            // ignore exception, fallback to original entity and ignore recording
         }
     }
 
@@ -151,14 +151,14 @@ public static void bufferResponseEntity(HttpResponse response) {
             return;
         }
         try {
-            EntityUtils.updateEntity(response, new BufferedHttpEntity(response.getEntity()));
+            EntityUtils.updateEntity(response, new ArexBufferedHttpEntity(response.getEntity()));
         } catch (Exception e) {
-            // ignore exception
+            // ignore exception, fallback to original entity and ignore recording
         }
     }
 
     private byte[] getEntityBytes(HttpEntity entity) {
-        if (!(entity instanceof BufferedHttpEntity)) {
+        if (!(entity instanceof ArexBufferedHttpEntity)) {
             return ZERO_BYTE;
         }
         try {

arex-instrumentation/httpclient/arex-httpclient-apache-v4/src/main/java/io/arex/inst/httpclient/apache/common/ArexBufferedHttpEntity.java

@@ -0,0 +1,49 @@
+package io.arex.inst.httpclient.apache.common;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import org.apache.http.HttpEntity;
+import org.apache.http.entity.HttpEntityWrapper;
+
+/**
+ * This class only buffer the original HttpEntity content into a byte array, tt does not modify any
+ * behavior of the original HttpEntity.
+ * This class is known to have performance issues comparing to the original BufferedHttpEntity, but
+ * it provides consistent behavior with the original HttpEntity.
+ * @see org.apache.http.entity.BufferedHttpEntity
+ * @author: QizhengMo
+ * @date: 2025/3/12 15:35
+ */
+public class ArexBufferedHttpEntity extends HttpEntityWrapper {
+  private final byte[] buffer;
+
+  public ArexBufferedHttpEntity(HttpEntity wrappedEntity) throws IOException {
+    super(wrappedEntity);
+    final ByteArrayOutputStream out = new ByteArrayOutputStream();
+
+    // This class is only used in Arex Agent, so we are almost always the first to consume the content.
+    wrappedEntity.writeTo(out);
+    out.flush();
+    this.buffer = out.toByteArray();
+  }
+
+  /**
+   * Return a copy of the original content of the wrapped HttpEntity.
+   */
+  @Override
+  public InputStream getContent() throws IOException {
+    return new ByteArrayInputStream(buffer);
+  }
+
+  @Override
+  public void writeTo(final OutputStream outStream) throws IOException {
+    if (this.buffer != null) {
+      outStream.write(this.buffer);
+    } else {
+      super.writeTo(outStream);
+    }
+  }
+}

arex-instrumentation/httpclient/arex-httpclient-apache-v4/src/test/java/io/arex/inst/httpclient/apache/async/BasicFutureInstrumentationTest.java

@@ -2,6 +2,7 @@
 
 import static org.junit.jupiter.api.Assertions.*;
 
+import io.arex.inst.httpclient.apache.common.ArexBufferedHttpEntity;
 import io.arex.inst.runtime.context.ContextManager;
 import java.io.IOException;
 import net.bytebuddy.description.method.MethodDescription;
@@ -54,7 +55,7 @@ void testFutureAdvice() throws IOException {
         ((FutureCallbackWrapper<?>) wrapper).setNeedRecord(true);
         BasicFutureInstrumentation.FutureAdvice.completed(httpResponse, wrapper);
 
-        assertInstanceOf(BufferedHttpEntity.class, httpResponse.getEntity());
+        assertInstanceOf(ArexBufferedHttpEntity.class, httpResponse.getEntity());
 
         BasicFutureInstrumentation.FutureAdvice.completed(httpResponse, null);
     }

arex-instrumentation/httpclient/arex-httpclient-apache-v4/src/test/java/io/arex/inst/httpclient/apache/async/RequestProducerInstrumentationTest.java

@@ -4,6 +4,7 @@
 import static org.mockito.Mockito.mockStatic;
 
 import io.arex.inst.httpclient.apache.async.RequestProducerInstrumentation.ConstructorAdvice;
+import io.arex.inst.httpclient.apache.common.ArexBufferedHttpEntity;
 import io.arex.inst.runtime.context.ContextManager;
 import java.lang.reflect.Constructor;
 import net.bytebuddy.description.method.MethodDescription.ForLoadedConstructor;
@@ -58,7 +59,7 @@ void onEnter() {
             HttpPost request = new HttpPost();
             request.setEntity(new ByteArrayEntity("test".getBytes()));
             ConstructorAdvice.onEnter(request);
-            assertInstanceOf(BufferedHttpEntity.class, request.getEntity());
+            assertInstanceOf(ArexBufferedHttpEntity.class, request.getEntity());
         }
     }
 }