Shri's Blog

Monday, November 16, 2015

How to use Iterator Mediate in WSO2 ESB

Iterator mediator is used when a message needs to be split into multiple messages by finding the XPATH expression. A new message is created in each matching elements.

Test Case:

We have a Manager Management portal in which we have to keep records like how many departments are taken care or come in one manager. For example one manager can handle more than 1 or 2 department like IT and CS department.

We have created a request in which we can submit the manager records with his owned departments.

Use of Iterator in this test case:

When we are submitting the department records, department may be more than one so we will use Iterator to create new messages everything for each department and save it into our database.

Database:

We have created 3 tables which contain Department mapping, department details and manager details.

Department
department_details
manager_detail

Now we have to create a stored procedure which will be called from the DSS to store the manager details with their department.

Stored Procedure:

-- --------------------------------------------------------------------------------

-- Routine DDL

-- Note: comments before and after the routine body will not be stored by the server

-- --------------------------------------------------------------------------------

DELIMITER $$

CREATE DEFINER=`root`@`localhost` PROCEDURE `MANAGE_MANAGER_DETAIL`(

IN MANAGER_ID VARCHAR(50),

IN MANAGER_NAME VARCHAR(50),

IN ADDRESS VARCHAR(50),

IN DEPARTMENT_NAME VARCHAR(50),

IN NO_OF_PEOPLE VARCHAR(50),

IN OFFICE_LOCATION VARCHAR(50) ,

OUT RESULT_CODE VARCHAR(10),

OUT RESULT_DESC VARCHAR(50)

)

BEGIN

declare DEPARTMENT_ID INT;

SELECT DEPARTMENT_ID_N INTO DEPARTMENT_ID FROM DEPARTMENT WHERE DEPARTMENT_NAME_V=DEPARTMENT_NAME;

IF DEPARTMENT_ID IS NOT NULL THEN

INSERT INTO MANAGER_DETAIL VALUES (MANAGER_ID, MANAGER_NAME, ADDRESS, DEPARTMENT_ID);

INSERT INTO DEPARTMENT_DETAILS VALUES (DEPARTMENT_NAME, NO_OF_PEOPLE, OFFICE_LOCATION);

SET RESULT_CODE = '0';

SET RESULT_DESC='SUCCESS';

elseif DEPARTMENT_ID is null then

SET RESULT_CODE = '1';

SET RESULT_DESC='FAILED';

rollback;

END if;

commit;

END

Create DSS (ManageManagerDetailsService.dbs):

<description>This service manage the managers details</description>

<property name="org.wso2.ws.dataservice.driver">com.mysql.jdbc.Driver</property>

<property name="org.wso2.ws.dataservice.protocol">jdbc:mysql://localhost:3308/emp</property>

</config>

<sql>call MANAGE_MANAGER_DETAIL(?,?,?,?,?,?,?,?)</sql>

</result>

</query>

<description>This service manage the managers details</description>

<call-query href="ManageManagerDetailsQuery">

<with-param name="MANAGER_ID" query-param="ManagerId"/>

<with-param name="MANAGER_NAME" query-param="ManagerName"/>

<with-param name="ADDRESS" query-param="Address"/>

<with-param name="DEPARTMENT_NAME" query-param="DepartmentName"/>

<with-param name="NO_OF_PEOPLE" query-param="NoOfPeople"/>

<with-param name="OFFICE_LOCATION" query-param="OfficeLocation"/>

</call-query>

</operation>

</data>

Create WSDL:

Now we have to create a WSDL in which multiple departments can be accepted for one employee id.

Request XML:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:man="http://shriwithjava.blogspot.co.nz/managerdetails/">

<soapenv:Header/>

<soapenv:Body>

<man:ManagerDetailsRequest>

<man:Id>?</man:Id>

<man:Name>?</man:Name>

<man:Address>?</man:Address>

<man:Departments>

<man:DepartmentDetails>

<man:DepartmentName>?</man:DepartmentName>

<man:NoOfPeople>?</man:NoOfPeople>

<man:OfficeLocation>?</man:OfficeLocation>

</man:DepartmentDetails>

</man:Departments>

</man:ManagerDetailsRequest>

</soapenv:Body>

</soapenv:Envelope>

Response XML:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:man="http://shriwithjava.blogspot.co.nz/managerdetails/">

<soapenv:Header/>

<soapenv:Body>

<man:ManagerDetailsResponse>

<man:ResponseCode>?</man:ResponseCode>

<man:ResponseDescription>?</man:ResponseDescription>

</man:ManagerDetailsResponse>

</soapenv:Body>

</soapenv:Envelope>

Use Iterator:

We have created a IN sequence, OUT sequence and fault sequence for this service, to use Iterator mediator go to below highlighted IN sequence and click on Edit.

You can find the Iterator mediator in Advance list. Select Iterator Mediator

There are some parameters which you need to define and also the Iterate Expression from which you need to split messages.

Iterator Id: we have to define a unique id for the iterator so than all the split message can be identify with this mediator. It is useful in case of aggregation.
Sequence Mediator: it defines that how message needs to be split parallel (False) or sequentially (True). By default it is False.
Continue Parent: Defines that original message needs to be continue or dropped. Default value is false.
Preserve Payload: Specify that original message needs to be used as a template for split message or not. Default value is False.
Iterate Expression: This is important parameter this expression matches the string that from where message needs to be split.
Attached Path: You can specify the XPATH expression for the new messages that split elements are attached to:

You will get the above screen once you click on the Target Configuration.

SOAP Action: Define the message Action.
To Address: Defines the endpoint address.
Sequence: You can define any sequence from the registry or define a new sequence by adding mediator to current target mediator as children.
Endpoint: Send the message from endpoints, you can pick up from registry or can define new one.

Synapse Code:

</proxy>

<man:ManagerDetailsResponse xmlns:man="http://shriwithjava.blogspot.co.nz/managerdetails/">

<man:ResponseCode>-1</man:ResponseCode>

<man:ResponseDescription>Unknown Exception</man:ResponseDescription>

</man:ManagerDetailsResponse>

</format>

</payloadFactory>

<send/>

<drop/>

</sequence>

<!—ITERATOR CODE -à

<!—Calling DSS - à

<send>

</send>

</sequence>

</target>

</iterate>

</sequence>

</completeCondition>

<then>

</then>

<else>

</else>

</filter>

<man:ManagerDetailsResponse xmlns:man="http://shriwithjava.blogspot.co.nz/managerdetails/">

<man:ResponseCode>$1</man:ResponseCode>

<man:ResponseDescription>$2</man:ResponseDescription>

</man:ManagerDetailsResponse>

</format>

<args>

</args>

</payloadFactory>

<send/>

<drop/>

</onComplete>

</aggregate>

</sequence>

<!—DSS Endpoint -à

<responseAction>fault</responseAction>

</timeout>

</suspendOnFailure>

</markForSuspension>

</address>

</endpoint>

Used JS:

<x><![CDATA[

function ManageManagerDetailsServiceRequest(mc) {

var Id = mc.getProperty("Id");

var Name = mc.getProperty("Name");

var Address = mc.getProperty("Address");

var DepartmentName = mc.getProperty("DepartmentName");

var NoOfPeople = mc.getProperty("NoOfPeople");

var OfficeLocation = mc.getProperty("OfficeLocation");

mc.setPayloadXML(

<man:ManageManagerDetails xmlns:man="http://shriwithjava.blogspot.co.nz/managemanagerdetails">

<man:ManagerId>{Id}</man:ManagerId>

<man:ManagerName>{Name}</man:ManagerName>

<man:Address>{Address}</man:Address>

<man:DepartmentName>{DepartmentName}</man:DepartmentName>

<man:NoOfPeople>{NoOfPeople}</man:NoOfPeople>

<man:OfficeLocation>{OfficeLocation}</man:OfficeLocation>

</man:ManageManagerDetails>

);

}

]]></x>

Execution:

To execute this service, load the project in SOAP UI and hit below request, in this request we are trying to insert data in database while using Iterator mediator. If you see below request you can find that one manager is handles 2 department (CS and IT) and same data we will insert into our database.

Request:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:man="http://shriwithjava.blogspot.co.nz/managerdetails/">

<soapenv:Header/>

<soapenv:Body>

<man:ManagerDetailsRequest>

<man:Id>1234</man:Id>

<man:Name>Shri</man:Name>

<man:Address>Raebareli</man:Address>

<man:Departments>

<man:DepartmentDetails>

<man:DepartmentName>IT</man:DepartmentName>

<man:NoOfPeople>30</man:NoOfPeople>

<man:OfficeLocation>Noida</man:OfficeLocation>

</man:DepartmentDetails>

<man:DepartmentDetails>

<man:DepartmentName>COMPUTER SCIENCE</man:DepartmentName>

<man:NoOfPeople>40</man:NoOfPeople>

<man:OfficeLocation>Delhi</man:OfficeLocation>

</man:DepartmentDetails>

</man:Departments>

</man:ManagerDetailsRequest>

</soapenv:Body>

</soapenv:Envelope>

Response:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">

<soapenv:Body>

<man:ManagerDetailsResponse xmlns:man="http://shriwithjava.blogspot.co.nz/managerdetails/">

<man:ResponseCode>0</man:ResponseCode>

<man:ResponseDescription>Success</man:ResponseDescription>

</man:ManagerDetailsResponse>

</soapenv:Body>

</soapenv:Envelope>

Now if you look at the database you can find the records.

Wednesday, November 4, 2015

How to use Cache Mediator in WSO2 ESB

Cache mediator in WSO2 ESB used when we see same type of message again and again and also process with same output. In this scenario if we want to optimize our ESB performance, we can use cache mediator. Cache mediator checks if the same type of message has been processed before, it cashes the message and on the same request mediator gets the message from the cache and reply back.

Cache mediator uses the hashes for checking the equivalence the message. In cache mediator you can define the cache response time and message size in bytes.

Test Case:

In our test case, we will use same service I have created in my last blog. Basically it is a data service and we have created a pass through proxy of this DSS service in ESB. This service gives the employee details based on the Employee Id.

We will try to cache the DSS response in ESB so that on same request of ESB does not hit the DSS server and reply the cached response to the client.

To understand whether cache is working fine or not, I will change the employee details in Database but change should not reflect in our response till message is cached. We are assuming that ESB cache Mediator will not hit the DSS and it will give response from the cached message.

Below is the DSS service I have created in my last blog.

Below is the ESB service, pass through proxy of DSS.

Service gives the details of employee based on the Employee Id. Below is the SOAP UI request and response of ESB pass through proxy.

To use the caching mediator I am going to sequences and updating the IN Sequence of this service.

You can add Cache mediator in Advance group.

Below are the fields you need to fill to use Cache mediator.

Cache Id: This is the cache id for the configuration.
Cache Scope: It is important when you are using cluster.

Per Host: It Cache the message for the current host of the cluster.
Per-Mediator: It Cache the message once for the whole cluster.

Cache Type: It is used to check the message is coming from the request or we need to cache the response for outgoing message.

Finder: When message needs to be cached from incoming path, it hash the each incoming message.
Collector: It indicates the message needs to be collected from cached message. It is used for outgoing path.

Hash Generator: It is by default selected to org.wso2.caching.digest.DOMHASHGenerator and it has the hash logic to check each incoming message.
Cache Timeout: We need to specify the timeout in seconds that how much we want to cache the message.
Maximum Message Size: The limit of cache message in bytes.

Cache Implementation Details

Implementation Type: Default to set “In-Memory” and this is the only available.
Maximum Size: 1000 is default selected.

On Cache Hit: It basically tells that which sequence needs to be followed from registry.

Now edit the out sequence as defined below.

Specify the Cache id, cache Scope and Cache Type. In out sequence we are using “Collector” Cache type because we need to get the response from cache in out going message.

Now we check that what is there in our database. You can see that for Employee Id 1, we have Employee Name as ‘Shri’ and address is ‘Delhi’ as highlighted in Yellow.

Let see what we are getting in SOAP UI response.

Same thing we are getting in response and in one hit the response is cached.

Now I am going to change the address from “Delhi” to “Noida” as below.

Now if you try within 20 second, this is what we have mentioned in our cache response. We should be getting same response.

And Yes, as above we are getting the same response because response is cached we it is not coming from DSS server. If we hit just after 20 second we can see the address is now updated from “Delhi” to “Noida”.

Now this response will be cached till net 20 second in each hit.

You can see that from the IN sequence we are getting the response.

ESB Synapse Code:

</proxy>

<shr:employees xmlns:shr="http://shriwithjava.blogspot.co.nz/">

<shr:employee>

<shr:id>Exception has been caught</shr:id>

<shr:name>Exception has been caught</shr:name>

<shr:address>Exception has been caught</shr:address>

</shr:employee>

</shr:employees>

</format>

</payloadFactory>

<send/>

<drop/>

</sequence>

</cache>

<send>

</send>

</sequence>

<send/>

</sequence>

<responseAction>fault</responseAction>

</timeout>

</suspendOnFailure>

</markForSuspension>

</address>

</endpoint>

Tuesday, November 3, 2015

How to use Fault sequence in WSO2 ESB

In WSO2 ESB, fault sequence is used for exception handling. In service logic if any exception comes and you want ESB to execute a particular scenario or just send a proper exception error to client, just put the logic in fault sequence and it will be executed. This is the same exception handling as we have in other programming language.

Test Case:

In our example, we are trying to call DSS service from the ESB. We have created a simple pass through proxy of DSS service. This DSS service gives you detail of employee based on the Employee ID.

To get an exception, I will stop the DSS server so that ESB will get an exception and we are assuming that on getting the exception, fault sequence will be executed. In fault sequence I have mentioned a normal exception message on the response and same response we will give back to the client.

Below is the EmployeeDataservice I have created in DSS.

Above service gives you detail of employee on passing Employee Id.

Below is the pass through proxy I have created in ESB with name of 'DSS_EmployeeDetailDataServiceProxy’.

From ESB URL, I have created a SOAP UI project which work the same as DSS does as it’s a pass through proxy.

Now I have stopped the DSS server and expecting to get an Exception in ESB for DSS and this scenario will trigger the fault sequence. In fault sequence I have put normal exception message in EmployeeDetailService response.

Exception in Logs:

Complete Exception Message:

You can see that fault block now have been executed and that is why we are getting expected error message what we have put in fault sequence.

ESB Synapse Code:

</proxy>

<send>

</send>

</sequence>

<shr:employees xmlns:shr="http://shriwithjava.blogspot.co.nz/">

<shr:employee>

<shr:id>Exception has been caught</shr:id>

<shr:name>Exception has been caught</shr:name>

<shr:address>Exception has been caught</shr:address>

</shr:employee>

</shr:employees>

</format>

</payloadFactory>

<send/>

<drop/>

</sequence>
<sequence name="CommonSequence_OUT">

<send/>

</sequence>

<responseAction>fault</responseAction>

</timeout>

</suspendOnFailure>

</markForSuspension>

</address>

</endpoint>