Module solana_pubsub_client::pubsub_client

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Expand description

A client for subscribing to messages from the RPC server.

The PubsubClient implements Solana WebSocket event subscriptions.

This is a blocking API. For a non-blocking API use the asynchronous client in crate::nonblocking::pubsub_client.

PubsubClient contains static methods to subscribe to events, like PubsubClient::account_subscribe. These methods each return their own subscription type, like AccountSubscription, that are typedefs of tuples, the first element being a handle to the subscription, like AccountSubscription, the second a Receiver of RpcResponse of whichever type is appropriate for the subscription. The subscription handle is a typedef of PubsubClientSubscription, and it must remain live for the receiver to continue receiving messages.

Because this is a blocking API, with blocking receivers, a reasonable pattern for using this API is to move each event receiver to its own thread to block on messages, while holding all subscription handles on a single primary thread.

While PubsubClientSubscription contains methods for shutting down, PubsubClientSubscription::send_unsubscribe, and PubsubClientSubscription::shutdown, because its internal receivers block on events from the server, these subscriptions cannot actually be shutdown reliably. For a non-blocking, cancelable API, use the asynchronous client in crate::nonblocking::pubsub_client.

By default the block_subscribe and vote_subscribe events are disabled on RPC nodes. They can be enabled by passing --rpc-pubsub-enable-block-subscription and --rpc-pubsub-enable-vote-subscription to solana-validator. When these methods are disabled, the RPC server will return a “Method not found” error message.

Examples

This example subscribes to account events and then loops forever receiving them.

use anyhow::Result;
use solana_sdk::commitment_config::CommitmentConfig;
use solana_pubsub_client::pubsub_client::PubsubClient;
use solana_rpc_client_api::config::RpcAccountInfoConfig;
use solana_sdk::pubkey::Pubkey;
use std::thread;

fn get_account_updates(account_pubkey: Pubkey) -> Result<()> {
    let url = "wss://api.devnet.solana.com/";

    let (mut account_subscription_client, account_subscription_receiver) =
        PubsubClient::account_subscribe(
            url,
            &account_pubkey,
            Some(RpcAccountInfoConfig {
                encoding: None,
                data_slice: None,
                commitment: Some(CommitmentConfig::confirmed()),
                min_context_slot: None,
            }),
        )?;

    loop {
        match account_subscription_receiver.recv() {
            Ok(response) => {
                println!("account subscription response: {:?}", response);
            }
            Err(e) => {
                println!("account subscription error: {:?}", e);
                break;
            }
        }
    }

    Ok(())
}

Re-exports

Structs

Type Aliases