API rest to remove a group to a user

[martins1930]

Hello,
I read the OpenAM documentation and I'm not seeing a way to remove a group to a user using the OpenAM Rest API.
Right now to remove a group we use this API: PUT /openam/json/{RealmName}/groups/{GroupName} removing the user in the uniqueMember list.
For example we have a group with the name mygroup that contains three users: myuser1@foobar.com, seconduser@foobar.com and toremove@foobar.com.
And we want to remove the user toremove@foobar.com of the group mygroup,
to do it we execute this API:

curl -X "PUT" "https://mydomain.com/openam/json/myrealm/groups/mygroup" \
     -H 'Content-Type: application/json' \
     -H 'iplanetDirectoryPro: ...' \
     -d $'{
  "_id": "mygroup",
  "_rev": "-243248344",
  "uniqueMember": [
    "mail=myuser1@foobar.com,ou=people,dc=openam,dc=forgerock,dc=org",
    "mail=seconduser@foobar.com,ou=people,dc=openam,dc=forgerock,dc=org"
  ]
}'

As you can see we remove the user toremove@foobar.com from the list uniqueMember .

But this is not ideal, because we have to load all the users (that belong to a group) into memory (and if we have a lot of users this could generate a bad performance in the API and also the service that is calling this API could consume a lot of memory RAM) and then remove the user in the list uniqueMember.
This approach also could generate a race condition for example: if two processes are trying to delete different users at the same time then one process can override the uniqueMember when invokes the API PUT /openam/json/{RealmName}/groups/{GroupName} .

Do you know if there is a better way to remove a group to a user? (I mean, for a specific user X I want to delete the group G, maybe an API that takes two parameters the username and the group and remove the user of the group ?)

Regards,
Martín.