OData Referencing Requests in a Change Set - odata

Question

I have batch request to update data.
Data Is:
Item : {
id : int,
name : string,
RefItem : {
int : id,
name : string }
}
I need
Create Item
Update RefItem reference for this newly created Item, in the same batch. (Suppose RefItems(1) already exists in data set)
According to OData spec:
--batch_1872-f36a-7ce8
Content-Type: multipart/mixed; boundary=changeset_8c16-9ba3-2260
--changeset_8c16-9ba3-2260
Content-Type: application/http
Content-Transfer-Encoding: binary
PUT $1/$links/ItemRef HTTP/1.1
Content-ID: 2
Accept: application/atomsvc+xml;q=0.8, application/json;q=0.5, /;q=0.1
DataServiceVersion: 1.0
Content-Type: application/json
{"uri":"ItemRefs(1)"}
--changeset_8c16-9ba3-2260
Content-Type: application/http
Content-Transfer-Encoding: binary
POST Products HTTP/1.1
Content-ID: 1
Accept: application/atomsvc+xml;q=0.8, application/json;q=0.5, /;q=0.1
DataServiceVersion: 1.0
Content-Type: application/json
{"id":-1,"name":"seven"}
--changeset_8c16-9ba3-2260--
--batch_1872-f36a-7ce8--
I suppose it should work, but I have response error :
--batchresponse_4febeba8-dd43-4040-9fdb-866afde5304e
Content-Type: multipart/mixed; boundary=changesetresponse_424dbf12-fa9a-4a59-8284-963fa0fa7b77
--changesetresponse_424dbf12-fa9a-4a59-8284-963fa0fa7b77
Content-Type: application/http
Content-Transfer-Encoding: binary
HTTP/1.1 500 Internal Server Error
Content-ID: 2
X-Content-Type-Options: nosniff
DataServiceVersion: 1.0;
Content-Type: application/json;charset=utf-8
{"d":{"error":{"code":"","message":{"lang":"ru-RU","value":"An error occurred while processing this request."}}}}
--changesetresponse_424dbf12-fa9a-4a59-...
Can somebody tell me where I'm wrong?
Thanks.

Answer 1

The batch request is processed as a stream. So you can only refer to content ID which was already seen. The above sample refers to content ID 1 before the request operation with that content ID. That is not valid.
You need to first create the new instance (POST) and then add a reference to it via the $links URL.