Don't log gzipped data. It isn't human readable.

okhttp-logging-interceptor/src/main/java/com/squareup/okhttp/logging/HttpLoggingInterceptor.java

@@ -178,8 +178,11 @@ public final class HttpLoggingInterceptor implements Interceptor {
         }
       }
 
-      String endMessage = "--> END " + request.method();
+      if (!logBody || !hasRequestBody) {
-      if (logBody && hasRequestBody) {
+        logger.log("--> END " + request.method());
+      } else if (bodyEncoded(request.headers())) {
+        logger.log("--> END " + request.method() + " (encoded body omitted)");
+      } else {
         Buffer buffer = new Buffer();
         requestBody.writeTo(buffer);
 
@@ -192,9 +195,9 @@ public final class HttpLoggingInterceptor implements Interceptor {
         logger.log("");
         logger.log(buffer.readString(charset));
 
-        endMessage += " (" + requestBody.contentLength() + "-byte body)";
+        logger.log("--> END " + request.method()
+            + " (" + requestBody.contentLength() + "-byte body)");
       }
-      logger.log(endMessage);
     }
 
     long startNs = System.nanoTime();
@@ -212,8 +215,11 @@ public final class HttpLoggingInterceptor implements Interceptor {
         logger.log(headers.name(i) + ": " + headers.value(i));
       }
 
-      String endMessage = "<-- END HTTP";
+      if (!logBody || !HttpEngine.hasBody(response)) {
-      if (logBody && HttpEngine.hasBody(response)) {
+        logger.log("<-- END HTTP");
+      } else if (bodyEncoded(response.headers())) {
+        logger.log("<-- END HTTP (encoded body omitted)");
+      } else {
         BufferedSource source = responseBody.source();
         source.request(Long.MAX_VALUE); // Buffer the entire body.
         Buffer buffer = source.buffer();
@@ -229,14 +235,18 @@ public final class HttpLoggingInterceptor implements Interceptor {
           logger.log(buffer.clone().readString(charset));
         }
 
-        endMessage += " (" + buffer.size() + "-byte body)";
+        logger.log("<-- END HTTP (" + buffer.size() + "-byte body)");
       }
-      logger.log(endMessage);
     }
 
     return response;
   }
 
+  private boolean bodyEncoded(Headers headers) {
+    String contentEncoding = headers.get("Content-Encoding");
+    return contentEncoding != null && !contentEncoding.equalsIgnoreCase("identity");
+  }
+
   private static String protocol(Protocol protocol) {
     return protocol == Protocol.HTTP_1_0 ? "HTTP/1.0" : "HTTP/1.1";
   }

okhttp-logging-interceptor/src/test/java/com/squareup/okhttp/logging/HttpLoggingInterceptorTest.java

@@ -27,7 +27,9 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.regex.Pattern;
+import okio.Buffer;
 import okio.BufferedSink;
+import okio.ByteString;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -519,6 +521,45 @@ public final class HttpLoggingInterceptorTest {
         .assertNoMoreLogs();
   }
 
+  @Test public void bodyResponseNotIdentityEncoded() throws IOException {
+    setLevel(Level.BODY);
+
+    server.enqueue(new MockResponse()
+        .setHeader("Content-Encoding", "gzip")
+        .setHeader("Content-Type", PLAIN)
+        .setBody(new Buffer().write(ByteString.decodeBase64(
+            "H4sIAAAAAAAAAPNIzcnJ11HwQKIAdyO+9hMAAAA="))));
+    client.newCall(request().build()).execute();
+
+    networkLogs
+        .assertLogEqual("--> GET " + url + " HTTP/1.1")
+        .assertLogEqual("Host: " + host)
+        .assertLogEqual("Connection: Keep-Alive")
+        .assertLogEqual("Accept-Encoding: gzip")
+        .assertLogMatch("User-Agent: okhttp/.+")
+        .assertLogEqual("--> END GET")
+        .assertLogMatch("<-- HTTP/1\\.1 200 OK \\(\\d+ms\\)")
+        .assertLogEqual("Content-Encoding: gzip")
+        .assertLogEqual("Content-Type: text/plain; charset=utf-8")
+        .assertLogMatch("Content-Length: \\d+")
+        .assertLogMatch("OkHttp-Sent-Millis: \\d+")
+        .assertLogMatch("OkHttp-Received-Millis: \\d+")
+        .assertLogEqual("<-- END HTTP (encoded body omitted)")
+        .assertNoMoreLogs();
+
+    applicationLogs
+        .assertLogEqual("--> GET " + url + " HTTP/1.1")
+        .assertLogEqual("--> END GET")
+        .assertLogMatch("<-- HTTP/1\\.1 200 OK \\(\\d+ms\\)")
+        .assertLogEqual("Content-Type: text/plain; charset=utf-8")
+        .assertLogMatch("OkHttp-Sent-Millis: \\d+")
+        .assertLogMatch("OkHttp-Received-Millis: \\d+")
+        .assertLogEqual("")
+        .assertLogEqual("Hello, Hello, Hello")
+        .assertLogEqual("<-- END HTTP (19-byte body)")
+        .assertNoMoreLogs();
+  }
+
   private Request.Builder request() {
     return new Request.Builder().url(url);
   }