Copyright © Cloud Software Group, Inc. All Rights Reserved

JSON XML Transformation

TIBCO API Exchange Gateway can handle non-XML request and response messages, and provide XSLT extension functions to handle non-XML message serializations.

Using the mapping feature of TIBCO API Exchange Gateway, you can transform the messages as follows:

•	Request message from one message format to other format using the forward mapper. For example, use the northbound forward mapper to modify the JSON request to an XML request. See BookQueryBE Example Request Message.

•	Response message from one message format to other format using the reverse mapper. For example, use northbound reverse mapper to modify the XML response message format to a JSON response message format. See BookQuery Example Response Message.

To support the JSON XML message transformations, TIBCO API Exchange Gateway provides the following:

JSON Extension

The JSON extension is defined in the namespace http://www.tibco.com/asg/functions/json

XSLT Functions

TIBCO API Exchange Gateway provides the following two functions:

•

parse()

The parse() function converts the JSON message format to XML message format.

•

render()

The render() function converts the XML message format to JSON message format.

The XML message format has a 1-to-1 correspondence with the JSON structure.

JSON Schema

TIBCO API Exchange Gateway provides the following built-in schema for JSON message:

---

 

<?xml version="1.0" encoding="UTF-8"?>

 

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"

xmlns:json="http://www.tibco.com/asg/content-types/json"

targetNamespace="http://www.tibco.com/asg/content-types/json"

elementFormDefault="qualified"

attributeFormDefault="unqualified">

<xs:element name="json_xml">

<xs:complexType>

<xs:sequence>

<xs:element ref="json:list"/>

</xs:sequence>

</xs:complexType>

</xs:element>

<xs:element name="list">

<xs:complexType>

<xs:choice minOccurs="0" maxOccurs="unbounded">

<xs:element ref="json:text"/>

<xs:element ref="json:double"/>

<xs:element ref="json:list"/>

<xs:element ref="json:dict"/>

</xs:choice>

<xs:attribute name="key" type="xs:string"/>

</xs:complexType>

</xs:element>

<xs:element name="text">

<xs:complexType>

<xs:simpleContent>

<xs:extension base="xs:string">

<xs:attribute name="key" type="xs:string"/>

</xs:extension>

</xs:simpleContent>

</xs:complexType>

</xs:element>

<xs:element name="double">

<xs:complexType>

<xs:simpleContent>

<xs:extension base="xs:string">

<xs:attribute name="key" type="xs:string"/>

</xs:extension>

</xs:simpleContent>

</xs:complexType>

</xs:element>

<xs:element name="dict">

<xs:complexType>

<xs:choice minOccurs="0" maxOccurs="unbounded">

<xs:element ref="json:text"/>

<xs:element ref="json:double"/>

<xs:element ref="json:list"/>

</xs:choice>

<xs:attribute name="key" type="xs:string"/>

</xs:complexType>

</xs:element>

</xs:schema>

---

 

Convert XML Message to JSON Message

By default, TIBCO API Exchange Gateway sends the response message in XML format from the target operation to the client. If a client requests the response message in a JSON format, you can convert the XML message to a JSON message as follows:

 

Task A Create an XSLT File

To create an XSLT file to render the data in JSON format, follow these high level steps:

•	Add namespaces

The render() function requires the following namespace: http://www.tibco.com/asg/functions/json

•	Build JSON structure

•	Use the render() function

See Example XSLT to Convert BookQuery XML Response to JSON Response for an example XSLT.

Task B Upload the XSLT File

Using the Config UI, upload the XSLT file in the northbound reverse mapper to render the XML response message in JSON message format as follows:

1.	Start the GUI server, if not already running.

2.	Log in to the Config UI using your credentials.

3.	Add a new project or select an existing project under Projects. For example, select BookQuery project.

4.	Add the mapping configuration as follows:

a.	Click the MAPPING > Mapping tab.

b.	Click the Add property to create a new mapping.

c.	Enter the parameters, as follows:

−	Mapping Name: XML_JSON_Mapping

−	Type:XSLT (select from the drop-down list.)

−	New File: Click Choose File and select the XSLT file.

−	Response Type:Full (select from the drop-down list.)

5.	Save the changes to your configuration.

6.	Select the mapper for the facade operation, as follows:

a.	Click the ROUTING > Facade Operations tab.

b.	Select the facade operation.

c.	In the Response Transform field, select the XML_JSON_Mapping mapper, as created in the mapping configuration from the drop-down list.

7.	Save the changes to your configuration.

BookQuery Example Response Message

When the BookQuery example is run, TIBCO API Exchange Gateway sends the response message in XML format to the client, by default.

BookQuery Example XML Response

The response message in XML format is shown as follows:

---

 

<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">

<SOAP-ENV:Body>

<ns0:BookStore xmlns:ns0="http://www.example.com/xsd/books">

<ns0:Book>

<ns0:Title>The Power of Now</ns0:Title>

<ns0:Author>Vivek Ranadive</ns0:Author>

<ns0:Date>1999</ns0:Date>

<ns0:ISBN>0-06-566778-9</ns0:ISBN>

<ns0:Publisher>Tibco Software Inc</ns0:Publisher>

</ns0:Book>

</ns0:BookStore>

</SOAP-ENV:Body>

</SOAP-ENV:Envelope>

Transformed JSON Response for BookQuery Service:

{

"BookStore": {

"Book": [

{

"Publisher": "Tibco Software Inc",

"ISBN": "0-06-566778-9",

"Author": "Vivek Ranadive",

"Title": "The Power of Now"

}

]

}

}

---

 

 

Example XSLT to Convert BookQuery XML Response to JSON Response

Use the following XSLT to convert XML message format to JSON message format:

---

 

<xsl:stylesheet version="1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:xsl="http://www.w3.org/1999/XSL/Transform"

xmlns:ns0="http://www.example.com/xsd/books"

xmlns:fn="http://www.tibco.com/asg/functions/json"

xmlns:json="http://www.tibco.com/asg/content-types/json"

xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"

exclude-result-prefixes="xsl fn json ns0 SOAP-ENV">

<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes" omit-xml-declaration="yes"/>

<xsl:variable name="cnResponseHref">

<xsl:value-of select="/transformation/cnResponse/@href"/>

</xsl:variable>

<xsl:variable name="cnResponse">

<xsl:copy-of select="document($cnResponseHref)/*"/>

</xsl:variable>

<xsl:variable name="JsonXmlResponse">

<json:json_xml>

<json:dict>

<json:dict key="BookStore">

<json:list key="Book">

<xsl:for-each select="$cnResponse/SOAP-ENV:Envelope/SOAP-ENV:Body/ns0:BookStore/ns0:Book">

<json:dict key="Book">

<json:text key="Title"><xsl:value-of select="ns0:Title"/></json:text>

<json:text key="ISBN"><xsl:value-of select="ns0:ISBN"/></json:text>

<json:text key="Author"><xsl:value-of select="ns0:Author"/></json:text>

<json:text key="Publisher"><xsl:value-of select="ns0:Publisher"/></json:text>

</json:dict>

</xsl:for-each>

</json:list>

</json:dict>

</json:dict>

</json:json_xml>

</xsl:variable>

<xsl:template match="/">

<xsl:value-of select="fn:render($JsonXmlResponse//json:json_xml/json:dict)"/>

</xsl:template>

</xsl:stylesheet>

 

---

 

BookQuery Example JSON Transformed Response

The following is the transformed JSON response message from the XSLT defined as Example XSLT to Convert BookQuery XML Response to JSON Response.

---

 

{

"BookStore": {

"Book": [

{

"Publisher": "Tibco Software Inc",

"ISBN": "0-06-566778-9",

"Author": "Vivek Ranadive",

"Title": "The Power of Now"

}

]

}

}

---

 

Convert JSON Message to XML Message

Using the northbound forward mapper, parse the JSON encoded string to generate an XML message. Usually, the JSON data is encoded using base64 format, therefore, the data must be converted from base64 to text. TIBCO API Exchange Gateway provides the codecs:base64ToText() function to convert the json data to text.

To parse a JSON encoded string in a north-side forward mapper, do the following:

 

Task A Create an XSLT File

To create an XSLT file to parse the JSON encoded, follow these steps:

•	Add namespaces

The parse() function requires the following namespaces: http://www.tibco.com/asg/functions/json

http://www.tibco.com/asg/functions/codecs

•	Use the parse() function as follows:

−	Extract the base64 encoded request payload from the context document.

−	Use the codecs:base64ToText() function to convert the payload to text message.

−	Pass the text message to the json:parse() function.

See Example XSLT to Convert BookQueryBE JSON Request to XML Request for an example XSLT.

Task B Upload the XSLT File

Using the Config UI, upload the XSLT file in the northbound forward mapper to parse the JSON encoded request message in XML message format as follows:

1.	Start the GUI server, if not already running.

2.	Log in to the Config UI using your credentials.

3.	Add a new project or select an existing project under Projects. For example, select the BookQueryBE project.

4.	Add the mapping configuration as follows:

a.	Click the MAPPING > Mapping tab.

b.	Click the Add property to create a new mapping.

c.	Enter the parameters, as follows:

−	Mapping Name: JSON_XML_Mapping

−	Type:XSLT (select from the drop-down list.)

−	New File: Click Choose File and select the XSLT file.

−	Response Type:Full (select from the drop-down list.)

5.	Save the changes to your configuration.

6.	Select the mapper for the facade operation, as follows:

a.	Click the ROUTING > Facade Operations tab.

b.	Select the facade operation.

c.	In the Request Transform field, select JSON_XML_Mapping mapper, as created in the mapping configuration from the drop-down list.

7.	Save the changes to your configuration.

BookQueryBE Example Request Message

For example, when the BookQueryBE example is run, the client can send a request message in JSON format. This section describes how to convert the JSON data to an XML request using the json:parse() function for the BookQueryBE example.

BookQueryBE Example JSON Message

The client sends the following request message in JSON encoded string:

---

 

 

{

"BookStore": {

"Book": [

{

"Publisher": "Tibco Software Inc",

"ISBN": "0-06-566778-9",

"Author": "Vivek Ranadive",

"Title": "The Power of Now"

}

]

}

}

 

---

 

Example XSLT to Convert BookQueryBE JSON Request to XML Request

Use the following XSLT to convert the JSON message to an XML message format:

---

 

<?xml version="1.0" encoding="UTF-8"?>

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"

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

xmlns:fn="http://www.w3.org/2005/xpath-functions"

xmlns:j="http://www.tibco.com/asg/content-types/json"

xmlns:f="http://www.tibco.com/asg/content-types/form"

xmlns:m="http://www.tibco.com/asg/mapping"

xmlns:c="http://www.tibco.com/schemas/asg/context"

xmlns:h="http://www.tibco.com/asg/protocols/http"

xmlns:v="http://tag-pg.vipnet.hr/pg/content-types/formdata"

xmlns:form="http://www.tibco.com/asg/functions/form"

xmlns:json="http://www.tibco.com/asg/functions/json"

xmlns:codecs="http://www.tibco.com/asg/functions/codecs"

exclude-result-prefixes="xsl soapenv fn h c j f v form json" >

<xsl:variable name="context">

<xsl:for-each select="/transformation/context">

<xsl:copy-of select="document(@href)"/>

</xsl:for-each>

</xsl:variable>

 

<xsl:variable name="httpRequest">

<xsl:copy-of select="$context/c:context/c:entry[@key='asg:httpRequest']/h:request"/>

</xsl:variable>

 

<xsl:template match="/">

<xsl:if test="$httpRequest/h:request/h:body">

<xsl:copy-of select="json:parse(codecs:base64ToText($httpRequest/h:request/h:body))"/>

</xsl:if>

</xsl:template>

</xsl:stylesheet>

---

 

 

BookQueryBE Example XML Transformed Request

The following is the transformed XML request message from the XSLT defined as Example XSLT to Convert BookQueryBE JSON Request to XML Request.

---

 

<?xml version="1.0" encoding="UTF-8"?>

<dict xmlns="http://www.tibco.com/asg/content-types/json">

<dict key="BookStore">

<list key="Book">

<dict>

<text key="Publisher">Tibco Software Inc</text>

<text key="ISBN">0-06-566778-9</text>

<text key="Author">Vivek Ranadive</text>

<text key="Title">The Power of Now</text>

</dict>

</list>

</dict>

</dict>

---

 

 

Copyright © Cloud Software Group, Inc. All Rights Reserved