PATCH and FETCH Methods for the Constrained Application Protocol (CoAP)
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From: The IESG <email@example.com> To: "IETF-Announce" <firstname.lastname@example.org> Cc: email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, "The IESG" <email@example.com>, firstname.lastname@example.org, email@example.com, "Jaime Jimenez" <firstname.lastname@example.org> Subject: Protocol Action: 'Patch and Fetch Methods for Constrained Application Protocol (CoAP)' to Proposed Standard (draft-ietf-core-etch-04.txt) The IESG has approved the following document: - 'Patch and Fetch Methods for Constrained Application Protocol (CoAP)' (draft-ietf-core-etch-04.txt) as Proposed Standard This document is the product of the Constrained RESTful Environments Working Group. The IESG contact persons are Alexey Melnikov, Ben Campbell and Alissa Cooper. A URL of this Internet Draft is: https://datatracker.ietf.org/doc/draft-ietf-core-etch/
Technical Summary The existing Constrained Application Protocol (CoAP) methods only allow access to a complete resource, not to parts of a resource. In case of resources with larger or complex data, or in situations where a resource continuity is required, replacing or requesting the whole resource is undesirable. Several applications using CoAP will need to perform partial resource accesses. Similar to HTTP, the existing Constrained Application Protocol (CoAP) GET method only allows the specification of a URI and request parameters in CoAP options, not the transfer of a request payload detailing the request. This leads to some applications to using POST where actually a cacheable, idempotent, safe request is desired. Again similar to HTTP, the existing Constrained Application Protocol (CoAP) PUT method only allows to replace a complete resource. This also leads applications to use POST where actually a cacheable, possibly idempotent request is desired. This specification adds new CoAP methods, FETCH, to perform the equivalent of a GET with a request body; and the twin methods PATCH and iPATCH, to modify parts of a CoAP resource. Working Group Summary The document has gone through multiple expert reviews and has been discussed on multiple IETF meetings. Before the last IETF the WGLC was completed. Document Quality There are no known implementations of the new COAP methods. Registration of new COAP media types was requested. Personnel Jaime Jiménez is the document shepherd. Alexey Melnikov is the responsible Area Director.