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dorm/vendor/github.com/mailru/go-clickhouse/v2/conn_go18.go

89 lines
2.2 KiB

//go:build go1.8
// +build go1.8
package clickhouse
import (
"context"
"database/sql/driver"
"fmt"
"io/ioutil"
"strings"
)
// pingExpectedPrefix represents expected answer for "SELECT 1" query
const pingExpectedPrefix = "1"
// Ping implements the driver.Pinger
func (c *conn) Ping(ctx context.Context) error {
if c.transport == nil {
return ErrTransportNil
}
req, err := c.buildRequest(ctx, "select 1", nil)
if err != nil {
return err
}
respBody, err := c.doRequest(ctx, req)
defer func() {
c.cancel = nil
}()
if err != nil {
return err
}
// Close response body to enable connection reuse
defer respBody.Close()
// drain the response body to check if we got expected `1`
resp, err := ioutil.ReadAll(respBody)
if err != nil {
return fmt.Errorf("ping: failed to read the response: %w", err)
}
if !strings.HasPrefix(string(resp), pingExpectedPrefix) {
return fmt.Errorf("ping: failed to get expected result (1), got '%s' instead", string(resp))
}
return nil
}
// BeginTx implements the driver.ConnBeginTx
func (c *conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
return c.beginTx(ctx)
}
// PrepareContext implements the driver.ConnPrepareContext
func (c *conn) PrepareContext(_ context.Context, query string) (driver.Stmt, error) {
return c.prepare(query)
}
// ExecContext implements the driver.ExecerContext
func (c *conn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
values, err := namedValueToValue(args)
if err != nil {
return nil, err
}
return c.exec(ctx, query, values)
}
// QueryContext implements the driver.QueryerContext
func (c *conn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
values, err := namedValueToValue(args)
if err != nil {
return nil, err
}
return c.query(ctx, query, values)
}
func namedValueToValue(named []driver.NamedValue) ([]driver.Value, error) {
dargs := make([]driver.Value, len(named))
for n, param := range named {
if len(param.Name) > 0 {
// TODO: support the use of Named Parameters #561
return nil, ErrNameParams
}
dargs[n] = param.Value
}
return dargs, nil
}