Added request body logging for OkHttp requests

hapi-fhir-client-okhttp/src/main/java/ca/uhn/fhir/okhttp/client/OkHttpRestfulRequest.java

@@ -26,8 +26,10 @@
 import ca.uhn.fhir.util.StopWatch;
 import okhttp3.Call;
 import okhttp3.Call.Factory;
+import okhttp3.MediaType;
 import okhttp3.Request;
 import okhttp3.RequestBody;
+import okio.Buffer;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -80,9 +82,16 @@ public Map<String, List<String>> getAllHeaders() {
 	}
 
 	@Override
-	public String getRequestBodyFromStream() {
-		// returning null to indicate this is not supported, as documented in IHttpRequest's contract
-		return null;
+	public String getRequestBodyFromStream() throws IOException {
+		if (myRequestBody == null) {
+			return null;
+		}
+		final Buffer buffer = new Buffer();
+		myRequestBody.writeTo(buffer);
+		MediaType contentType = myRequestBody.contentType();
+		return contentType == null || contentType.charset() == null
+				? buffer.readUtf8()
+				: buffer.readString(contentType.charset());
 	}
 
 	@Override

hapi-fhir-client-okhttp/src/test/java/ca/uhn/fhir/okhttp/client/OkHttpRestfulRequestTest.java

@@ -1,12 +1,19 @@
 package ca.uhn.fhir.okhttp.client;
 
 import ca.uhn.fhir.rest.api.RequestTypeEnum;
+import okhttp3.MediaType;
+import okhttp3.RequestBody;
 import org.junit.jupiter.api.Test;
 
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 public class OkHttpRestfulRequestTest {
 
+	private final String ENTITY_CONTENT = "Some entity with special characters: é";
+
 	@Test
 	void toString_afterCreation_GetUsefulDataForLogging() {
 		String theUrl = "https://example.com/fhir/meta";
@@ -24,4 +31,22 @@ void toString_afterCreationPostUsefulDataForLogging() {
 		OkHttpRestfulRequest okHttpRestfulRequest = new OkHttpRestfulRequest(clientFactory.getNativeClient(), theUrl, RequestTypeEnum.POST, null);
 		assertEquals("POST https://another.example.com/fhir/Task", okHttpRestfulRequest.toString());
 	}
+
+	@Test
+	public void testGetRequestBodyFromStream() throws IOException {
+		RequestBody requestBody = RequestBody.create(ENTITY_CONTENT.getBytes(StandardCharsets.ISO_8859_1), MediaType.parse("text/plain; charset=ISO-8859-1"));
+
+		String result = new OkHttpRestfulRequest(null, "https://test.com", null, requestBody).getRequestBodyFromStream();
+
+		assertEquals(ENTITY_CONTENT, result);
+	}
+
+	@Test
+	public void testGetRequestBodyFromStreamWithUnknownCharset() throws IOException {
+		RequestBody requestBody = RequestBody.create(ENTITY_CONTENT.getBytes(StandardCharsets.UTF_8), MediaType.parse("text/plain; charset=UTF-8"));
+
+		String result = new OkHttpRestfulRequest(null, "https://test.com", null, requestBody).getRequestBodyFromStream();
+
+		assertEquals(ENTITY_CONTENT, result);
+	}
 }