Gson map empty to null field in Pojo (rest-service.xml)

Support
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#1

Hi,
I use rest-service.xml with simple pojos as parameters for my Rest-API. I implemented a bean validation in this pojos too. For example I have there a @NotNull constraint. I noticed that my (own and not cuba) frontend send empty strings. So the validation does not fire because the value is not null.
Is there a way to define the “global” GSON mapping to map empty strings to null?

Thanks! Reini

#2

Hi Reinhard,

Assuming you are using bean validation, note that there are several annotations so perform the validation of different empty string variants: @notEmpty and @notBlank as well. Here is an explanation on them: https://www.baeldung.com/java-bean-validation-not-null-empty-blank

Perhaps you can just leverage those.

Cheers
Mario

#3

Thank you @mario!
I know this constraints and @NotBlank would be much better than @NotNull for my use case. But is there a way to manipulate the internal gson builder from CUBA? Because I have also the use case that some fields must be null in some use case…

Thanks! Reini

#5

Hi,
Services invocations are handled by the com.haulmont.addon.restapi.api.controllers.ServicesController which delegates the calls to the com.haulmont.addon.restapi.api.service.ServicesControllerManager.

Inside the _invokeServiceMethod method you’ll find that request parameter is converted to the object using the com.haulmont.addon.restapi.api.common.RestParseUtils#toObject method. Both RestParseUtils and ServicesControllerManager are spring beans so you a free to override these beans in your project.