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package pq
import (
"context"
"database/sql/driver"
"errors"
"fmt"
"os"
"strings"
)
// Connector represents a fixed configuration for the pq driver with a given
// name. Connector satisfies the database/sql/driver Connector interface and
// can be used to create any number of DB Conn's via the database/sql OpenDB
// function.
//
// See https://golang.org/pkg/database/sql/driver/#Connector.
// See https://golang.org/pkg/database/sql/#OpenDB.
type Connector struct {
opts values
dialer Dialer
}
// Connect returns a connection to the database using the fixed configuration
// of this Connector. Context is not used.
func (c *Connector) Connect(ctx context.Context) (driver.Conn, error) {
return c.open(ctx)
}
// Driver returnst the underlying driver of this Connector.
func (c *Connector) Driver() driver.Driver {
return &Driver{}
}
// NewConnector returns a connector for the pq driver in a fixed configuration
// with the given dsn. The returned connector can be used to create any number
// of equivalent Conn's. The returned connector is intended to be used with
// database/sql.OpenDB.
//
// See https://golang.org/pkg/database/sql/driver/#Connector.
// See https://golang.org/pkg/database/sql/#OpenDB.
func NewConnector(dsn string) (*Connector, error) {
var err error
o := make(values)
// A number of defaults are applied here, in this order:
//
// * Very low precedence defaults applied in every situation
// * Environment variables
// * Explicitly passed connection information
o["host"] = "localhost"
o["port"] = "5432"
// N.B.: Extra float digits should be set to 3, but that breaks
// Postgres 8.4 and older, where the max is 2.
o["extra_float_digits"] = "2"
for k, v := range parseEnviron(os.Environ()) {
o[k] = v
}
if strings.HasPrefix(dsn, "postgres://") || strings.HasPrefix(dsn, "postgresql://") {
dsn, err = ParseURL(dsn)
if err != nil {
return nil, err
}
}
if err := parseOpts(dsn, o); err != nil {
return nil, err
}
// Use the "fallback" application name if necessary
if fallback, ok := o["fallback_application_name"]; ok {
if _, ok := o["application_name"]; !ok {
o["application_name"] = fallback
}
}
// We can't work with any client_encoding other than UTF-8 currently.
// However, we have historically allowed the user to set it to UTF-8
// explicitly, and there's no reason to break such programs, so allow that.
// Note that the "options" setting could also set client_encoding, but
// parsing its value is not worth it. Instead, we always explicitly send
// client_encoding as a separate run-time parameter, which should override
// anything set in options.
if enc, ok := o["client_encoding"]; ok && !isUTF8(enc) {
return nil, errors.New("client_encoding must be absent or 'UTF8'")
}
o["client_encoding"] = "UTF8"
// DateStyle needs a similar treatment.
if datestyle, ok := o["datestyle"]; ok {
if datestyle != "ISO, MDY" {
return nil, fmt.Errorf("setting datestyle must be absent or %v; got %v", "ISO, MDY", datestyle)
}
} else {
o["datestyle"] = "ISO, MDY"
}
// If a user is not provided by any other means, the last
// resort is to use the current operating system provided user
// name.
if _, ok := o["user"]; !ok {
u, err := userCurrent()
if err != nil {
return nil, err
}
o["user"] = u
}
return &Connector{opts: o, dialer: defaultDialer{}}, nil
}
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