can-connect does not delete the instance in localstorage ~8

@pYr0x commented on Sun Nov 22 2015

can-connect does not delete the instance in localstorage if they are not present in any sets anymore.

if we received a response like that:

{
    "data": [
        {
            "_id": 2,
            "gruppe": "besteck",
            "name": "messer"
        },
        {
            "_id": 3,
            "gruppe": "besteck",
            "name": "gabel"
        },
        {
            "_id": 4,
            "gruppe": "besteck",
            "name": "loeffel"
        }
    ]
}

the localstroage key todosCache/set/{"gruppe":"besteck"} has the value [2,3,4]

if in the second request the instance 4 will not be responsed with, the value of the todosCache/set/{"gruppe":"besteck"} changes to [2,3]. thats fine! but the key todosCache/instance/4 still exists in storage.

can-connect should check any instance if it is on a set, if not, delete the instance in storage.

@justinbmeyer commented on Thu Sep 01 2016

I think the fix to this will be to go through all the ids of the sets stored and see what ids are not present and delete them.

@justinbmeyer commented on Mon Oct 03 2016

There's a problem here ... what if something like the following happens:

.getList({group: "house"}) --> 2,3,4
// then
.get({id: 4})
// then
.getList({group: "house"}) --> 2,3

Then 4 shouldn't be removed from the instances data.

I think there are 2 solutions:

Store that updateData was was used on 4. That way 4 doesn't get removed by the 2nd getList. However, this is fraught with problems.
Implement a least recently used (LRU) cache. This would keep 4 in localStorage, but mark it as not being read very much, eventually removing it.

Ideally, the LRU cache could sit on-top of any other connection.

updateListData: function(listData, set){
  // check if there's room
  if( this.availableSize() < = CURRENT_SIZE + SIZE_OF(listData) )
    // get the saved data in the underlying connection. 
    base.getSets()
    base.getInstances() // might need to be added.  This is sorta like a .getList({}).
    // go through and remove smallest ... repeat until we can fit listData
  }

   // for every instance
},
getListData: function(set){
  base.getListData().then(function(listData){
     INCREMENT_AND_TIMESTAMP( set );
     response.data.forEach(function(instance){
       INCREMENT_AND_TIMESTAMP( instance );
     })
  })
}

@pYr0x commented on Mon Oct 03 2016

that is to confusing for me ;) but i think you will do a great job :)

canjs / can-memory-store

can-connect does not delete the instance in localstorage ~8 #2