API Management string in payload encoding

Question

API Management string in payload encoding

Siva Krishna Pokuri 21

I have an API that accepts JSON and transforms to XML for the backend calls using Liquid transformation as sample payload below -

Input Payload from the client

{

"userPriority": "Medium",

"area": "Safety & Security"

}

transformed XML payload to the backend service

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

<soapenv:Header>

    <UserPriority>3-Medium</UserPriority>

    <Area>Safety & Security</Area>

</soapenv:Body>

</soapenv:Envelope>

Because of the '&' unique character, the backend throws an HTTP 500 error message. If the & is encoded, the backend service will accept the request.

I have tried the options below in the Azure APIM transformation logic, but none of them encode special characters using "escape" and "xml_escape."

I appreciate any suggestion to solve the issue.

<set-body template="liquid">

<soapenv:Body>

<UserPriority>{{body.Document.UserPriority}}</UserPriority>

<Area>{{ body.Document.Area | escape }}</Area>

<Area>{{ body.Document.Area | xml_escape }}</Area>

	</soapenv:Body>

2 answers

Your answer

Answer 1

Khadeer Ali 5,055 Microsoft External Staff

@Siva Krishna Pokuri ,

Welcome to Microsoft Q&A Platform!

Thank you for your query.

To address the issue with special characters causing errors in your backend system, please try to use the replace filter within your Liquid transformation.

While other options like escape or xml_escape might seem suitable, they might not always handle the full range of characters that need encoding for XML. The replace filter gives you precise control, allowing you to specifically encode characters like &, <, >, ", and ' into their correct XML equivalents: &, <, >, ", and ', respectively.

Here’s an example of how to do this:


<Area>
{{
 body.area | replace: '&', '
 }}
</Area>

Hope this helps. Do let us know if you any further queries.

If this answers your query, do click Accept Answer and Yes for was this answer helpful. And, if you have any further query do let us know.

Siva Krishna Pokuri 21 Reputation points

2025-01-09T15:45:34.83+00:00

Thanks for your kind reply. However, the replace command does not allow the policy to be saved and throws a validation error message. Please suggest.
Khadeer Ali 5,055 Reputation points Microsoft External Staff

2025-01-09T15:55:47.44+00:00

Thank you for your feedback. I understand that the replace method did not work as expected. After further review, could you try using the find-and-replace policy in Azure API Management to handle encoding special characters like & .
You could check in the below document on how to use the find and replace
https://learn.microsoft.com/en-us/azure/api-management/find-and-replace-policy#policy-statement

Answer 2

Lee, YongKyu 0

Hello

I met a same condition.

Answer that I found is to use 'Pascal casing for Liquid filter names'.

https://learn.microsoft.com/en-us/azure/api-management/set-body-policy#supported-liquid-filters

As example in your issue,

[before]

<Area>{{ body.Document.Area | escape }}</Area>

[after]

<Area>{{ body.Document.Area | Escape }}</Area>

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API Management string in payload encoding

2 answers

Your answer