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HADOOP-8922. Provide alternate JSONP output for JMXJsonServlet to allow javascript in browser (Damien Hardy via bobby) 

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1399001 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Robert Joseph Evans 2012-10-16 21:40:53 +00:00
parent 4b27351435
commit dc154bd209
3 changed files with 57 additions and 4 deletions
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3
hadoop-common-project/hadoop-common/CHANGES.txt
View File

@ -51,6 +51,9 @@ Release 2.0.3-alpha - Unreleased
HADOOP-8929. Add toString, other improvements for SampleQuantiles (todd)
HADOOP-8922. Provide alternate JSONP output for JMXJsonServlet to allow
javascript in browser (Damien Hardy via bobby)
OPTIMIZATIONS
HADOOP-8866. SampleQuantiles#query is O(N^2) instead of O(N). (Andrew Wang

34
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/jmx/JMXJsonServlet.java
View File

@ -113,6 +113,9 @@
* All other objects will be converted to a string and output as such.
*
* The bean's name and modelerType will be returned for all beans.
*
* Optional paramater "callback" should be used to deliver JSONP response.
*
*/
public class JMXJsonServlet extends HttpServlet {
private static final Log LOG = LogFactory.getLog(JMXJsonServlet.class);
@ -120,6 +123,8 @@ public class JMXJsonServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
// ----------------------------------------------------- Instance Variables
private static final String CALLBACK_PARAM = "callback";
/**
* MBean server.
*/
@ -145,20 +150,33 @@ public void init() throws ServletException {
*/
@Override
public void doGet(HttpServletRequest request, HttpServletResponse response) {
String jsonpcb = null;
PrintWriter writer = null;
try {
if (!HttpServer.isInstrumentationAccessAllowed(getServletContext(),
request, response)) {
return;
}
JsonGenerator jg = null;
response.setContentType("application/json; charset=utf8");
PrintWriter writer = response.getWriter();
writer = response.getWriter();
// "callback" parameter implies JSONP outpout
jsonpcb = request.getParameter(CALLBACK_PARAM);
if (jsonpcb != null) {
response.setContentType("application/javascript; charset=utf8");
writer.write(jsonpcb + "(");
} else {
response.setContentType("application/json; charset=utf8");
}
JsonFactory jsonFactory = new JsonFactory();
JsonGenerator jg = jsonFactory.createJsonGenerator(writer);
jg = jsonFactory.createJsonGenerator(writer);
jg.disable(JsonGenerator.Feature.AUTO_CLOSE_TARGET);
jg.useDefaultPrettyPrinter();
jg.writeStartObject();
if (mBeanServer == null) {
jg.writeStringField("result", "ERROR");
jg.writeStringField("message", "No MBeanServer could be found");
@ -183,6 +201,7 @@ public void doGet(HttpServletRequest request, HttpServletResponse response) {
response);
jg.close();
return;
}
// query per mbean
@ -199,6 +218,13 @@ public void doGet(HttpServletRequest request, HttpServletResponse response) {
} catch ( MalformedObjectNameException e ) {
LOG.error("Caught an exception while processing JMX request", e);
response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
} finally {
if (jsonpcb != null) {
writer.write(");");
}
if (writer != null) {
writer.close();
}
}
}

24
hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/jmx/TestJMXJsonServlet.java
View File

@ -78,5 +78,29 @@ public static void assertReFind(String re, String value) {
"/jmx?get=java.lang:type=Memory::"));
LOG.info("/jmx RESULT: "+result);
assertReFind("\"ERROR\"", result);
// test to get JSONP result
result = readOutput(new URL(baseUrl, "/jmx?qry=java.lang:type=Memory&callback=mycallback1"));
LOG.info("/jmx?qry=java.lang:type=Memory&callback=mycallback RESULT: "+result);
assertReFind("^mycallback1\\(\\{", result);
assertReFind("\\}\\);$", result);
// negative test to get an attribute of a mbean as JSONP
result = readOutput(new URL(baseUrl,
"/jmx?get=java.lang:type=Memory::&callback=mycallback2"));
LOG.info("/jmx RESULT: "+result);
assertReFind("^mycallback2\\(\\{", result);
assertReFind("\"ERROR\"", result);
assertReFind("\\}\\);$", result);
// test to get an attribute of a mbean as JSONP
result = readOutput(new URL(baseUrl,
"/jmx?get=java.lang:type=Memory::HeapMemoryUsage&callback=mycallback3"));
LOG.info("/jmx RESULT: "+result);
assertReFind("^mycallback3\\(\\{", result);
assertReFind("\"name\"\\s*:\\s*\"java.lang:type=Memory\"", result);
assertReFind("\"committed\"\\s*:", result);
assertReFind("\\}\\);$", result);
}
}