Configuration

Each query or infinite query can be configured using the QueryConfig.

final config = QueryConfig(
  storageSerializer: null,
  storageDeserializer: null,
  ignoreCacheDuration: false,
  storeQuery: true,
  refetchDuration: Duration(seconds: 4),
  cacheDuration: Duration(minutes: 5),
  shouldRethrow: false,
  shouldRefetch: null,
);

Refetch Duration

The refetchDuration, which defaults to 4 seconds is the amount of time after a request and before the data is marked as stale. So if a query is requested twice in 4 seconds there will be no call made to the queryFn, however, if a request is made after 4 seconds the data will be assumed to be stale and re-fetched in the background.

Cache Duration

The cacheDuration is the length of time between the last listener being removed from a query and the query being deleted from the cache. The time can be ignored completely using ignoreCacheDuration, however using this would mean the query is never removed from memory.

Serialization

The storageSerializer and storageDeserializer are used to transform the data to and from the storage interface. If you are using Cached Storage then the data is always stored as json, so you would use the storageSerializer to turn it back to the required object. Individually choose to store a query or not with storeQuery.

Should Rethrow

By default, a query catches any error and emits it as part of the query state. However, in development it is sometimes useful to have the query rethrow to quickly see the full stacktrace in the console, to do this set shouldRethrow to true.

caution

Using shouldRethrow can cause unexpected errors as it prevents most things from happening after an error has occurred.

Should Refetch

Should refetch callback is rarely necessary but it can offer more flexibility on when a query should be automatically re-fetched. By default the should refetch callback is null, this is the recommended setting and in most cases you will not need to use it.

QueryConfig(
  shouldRefetch: (query, fromStorage) => true,
);

It is before a query is automatically re-fetched and after any data is fetched from storage. It passes the query and a boolean to mark if the data was fetched from storage. If the function returns false then the query will not be re-fetched.

This does not effect the Query.refetch method.

Global Configuration

Global configuration allows defaults to be set for all queries. Using the QueryConfig on an individual query will always override the global default. To set global defaults pass a config to the cached query instance before any queries are called.

CachedQuery.instance.config(
  config: QueryConfig(
    refetchDuration: Duration(seconds: 10),
    cacheDuration: Duration(minutes: 2),
  ),
);