Fetch returns expired items

[dvdplm]

I would expect Fetch() to behave a little differently and not return stale items. Instead it seems like the fetch function argument is invoked only if the item is missing entirely from the cache. Would you be open to PRs changing that behavior, or provide a FetchAndRefresh() that runs the fetch function both if the item is expired and missing?

Essentially this:

func (c *Cache) Fetch(key string, duration time.Duration, fetch func() (interface{}, error)) (*Item, error) {
    item := c.Get(key)
    if item != nil && !item.Expired() {
        return item, nil
    }
    value, err := fetch()
    if err != nil {
        return nil, err
    }
    return c.set(key, value, duration), nil
}

[karlseguin]

I think changing the behavior of Fetch is warranted. Anyone who possibly wants a stale value can achieve it themselves. PR welcomed

[dvdplm]

See PR #5

[utrack]

I think it can be closed?

[dvdplm]

I agree.