nostr-rs-relay/src/conn.rs

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//! Client connection state
use crate::close::Close;
use crate::error::Error;
use crate::error::Result;
use crate::event::Event;
use crate::subscription::Subscription;
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use log::{debug, info};
use std::collections::HashMap;
use uuid::Uuid;
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/// A subscription identifier has a maximum length
const MAX_SUBSCRIPTION_ID_LEN: usize = 256;
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/// State for a client connection
pub struct ClientConn {
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/// Unique client identifier generated at connection time
client_id: Uuid,
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/// The current set of active client subscriptions
subscriptions: HashMap<String, Subscription>,
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/// Per-connection maximum concurrent subscriptions
max_subs: usize,
}
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impl Default for ClientConn {
fn default() -> Self {
Self::new()
}
}
impl ClientConn {
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/// Create a new, empty connection state.
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#[must_use]
pub fn new() -> Self {
let client_id = Uuid::new_v4();
ClientConn {
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client_id,
subscriptions: HashMap::new(),
max_subs: 32,
}
}
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/// Get a short prefix of the client's unique identifier, suitable
/// for logging.
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#[must_use]
pub fn get_client_prefix(&self) -> String {
self.client_id.to_string().chars().take(8).collect()
}
/// Find all matching subscriptions.
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#[must_use]
pub fn get_matching_subscriptions(&self, e: &Event) -> Vec<&str> {
let mut v: Vec<&str> = vec![];
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for (id, sub) in &self.subscriptions {
if sub.interested_in_event(e) {
v.push(id);
}
}
v
}
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/// Add a new subscription for this connection.
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/// # Errors
///
/// Will return `Err` if the client has too many subscriptions, or
/// if the provided name is excessively long.
pub fn subscribe(&mut self, s: Subscription) -> Result<()> {
let k = s.get_id();
let sub_id_len = k.len();
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// prevent arbitrarily long subscription identifiers from
// being used.
if sub_id_len > MAX_SUBSCRIPTION_ID_LEN {
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info!(
"ignoring sub request with excessive length: ({})",
sub_id_len
);
return Err(Error::SubIdMaxLengthError);
}
// check if an existing subscription exists, and replace if so
if self.subscriptions.contains_key(&k) {
self.subscriptions.remove(&k);
self.subscriptions.insert(k, s);
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debug!("replaced existing subscription");
return Ok(());
}
// check if there is room for another subscription.
if self.subscriptions.len() >= self.max_subs {
return Err(Error::SubMaxExceededError);
}
// add subscription
self.subscriptions.insert(k, s);
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debug!(
"registered new subscription, currently have {} active subs",
self.subscriptions.len()
);
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Ok(())
}
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/// Remove the subscription for this connection.
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pub fn unsubscribe(&mut self, c: &Close) {
// TODO: return notice if subscription did not exist.
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self.subscriptions.remove(&c.id);
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debug!(
"removed subscription, currently have {} active subs (cid={})",
self.subscriptions.len(),
self.client_id
);
}
}