# twilight-cache-inmemory
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`twilight-cache-inmemory` is an in-process-memory cache for the
[`twilight-rs`] ecosystem. It's responsible for processing events and
caching things like guilds, channels, users, and voice states.
## Statistics
Statistics can be an important debugging tool for determining how large a
cache is or determining whether a cache has an expected amount of resources
within it. An interface for retrieving statistics about the amount of a
resource within the cache as a whole or on a guild-level can be retrieved
via [`InMemoryCache::stats`].
## Features
By default no feature is enabled.
### `permission-calculator`
The `permission-calculator` feature flag will bring in support for the
`PermissionCalculator`; an API for calculating permissions through it is
exposed via `InMemoryCache::permissions`. Support for calculating the
permissions of a member on a root guild-level and in a guild channel is
included.
Refer to the `permission` module for more documentation.
## Examples
Update a cache with events that come in through the gateway:
```rust,no_run
use std::{env, error::Error};
use twilight_cache_inmemory::InMemoryCache;
use twilight_gateway::{Intents, Shard, ShardId};
#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
// Initialize the tracing subscriber.
tracing_subscriber::fmt::init();
let token = env::var("DISCORD_TOKEN")?;
let mut shard = Shard::new(ShardId::ONE, token, Intents::GUILD_MESSAGES);
// Create a cache, caching up to 10 messages per channel:
let cache = InMemoryCache::builder().message_cache_size(10).build();
loop {
let event = match shard.next_event().await {
Ok(event) => event,
Err(source) => {
tracing::warn!(?source, "error receiving event");
if source.is_fatal() {
break;
}
continue;
}
};
// Update the cache with the event.
cache.update(&event);
}
Ok(())
}
```
## License
All first-party crates are licensed under [ISC][LICENSE.md]
[LICENSE.md]: https://github.com/twilight-rs/twilight/blob/main/LICENSE.md
[`twilight-rs`]: https://github.com/twilight-rs/twilight
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[codecov link]: https://app.codecov.io/gh/twilight-rs/twilight/
[discord badge]: https://img.shields.io/discord/745809834183753828?color=%237289DA&label=discord%20server&logo=discord&style=for-the-badge
[discord link]: https://discord.gg/7jj8n7D
[github badge]: https://img.shields.io/badge/github-twilight-6f42c1.svg?style=for-the-badge&logo=github
[github link]: https://github.com/twilight-rs/twilight
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[license link]: https://github.com/twilight-rs/twilight/blob/main/LICENSE.md
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