Short description

I use Play forms to validate API request bodies and bind the request to the form as follows:

final Form<TaskForm> form = formFactory.form(TaskForm.class)
                .bind(messagesApi.preferred(request).lang(), request.attrs(), request.body().asJson(), 102400);

When the request body contains snake_case fields, they aren't mapped to the corresponding camelCase fields on the Play form, even when explicit @JsonProperty or @JsonNaming strategies are defined.

Request

{
    "title": "Some Task",
    "author_name": "John"
}

Form

@Constraints.Validate
@JsonNaming(SnakeCaseStrategy.class) // -> has no effect on play's form mapping
public class TaskForm implements Constraints.Validatable<List<ValidationError>> {

    @Constraints.Required
    protected String title;

    @Constraints.Required
    @JsonProperty("author_name") // -> has no effect either
    protected String authorName;

}

Play Version

2.8.13

API

Java

Operating System

Linux inf-nb 5.16.8-arch1-1 #1 SMP PREEMPT Tue, 08 Feb 2022 21:21:08 +0000 x86_64 GNU/Linux

JDK

openjdk version "1.8.0_322"
OpenJDK Runtime Environment Corretto-8.322.06.2 (build 1.8.0_322-b06)
OpenJDK 64-Bit Server VM Corretto-8.322.06.2 (build 25.322-b06, mixed mode)

Library Dependencies

irrelevant

Expected Behavior

When sending a POST request with JSON body, where the fields are in snake_case, the Play forms should be able to map the snake_case fields to camelCase fields on the Play form (if they are annotated with a matching @JsonProperty or when a @JsonNaming strategy has been defined).

Actual Behavior

JSON request bodies with snake_case fields do not map to camelCase fields of Play forms. Even when @JsonNaming or @JsonProperty are explicitly specified.

Current workaround

My current workaround to address this issue is to simply specify the fields in the Java Play form in snake_case too. It goes against our naming convention of how to name fields in Java classes, but is the simplest workaround to cirvumvent the issue.

Reproducible Test Case

I created a public repository with a simple form, showcasing the issue: hertg/play-form-json-issue