Struct DefaultBackend 

pub struct DefaultBackend { /* private fields */ }

Available on crate feature memorydb only.

Built-in in-process memory database backend.

Keys and values live in a HashMap guarded by an RwLock; expired entries are removed lazily on access, plus eagerly during capacity-driven GC.

Warning

The default backend is only for demo purpose. The performance is not guaranteed. Use RedisBackend or your own MemoryDB implementation for production workloads.

When capacity is set and the database is full, the eviction policy is:

• Evict 10% keys at a time (at least 1).
• Expired keys go first, then keys having TTL attribute, sorted by TTL from shortest to longest.
• If no keys are evicted, an error will be returned.

Implementations

impl DefaultBackend

pub fn new(capacity: Option<usize>) -> Self

Create a new backend.

capacity limits the maximum number of entries (None means unbounded — be aware that this allows memory exhaustion).

Trait Implementations

impl Clone for DefaultBackend

fn clone(&self) -> DefaultBackend

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for DefaultBackend

fn default() -> Self

Returns the “default value” for a type.

impl MemoryDB for DefaultBackend

fn set<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, key: &'life1 str, value: &'life2 str, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Set key to value without expiration.

fn get<'life0, 'life1, 'async_trait>( &'life0 self, key: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<Option<String>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Get the value of key, or None if it does not exist or has expired.

fn get_del<'life0, 'life1, 'async_trait>( &'life0 self, key: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<Option<String>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Get the value of key and delete it atomically.

fn get_ex<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, key: &'life1 str, ttl: &'life2 Duration, ) -> Pin<Box<dyn Future<Output = Result<Option<String>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Get the value of key and reset its TTL to ttl.

fn set_ex<'life0, 'life1, 'life2, 'life3, 'async_trait>( &'life0 self, key: &'life1 str, value: &'life2 str, ttl: &'life3 Duration, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait, 'life3: 'async_trait,

Set key to value with an expiration of ttl.

fn del<'life0, 'life1, 'async_trait>( &'life0 self, key: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<bool>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Delete key. Returns whether the key existed.

fn expire<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, key: &'life1 str, ttl: &'life2 Duration, ) -> Pin<Box<dyn Future<Output = Result<bool>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Set the TTL of key to ttl. Returns whether the key exists. A zero ttl deletes the key.

fn flush<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Remove all keys from the database.

fn keys<'life0, 'life1, 'async_trait>( &'life0 self, key: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<Vec<String>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Get all keys matching the glob key pattern (e.g. prefix*).

fn dels<'life0, 'life1, 'async_trait>( &'life0 self, keys: &'life1 [String], ) -> Pin<Box<dyn Future<Output = Result<u64>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Delete multiple keys. Returns the number of keys deleted.

fn ttl<'life0, 'life1, 'async_trait>( &'life0 self, key: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<Option<Duration>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Get the remaining TTL of key, or None if the key does not exist or has no TTL.