Technical Articles

October 2, 2020 4 minute read

Custom JSON to XML Converter in CPI

Introduction

As we are working on SAP CPI project it is a common requirements to have a message transformation from JSON to XML in our integration flow.

And based on our experience we found that there are some limitations in the JSON2XML component of the SAP CPI.

Some JSON format cannot be converted to XML by the standard CPI component for the JSON2XML converter.

If you want read further about the current limitations you can check the bellow reference :

SAP notes : 2478282
As well as from the SAP help portal : https://help.sap.com/doc/bd0ff312719b460f87556fc14e93f67a/Cloud/en-US/3a02829ea84e4f7dac62bdd10d06b084.html

The case and the Alternate Solution

Ok now lets jump in into the sample case and how we are going to deal with it 🙂

Here I will create two integration flow.

The first one is using the default/standard SAP CPI’s JSON to XML converter.

And the second one is using a simple groovy script + custom library(*.jar files) to do the same(JSON to XML conversion.

Here we go our first integration flow:

IFlow-1

First Integration Flow

The above integration flow is a very simple one, it will receive a JSON format and do the conversion to XML using CPI’s standard JSON to XML converter.

We will use the following JSON payload to test our integration flow :

{
    "severity": "medium",
    "createdDate": "Wed Sep 30 08:42:43 UTC 2020",
    "topic": "instance-xxx-outlookemail-events",
    "action": "create",
    "id": "xxx",
    "message": {
        "elementKey": "outlookemail",
        "accountId": 99999,
        "eventId": "eventId",
        "companyId": 66666,
        "instanceId": 777777,
        "instance_id": 777777,
        "instanceName": "test-mail",
        "instanceTags": [
            "soltius-mail"
        ],
        "raw": {
            "eventHeaders": {
                "id": "777777",
                "encodedid": "NTkwMzAw",
                "Raw-Element-Key": "outlookemail"
            },
            "pollDate": 1601455361934,
            "messages": [
                {
                    "ChangeKey": "CQAAABYAAADFfXRs5qJyQJRUntt2T2ZWAAD7AKgT",
                    "ConversationId": "AAQkADY4ZmFkZDEwLTBlMzctNGViMy05ZDc3LTQ4NWU2MTdlOTliMgAQAAXvfXGAyEHBgsssBzbAq18=",
                    "IsRead": false,
                    "ReceivedDateTime": "2020-09-30T08:38:07Z",
                    "Importance": "Normal",
                    "@odata.id": "odata.id",
                    "CcRecipients": [
                        {
                            "EmailAddress": {
                                "Address": "testcc1@test.com",
                                "Name": "testcc1"
                            }
                        },
                        {
                            "EmailAddress": {
                                "Address": "testcc2@test.com",
                                "Name": "testcc2"
                            }
                        }
                    ],
                    "Body": {
                        "ContentType": "HTML",
                        "Content": "<html><head></head><body><div class=\"WordSection1\">Dear all</div></body></html>"
                    },
                    "ConversationIndex": "ConversationIndex",
                    "BodyPreview": "Dear all,\r\n\r\nFor your information",
                    "IsDraft": false,
                    "InferenceClassification": "Focused",
                    "LastModifiedDateTime": "2020-09-30T08:38:09Z",
                    "HasAttachments": true,
                    "ToRecipients": [
                        {
                            "EmailAddress": {
                                "Address": "rcvto1@test.com",
                                "Name": "rcvto1"
                            }
                        },
                        {
                            "EmailAddress": {
                                "Address": "rcvto2@test.com",
                                "Name": "rcvto2"
                            }
                        }
                    ],
                    "@odata.etag": "W/\"CQAAABYAAA\"",
                    "SentDateTime": "2020-09-30T08:38:03Z",
                    "From": {
                        "EmailAddress": {
                            "Address": "sender@test.com",
                            "Name": "sender"
                        }
                    },
                    "Flag": {
                        "FlagStatus": "NotFlagged"
                    },
                    "ParentFolderId": "ParentFolderId",
                    "Subject": "Subject",
                    "WebLink": "WebLin",
                    "Sender": {
                        "EmailAddress": {
                            "Address": "sender@test.com",
                            "Name": "Sender"
                        }
                    },
                    "IsDeliveryReceiptRequested": false,
                    "InternetMessageId": "InternetMessageId",
                    "Id": "AAMkADY4Z",
                    "IsReadReceiptRequested": false,
                    "CreatedDateTime": "2020-09-30T08:38:06Z"
                }
            ],
            "objectType": "messages"
        },
        "userId": 99999,
        "events": [
            {
                "elementKey": "outlookemail",
                "pollDate": "2020-09-30T08:42:41Z",
                "eventType": "UPDATED",
                "hubKey": "general",
                "objectId": "objectId",
                "objectType": "messages"
            }
        ]
    },
    "user": "notifications@cloud-elements.com"
}

In order to test our first integration flow, we use Postman and the above JSON as the payload:

Error%20in%20Postman

From above screen capture we can see that we got an error in our first integration flow.

So for the next step we will go to the message monitoring of our CPI and we can see the detailed error as follows :

Message%20Processing%20Log

As we can see from the above error the standard JSON to XML converter is unable to do the conversion of our JSON payload to the XML format

As a CPI developer one of our favorite feature of the CPI is we are able to write a groovy script 🙂

We also able to use/upload custom library (*.jar files) in the resource tab of our integration flow.

As we are trying to overcome the issue from our first IFlow.

We create our second IFlow as shown below:

Second%20Integration%20Flow

Second Integration Flow

From the above IFlow we can see that we will be using a groovy script to perform the JSON to XML conversion.

The groovy script snippet is as follows:

import com.sap.gateway.ip.core.customdev.util.Message;
import java.util.HashMap;
import groovy.json.JsonOutput;
import groovy.json.JsonSlurper;
import groovy.json.JsonBuilder;
import java.text.SimpleDateFormat;
import java.sql.Timestamp;
import net.sf.json.JSON
import net.sf.json.JSONSerializer
import net.sf.json.xml.XMLSerializer


def Message processData(Message message) {
    String payload = message.getBody(java.lang.String)
    def jsonSlurper = new JsonSlurper();
    def object = jsonSlurper.parseText(payload.toString())

    JSON json = JSONSerializer.toJSON( payload )
    XMLSerializer xmlSerializer = new XMLSerializer()
    xmlSerializer.setTypeHintsCompatibility( false )
    xmlSerializer.setTypeHintsEnabled( false )
    String xml = xmlSerializer.write( json )

    message.setBody(xml);
    return message;
}

As we can see from the above groovy script we will need several custom libraries for the:

import net.sf.json.*

The library(*.jar files) can be downloaded in the following source :

https://sourceforge.net/projects/json-lib/

After downloading the custom library.

We need to upload the jar files, in the following section of our Integration Flow:

Custom%20Jar%20Files

Finally let’s test our second integration flow using the same JSON format via postman :

Postman%20Result

From the above image we can see that the second Integration Flow works well with the same JSON payload and able to convert the JSON payload into XML format as we expected.

Conclusion and call to action

From this post we understand that the CPI’s standard JSON to XML converter has some limitation.

And as(one of) the alternate solution we can use the groovy script and the custom libraries to do the JSON to XML Conversion.

Please feel free to share n the comment section, if you found the same issue related to the JSON to XML conversion and how you solve it.

We will be more than happy to discuss about 🙂

13 Comments

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Eng Swee Yeoh

October 2, 2020 at 12:13 pm

Hi Hari

It would be useful to show what exactly in your input JSON payload that is causing the error/hitting a limitation.

Regards

Eng Swee

Hari Cahyadi Windyadi

Blog Post Author

October 2, 2020 at 12:40 pm

Hi Eng Swee,

Thank you for the input. But to be honest I'm not really know what's wrong in my json payload that causing the error 🙂

So I just trying to write the script and it can convert my payload.

If someone can help me identify what's wrong with my json, payload it will be nice.

So we can take a note when we should looking for workaround or using the standard json to xml converter from SAP CPI.

Since the drawback of using my solution above is the IFlow size is getting bigger when we download it.

Cheer,

Hari

Raffael Herrmann

October 2, 2020 at 4:22 pm

Eng Swee Yeoh I just tested it out of curiosity. The error of CPI's converter is "Trying to write an attribute when there is no open start element". After some trial'n'error it seems like that the standard converter doesn't handle the JSON because of the two JSON properties named "@odata.id" and "@odata.etag".

Hari Cahyadi Windyadi if you remove the @ chars from the properties (e.g. via Script), you can use the official JSON to XML converter.

Eng Swee Yeoh

October 2, 2020 at 6:18 pm

Nice one, Raffael. You are always one that is up for a challenge 😉

Hari Cahyadi Windyadi

Blog Post Author

October 3, 2020 at 12:16 am

Hi Raffael,

Thank you so much for your curiosity and taking your time to check my JSON payload.

Well noted.

Later we can write a small script to remove the wild characters and pass it to the official JSON to XML converter.

Happy weekend 🙂

Rashmi Joshi

November 16, 2020 at 3:20 pm

Hi Hari Cahyadi Windyadi ,

As suggested by Raffael Herrmann remove special characters and before using JSON to XML converter use Content modifier in below format, it should work now without script: -

{"root":
${in.body}
}

Regards,

Rashmi Joshi

Hari Cahyadi Windyadi

Blog Post Author

November 16, 2020 at 3:29 pm

Hi Rashmi Joshi,

Thanks for your advise.

At the time being I just left the payload as it is since it was sent from open connector when an event is triggered. I will consider your to use it in my next project so we can use the official converter ☺

Best regards,

Hari Cahyadi

Dinesh M

October 5, 2021 at 2:58 pm

Hi ,

I have downloaded from the link given and I see only one file with name "json-lib-2.4-jdk15.jar"

Could you let me know how to get all the other files you uploaded(I see around 7 Jars in your snapshot)

Thanks,

Dinesh

Akshay Bakliwal

March 10, 2022 at 6:31 am

@ Dinesh M,

You can download the required JAR files for JSON to XML conversion from here

Thanks,

Akshay Bakliwal

Catia Silva

May 31, 2022 at 2:22 pm

Hi Hari Cahyadi Windyadi i downloaded the jar files and try to executed for my JSON structure.

Thanks a lot. It works fine 🙂

Cátia

Vinicius Souza

September 15, 2022 at 6:27 pm

Hello,

In my scenario I have a Request/Reply that gets a info from HTTP connection (it is one value only).

I should get this value and send it to S/4.

Is this case should I use the groovy script to convert the JSON to XML and pass it to XI connection?

Att.,

Vinicius

Jiggs Roger Peter Lewis

September 23, 2022 at 9:48 pm

Hello Hari and fellow experts,

I tried this method with a custom groovy to convert from JSON to XML for a response to my ERP but the ERP can't seem to parse the message in any case. Behaves the same with the standard as well as the script. Any recommendations?

Thank you!

CPI Corona

October 19, 2022 at 4:49 pm

hola, como puedo quitar en mi caso [ ] ya que los tengo al inicio y final del JSON y por eso no me deja convertirlo

Technical Articles

Custom JSON to XML Converter in CPI

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