Add substitutePlaceholder option to DSN

connection.go

@@ -34,19 +34,20 @@ type mysqlConn struct {
 }
 
 type config struct {
-	user              string
-	passwd            string
-	net               string
-	addr              string
-	dbname            string
-	params            map[string]string
-	loc               *time.Location
-	tls               *tls.Config
-	timeout           time.Duration
-	collation         uint8
-	allowAllFiles     bool
-	allowOldPasswords bool
-	clientFoundRows   bool
+	user                  string
+	passwd                string
+	net                   string
+	addr                  string
+	dbname                string
+	params                map[string]string
+	loc                   *time.Location
+	tls                   *tls.Config
+	timeout               time.Duration
+	collation             uint8
+	allowAllFiles         bool
+	allowOldPasswords     bool
+	clientFoundRows       bool
+	substitutePlaceholder bool
 }
 
 // Handles parameters set in DSN after the connection is established
@@ -281,6 +282,9 @@ func (mc *mysqlConn) Exec(query string, args []driver.Value) (driver.Result, err
 		return nil, driver.ErrBadConn
 	}
 	if len(args) != 0 {
+		if !mc.cfg.substitutePlaceholder {
+			return nil, driver.ErrSkip
+		}
 		// try client-side prepare to reduce roundtrip
 		prepared, err := mc.buildQuery(query, args)
 		if err != nil {
@@ -329,6 +333,9 @@ func (mc *mysqlConn) Query(query string, args []driver.Value) (driver.Rows, erro
 		return nil, driver.ErrBadConn
 	}
 	if len(args) != 0 {
+		if !mc.cfg.substitutePlaceholder {
+			return nil, driver.ErrSkip
+		}
 		// try client-side prepare to reduce roundtrip
 		prepared, err := mc.buildQuery(query, args)
 		if err != nil {

driver_test.go

@@ -87,10 +87,19 @@ func runTests(t *testing.T, dsn string, tests ...func(dbt *DBTest)) {
 
 	db.Exec("DROP TABLE IF EXISTS test")
 
+	dbp, err := sql.Open("mysql", dsn+"&substitutePlaceholder=true")
+	if err != nil {
+		t.Fatalf("Error connecting: %s", err.Error())
+	}
+	defer dbp.Close()
+
 	dbt := &DBTest{t, db}
+	dbtp := &DBTest{t, dbp}
 	for _, test := range tests {
 		test(dbt)
 		dbt.db.Exec("DROP TABLE IF EXISTS test")
+		test(dbtp)
+		dbtp.db.Exec("DROP TABLE IF EXISTS test")
 	}
 }
 

utils.go

@@ -180,6 +180,14 @@ func parseDSNParams(cfg *config, params string) (err error) {
 		// cfg params
 		switch value := param[1]; param[0] {
 
+		// Enable client side placeholder substitution
+		case "substitutePlaceholder":
+			var isBool bool
+			cfg.substitutePlaceholder, isBool = readBool(value)
+			if !isBool {
+				return fmt.Errorf("Invalid Bool value: %s", value)
+			}
+
 		// Disable INFILE whitelist / enable all files
 		case "allowAllFiles":
 			var isBool bool

utils_test.go

@@ -22,18 +22,18 @@ var testDSNs = []struct {
 	out string
 	loc *time.Location
 }{
-	{"username:password@protocol(address)/dbname?param=value", "&{user:username passwd:password net:protocol addr:address dbname:dbname params:map[param:value] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false}", time.UTC},
-	{"user@unix(/path/to/socket)/dbname?charset=utf8", "&{user:user passwd: net:unix addr:/path/to/socket dbname:dbname params:map[charset:utf8] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false}", time.UTC},
-	{"user:password@tcp(localhost:5555)/dbname?charset=utf8&tls=true", "&{user:user passwd:password net:tcp addr:localhost:5555 dbname:dbname params:map[charset:utf8] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false}", time.UTC},
-	{"user:password@tcp(localhost:5555)/dbname?charset=utf8mb4,utf8&tls=skip-verify", "&{user:user passwd:password net:tcp addr:localhost:5555 dbname:dbname params:map[charset:utf8mb4,utf8] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false}", time.UTC},
-	{"user:password@/dbname?loc=UTC&timeout=30s&allowAllFiles=1&clientFoundRows=true&allowOldPasswords=TRUE&collation=utf8mb4_unicode_ci", "&{user:user passwd:password net:tcp addr:127.0.0.1:3306 dbname:dbname params:map[] loc:%p tls:<nil> timeout:30000000000 collation:224 allowAllFiles:true allowOldPasswords:true clientFoundRows:true}", time.UTC},
-	{"user:p@ss(word)@tcp([de:ad:be:ef::ca:fe]:80)/dbname?loc=Local", "&{user:user passwd:p@ss(word) net:tcp addr:[de:ad:be:ef::ca:fe]:80 dbname:dbname params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false}", time.Local},
-	{"/dbname", "&{user: passwd: net:tcp addr:127.0.0.1:3306 dbname:dbname params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false}", time.UTC},
-	{"@/", "&{user: passwd: net:tcp addr:127.0.0.1:3306 dbname: params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false}", time.UTC},
-	{"/", "&{user: passwd: net:tcp addr:127.0.0.1:3306 dbname: params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false}", time.UTC},
-	{"", "&{user: passwd: net:tcp addr:127.0.0.1:3306 dbname: params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false}", time.UTC},
-	{"user:p@/ssword@/", "&{user:user passwd:p@/ssword net:tcp addr:127.0.0.1:3306 dbname: params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false}", time.UTC},
-	{"unix/?arg=%2Fsome%2Fpath.ext", "&{user: passwd: net:unix addr:/tmp/mysql.sock dbname: params:map[arg:/some/path.ext] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false}", time.UTC},
+	{"username:password@protocol(address)/dbname?param=value", "&{user:username passwd:password net:protocol addr:address dbname:dbname params:map[param:value] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false substitutePlaceholder:false}", time.UTC},
+	{"user@unix(/path/to/socket)/dbname?charset=utf8", "&{user:user passwd: net:unix addr:/path/to/socket dbname:dbname params:map[charset:utf8] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false substitutePlaceholder:false}", time.UTC},
+	{"user:password@tcp(localhost:5555)/dbname?charset=utf8&tls=true", "&{user:user passwd:password net:tcp addr:localhost:5555 dbname:dbname params:map[charset:utf8] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false substitutePlaceholder:false}", time.UTC},
+	{"user:password@tcp(localhost:5555)/dbname?charset=utf8mb4,utf8&tls=skip-verify", "&{user:user passwd:password net:tcp addr:localhost:5555 dbname:dbname params:map[charset:utf8mb4,utf8] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false substitutePlaceholder:false}", time.UTC},
+	{"user:password@/dbname?loc=UTC&timeout=30s&allowAllFiles=1&clientFoundRows=true&allowOldPasswords=TRUE&collation=utf8mb4_unicode_ci", "&{user:user passwd:password net:tcp addr:127.0.0.1:3306 dbname:dbname params:map[] loc:%p tls:<nil> timeout:30000000000 collation:224 allowAllFiles:true allowOldPasswords:true clientFoundRows:true substitutePlaceholder:false}", time.UTC},
+	{"user:p@ss(word)@tcp([de:ad:be:ef::ca:fe]:80)/dbname?loc=Local", "&{user:user passwd:p@ss(word) net:tcp addr:[de:ad:be:ef::ca:fe]:80 dbname:dbname params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false substitutePlaceholder:false}", time.Local},
+	{"/dbname", "&{user: passwd: net:tcp addr:127.0.0.1:3306 dbname:dbname params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false substitutePlaceholder:false}", time.UTC},
+	{"@/", "&{user: passwd: net:tcp addr:127.0.0.1:3306 dbname: params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false substitutePlaceholder:false}", time.UTC},
+	{"/", "&{user: passwd: net:tcp addr:127.0.0.1:3306 dbname: params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false substitutePlaceholder:false}", time.UTC},
+	{"", "&{user: passwd: net:tcp addr:127.0.0.1:3306 dbname: params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false substitutePlaceholder:false}", time.UTC},
+	{"user:p@/ssword@/", "&{user:user passwd:p@/ssword net:tcp addr:127.0.0.1:3306 dbname: params:map[] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false substitutePlaceholder:false}", time.UTC},
+	{"unix/?arg=%2Fsome%2Fpath.ext", "&{user: passwd: net:unix addr:/tmp/mysql.sock dbname: params:map[arg:/some/path.ext] loc:%p tls:<nil> timeout:0 collation:33 allowAllFiles:false allowOldPasswords:false clientFoundRows:false substitutePlaceholder:false}", time.UTC},
 }
 
 func TestDSNParser(t *testing.T) {