lemmy/lemmy_rate_limit/src/rate_limiter.rs

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use lemmy_utils::{APIError, IPAddr, LemmyError};
2020-05-16 14:04:08 +00:00
use log::debug;
use std::{collections::HashMap, time::SystemTime};
use strum::IntoEnumIterator;
#[derive(Debug, Clone)]
pub struct RateLimitBucket {
last_checked: SystemTime,
allowance: f64,
}
#[derive(Eq, PartialEq, Hash, Debug, EnumIter, Copy, Clone, AsRefStr)]
pub enum RateLimitType {
Message,
Register,
Post,
Image,
}
/// Rate limiting based on rate type and IP addr
#[derive(Debug, Clone)]
pub struct RateLimiter {
pub buckets: HashMap<RateLimitType, HashMap<IPAddr, RateLimitBucket>>,
}
impl Default for RateLimiter {
fn default() -> Self {
Self {
buckets: HashMap::<RateLimitType, HashMap<IPAddr, RateLimitBucket>>::new(),
}
}
}
impl RateLimiter {
fn insert_ip(&mut self, ip: &str) {
for rate_limit_type in RateLimitType::iter() {
if self.buckets.get(&rate_limit_type).is_none() {
self.buckets.insert(rate_limit_type, HashMap::new());
}
if let Some(bucket) = self.buckets.get_mut(&rate_limit_type) {
if bucket.get(ip).is_none() {
bucket.insert(
ip.to_string(),
RateLimitBucket {
last_checked: SystemTime::now(),
allowance: -2f64,
},
);
}
}
}
}
#[allow(clippy::float_cmp)]
pub(super) fn check_rate_limit_full(
&mut self,
type_: RateLimitType,
ip: &str,
rate: i32,
per: i32,
check_only: bool,
) -> Result<(), LemmyError> {
self.insert_ip(ip);
if let Some(bucket) = self.buckets.get_mut(&type_) {
if let Some(rate_limit) = bucket.get_mut(ip) {
let current = SystemTime::now();
let time_passed = current.duration_since(rate_limit.last_checked)?.as_secs() as f64;
// The initial value
if rate_limit.allowance == -2f64 {
rate_limit.allowance = rate as f64;
};
rate_limit.last_checked = current;
rate_limit.allowance += time_passed * (rate as f64 / per as f64);
if !check_only && rate_limit.allowance > rate as f64 {
rate_limit.allowance = rate as f64;
}
if rate_limit.allowance < 1.0 {
debug!(
"Rate limited type: {}, IP: {}, time_passed: {}, allowance: {}",
type_.as_ref(),
ip,
time_passed,
rate_limit.allowance
);
Err(
APIError {
message: format!(
"Too many requests. type: {}, IP: {}, {} per {} seconds",
type_.as_ref(),
ip,
rate,
per
),
}
.into(),
)
} else {
if !check_only {
rate_limit.allowance -= 1.0;
}
Ok(())
}
} else {
Ok(())
}
} else {
Ok(())
}
}
}