From dc154bd2095b9d71483c1167ba0cc15bd9086d84 Mon Sep 17 00:00:00 2001 From: Robert Joseph Evans Date: Tue, 16 Oct 2012 21:40:53 +0000 Subject: [PATCH] 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 --- .../hadoop-common/CHANGES.txt | 3 ++ .../org/apache/hadoop/jmx/JMXJsonServlet.java | 34 ++++++++++++++++--- .../apache/hadoop/jmx/TestJMXJsonServlet.java | 24 +++++++++++++ 3 files changed, 57 insertions(+), 4 deletions(-) diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt index e4c532aa8c6..095e7e47801 100644 --- a/hadoop-common-project/hadoop-common/CHANGES.txt +++ b/hadoop-common-project/hadoop-common/CHANGES.txt @@ -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 diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/jmx/JMXJsonServlet.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/jmx/JMXJsonServlet.java index fe8dbdb46b9..3b605e01a9e 100644 --- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/jmx/JMXJsonServlet.java +++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/jmx/JMXJsonServlet.java @@ -113,6 +113,9 @@ import org.codehaus.jackson.JsonGenerator; * 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 class JMXJsonServlet extends HttpServlet { */ @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 class JMXJsonServlet extends HttpServlet { response); jg.close(); return; + } // query per mbean @@ -199,6 +218,13 @@ public class JMXJsonServlet extends HttpServlet { } 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(); + } } } diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/jmx/TestJMXJsonServlet.java b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/jmx/TestJMXJsonServlet.java index 62a2af95552..a03eba92c39 100644 --- a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/jmx/TestJMXJsonServlet.java +++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/jmx/TestJMXJsonServlet.java @@ -78,5 +78,29 @@ public class TestJMXJsonServlet extends HttpServerFunctionalTest { "/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); + } }