Re-allow handling empty request body [SPR-12778]

[spring-projects-issues]

Oliver Drotbohm opened SPR-12778 and commented

In case a request contains an empty body, Spring 4.1's RequestResponseBodyMethodProcessor calls handleEmptyBody(…) and immediately returns null without further consideration of HandlerMethodArgumentResolver instances that might be able to deal with an empty request body.

This is a regression in cases where the HandlerMethodArgumentResolver was explicitly designed to return a default value, which worked fine with 4.0.x.

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Affects: 4.1.5

Issue Links:

• Contract of @RequestBody(required=true) not obeyed [SPR-11828] #16447 Contract of @RequestBody(required=true) not obeyed
• ResponseBodyAdvice to accept null values? [SPR-12152] #16766 ResponseBodyAdvice to accept null values?
• DATAREST-485 RepositoryPropertyReferenceController.createPropertyReference(…) does not work for empty content supplied on Spring 4.1
• Spring Controller is not able to detect empty string ("") as a string object in RequestBody [SPR-13861] #18434 Spring Controller is not able to detect empty string ("") as a string object in RequestBody
• Contract of @RequestPart(required=false) not obeyed [SPR-12860] #17458 Contract of @RequestPart(required=false) not obeyed
• HttpEntity controller method arguments should allow null body [SPR-12861] #17459 HttpEntity controller method arguments should allow null body
• Commons FileUpload failed after Spring framework upgrade [SPR-13014] #17605 Commons FileUpload failed after Spring framework upgrade

0 votes, 5 watchers

[spring-projects-issues]

Juergen Hoeller commented

On a related note, #16766 suggested a softer landing for null return values, letting them go through ResponseBodyAdvice for the purpose of turning it into a default value. That use case seems similar to the present one, since this issue is essentially about passing a null request body to converters for the purpose of returning a default value.

[spring-projects-issues]

Juergen Hoeller commented

Since this more or less worked accidentally before, we're trying to provide a proper solution for the problem in 4.2, not messing with the behavior in the 4.1.x line anymore (since any change might be a regression for somebody).

Juergen

[spring-projects-issues]

Rossen Stoyanchev commented

Commits 0556ed and 36ed4d introduce RequestBodyAdvice and provide it full control over the handling of an empty request body.