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| <title>HTTP Connection Tracer Diagnostic Utility</title> |
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| <h1>HTTP Connection Tracer Diagnostic Utility</h1> |
| <p>NOTE: this page is out of date, and should be considered deprecated. See the <a href="https://wiki.eclipse.org/WTP/HTTP_Connection_Tracer_Diagnostic_Utility">HTTP Tracer wiki page</a> for current inforamtion.</p> |
| <h2>Problem</h2> |
| <p>In the past we have encountered many different 'going off to the internet problems' in various parts of our tools |
| (on the development side and the server side). As you know these problems have proven to be a real pain for support and |
| development .... they're difficult to track down and take a great deal of effort to reproduce. I'm sure these are also a |
| real pain for customers who are nagged by many different variations of the 'going off to the internet problem'.</p> |
| <h2>The solution (for diagnosis)</h2> |
| <p>I've finally found a few hours to write an "HTTP Connection Tracer" tool to help us manage these 'going off to |
| the internet problems' Really the tool has two purposes:</p> |
| <ul> |
| <li><b>to help development and support understand these problems</b> by providing logging information so were |
| can see where the code is 'going off to the internet'</li> |
| <li><b>to help customers workaround these problems</b> by providing a crude means to redirect http connections |
| ... so instead of 'going off to the internet' they go to the local file system</li> |
| </ul> |
| <p>I should emphasize that this tool is not intended to be a 'solution' ... just a useful short term aid until a |
| time that we can provide 'proper' fixes. Below I've described how to install \ and configure the tool and how to use it. |
| <b>Please help test this out!</b> If you agree that it proves useful I would encourage you to direct users to utilize |
| this when helping address these sorts of problems.</p> |
| <p>Please address any questions, comments or suggestions in <a |
| href="https://bugs.eclipse.org/bugs/enter_bug.cgi?product=Web%20Tools" |
| target="_top">bugs</a> or via the <a |
| href="https://dev.eclipse.org/mailman/listinfo/wtp-dev" |
| target="_top">wtp-dev@eclipse.org</a> mailing list.</p> |
| <h3>Installation</h3> |
| <p>Download the <a href="httphandler.jar">HTTP connection tracer diagnostic utility</a> jar file.</p> |
| <p>The httphandler.jar file must be added to the JRE's lib/ext directory. This must be done for each JRE that you're |
| using in your environment. So if you're developing your code with eclipse and deploying to a server (and you want to get |
| trace information for both) you'll need to make the JAR available for both the eclipse JRE and the server's JRE.</p> |
| <h3>Configuration</h3> |
| <p>When you launch eclipse or run your sever, you'll need to specify some vmargs to activate the "HTTP Connection |
| Tracer" tool. Here's an example of how you'd do this on the command line for Eclipse.</p> |
| <code>eclipse.exe -vmargs -Djava.protocol.handler.pkgs=com.ibm.etools.www.protocol -DurlMapLocation=C:\map.txt -DurlLogLocation=C:\log.txt</code> |
| <p>Here's a description of what each argument does ....</p> |
| <table border="1"> |
| <tr> |
| <th>name</th> |
| <th>example value</th> |
| <th>description</th> |
| </tr> |
| <tr> |
| <td>java.protocol.handler.pkgs</td> |
| <td>com.ibm.etools.www.protocol</td> |
| <td>Tells the JVM to utilize the "HTTP Connection Tracer" tool.</td> |
| </tr> |
| <tr> |
| <td>urlMapLocation</td> |
| <td>C:\map.txt</td> |
| <td>Specifies the location of a 'properties' file where URL mapping information can be provided. Note that |
| if no map location is specified then URL redirection never occurs.</td> |
| </tr> |
| <tr> |
| <td>urlLogLocation</td> |
| <td>C:\log.txt</td> |
| <td>Specifies the location of a log file where logging information will be written. Note that if no log |
| location is specified the logging information will be written to System.out. Note also that if no HTTP requests |
| are made, then no log or output is produced. If there is no output, you may want to confirm your setup by |
| running a small test program that explicitly does a URL connection. See <a |
| href="https://bugs.eclipse.org/bugs/show_bug.cgi?id=216524">bug 216524</a> for an example.</td> |
| </tr> |
| </table> |
| <h4>The Map File</h4> |
| <p>Here's an example of what the map file looks like....</p> |
| <blockquote>http://www.hello.com/bar.xsd =file:///D:/my-schema-cache/bar.xsd<br /> |
| http://www.ibm.com/foo.xsd=file:///D:/my-schema-cache/foo.xsd</blockquote> |
| <p>Notice its just a list of mapping pairs (separated by an '=' sign) that specifies how a web address should be |
| redirected to a local file system address. By editing this file, a customer can workaround nagging 'going off to the |
| internet problems' until a proper fix is delivered.</p> |
| <h4>The Log File</h4> |
| <p>Each time the JVM attempts to create an HTTP connection, an entry is added to the log file. Below I've shown an |
| example log file entry. It consists of three interesting pieces of information...</p> |
| <blockquote>URL request - provides the URL address for the connection<br /> |
| URL mapped - provides the 'mapped' address (as specified in the 'map.txt' file) to help the customer see that the URL |
| has been succesfully redirected<br /> |
| STACK TRACE - dumps of stack to help the support and development teams understand the code paths involved in creating |
| the connection request</blockquote> |
| <p>Note that the presense of an entry in the log does not neccessarily imply an defect in the product. Some attempts |
| to create an HTTP connections are expected. So I'd encourage you to scrutinize the entries in the log file. At the very |
| least the logs will provide you some useful stack trace information that will help developers understand the nature of |
| the HTTP connections.</p> |
| <h3>Example Output</h3> |
| <pre> |
| <code> |
| URL requested : http://www.ibm.com/foo.xsd |
| URL mapped : file:///D:/workspaces/corona-test/XMLExamples/substitutionGroup/Catalogue4.xsd |
| STACK TRACE : |
| java.lang.Exception: dumpTheStack |
| at com.ibm.etools.www.protocol.http.Handler.openConnection(Handler.java:156) |
| at java.net.URL.openConnection(URL.java:924) |
| at org.apache.xerces.impl.XMLEntityManager.setupCurrentEntity(Unknown Source) |
| at org.apache.xerces.impl.XMLVersionDetector.determineDocVersion(Unknown Source) |
| at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source) |
| at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source) |
| at org.apache.xerces.parsers.XMLParser.parse(Unknown Source) |
| at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source) |
| at javax.xml.parsers.SAXParser.parse(Unknown Source) |
| at org.eclipse.xsd.util.XSDParser.parse(XSDParser.java:175) |
| at com.ibm.xsdeditor.internal.wizards.XSDSelectIncludeFileWizard.doLoadExternalModel(XSDSelectIncludeFileWizard.java:183) |
| at com.ibm.xsdeditor.internal.wizards.XSDSelectIncludeFileWizard$XSDURLPage.openExternalSchema(XSDSelectIncludeFileWizard.java:293) |
| at com.ibm.xsdeditor.internal.wizards.XSDSelectIncludeFileWizard$XSDURLPage.access$0(XSDSelectIncludeFileWizard.java:271) |
| at com.ibm.xsdeditor.internal.wizards.XSDSelectIncludeFileWizard$1.run(XSDSelectIncludeFileWizard.java:318) |
| at org.eclipse.jface.operation.ModalContext.runInCurrentThread(ModalContext.java:303) |
| at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:253) |
| at org.eclipse.jface.wizard.WizardDialog.run(WizardDialog.java:752) |
| at com.ibm.xsdeditor.internal.wizards.XSDSelectIncludeFileWizard.performFinish(XSDSelectIncludeFileWizard.java:130) |
| at org.eclipse.jface.wizard.WizardDialog.finishPressed(WizardDialog.java:609) |
| at org.eclipse.jface.wizard.WizardDialog.buttonPressed(WizardDialog.java:305) |
| at org.eclipse.jface.dialogs.Dialog$2.widgetSelected(Dialog.java:506) |
| at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:89) |
| at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java(Compiled Code)) |
| at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:796) |
| at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:2772) |
| at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java(Compiled Code)) |
| at org.eclipse.jface.window.Window.runEventLoop(Window.java:668) |
| at org.eclipse.jface.window.Window.open(Window.java:648) |
| at com.ibm.xsdeditor.internal.properties.section.NamespaceAndSchemaLocationSection.widgetSelected(NamespaceAndSchemaLocationSection.java:159) |
| at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:89) |
| at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java(Compiled Code)) |
| at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:796) |
| at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:2772) |
| at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2431) |
| at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:1377) |
| at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:1348) |
| at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:254) |
| at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:141) |
| at org.eclipse.ui.internal.ide.IDEApplication.run(IDEApplication.java:96) |
| at org.eclipse.core.internal.runtime.PlatformActivator$1.run(PlatformActivator.java:335) |
| at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:273) |
| at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:129) |
| at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) |
| at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:85) |
| at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:58) |
| at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:60) |
| at java.lang.reflect.Method.invoke(Method.java:391) |
| at org.eclipse.core.launcher.Main.basicRun(Main.java:185) |
| at org.eclipse.core.launcher.Main.run(Main.java:704) |
| at org.eclipse.core.launcher.Main.main(Main.java:688) |
| </code> |
| </pre> |
| <h2>The solution (for code)</h2> |
| <p>While there is no one solution for all situations where you want to avoid or minimize network access, here we will mention a few |
| things to consider.</p> |
| <ul> |
| <li>Use an XML Catalog, with copies of resources on your local disk.</li> |
| <li>Set validation off, and set a null resolver.</li> |
| <li>Use a cache, so resources are at least only retrieved once, such as the cache in WTP!</li> |
| </ul> |
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