Calling Java Class in GEL

[Leo Dsouza]

Hi,

 

I want to use the HttpURLConnection for invoking a REST URL in GEL. How do I build the below statements in GEL?

 

          URL url = new URL ("http://www.test.com");
          HttpURLConnection connection = (HttpURLConnection) url.openConnection();

 

I can use the core:new tag for the first statement. Need help with the second statement.

Thanks in advance,

 

Leo.

[navzjoshi00]

Have you checked this ?

 

https://communities.ca.com/message/17961369#17961369

 

NJ

[Leo Dsouza]

The answer mentioned in that post is incorrect. You cannot instantiate an object of HttpURLConnection class as it has a protected constructor.

[Nick Darlington]

Could you live without the class cast?  If it is to communicate with a web service that requires basic authentication, that can be achieved without writing code that perfectly replicates the java equivalent with a cast: Re: Calling external SOAP from Clarity GEL

[Roberto Barra]

Hi,

 

If you create a new URL object and store it on the url var, you can try this:

 

<core:invoke method="openConnection" on="${url}" var="connection"/>

 

This means: var connection = url.openConnection();

 

Regards,

Roberto Barra

[Eugene Greiff]

Here is one I built to test if a URL was accessible using URL and openConnection.

 

 

<?xml version="1.0" encoding="utf-8"?>
<gel:script
    xmlns:core="jelly:core"
    xmlns:log="jelly:log"
    xmlns:gel="jelly:com.niku.union.gel.GELTagLibrary"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

    <!-- StringBuilder for the output -->
    <core:new className="java.lang.StringBuilder" var="stringBuilder" />

    <!-- URL for the web url -->
    <core:new className="java.net.URL" var="url">
        <core:arg type="java.lang.String" value="http://www.ca.com/us/default.aspx"/>
    </core:new>

    <!-- Open and read the response stream -->
    <core:set var="httpUrl" value="${url.openConnection()}" />
   
    <gel:out>Encoding Type</gel:out>
    <gel:out>${httpUrl.getResponseCode()}</gel:out>
    <core:new className="java.io.InputStreamReader" var="inputStreamReader">
        <core:arg type="java.io.InputStream" value="${httpUrl.getInputStream()}"/>
    </core:new>
    <core:new className="java.io.BufferedReader" var="bufferedReader">
        <core:arg type="java.io.InputStreamReader" value="${inputStreamReader}"/>
    </core:new>

    <!-- l anoop through the response appending each line into the stringbuilder -->
    <core:set var="line" value="" />
    <core:while test="${line != null}">
        <core:set var="line" value="${bufferedReader.readLine()}" />
        <core:if test="${line != null}">
            <core:invoke method="append" on="${stringBuilder}">
                <core:arg value="${line}" />
            </core:invoke>
        </core:if>
    </core:while>

    <!-- Close the bufferReader -->
    <core:if test="${bufferedReader != null}">
        <core:invoke method="close" on="${bufferedReader}" />
    </core:if>

    <core:new className="java.io.PrintWriter" var="FileOne">
        <!-- /fs0/clarity1/share/UrlOutput.txt -->
        <core:arg type="java.lang.String" value="UrlOutput.txt"/>
    </core:new>

    <core:invoke method="println" on="${FileOne}">
        <core:arg value="${stringBuilder.toString()}" />
    </core:invoke>

<!--    <gel:out>${stringBuilder.toString()}"</gel:out>-->
    <gel:out>End this Script</gel:out>

</gel:script>

 

Depending if you are looking for something simple (no auth) and have access to the util taglib.

 

<?xml version="1.0" encoding="utf-8"?>
<gel:script
    xmlns:core="jelly:core"
    xmlns:log="jelly:log"
    xmlns:util="jelly:util"
    xmlns:gel="jelly:com.niku.union.gel.GELTagLibrary"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

    <gel:out>Start this Script</gel:out>
    
    <util:available uri="http://www.ca.com/us/default.aspx">
        <gel:out>This URL is available</gel:out>
        <util:loadText uri="http://www.ca.com/us/default.aspx" var="urlText" />
    </util:available>
    
    <gel:log>Dump Context Variables</gel:log>
        <core:set var="entries" value="${context.getVariables().entrySet().toArray()}" />    
        <core:forEach var="entry" items="${entries}">
            <core:if test="${!entry.getKey().equalsIgnoreCase('systemScope')}" >
                <gel:log>${entry.getKey()} = ${entry.getValue()} |  ${entry.getValue().getClass().getName()} </gel:log>
            </core:if>
        </core:forEach>

    <gel:out>End this Script</gel:out>

</gel:script>

 

V/r,

Gene

[Leo Dsouza]

Thanks for your replies.

 

gcubed: I'm already leveraging the code you shared in earlier posts around invoking servicenow. I realized my problem is with maintaining sessions rather than the HTTPConnection object. In this third party application which I have, I need to first make a rest call to authenticate URL, get the session ID/token and send it as a parameter to the second rest call to object creation URL. When I use the session ID to create the object, it says the session ID is invalid. This is because it creates a new session every time I call the url.openConnection().

 

I tried to use CookieManager to maintain the session and it works great in Java, but in GEL it doesn’t seem to work.

 

<core:new className="java.net.CookieManager" var="cManager">

                </core:new>

                <core:expr value="${cManager.setCookiePolicy(java.net.CookiePolicy.ACCEPT_ALL)}"/>

                <core:expr value="${java.net.CookieHandler.setDefault(cManager)}"/>

 

 

Any ideas on how to manage HTTP sessions in GEL?

 

Thanks,

 

Leo.

[Eugene Greiff]

I have had little success using the core:expr tag except on primitive data types.

 

Try using the invoke, getStatic and invokeStatic tags to set up your java.net.CookieManager

 

<core:new className="java.net.CookieManager" var="cManager" />

<!-- <core:expr value="${cManager.setCookiePolicy(java.net.CookiePolicy.ACCEPT_ALL)}"/> -->
<core:invoke method="setCookiePolicy" on="${cManager}" >
     <core:arg>
          <core:getStatic var="dummy" className="java.net.CookiePolicy" field="ACCEPT_ALL"/>
     </core:arg>
</core:invoke>

<!-- <core:expr value="${java.net.CookieHandler.setDefault(cManager)}"/> -->
<core:invokeStatic className="java.net.CookieHandler" method="setDefault">
     <core:arg value="${cManager}" />
</core:invokeStatic>

 

V/r,

Gene

[Leo Dsouza]

gcubed You are amazing! That worked perfectly..

 

I had to make a one minor change of declaring the policy first and then using it in the invoke tag.

 

 <core:new className="java.net.CookieManager" var="cManager" />

 <core:getStatic var="cPolicy" className="java.net.CookiePolicy" field="ACCEPT_ALL"/>

 <core:invoke var="test" method="setCookiePolicy" on="${cManager}" >
   <core:arg value="${cPolicy}"></core:arg>
 </core:invoke>

 <core:invokeStatic className="java.net.CookieHandler" method="setDefault">
   <core:arg type="java.net.CookieHandler" value="${cManager}" />
 </core:invokeStatic>

 

Thanks a ton for your help!

 

Leo.