001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements. See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache license, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License. You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the license for the specific language governing permissions and
015     * limitations under the license.
016     */
017    package org.apache.logging.log4j.core.layout;
018    
019    import java.io.IOException;
020    import java.io.InterruptedIOException;
021    import java.io.LineNumberReader;
022    import java.io.PrintWriter;
023    import java.io.StringReader;
024    import java.io.StringWriter;
025    import java.nio.charset.Charset;
026    import java.util.ArrayList;
027    import java.util.HashMap;
028    import java.util.List;
029    import java.util.Map;
030    
031    import org.apache.logging.log4j.core.config.plugins.Plugin;
032    import org.apache.logging.log4j.core.config.plugins.PluginAttr;
033    import org.apache.logging.log4j.core.config.plugins.PluginFactory;
034    import org.apache.logging.log4j.core.helpers.Charsets;
035    import org.apache.logging.log4j.core.helpers.Transform;
036    import org.apache.logging.log4j.core.LogEvent;
037    import org.apache.logging.log4j.message.Message;
038    import org.apache.logging.log4j.message.MultiformatMessage;
039    
040    
041    /**
042     * The output of the XMLLayout consists of a series of log4j:event
043     * elements as defined in the <a href="log4j.dtd">log4j.dtd</a>. If configured to do so it will
044     * output a complete well-formed XML file. The output is designed to be
045     * included as an <em>external entity</em> in a separate file to form
046     * a correct XML file.
047     * <p/>
048     * <p>For example, if <code>abc</code> is the name of the file where
049     * the XMLLayout ouput goes, then a well-formed XML file would be:
050     * <p/>
051     * <pre>
052     * &lt;?xml version="1.0" ?&gt;
053     *
054     * &lt;!DOCTYPE log4j:eventSet SYSTEM "log4j.dtd" [&lt;!ENTITY data SYSTEM "abc"&gt;]&gt;
055     *
056     * &lt;log4j:eventSet version="1.2" xmlns:log4j="http://logging.apache.org/log4j/"&gt;
057     * &nbsp;&nbsp;&data;
058     * &lt;/log4j:eventSet&gt;
059     * </pre>
060     * <p/>
061     * <p>This approach enforces the independence of the XMLLayout and the
062     * appender where it is embedded.
063     * <p/>
064     * <p>The <code>version</code> attribute helps components to correctly
065     * interpret output generated by XMLLayout. The value of this
066     * attribute should be "1.1" for output generated by log4j versions
067     * prior to log4j 1.2 (final release) and "1.2" for release 1.2 and
068     * later.
069     * <p/>
070     * Appenders using this layout should have their encoding
071     * set to UTF-8 or UTF-16, otherwise events containing
072     * non ASCII characters could result in corrupted
073     * log files.
074     */
075    @Plugin(name = "XMLLayout", type = "Core", elementType = "layout", printObject = true)
076    public class XMLLayout extends AbstractStringLayout {
077    
078        private static final int DEFAULT_SIZE = 256;
079    
080        private static final String[] FORMATS = new String[] {"xml"};
081    
082        private final boolean locationInfo;
083        private final boolean properties;
084        private final boolean complete;
085    
086        protected XMLLayout(final boolean locationInfo, final boolean properties, final boolean complete,
087                            final Charset charset) {
088            super(charset);
089            this.locationInfo = locationInfo;
090            this.properties = properties;
091            this.complete = complete;
092        }
093    
094        /**
095         * Formats a {@link org.apache.logging.log4j.core.LogEvent} in conformance with the log4j.dtd.
096         *
097         * @param event The LogEvent.
098         * @return The XML representation of the LogEvent.
099         */
100        public String toSerializable(final LogEvent event) {
101            final StringBuilder buf = new StringBuilder(DEFAULT_SIZE);
102    
103            // We yield to the \r\n heresy.
104    
105            buf.append("<log4j:event logger=\"");
106            String name = event.getLoggerName();
107            if (name.length() == 0) {
108                name = "root";
109            }
110            buf.append(Transform.escapeTags(name));
111            buf.append("\" timestamp=\"");
112            buf.append(event.getMillis());
113            buf.append("\" level=\"");
114            buf.append(Transform.escapeTags(String.valueOf(event.getLevel())));
115            buf.append("\" thread=\"");
116            buf.append(Transform.escapeTags(event.getThreadName()));
117            buf.append("\">\r\n");
118    
119            final Message msg = event.getMessage();
120            if (msg != null) {
121                boolean xmlSupported = false;
122                if (msg instanceof MultiformatMessage) {
123                    final String[] formats = ((MultiformatMessage) msg).getFormats();
124                    for (final String format : formats) {
125                        if (format.equalsIgnoreCase("XML")) {
126                            xmlSupported = true;
127                        }
128                    }
129                }
130                if (xmlSupported) {
131                    buf.append("<log4j:message>");
132                    buf.append(((MultiformatMessage) msg).getFormattedMessage(FORMATS));
133                    buf.append("</log4j:message>");
134                } else {
135                    buf.append("<log4j:message><![CDATA[");
136                    // Append the rendered message. Also make sure to escape any
137                    // existing CDATA sections.
138                    Transform.appendEscapingCDATA(buf, event.getMessage().getFormattedMessage());
139                    buf.append("]]></log4j:message>\r\n");
140                }
141            }
142    
143            if (event.getContextStack().getDepth() > 0) {
144                buf.append("<log4j:NDC><![CDATA[");
145                Transform.appendEscapingCDATA(buf, event.getContextStack().toString());
146                buf.append("]]></log4j:NDC>\r\n");
147            }
148    
149            final Throwable throwable = event.getThrown();
150            if (throwable != null) {
151                final List<String> s = getThrowableString(throwable);
152                buf.append("<log4j:throwable><![CDATA[");
153                for (final String str : s) {
154                    Transform.appendEscapingCDATA(buf, str);
155                    buf.append("\r\n");
156                }
157                buf.append("]]></log4j:throwable>\r\n");
158            }
159    
160            if (locationInfo) {
161                final StackTraceElement element = event.getSource();
162                buf.append("<log4j:locationInfo class=\"");
163                buf.append(Transform.escapeTags(element.getClassName()));
164                buf.append("\" method=\"");
165                buf.append(Transform.escapeTags(element.getMethodName()));
166                buf.append("\" file=\"");
167                buf.append(Transform.escapeTags(element.getFileName()));
168                buf.append("\" line=\"");
169                buf.append(element.getLineNumber());
170                buf.append("\"/>\r\n");
171            }
172    
173            if (properties && event.getContextMap().size() > 0) {
174                buf.append("<log4j:properties>\r\n");
175                for (final Map.Entry<String, String> entry : event.getContextMap().entrySet()) {
176                    buf.append("<log4j:data name=\"");
177                    buf.append(Transform.escapeTags(entry.getKey()));
178                    buf.append("\" value=\"");
179                    buf.append(Transform.escapeTags(String.valueOf(entry.getValue())));
180                    buf.append("\"/>\r\n");
181                }
182                buf.append("</log4j:properties>\r\n");
183            }
184    
185            buf.append("</log4j:event>\r\n\r\n");
186    
187            return buf.toString();
188        }
189    
190        /**
191         * Returns appropriate XML headers.
192         * @return a byte array containing the header.
193         */
194        @Override
195        public byte[] getHeader() {
196            if (!complete) {
197                return null;
198            }
199            final StringBuilder sbuf = new StringBuilder();
200            sbuf.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n");
201            sbuf.append("<log4j:eventSet xmlns:log4j=\"http://logging.apache.org/log4j/\">\r\n");
202            return sbuf.toString().getBytes(getCharset());
203        }
204    
205    
206        /**
207         * Returns appropriate XML headers.
208         * @return a byte array containing the footer.
209         */
210        @Override
211        public byte[] getFooter() {
212            if (!complete) {
213                return null;
214            }
215            final StringBuilder sbuf = new StringBuilder();
216            sbuf.append("</log4j:eventSet>\r\n");
217            return sbuf.toString().getBytes(getCharset());
218        }
219    
220        /**
221         * XMLLayout's content format is specified by:<p/>
222         * Key: "dtd" Value: "log4j.dtd"<p/>
223         * Key: "version" Value: "1.2"
224         * @return Map of content format keys supporting XMLLayout
225         */
226        public Map<String, String> getContentFormat() {
227            Map<String, String> result = new HashMap<String, String>();
228            result.put("dtd", "log4j.dtd");
229            result.put("version", "1.2");
230            return result;
231        }
232    
233        @Override
234        /**
235         * @return The content type.
236         */
237        public String getContentType() {
238            return "text/xml";
239        }
240    
241        List<String> getThrowableString(final Throwable throwable) {
242            final StringWriter sw = new StringWriter();
243            final PrintWriter pw = new PrintWriter(sw);
244            try {
245                throwable.printStackTrace(pw);
246            } catch (final RuntimeException ex) {
247                // Ignore any exceptions.
248            }
249            pw.flush();
250            final LineNumberReader reader = new LineNumberReader(new StringReader(sw.toString()));
251            final ArrayList<String> lines = new ArrayList<String>();
252            try {
253              String line = reader.readLine();
254              while (line != null) {
255                lines.add(line);
256                line = reader.readLine();
257              }
258            } catch (final IOException ex) {
259                if (ex instanceof InterruptedIOException) {
260                    Thread.currentThread().interrupt();
261                }
262                lines.add(ex.toString());
263            }
264            return lines;
265        }
266    
267        /**
268         * Create an XML Layout.
269         * @param locationInfo If "true" include the location information in the generated XML.
270         * @param properties If "true" include the thread context in the generated XML.
271         * @param complete If "true" include the XML header.
272         * @param charsetName The character set to use.
273         * @return An XML Layout.
274         */
275        @PluginFactory
276        public static XMLLayout createLayout(@PluginAttr("locationInfo") final String locationInfo,
277                                             @PluginAttr("properties") final String properties,
278                                             @PluginAttr("complete") final String complete,
279                                             @PluginAttr("charset") final String charsetName) {
280            final Charset charset = Charsets.getSupportedCharset(charsetName);
281            final boolean info = locationInfo == null ? false : Boolean.valueOf(locationInfo);
282            final boolean props = properties == null ? false : Boolean.valueOf(properties);
283            final boolean comp = complete == null ? false : Boolean.valueOf(complete);
284            return new XMLLayout(info, props, comp, charset);
285        }
286    }