How to Use WSO2 Data Mapping Mediator in ESB (Updated for-ESB-5.0.0-Beta2)

How to Use WSO2 Data Mapping Mediator in ESB (Updated for-ESB-5.0.0-Beta2)

INTRODUCTION

WSO2 data mapper is a data mapping solution that convert and transform one format of data to a different format. It provides a WSO2 Developer Studio based tool to create the graphical mapping configuration and generate the files needed to execute the mapping configuration by the WSO2 Data mapper engine as shown in the below diagrams. As the this is really useful feature in message mediation, WSO2 ESB comes with a data mapper mediator which can be integrate into a mediation sequence since WSO2 ESB 5.0.0.

PREREQUISITES

First we need to have the data mapper mediator supported ESB distribution. WSO2 ESB 5.0.0 is the distribution packed with data mapper mediator. You can download beta2 pack from here.

And also we need to have a data mapping editor supported Developer Studio ESB Tool. You can follow this article to install the WSO2 Developer Studio ESB Tool 5.0.0.

For this post I will use 5.0.0-beta2 packs of wso2 esb runtime and tooling, which are the latest packs. So the operations mentioned here will be only available with 5.0.0 beta2 or onwards.

We will use the Postman as out client to send the requests to esb and receive responses.

OVERVIEW

Since our main focus is to check the functionality of the Data Mapper we will use a very simple configuration in the esb with a data mapping mediator and a respond mediator. We will check following message conversions,

  • XML->XML/JSON/CSV
  • JSON->XML/JSON/CSV
  • CSV->XML/JSON/CSV

To understand the data mapper further and to examine the operators provided in the data mapper, which we can use to map elements from input to output look in to Understanding WSO2 Data Mapper post.

CREATE ESB CONFIGURATION PROJECT

First this we would need to do is create esb configuration to contain the data mapper mediator. ESB Tooling now provides a new option to create a ESB Solution Project so that you can define the all different projects you need for the project in the wizard. Right click on the Project Explorer area and go to new-> ESB Solution Project

ESBSolutionProject

You will get the following wizard page and give project name and unpick the Connector Exporter Project since we are not going to need connector in our configuration.

ESBSolutionProjectWizard

And you will get the following project files created in your workspace.

ProjectExplorer

Now what we will do is create a new REST Api project in ESB and configure it to listen for POST requests on url “/convertMenu”.

RESTAPIfoodMenuAPI

Then create the API resource with data mapper mediator and listening to POST request.

createAPIAndDataMapperapiPropertiesTable

To configure data mapping mediator double click on the mediator and you will get a dialog box asking to create a registry resource project as below.

createMappingFiles

This name would be the prefix for the configuration files we will deploy in esb server related to data mapper. Since we created a ESB Solution Project we were directly pointed that project in here otherwise go to Create new project link and create a new Registry Resource project.

Then click OK after giving the prefix and pointing the Registry resource project to save it.  Following diagram editor will appeared in new perspective named “WSO2 Data Mapper Graphical”. You can switch this perspective as you wish by selecting in top tool bar tags or Window->perspective->Open Perspective->Other

dataMappingEditor

In the left hand side you can see the operation pallet and in the middle input output boxes. We need to provide the input and output message formats to begin the mapping. So right click on the top title bar of the input box and select command Load Input.

loadInputinputType

As you can see in the above image, there are several options for you to load the input and output message formats to data mapper.

You can select the resource type as XML, JSON, CSV ,XSD ,JSONSCHEMA or CONNECTOR.

If you selects XML, you can load a sample xml message you expect and WSO2 Data Mapper Editor will generate the JSON schema to represent the xml according to the WSO2 Data Mapper Schema specification.

Same as for XML, if you select  JSON/CSV as resource type you can load a sample JSON/CSV message. For CSV you need to provide the column names as the first record.

If you have a xsd schema which defines you xml message format, you can select the resource type as XSD and load the xsd file.

And also if you have the JSON schema for your message according to the WSO2 Data Mapper schema specification you can load it by selecting resource type as JSON schema.

Connector type will come if you are going to map message which is an output of a connector, in the input box you can select connector type and it will list down available connectors and then select the operation in-front of data mapper. This is not the time to explain the connector integration with data mapper. We will discuss it later in a different post. 🙂

For this moment we will load from a sample XML file.

Input xml sample for food menu.

<?xml version="1.0" encoding="UTF-8"?>
<breakfast_menu>
<food>
<name>Belgian Waffles</name>
<price>$5.95</price>
<description>Two of our famous Belgian Waffles with plenty of real maple syrup</description>
<calories>650</calories>
<orgin>Belgian</orgin>
<veg>true</veg>
</food>
<food>
<name>Strawberry Belgian Waffles</name>
<price>$7.95</price>
<description>Light Belgian waffles covered with strawberries and whipped cream</description>
<calories>900</calories>
<orgin>Belgian</orgin>
<veg>true</veg>
</food>
<food>
<name>Berry-Berry Belgian Waffles</name>
<price>$8.95</price>
<description>Light Belgian waffles covered with an assortment of fresh berries and whipped cream</description>
<calories>900</calories>
<orgin>Belgian</orgin>
<veg>true</veg>
</food>
<food>
<name>French Toast</name>
<price>$4.50</price>
<description>Thick slices made from our homemade sourdough bread</description>
<calories>600</calories>
<orgin>French</orgin>
<veg>true</veg>
</food>
<food>
<name>Homestyle Breakfast</name>
<price>$6.95</price>
<description>Two eggs, bacon or sausage, toast, and our ever-popular hash browns</description>
<calories>950</calories>
<orgin>French</orgin>
<veg>false</veg>
</food>
</breakfast_menu>

Output xml sample for food menu.

<?xml version="1.0" encoding="UTF-8"?>
<menu>
<item>
<name>Belgian Waffles</name>
<price>$5.95</price>
<calories>650</calories>
<orgin>Belgian</orgin>
<veg>true</veg>
<description>Two of our famous Belgian Waffles with plenty of real maple syrup</description>
</item>
<item>
<name>Strawberry Belgian Waffles</name>
<price>$7.95</price>
<calories>900</calories>
<orgin>Belgian</orgin>
<veg>true</veg>
<description>Light Belgian waffles covered with strawberries and whipped cream</description>
</item>
<item>
<name>Berry-Berry Belgian Waffles</name>
<price>$8.95</price>
<calories>900</calories>
<orgin>Belgian</orgin>
<veg>true</veg>
<description>Light Belgian waffles covered with an assortment of fresh berries and whipped cream</description>
</item>
<item>
<name>French Toast</name>
<price>$4.50</price>
<calories>600</calories>
<orgin>French</orgin>
<veg>true</veg>
<description>Thick slices made from our homemade sourdough bread</description>
</item>
<item>
<name>Homestyle Breakfast</name>
<price>$6.95</price>
<calories>950</calories>
<orgin>French</orgin>
<veg>false</veg>
<description>Two eggs, bacon or sausage, toast, and our ever-popular hash browns</description>
</item>
</menu>

Load above files as input and outputs and look the input output boxes with sample message. Is the element types are correctly identified or not. (Arrays, Objects and Primitive values). Following signs will help you to identify it correctly.

  • {}  – represent object elements
  • []   – represent array elements
  • <> – primitive field values
  • A   – xml attribute values

Now use operators and do the mapping as you desire. You can only connect primitive data values such as Strings, numbers, boolean and etc. Array and object values can not be mapped.

mapping

What I have done here is name is mapped via uppercase operator and calories undergoes and mathematical calculation to the output.

output calories =Round( (calories*1.13) + 6.75)

Now save the all configurations. We can now deploy the created REST API in the ESB server and test our mapping.

To deploy our configuration we need to include these in a CAPP project. When we created the ESB Solution Project we created the CAPP project too. So open the CAPP project and double click on the pom file. You will get the following page to select project files into CAPP.

CAPPProject.png

Here you do not see the registry resource files. We need to refresh the page to see it. Use refresh button in the top right conner to load newly added registry files.

refreshBUtton

Then you will see the all artifacts in the workspace. Select REST API file and the three registry resource files containing mapping configuration , input schema and output schema.

cappProjectselection

 

  • Mapping Configuration : This file contain the script file used to execute the mapping
  • Input Schema: JSON schema which represent input message format
  • Output Schema: JSON schema which represent the output message format

And also see the data mapper mediator configuration in the REST API.

DMMconfig.png

 

  • Input Type : Expected input message type (xml/json/csv)
  • Output Type: Target Output message type (xml/json/csv)

If your mapping failed at the runtime the first thing you need check whether the mediator configuration. Is the input type and output type are set correctly.

Now start WSO2 ESB server and connect it to ESB tool as a remote server or start ESB server from inside the ESB tool. And add out CAPP to the server and deploy it.

addwso2servercappAdding

Then goto management console from https://localhost:9443/carbon

See the deployed API and get the url it is listening.

APIDeployed.png

Start the POST Man and send the request for the above url.

postMan.png

You will get the response with accordingly to post man when you send the message.

To see the XML -> JSON conversion  just go to REST API  configuration and data mapper properties. Select Output Type as JSON . Deploy the configuration and send the request. You will get the JSON message.

Do the same for see the XML->CSV.

But this is not guaranteed every occasion. If t you have defined complex XML output message with name spaces and attributes JSON message or CSV will not built as you will imagine. In this case output message format is fully compatible to represent as JSON and CSV.

Now you have the basic end to end knowledge to develop a ESB configuration with a data mapper mediator. So you can try this and report the bugs and suggest improvements from the following link as JIRAs.

 

 

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