How to verify whether a property value is null or not

Assume you have a scenario where want to do something based on the fact whether a property value is null or not.

Using the Filter mediator, this is possible. See below for the configuration.

<filter regex="^\d+$" xpath="get-property('memberId')">
   <then>//Do something</then>
       

<else>//Do something else</else>
     

</filter>

Why don't I see "Request Body" in the "Raw tab" of SOAP UI

When sending requests in SOAP UI, I was not able to see the Request Body in the Raw tab.

The reason for was this was a setting in SOAP UI.

To enable this, all you have to do is, go to Preferences and then go to Editor Settings and check Validate Requests and Validate Responses check boxes.

How to resolve "Could not generate DH keypair" issue faced with WSO2 products

When working with WSO2 products, sometimes, you might see the below exception when trying out security scenarios with JDK 1.7.

TID: [0] [AS] [2017-11-07 05:02:26,655] ERROR {org.apache.tomcat.util.net.NioEndpoint$SocketProcessor} -   {org.apache.tomcat.util.net.NioEndpoint$SocketProcessor}
java.lang.RuntimeException: Could not generate DH keypair
    at sun.security.ssl.Handshaker.checkThrown(Handshaker.java:1345)
    at sun.security.ssl.SSLEngineImpl.checkTaskThrown(SSLEngineImpl.java:519)
    at sun.security.ssl.SSLEngineImpl.readNetRecord(SSLEngineImpl.java:796)
    at sun.security.ssl.SSLEngineImpl.unwrap(SSLEngineImpl.java:764)
    at javax.net.ssl.SSLEngine.unwrap(SSLEngine.java:624)
    at org.apache.tomcat.util.net.SecureNioChannel.handshakeUnwrap(SecureNioChannel.java:335)
    at org.apache.tomcat.util.net.SecureNioChannel.handshake(SecureNioChannel.java:193)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1642)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.RuntimeException: Could not generate DH keypair
    at sun.security.ssl.ECDHCrypt.(ECDHCrypt.java:68)
    at sun.security.ssl.ServerHandshaker.setupEphemeralECDHKeys(ServerHandshaker.java:1215)
    at sun.security.ssl.ServerHandshaker.trySetCipherSuite(ServerHandshaker.java:1069)
    at sun.security.ssl.ServerHandshaker.chooseCipherSuite(ServerHandshaker.java:896)
    at sun.security.ssl.ServerHandshaker.clientHello(ServerHandshaker.java:629)
    at sun.security.ssl.ServerHandshaker.processMessage(ServerHandshaker.java:167)
    at sun.security.ssl.Handshaker.processLoop(Handshaker.java:913)
    at sun.security.ssl.Handshaker$1.run(Handshaker.java:853)
    at sun.security.ssl.Handshaker$1.run(Handshaker.java:851)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.security.ssl.Handshaker$DelegatedTask.run(Handshaker.java:1285)
    at org.apache.tomcat.util.net.SecureNioChannel.tasks(SecureNioChannel.java:285)
    at org.apache.tomcat.util.net.SecureNioChannel.handshakeUnwrap(SecureNioChannel.java:343)
    ... 5 more
Caused by: java.security.InvalidAlgorithmParameterException: unknown curve name: 1.2.840.10045.3.1.7
    at org.bouncycastle.jce.provider.JDKKeyPairGenerator$EC.initialize(Unknown Source)
    at sun.security.ssl.ECDHCrypt.(ECDHCrypt.java:63)
    ... 17 more 
The reason for this is missing JCE policy files in the JDK. So in order to do this, you need to download the relevant JCE policy files from [2] and patch the JDK.

[1] - https://stackoverflow.com/questions/6851461/java-why-does-ssl-handshake-give-could-not-generate-dh-keypair-exception?answertab=votes#tab-top
[2] - http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html

Transfering PDF files via the VFS transport with WSO2 ESB

This post will explain how one can transfer PDF files through VFS transport within WSO2 ESB.

In this example, I will be providing the configuration which is tested on WSO2 ESB 4.8.1.


In order for you to get the scenario to work, first you will need to enable the VFS sender and listener through the following configuration in the axis2.xml. The below lines will be commented out by default and all you need to do to enable the VFS transport is uncomment the following two entries.

<transportReceiver name="vfs" class="org.apache.synapse.transport.vfs.VFSTransportListener"/>

<transportSender name="vfs" class="org.apache.synapse.transport.vfs.VFSTransportSender"/>

Next, to enable PDF file transferring within ESB, you will have to enable the message relay feature. For this, we need to add the appropriate message builder and formatter to the axis2.xml file.

<messageFormatters>

        <messageFormatter contentType="application/pdf" class="org.wso2.carbon.relay.ExpandingMessageFormatter"/>
        :
        :
</messageFormatters>

<messageBuilders>
         <messageBuilder contentType="application/pdf" class="org.wso2.carbon.relay.BinaryRelayBuilder"/>
          :
          :
</messageBuilders>


Once the above changes have been done, create a Proxy Service as shown below.

   <proxy name="PdfProxy" transports="vfs" startOnLoad="true">
      <target>
         <inSequence>
            <log level="custom">
               <property name="status=" value="PDF file transferred"/>
            </log>
            <drop/>
         </inSequence>
      </target>
      <parameter name="transport.vfs.ActionAfterProcess">MOVE</parameter>
      <parameter name="transport.PollInterval">15</parameter>
      <parameter name="transport.vfs.MoveAfterProcess">file:///Users/evanthika/Downloads/vfs/out</parameter>
      <parameter name="transport.vfs.FileURI">file:///Users/evanthika/Downloads/vfs/in</parameter>
      <parameter name="transport.vfs.MoveAfterFailure">file:///Users/evanthika/Downloads/vfs/failure</parameter>
      <parameter name="transport.vfs.FileNamePattern">.*\.pdf</parameter>
      <parameter name="transport.vfs.ContentType">application/pdf</parameter>
      <parameter name="transport.vfs.ActionAfterFailure">MOVE</parameter>
   </proxy>

Now drop the relevant PDF file to the location mentioned in the transport.vfs.FileURI
parameter. After the time specified in the transport.PollInterval parameter, the relevant PDF file will be read and moved to the folder specified as the transport.vfs.MoveAfterProcess parameter value.

How to accept requests from different URLs that has different query parameters through ESB APIs

Products used - WSO2 ESB 4.8.1
                          WSO2 DSS 3.5.0


Assume that we have a back-end service which reads a database and returns employee information depending on particular parameters that are being passed. Let's say that we are using the following Data Services Server which is hosted in WSO2 DSS product.

<data name="GetEmployees" transports="http https local">
   <config enableOData="false" id="mysql">
      <property name="driverClassName">com.mysql.jdbc.Driver</property>
      <property name="url">jdbc:mysql://localhost:3306/employee</property>
      <property name="username">root</property>
      <property name="password">root</property>
   </config>
   <query id="query1" useConfig="mysql">
      <sql>select * from employees where id=? and lastname=?</sql>
      <result element="employees" rowName="employee">
         <element column="id" name="id" xsdType="string"/>
         <element column="lastname" name="lastname" xsdType="string"/>
         <element column="firstname" name="firstname" xsdType="string"/>
      </result>
      <param name="id" sqlType="STRING"/>
      <param name="lastname" sqlType="STRING"/>
   </query>
   <query id="query2" useConfig="mysql">
      <sql>select * from employees</sql>
      <result element="employees" rowName="employee">
         <element column="id" name="id" xsdType="string"/>
         <element column="lastname" name="lastname" xsdType="string"/>
         <element column="firstname" name="firstname" xsdType="string"/>
      </result>
   </query>
   <query id="query3" useConfig="mysql">
      <sql>select * from employees where id=?</sql>
      <result element="employees" rowName="employee">
         <element column="id" name="id" xsdType="string"/>
         <element column="lastname" name="lastname" xsdType="string"/>
         <element column="firstname" name="firstname" xsdType="string"/>
      </result>
      <param name="param0" sqlType="STRING"/>
   </query>
   <operation name="getemployee">
      <call-query href="query1">
         <with-param name="id" query-param="id"/>
         <with-param name="lastname" query-param="lastname"/>
      </call-query>
   </operation>
   <operation name="getemployeeid">
      <call-query href="query3">
         <with-param name="param0" query-param="param0"/>
      </call-query>
   </operation>
   <operation name="getAllEmployees">
      <call-query href="query2"/>
   </operation>
</data>


Lets assume that the client expects to send the requests in the following format.

To get all the employee details of the database - http://localhost:8280/newsample/employee/get/employees

To get employee details which matches a particular id - http://localhost:8280/newsample/employee/get/employees?id={id_number}

To get details of a particular employee which matches a particular id and the lastname - http://localhost:8280/newsample/employee/get/employees?id=1&lastname=Amarasiri

To support this, we can create an API in WSO2 ESB with the following configuration.

      <api name="EmployeeDetApi" context="/newsample">
      <resource methods="GET"
                uri-template="/employee/get/employees?id={id}&lastname={lastname}">
         <inSequence>
            <payloadFactory media-type="xml">
               <format>
                  <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
                                    xmlns:dat="http://ws.wso2.org/dataservice">
                     <soapenv:Header/>
                     <soapenv:Body>
                        <dat:getemployee>
                           <dat:id>$1</dat:id>
                           <dat:lastname>$2</dat:lastname>
                        </dat:getemployee>
                     </soapenv:Body>
                  </soapenv:Envelope>
               </format>
               <args>
                  <arg evaluator="xml" expression="$url:id"/>
                  <arg evaluator="xml" expression="$url:lastname"/>
               </args>
            </payloadFactory>
            <property name="SOAPAction"
                      value="urn:getemployee"
                      scope="transport"
                      type="STRING"/>
            <property name="ContentType" value="text/xml" scope="axis2" type="STRING"/>
            <log>
               <property name="incoming_message"
                         value="*******GET EMPLOYEE DETAILS - id ,lastname *******"/>
            </log>
            <send>
               <endpoint key="AddressEpr"/>
            </send>
         </inSequence>
      </resource>
      <resource methods="GET" uri-template="/employee/get/employees?id={param0}">
         <inSequence>
            <payloadFactory media-type="xml">
               <format>
                  <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
                                    xmlns:dat="http://ws.wso2.org/dataservice">
                     <soapenv:Header/>
                     <soapenv:Body>
                        <dat:getemployeeid>
                           <dat:param0>$1</dat:param0>
                        </dat:getemployeeid>
                     </soapenv:Body>
                  </soapenv:Envelope>
               </format>
               <args>
                  <arg evaluator="xml" expression="$url:id"/>
               </args>
            </payloadFactory>
            <property name="SOAPAction"
                      value="urn:getemployeeid"
                      scope="transport"
                      type="STRING"/>
            <property name="ContentType" value="text/xml" scope="axis2" type="STRING"/>
            <log>
               <property name="incoming_message"
                         value="*******GET EMPLOYEE DETAILS - id *******"/>
            </log>
            <send>
               <endpoint key="AddressEpr"/>
            </send>
         </inSequence>
      </resource>
      <resource methods="GET" uri-template="/employee/get/employees">
         <inSequence>
            <payloadFactory media-type="xml">
               <format>
                  <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
                                    xmlns:dat="http://ws.wso2.org/dataservice">
                     <soapenv:Header/>
                     <soapenv:Body>
                        <dat:getAllEmployees/>
                     </soapenv:Body>
                  </soapenv:Envelope>
               </format>
               <args/>
            </payloadFactory>
            <property name="SOAPAction"
                      value="urn:getemployeedetails"
                      scope="transport"
                      type="STRING"/>
            <property name="ContentType" value="text/xml" scope="axis2" type="STRING"/>
            <log>
               <property name="incoming_message"
                         value="*******GET EMPLOYEE DETAILS - All employees details *******”/>
            </log>
            <send>
               <endpoint key="AddressEpr"/>
            </send>
         </inSequence>
      </resource>
   </api>

Analysing data with Data Analytics Server

When we talk about WSO2 DAS there are a few important things we need to give focus to. They are, Event receivers, Event Streams, Event Stream definitions and Event Stores.

Events, are units of data, that are received by WSO2 DAS using Event Receivers. Through these Event Receivers WSO2 DAS receives events from different transports in JSON, XML, WSO2 Event formats, etc. formats. There are many different Event receivers available in WSO2 DAS, such as HTTP Event Receivers, SOAP Event Receivers, WSO2Event Event Receivers, etc.

Event Streams are known to be a sequence of events of a particular type. The “type” in this context can be defined as an event stream definition.

An Event Stream definition is sort of a schema which describes in which format the events that comes into WSO2 DAS server should be in. Each Event Stream Definition would have a name, a version and most importantly the type of the data that it expects to be sent in to WSO2 DAS as Events.

Once an event is received by the Event Receiver, it would be checked against the Event Stream definition and be persisted to an Event Store. This is happening through the Data Analytics Layer (DAL) where the events will be stored in the Event store (can be a relational database) as a BLOB which is in human unreadable format. Then these events will be analyzed and processed and the processed information will then again be store in a Process Store (This too can be a relational database) in a BLOB format.
These analyzed data will be decrypted by DAL and presented in a human readable format through the Data Explorer of WSO2 DAS.

When it comes to IS Analytics, whatever the analyzed data that are in the Process Store will be presented through the Analytics Dashboard which is available in WSO2 DAS after the data being decrypted from DAL.

However, the API Manager Analytics are visible from the Store/Publisher portals that are shipped with the API Manager product. However, the API manager related events that are stored in the Process store cannot be read directly from the API Manager dashboards as they are in a encrypted format. Only a DAL can decrypt this information into a human readable format. Because of this, we have introduced a way which is using a method called carbonJDBC where the DAL converts these information that are in the process store and store them in an external relational database. This database is then pointed to, from the API Manager dashboards and you will see API Manager analytics accordingly.

How to resolve "Un-recognized attribute 'targetFramework'. Note that attribute names are case-sensitive." in IIS

While trying to configure a SOAP service in IIS, I came across various issues where I had to do many things to resolve them. One of them is the following issue.

Server Error in '/' Application.
Configuration Error
Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: Un-recognized attribute 'targetFramework'. Note that attribute names are case-sensitive.

Source Error:

Line 3: 
Line 4:   
Line 5:     
Line 6:   
Line 7:   

Source File: C:\RestService\RestService2\RestService\web.config    Line: 5

Version Information: Microsoft .NET Framework Version:2.0.50727.5420; ASP.NET Version:2.0.50727.5459

To resolve this issue, what you need to do is, check whether you have installed ASP.NET 4 on your Windows instance.
If it is installed, open up a command window, go to the location where .NET 4 is available,

C:\Users\Administrator>cd C:\Windows\Microsoft.NET\Framework\v4.0.30319

Then run the following command

aspnet_regiis -i

E.g.:- C:\Windows\Microsoft.NET\Framework\v4.0.30319>aspnet_regiis -i

Once this is done, open your IIS (type inetmgr in run) and change your Application pool setting to .Net4 (Go to Application Pools -> click on your project -> Right click and select 'Basic Settings')