WSO2 EI JSONBuilder configuration

Question

I have this xml which needed to be processed and converted to JSON:

<jsonObject>
    <number>1234</number>
    <emptyString/>
    <string>hello</string>
</jsonObject>

When it runs through JsonStreamBuilder like this:

<property name="messageType" scope="axis2" type="STRING" value="application/json"/>

I get JSON like that:

{
  "number":1234,
  "emptyString": null,
  "string":"hello"
}

So I am wondering is there any way that I can configure JsonStreamBuilder to treat empty tag not as null, but as empty string, furthermore I want numbers to be treated as strings as well.

Maybe I can modify the default XML to fit my needs?

BTW I am using WSO2 EI 6.1.1

score 4 · Answer 1 · answered Dec 31 '18 at 09:37

The default behavior of JsonFormatter is to allow primitive types in the JSON output. This means any content that is a valid number will be represented in the JSON message as a number.

As a solution for this issue, you could disable, the conversion to primitive type after adding below property to the synapse.properties file of EI_HOME/conf directory.

synapse.commons.json.output.autoPrimitive=false

However, this property is a global property, so it will be effected to all the services (Proxy services and the APIs). So this means any string that is a valid number will not be converted to a number.

According to your issue, you need to disable the conversion of String to Integer. You could solve this, adding below properties into EI_HOME/conf/synapse.properties file also.

synapse.commons.json.output.autoPrimitive=true

synapse.commons.json.output.disableAutoPrimitive.regex=^[1-9]*$

In this case, auto primitive disables for the numbers only.

NOTE: Once autoprimitive is enabled, some fields can be excluded from the auto primitive functionality based on the regular expression defined in the synapse.properties file.

And the empty tag as the not null issue, you can resolve following the above-mentioned blog post.

Great explanation, but how would OP exclude empty strings from the auto primitive functionality? Since that seems to be what he needs — ophychius, Dec 31 '18 at 10:31
You can follow https://medium.com/@lashan/class-mediator-to-handle-null-values-in-json-payload-wso2-ei-34a43246f0f blog to address this issue — Dil, Dec 31 '18 at 18:18
Dear Dil, the purpose of SO is so that the answer is recorded here. A link is fine as support but the solution should be here — ophychius, Jan 01 '19 at 10:33
Thanks for the answer, but that link explains the opposite of what I need to achieve json null to xml empty tag, whereas I need to transform xml empty tag to empty string in json. And that task has higher priority. Nevertheless thanks for the answer. — Constantine, Jan 17 '19 at 08:10

score 0 · Answer 2 · answered Dec 29 '18 at 09:41

This looks like restriction in wso itlsef, documentation states that is desired behavior. To overcome issue have try script mediator WSO2ESB: Property setting not accepting empty value or getting even lower (more complicated) https://medium.com/@lashan/class-mediator-to-handle-null-values-in-json-payload-wso2-ei-34a43246f0f

score 0 · Answer 3 · answered Jun 09 '21 at 14:46

If you were using a more recent WSO version, there is a solution: https://docs.wso2.com/display/EI630/Working+with+Message+Payloads#WorkingwithMessagePayloads-EmptyXMLelementswiththe'nil'attribute

You can set synapse configs locally with the help of JSON Transform mediator

WSO2 EI JSONBuilder configuration

3 Answers3