Add escaping to logging output

This aligns the other formatters with the JSON formatter

Author: markt-asf

java/org/apache/juli/JdkLoggerFormatter.java

@@ -96,7 +96,7 @@ public String format(LogRecord record) {
         buf.append(" ".repeat(Math.max(0, 8 - buf.length())));
 
         // Append the message
-        buf.append(message);
+        buf.append(LogUtil.escape(message));
 
         // Append stack trace if not null
         if (t != null) {
@@ -106,7 +106,7 @@ public String format(LogRecord record) {
             java.io.PrintWriter pw = new java.io.PrintWriter(sw);
             t.printStackTrace(pw);
             pw.close();
-            buf.append(sw);
+            buf.append(LogUtil.escape(sw.toString()));
         }
 
         buf.append(System.lineSeparator());

java/org/apache/juli/LogUtil.java

@@ -0,0 +1,64 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.juli;
+
+public class LogUtil {
+
+    private LogUtil() {
+        // Utility class. Hide default constructor
+    }
+
+
+    /**
+     * Escape a string so it can be displayed in a readable format. Characters that may not be printable in some/all of
+     * the contexts in which log messages will be viewed will be escaped using Java \\uNNNN escaping.
+     * <p>
+     * All control characters are escaped apart from horizontal tab (\\u0009), new line (\\u000a) and carriage return
+     * (\\u000d).
+     *
+     * @param input The string to escape
+     *
+     * @return The escaped form of the input string
+     */
+    @SuppressWarnings("null") // sb is not null when used
+    public static String escape(final String input) {
+        final int len = input.length();
+        int i = 0;
+        int lastControl = -1;
+        StringBuilder sb = null;
+        while (i < len) {
+            char c = input.charAt(i);
+            if (Character.getType(c) == Character.CONTROL) {
+                if (!(c == '\t' || c == '\n' || c == '\r')) {
+                    if (lastControl == -1) {
+                        sb = new StringBuilder(len + 20);
+                    }
+                    sb.append(input.substring(lastControl + 1, i));
+                    sb.append(String.format("\\u%1$04x", Integer.valueOf(c)));
+                    lastControl = i;
+                }
+            }
+            i++;
+        }
+        if (lastControl == -1) {
+            return input;
+        } else {
+            sb.append(input.substring(lastControl + 1, len));
+            return sb.toString();
+        }
+    }
+}

java/org/apache/juli/OneLineFormatter.java

@@ -147,7 +147,7 @@ public String format(LogRecord record) {
 
         // Message
         sb.append(' ');
-        sb.append(formatMessage(record));
+        sb.append(LogUtil.escape(formatMessage(record)));
 
         // New line for next record
         sb.append(System.lineSeparator());
@@ -158,7 +158,7 @@ public String format(LogRecord record) {
             PrintWriter pw = new IndentingPrintWriter(sw);
             record.getThrown().printStackTrace(pw);
             pw.close();
-            sb.append(sw.getBuffer());
+            sb.append(LogUtil.escape(sw.toString()));
         }
 
         return sb.toString();

java/org/apache/juli/VerbatimFormatter.java

@@ -20,9 +20,9 @@
 import java.util.logging.LogRecord;
 
 /**
- * Outputs just the log message with no additional elements. Stack traces are not logged. Log messages are separated by
- * <code>System.lineSeparator()</code>. This is intended for use by access logs and the like that need complete control
- * over the output format.
+ * Outputs just the log message with no additional elements and no escaping. Stack traces are not logged. Log messages
+ * are separated by <code>System.lineSeparator()</code>. This is intended for use by access logs and the like that need
+ * complete control over the output format.
  */
 public class VerbatimFormatter extends Formatter {
 
@@ -31,5 +31,4 @@ public String format(LogRecord record) {
         // Timestamp + New line for next record
         return record.getMessage() + System.lineSeparator();
     }
-
 }

test/org/apache/juli/TestLogUtil.java

@@ -0,0 +1,93 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.juli;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class TestLogUtil {
+
+    @Test
+    public void testEscapeForLoggingEmptyString() {
+        doTestEscapeForLogging("");
+    }
+
+
+    @Test
+    public void testEscapeForLoggingNone() {
+        doTestEscapeForLogging("No escaping");
+    }
+
+
+    @Test
+    public void testEscapeForLoggingControlStart() {
+        doTestEscapeForLogging("\u0006Text", "\\u0006Text");
+    }
+
+
+    @Test
+    public void testEscapeForLoggingControlMiddle() {
+        doTestEscapeForLogging("Text\u0006Text", "Text\\u0006Text");
+    }
+
+
+    @Test
+    public void testEscapeForLoggingControlEnd() {
+        doTestEscapeForLogging("Text\u0006", "Text\\u0006");
+    }
+
+
+    @Test
+    public void testEscapeForLoggingControlOnly() {
+        doTestEscapeForLogging("\u0006", "\\u0006");
+    }
+
+
+    @Test
+    public void testEscapeForLoggingControlsStart() {
+        doTestEscapeForLogging("\u0006\u0007Text", "\\u0006\\u0007Text");
+    }
+
+
+    @Test
+    public void testEscapeForLoggingControlsMiddle() {
+        doTestEscapeForLogging("Text\u0006\u0007Text", "Text\\u0006\\u0007Text");
+    }
+
+
+    @Test
+    public void testEscapeForLoggingControlsEnd() {
+        doTestEscapeForLogging("Text\u0006\u0007", "Text\\u0006\\u0007");
+    }
+
+
+    @Test
+    public void testEscapeForLoggingControlsOnly() {
+        doTestEscapeForLogging("\u0006\u0007", "\\u0006\\u0007");
+    }
+
+
+    private void doTestEscapeForLogging(String input) {
+        doTestEscapeForLogging(input, input);
+    }
+
+
+    private void doTestEscapeForLogging(String input, String expected) {
+        String result = LogUtil.escape(input);
+        Assert.assertEquals(expected, result);
+    }
+}

webapps/docs/changelog.xml

@@ -120,6 +120,9 @@
         by default rather then just the exception message when logging an error
         or warning in response to an exception. (markt)
       </scode>
+      <add>
+        Add escaping to log formatters to align with JSON formatter. (markt)
+      </add>
     </changelog>
   </subsection>
 </section>