1060 Forum - Recent Entries

ROC Tutorial - Part 2 no longer works after install of 4.1.1

Thu, 02 Sep 2010 18:09:00 GMT

After installing fresh EE 4.1.1, ROC tutorial - Part 2 (Servlet) no longer works. Will send a separate email with Visualizer debug file.

sorry about that...

Thu, 02 Sep 2010 13:17:00 GMT

Hi Kansberry,
your visualizer files show that you still have the same situation. It looks like I didn't test the change I proposed well enough! :-(

The layer1 import was deeply nested inside the mapper and so wasn't visible on the outside the module when it was need to serialize the string.

Try changing the rootspace to this:

<rootspace>
  <!-- Dynamic Import into the HTTP fulcrum -->
  <fileset>
    <regex>res:/etc/system/SimpleDynamicImportHook.xml</regex>
  </fileset>
  <mapper>
    <config>
      <!-- Endpoint for the 'Hello World' resource -->
      <endpoint>
        <grammar>res:/tutorial/firstmodule/helloworld</grammar>
        <request>
          <identifier>active:groovy</identifier>
          <argument name="operator">res:/resources/scripts/helloworld.gy</argument>
        </request>
      </endpoint>
    </config>
    <space>
      <fileset>
        <private />
        <regex>res:/resources/.*</regex>
      </fileset>
      <import>
        <private />
        <uri>urn:org:netkernel:lang:groovy</uri>
      </import>
    </space>
  </mapper>
  <import>
    <uri>urn:org:netkernel:ext:layer1</uri>
  </import>
</rootspace>

Cheers, Tony

Any plans to port the address book and forum applications to NK4?

Wed, 01 Sep 2010 19:57:00 GMT

Hi,

I had found useful the address book and forum applications in NK3 for learning to build apps in NetKernel.

Do you plan to port them to NK4?

Thanks,
Mircea

Wed, 01 Sep 2010 18:49:00 GMT

I finally had time to get back to this problem. Looks like I now have a new error with the change you suggested. I am emailing you the Visualizer files of the error I get. Let me know how to fix when you get time.

JSONFromXML part II - NK3 only

Tue, 31 Aug 2010 14:34:00 GMT

Greetings all,

-- All of the below FYI

Some time ago I wrote http://www.netkernel.org/forum/topic/534/1. I haven't been able to check the JSON implementation in NK4, but there's some other funy stuff in the NK3 implementation ...

Say you want to return this :

{
 "errors": {},
 "success": true
}

That may not look like a lot, but a lot of services require your result to be like that. So you start writing your service and you end up with the following XML :
<root>
<errors></errors>
<success>true</success>
</root>

Nice, but how to convert this valid XML that to the above (valid) JSON. The answer is ... you can't. The conversion will keep the root element (which has to be there in order to have valid XML ... and that closes the circle).

In order to resolve this I hacked the JSONAspect.java source as follows :

/*
 * JSONAspect.java
 *
 * Created on 16 June 2006, 10:09
 */

package org.ten60.json.representation;

import org.json.*;

/**
 *
 * @author  pjr
 */
public class JSONAspect implements IAspectJSON
{
   private JSONObject mJSON;
   
   /** Creates a new instance of JSONAspect */
   public JSONAspect(JSONObject aJSON)
   {  
           if (aJSON.has("removeme")){
             try{ 
               mJSON=aJSON.getJSONObject("removeme");
             }
             catch(JSONException e){
             }
           }
           else{
             mJSON=aJSON;
           }
   }
   
   public IJSONObjectReadOnly getJSONObject()
   {   return (IJSONObjectReadOnly)mJSON;
   }
   
}

Simply put, if the root-tag is <removeme>, it gets ... you guessed it ... removed (only the tag, not the content).

There's another issue with the NK3 implementation of JSONFromXML that does something wrong. For one reason or another the resulting JSON will always look like :
{
"errors": {},
"success": "true"
}
Note the double quotes around the boolean value. Same happens with numbers. Probably I do not understand the correct syntax in this case, I do see relevant code in the JSONObject.java source (valueToString method to be exact), it just doesn't work for me. Wrote an ugly hack for the boolean values (since yes, the services I work with require a boolean to be without the quotes).

Enjoy,
Tom

NetKernel News Volume 1 Issue 43

Sat, 28 Aug 2010 09:59:00 GMT

News is now published in the NetKernel.org wiki.

Issue 43 is available here:

http://wiki.netkernel.org/wink/wiki/NetKernel/News/1/43/August_27th_2010

Topics include:

* Repository Updates
* NetKernel ClassLoaders
* Talk: Resource Oriented Cloud Architectures

To get the most current issue visit:

http://wiki.netkernel.org/wink/wiki/NetKernel/News/latest

NetKernel News Volume 1 Issue 42

Sat, 28 Aug 2010 09:58:00 GMT

News is now published in the NetKernel.org wiki.

Issue 42 is available here:

http://wiki.netkernel.org/wink/wiki/NetKernel/News/1/42/August_19th_2010

Topics include:

* NetKernel Enterprise Edition Released to Manufacture.
* WiNK updates, including Latex mathematics.

To get the most current issue visit:

http://wiki.netkernel.org/wink/wiki/NetKernel/News/latest

NetKernel News Volume 1 Issue 41

Sat, 28 Aug 2010 09:56:00 GMT

News is now published in the NetKernel.org wiki.

Issue 41 is available here:

http://wiki.netkernel.org/wink/wiki/NetKernel/News/1/41/August_13th_2010

Topics include:

* NetKernel Enterprise Edition Heads Up
* NetKernel ssh daemon
* An Independent View: What is this NetKernel thing Anyway?
* NetKernel News Volume 1 Anthology (The power of the wiki goes to pjr's head).
* P v NP

To get the most current issue visit:

http://wiki.netkernel.org/wink/wiki/NetKernel/News/latest

Variant 2 is the closest

Fri, 27 Aug 2010 16:30:00 GMT

Hi Mircea,

Variant 2 is the way to go. xrl:eval is the correct operation because it sets a string value into the xml document, xrl:include inserts an xml fragment into the document.

However there are two mistakes in your variant2:

1) xrl:eval attempts to source the specified request. Your argument month-number cannot be sourced because it is not an identifier to a resource, instead it is just a string. To fix this you can change your mapper to convert the argument it a pass-by-value string like this:

<request>
<identifier>active:xrl2</identifier>
<argument name="template">xrl:template</argument>
<argument name="content">xrl:content</argument>
<argument name="month-number" method="as-string">arg:month-number</argument>
</request>

For more details of the method attribute on declarative requests see:
http://docs.netkernel.org/book/view/book:guide:logicalreference/doc:logicalreference:module:standard:logical:declarative:request:syntax

2) When xrl process a document all xrl namespace tags are removed from the document as they are processed. What this means is that the xpath of "." will no longer be there and so cannot be substituted.

Try this:

<html xmlns:xrl="http://netkernel.org/xrl">
<body>
<h1>Monthly expenses</h1>
<xrl:eval>
<xrl:xpath>../h1</xrl:xpath>
<xrl:identifier>arg:month-number</xrl:identifier>
</xrl:eval>
<xrl:include identifier="arg:content"/>
</body>
</html>

Cheers, Tony

Use XSLT 2.0 and its accessor

Fri, 27 Aug 2010 05:26:00 GMT

Hi, Mircea,

You seem to be trying to use XPath 2.0 functions in a XSLT 1.0 stylesheet. That won't work, you'll either have to use EXSLT functions or switch to XSLT 2.0. XSLT 2.0 is much easier for many tasks then XSLT 1.0, so that would be my advice.

Here is an XSLT 2.0 version of your example:


<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">

    <xsl:template match="resultset">
        <expenses>
            <xsl:attribute name="total" select="max((1,2,3))"/>
            <xsl:apply-templates/>
        </expenses>
    </xsl:template>

</xsl:stylesheet>

Please notice the following changes:
- stylesheet version is now 2.0
- there is no need to declare the fn namespace prefix, the XSLT 2.0 processor will use that as default
- the max function takes a sequence, so in this case you need an extra set of brackets (you won't need those of you select a nodeset using XPath expression)

You'll need to use the XSLT 2.0 accessor in NK (see http://docs.netkernel.org/book/view/book:xml:saxon:book/doc:xml:saxon:xslt2 for NK4, for NK3 I couldn't find a public website anymore but you can try http://localhost:1060/book/developerreference/doc_ura_xslt2 (notice it's in the xquery module)).

If you've to stick to XSLT 1.0 you find information about EXSLT here: http://www.exslt.org/. It depends a bit on the XSLT processor of some of these functions are already by default available. I'm sorry I haven't been using XSLT 1.0 for a long time, so I don't know the current status ...

Hope this helps,

Menzo

How to use xpath-functions in xslt stylesheets

Fri, 27 Aug 2010 04:13:00 GMT

Hi,

I try to use xpath-functions in one of my xslt file in a NK4 module.

My xslt declares the "fn" namespace like this:

<?xml version="1.0" encoding="UTF-8" ?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:nk="http://1060.org/netkernel"
                        xmlns:fn="http://www.w3.org/2005/xpath-functions">

In the xslt file I have a template like this:

   <xsl:template match="resultset">
      <expenses>
         <xsl:attribute name="total">
            <xsl:value-of select="fn:max(1,2,3)"/>
         </xsl:attribute>
         <xsl:apply-templates/>
      </expenses>
   </xsl:template>

Note: Precisely, I need the "sum" function, so instead of <xsl:value-of select="fn:max(1,2,3)"/> above I'll use:

<xsl:value-of select="fn:sum(//AMOUNT)"/>

NetKernel reports errors like:

(Location of error unknown)java.lang.NoSuchMethodException: For extension function, could not find method org.apache.xml.utils.NodeVector.su
m([ExpressionContext,] ).

(Location of error unknown)java.lang.NoSuchMethodException: For extension function, could not find method java.lang.String.sum([ExpressionCo
ntext,] ).

(Location of error unknown)java.lang.NoSuchMethodException: For extension function, could not find method java.lang.Double.sum([ExpressionCo
ntext,] #NUMBER, #NUMBER).

depending on what fn functions I try to use.

Is it possible to use xpath-functions in NetKernel? If yes, what library do I need to add and where?

Thanks,
Mircea

How to inline argument passed to xrl2 in its template

Wed, 25 Aug 2010 15:54:00 GMT

Hi,

I'm trying to inline an argument passed to xrl2 in its template.

I start with this external request:

http://localhost:8080/expenses/month/7

In the mapper's configuration I have the following endpoints:

   <endpoint>
      <id>expensesByMonth</id>
      <grammar>res:/expenses
         <optional>/month/
            <group name="month-number">
               <regex type="integer"/>
            </group>
         </optional>
      </grammar>
      <request>
         <identifier>active:xrl2</identifier>
         <argument name="template">xrl:template</argument>
         <argument name="content">xrl:content</argument>
         <argument name="month-number">arg:month-number</argument>
      </request>
      <header name="mime">text/html</header>
   </endpoint>
   <endpoint>
      <id>monthly-expenses-template</id>
      <grammar>xrl:template</grammar>
      <request>
         <identifier>res:/resources/xrl/template.xml</identifier>
      </request>
   </endpoint>
   <endpoint>
      <id>monthly-expenses-content</id>
      <grammar>xrl:content</grammar>
      <request>
         <identifier>res:/resources/xrl/content.xml</identifier>
      </request>
   </endpoint>

I played with the following template variants. None of them works.

variant 1

<html xmlns:xrl="http://netkernel.org/xrl">
   <body>
      <h1>Monthly expenses <xrl:eval><xrl:identifier>arg:month-number</xrl:identifier></xrl:eval></h1>
      <xrl:include identifier="arg:content"/>
   </body>
</html>

variant 2

<html xmlns:xrl="http://netkernel.org/xrl">
   <body>
      <h1>Monthly expenses</h1>
      <xrl:eval>
         <xrl:xpath>.</xrl:xpath>
         <xrl:identifier>arg:month-number</xrl:identifier>
      </xrl:eval>
      <xrl:include identifier="arg:content"/>
   </body>
</html>

variant 3

<html xmlns:xrl="http://netkernel.org/xrl">
   <body>
      <h1>Monthly expenses [[arg:month-number]]</h1>
      <xrl:include identifier="arg:content"/>
   </body>
</html>

Note: Tony already said in a previous post answer that the syntax [[arg:month-number]] is not supported anymore in xrl2.

How should I do it?

Thanks,
Mircea

Exactly what I needed

Tue, 24 Aug 2010 13:41:00 GMT

Hi Tony,

Thanks a lot for your detailed and to the point solution to my problem. It worked beautifully.

Mircea

Tue, 24 Aug 2010 11:06:00 GMT

Hi Mircea,

XRL2 doesn't support the [[arg:name]] syntax that you are using. I know that xrl(1) in NetKernel 3 did support it, and now in NetKernel 4 the mapper does support it too. The documentation for XRL2 doesn't mention it but I've noticed in the codebase there is a limited support for it in the compact xrl:resolve!

It could be an enhancement to add this functionality but there is another way now. Arguments can be added to requests:

<xrl:include xmlns:xrl="http://netkernel.org/xrl">
 <xrl:identifier>meta:expensesByMonth</xrl:idenfifier>
 <xrl:argument name="month">arg:month-number</xrl:argument>
</xrl:include>

or compactly:

<xrl:include identifier="meta:expensesByMonth" argument-month="arg:month-number"/>

Then ensure your endpoint definition has an <id> tag on it so that the meta request in the xrl:include can find it:

<endpoint>
 <id>expensesByMonth</id>
 <grammar>res:/expenses/variable/month
  <group name="month-number><regex type="integer"/></group>
 </grammar>
 .....
</endpoint>

Then the request issued by the xrl:include will be constructed with the correct identifier syntax however that is defined.

Hope that helps,
Tony

How to construct programmatically a resource URI from parts

Tue, 24 Aug 2010 04:46:00 GMT

Hi,

I'm struggling trying to do something simple in concept. Essentially, I need to programmatically construct an URI by concatenating 2 parts a fix one and another being variable.

In some sort of pseudo-code:
URI= "res:/expenses/fixed/month" + ${arg:month-number} => "res:/expenses/fixed/month/7"
Note: By design, the URI-like string above "res:/expenses/fixed/month" does not resolve to any endpoint. But res:/expenses/fixed/month/7 does.

The following is the content of a content.xml file that is to be pushed into an XRL template. "month-number" is an argument that is passed to active:xrl2 so it is available when the content.xml is resolved.

<div xmlns:xrl="http://netkernel.org/xrl">
<xrl:include>
   <xrl:identifier>meta:id-builder</xrl:identifier>
   <xrl:argument name="base">
      <literal>res:/expenses/fixed/month</literal>
   </xrl:argument>
   <xrl:argument name="appender">arg:month-number</xrl:argument>
</xrl:include>
<xrl:include identifier="res:/expenses/variable/month/[[arg:month-number]]"/>
<xrl:include identifier="res:/expenses/variable/month/6"/>
</div>

In the div element above you can see 2 failed and one successful attempts to achieve my goal. The third xrl:include works fine but the month is hard-coded.

Please advise on a workable solution.

Thanks a lot,
Mircea

Fixed tutorial text

Mon, 23 Aug 2010 18:57:00 GMT

I've updated the tutorial to reflect this change.

Missing import in tutorial module

Mon, 23 Aug 2010 18:46:00 GMT

Hi Kevin, I received the files. Thank you. The problem is that the optional Wink wiki module is interfering with the operation of tutorial module due a slight error in the details of the tutorial module - it is missing an import of layer1 which would allow it transrept the returned String into a binary stream.

Try adding an import of layer1 just below the groovy import in the tutorial module.xml:

<import>
  <uri>urn:org:netkernel:ext:layer1</uri>
  <private />
</import>

Sorry for the confusion. Tony

Mon, 23 Aug 2010 16:45:00 GMT

Tony,
I just emailed you two files from the visualizer after running the "firstmodule" code. Let me know what I have wrong.

Thanks.

System Health - HEALTHY

Sun, 22 Aug 2010 15:07:00 GMT

Hi Peter,

Thanks for your quick fix. Hopefully you did not have to interrupt your wonderful long summer weekend :)

Stack trace is clean now:

I 09:57:53 FirstTimeSync Performing post install synchronization with repositories
I 09:57:55 updateProc.gy Starting repository synchronization
I 09:57:55 updateProc.gy Repository base / distribution [https://apposite.1060research.com/repo/netkernel/1060-NetKernel-EE/4.1.1/]
I 09:57:57 updateProc.gy Synchronizing [base/main]
I 09:57:58 updateProc.gy Synchronizing [update/main]
I 09:57:58 updateProc.gy Synchronizing [security/main]
I 09:57:58 updateProc.gy Repository synchronization completed.
I 09:57:58 updateProc.gy Repository base / distribution [https://apposite.1060research.com/repo/netkernel/1060-NetKernel-EE/4.1.1/]
I 09:57:59 updateProc.gy Synchronizing [base/universe]
I 09:57:59 updateProc.gy Synchronizing [update/universe]
I 09:58:00 updateProc.gy Synchronizing [security/universe]
I 09:58:00 updateProc.gy Repository synchronization completed.
I 09:58:00 updateProc.gy Repository base / distribution [https://apposite.1060research.com/repo/netkernel/1060-NetKernel-EE/4.1.1/]
I 09:58:00 updateProc.gy Synchronizing [base/multiverse]
I 09:58:00 updateProc.gy Synchronizing [update/multiverse]
I 09:58:01 updateProc.gy Synchronizing [security/multiverse]
I 09:58:01 updateProc.gy Repository synchronization completed.
I 09:58:01 CronTransport Searching for spaces with CronConfig, loading jobs...
I 09:58:01 HTTPTranspor~ Commissioning HTTP Transport
I 09:58:01 HTTPTranspor~ Registered NetKernel Synchronous HTTP Handler
I 09:58:01 HTTPTranspor~ Starting [HTTP] on port [1060]
I 09:58:01 HTTPTranspor~ jetty-6.1.x
I 09:58:01 HTTPTranspor~ Started {}
I 09:58:01 SearchIndexA~ Indexing System
I 09:58:02 Kernel        NetKernel Ready, accepting requests...
I 09:58:03 ModuleManager System now at RunLevel [7]
I 09:58:03 InitEndpoint  Init completed - system at RunLevel [7]
I 09:58:03 CronTransport Added Job [Apposite Synchronize @ Every 3rd Day] of type [crontab]

Thanks a lot,
Mircea

Server Offline

Sun, 22 Aug 2010 14:48:00 GMT

Hi Guys,

Only just had chance to catch up with email etc. Sorry with all the excitement getting the NKEE release out we failed to notice a server error on the NKEE apposite server.

Its now rebooted. Please try it now.

We will add a system monitor to this asap next week.

Cheers,

Peter