Struct Client

Source

pub struct Client<'fd> { /* private fields */ }

Expand description

Active blocking ClickHouse connection.

Client owns C connection, I/O transport, and optional compression codec.

Implementations§

Source §

impl<'fd> Client<'fd>

Source

pub fn init<I: Io + Send + 'fd>( opts: &ClientOpts, alloc: Allocator, io: Pin<Box>, codec: Option<Pin<Box<Codec>>>, ) -> Result<Self>

Creates client and completes Hello handshake using supplied transport.

Method takes ownership of io and codec. io can be PosixIo, tls::TlsIo, or custom Io implementation.

codec can be None only when compression is disabled.

Server rejection returns ErrorKind::Server carrying exception code, class, and untruncated message.

Lifetime 'fd prevents client from outliving a borrowed file descriptor:

use clickhouse_c::{Allocator, Client, ClientOpts, PosixIo};
use std::net::TcpStream;
use std::os::fd::AsFd;

fn build() -> clickhouse_c::Result<Client<'static>> {
    let sock = TcpStream::connect("localhost:9000")?;
    let io = PosixIo::new(sock.as_fd());
    // Borrowed socket cannot produce Client<'static>.
    Client::init(&ClientOpts::new(), Allocator::stdlib(), io, None)
}

Source

pub fn server_info(&self) -> Option<ServerInfo>

Returns server information received during handshake.

Source

pub fn set_read_timeout(&mut self, timeout: Option<Duration>) -> Result<()>

Sets transport read timeout.

PosixIo uses an absolute deadline. Set timeout again before each operation that requires a fresh deadline.

Source

pub fn send_query(&mut self, sql: &str, query_id: Option<&str>) -> Result<()>

Sends a query without settings or parameters.

Server profile supplies all query settings. Use QuerySetting::TEXT_TYPE_NAMES with send_query_with when profile may enable binary type names.

Source

pub fn send_query_with(&mut self, sql: &str, opts: &QueryOpts<'_>) -> Result<()>

Sends a query with settings and {name:Type} parameters.

use clickhouse_c::{QueryOpts, QueryParam, QuerySetting};
let settings = [
    QuerySetting::TEXT_TYPE_NAMES,
    QuerySetting::new("max_block_size", "8192"),
];
let params = [QueryParam::new("cutoff", "'100'")];
client.send_query_with(
    "SELECT number FROM numbers(1000) WHERE number > {cutoff:UInt64}",
    &QueryOpts::new().settings(&settings).params(&params),
)?;

Source

pub fn send_data(&mut self, builder: Option<&BlockBuilder<'_>>) -> Result<()>

Sends a Data block.

None sends empty block that ends INSERT input.

Source

pub fn send_cancel(&mut self) -> Result<()>

Sends protocol Cancel packet for active query.

Continue receiving events until Event::EndOfStream because packets already sent by server can still arrive. Use CancelToken to cancel local reads without sending a packet.

Source