On 31/10/17 09:24, sunlf wrote: > > Hi, devs, > > > > For C++ API, here are 2 functions, PUT and POST. > > > > What’s the difference between these 2?
Thanks for asking, because it's not obvious, It worth to be confirmed, but I am not sure there is a direct mapping from 4 CRUD ops to POST, GET, PUT, DELETE verbs. Before let me share some investigation I made, In HTTP/REST world my understanding, is that POST is (usually) for creating new (children) resources, while PUT is (usually) for updating a fixed one, but it's not that easy, check: https://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9.5 { POST: "The actual function performed by the POST method is *determined by the server* and is usually dependent on the Request-URI." If a resource *has been created *on the origin server, the response SHOULD be 201 (Created) and contain an entity which describes the status of the request and *refers to the new* resource, and a Location header PUT: If the Request-URI does not point to an existing resource, and that URI is capable of being defined as *a new resource* by the requesting user agent, the origin server *can create* the resource with that URI } So it's server side to decide which strategy to use, (update can be done using POST or PUT) Similar in CoAP world: https://tools.ietf.org/html/rfc7252#section-5.8.2 { POST: It usually results in *a new resource being created* If the POST succeeds but does not result in a new resource being created on the server, the response SHOULD have a 2.04 (Changed) POST is neither safe nor idempotent. PUT: If a resource exists at the request URI, the enclosed representation SHOULD be considered a modified version of that resource, and a 2.04 (Changed) Response Code SHOULD be returned. If no resource exists, then the server *MAY create a new resource* with that URI, PUT is not safe but is idempotent. } Now in OCF/OIC world see: p115 https://openconnectivity.org/specs/OCF_Core_Specification_v1.0.0.pdf Mapping is more clear and POST is only used for update, UPDATE with POST, CREATE with PUT new existing URL (or use POST to create sub EndPoints on existing URL) while POST on existing URL is not listed in the table, (even if undetermined I guess it is assumed that iotivity do the same as POST verb) Note that most OneIoA models are using POST for update, this what you will mostly use. Confirmation is welcome, because it's still confusing It will help to fix this pending bug regarding iotivity's examples https://jira.iotivity.org/browse/IOT-948 Regards -- mailto:philippe.co...@osg.samsung.com gpg:0x467094BC https://blogs.s-osg.org/author/pcoval/ _______________________________________________ iotivity-dev mailing list iotivity-dev@lists.iotivity.org https://lists.iotivity.org/mailman/listinfo/iotivity-dev
