在Google App Engine中将reflect.Value传递到datastore.GetMulti

Question

I have a wrapper function mypkg.GetStart around datastore.GetMulti. The arguments of the wrapper function must be identical to appengine.GetMulti. I would like to get the first two entities of dst, for the sake of this example. My code currently looks like below but does not work. datastore.GetMulti produces the error datastore: dst has invalid type.

type myEntity struct {
    Val Int
}

keys := []*datastore.Key{keyOne, keyTwo, keyThree}
entities := make([]myEntity, 3)
mypkg.GetStart(c, keys, enities)

My mypkg.GetStart code is as follows:

func GetStart(c appengine.Context, keys []*datastore.Key, dst interface{}) error{
    v := reflect.ValueOf(dst)
    dstSlice := v.Slice(0, 2)
    return datastore.GetMulti(c, keys, dstSlice)
}

How can I make this work? Note this is a follow up question to How to sub slice an interface{} that is a slice?

Answer 1

I got this to work by adding Interface() to dstSlice:

func GetStart(c appengine.Context, keys []*datastore.Key, dst interface{}) error{
    v := reflect.ValueOf(dst)
    dstSlice := v.Slice(0, 2)
    return datastore.GetMulti(c, keys, dstSlice.Interface())
}