Attribute Macro cached_proc_macro::io_cached

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#[io_cached]
Expand description

Define a memoized function using a cache store that implements cached::IOCached (and cached::IOCachedAsync for async functions)

Attributes

  • map_error: (string, expr closure) specify a closure used to map any IO-store errors into the error type returned by your function.
  • name: (optional, string) specify the name for the generated cache, defaults to the function name uppercase.
  • redis: (optional, bool) default to a RedisCache or AsyncRedisCache
  • time: (optional, u64) specify a cache TTL in seconds, implies the cache type is a TimedCached or TimedSizedCache.
  • time_refresh: (optional, bool) specify whether to refresh the TTL on cache hits.
  • type: (optional, string type) explicitly specify the cache store type to use.
  • cache_prefix_block: (optional, string expr) specify an expression used to create the string used as a prefix for all cache keys of this function, e.g. cache_prefix_block = r##"{ "my_prefix" }"##. When not specified, the cache prefix will be constructed from the name of the function. This could result in unexpected conflicts between io_cached-functions of the same name, so it’s recommended that you specify a prefix you’re sure will be unique.
  • create: (optional, string expr) specify an expression used to create a new cache store, e.g. create = r##"{ CacheType::new() }"##.
  • key: (optional, string type) specify what type to use for the cache key, e.g. type = "TimedCached<u32, u32>". When key is specified, convert must also be specified.
  • convert: (optional, string expr) specify an expression used to convert function arguments to a cache key, e.g. convert = r##"{ format!("{}:{}", arg1, arg2) }"##. When convert is specified, key or type must also be set.
  • with_cached_flag: (optional, bool) If your function returns a cached::Return or Result<cached::Return, E>, the cached::Return.was_cached flag will be updated when a cached value is returned.

Note

The type, create, key, and convert attributes must be in a String This is because darling, which is used for parsing the attributes, does not support directly parsing attributes into Types or Blocks.