RESTful Alternatives to DELETE Request Body
While the HTTP 1.1 spec seems to allow message bodies on DELETE requests, it seems to indicate that servers should ignore it since there are no defined semantics for it.
4.3 Message Body
A server SHOULD read and forward a message-body on any request; if the request method does not include defined semantics for an entity-body, then the message-body SHOULD be ignored when handling the request.
I've already reviewed several related discussions on this topic on SO and beyond, such as:
- Is an entity body allowed for an HTTP DELETE request?
- Payloads of HTTP Request Methods
- HTTP GET with request body
Most discussions seem to concur that providing a message body on a DELETE may be allowed, but is generally not recommended.
Further, I've noticed a trend in various HTTP client libraries where more and more enhancements seem to be getting logged for these libraries to support request bodies on DELETE. Most libraries seem to oblige, although occasionally with a little bit of initial resistance.
My use case calls for the addition of some required metadata on a DELETE (e.g. the "reason" for deletion, along with some other metadata required for deletion). I've considered the following options, none of which seem completely appropriate and inline with HTTP specs and/or REST best practices:
- Message Body - The spec indicates that message bodies on DELETE have no semantic value; not fully supported by HTTP clients; not standard practice
- Custom HTTP Headers - Requiring custom headers is generally against standard practices; using them is inconsistent with the rest of my API, none of which require custom headers; further, no good HTTP response available to indicate bad custom header values (probably a separate question altogether)
- Standard HTTP Headers - No standard headers are appropriate
- Query Parameters - Adding query params actually changes the Request-URI being deleted; against standard practices
- POST Method - (e.g.
POST /resourceToDelete { deletemetadata }) POST is not a semantic option for deleting; POST actually represents the opposite action desired (i.e. POST creates resource subordinates; but I need to delete the resource) - Multiple Methods - Splitting the DELETE request into two operations (e.g. PUT delete metadata, then DELETE) splits an atomic operation into two, potentially leaving an inconsistent state. The delete reason (and other related metadata) are not part of the resource representation itself.
My first preference would probably be to use the message body, second to custom HTTP headers; however, as indicated, there are some downsides to these approaches.
Are there any recommendations or best practices inline with REST/HTTP standards for including such required metadata on DELETE requests? Are there any other alternatives that I haven't considered?
Answer
Despite some recommendations not to use the message body for DELETE requests, this approach may be appropriate in certain use cases. This is the approach we ended up using after evaluating the other options mentioned in the question/answers, and after collaborating with consumers of the service.
While the use of the message body is not ideal, none of the other options were perfectly fitting either. The request body DELETE allowed us to easily and clearly add semantics around additional data/metadata that was needed to accompany the DELETE operation.
I'd still be open to other thoughts and discussions, but wanted to close the loop on this question. I appreciate everyone's thoughts and discussions on this topic!