stmt: add json.RawMessage for converter and prepared statement (go-sql-driver#1059)

Following go-sql-driver#1058, in order for the driver.Value to get as a json.RawMessage,
the converter should accept it as a valid value, and handle it as bytes in
case where interpolation is disabled

Author: a8m

AUTHORS

@@ -17,6 +17,7 @@ Alex Snast <alexsn at fb.com>
 Alexey Palazhchenko <alexey.palazhchenko at gmail.com>
 Andrew Reid <andrew.reid at tixtrack.com>
 Arne Hormann <arnehormann at gmail.com>
+Ariel Mashraki <ariel at mashraki.co.il>
 Asta Xie <xiemengjun at gmail.com>
 Bulat Gaifullin <gaifullinbf at gmail.com>
 Carlos Nieto <jose.carlos at menteslibres.net>

driver_test.go

@@ -14,6 +14,7 @@ import (
 	"crypto/tls"
 	"database/sql"
 	"database/sql/driver"
+	"encoding/json"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -559,6 +560,29 @@ func TestRawBytes(t *testing.T) {
 	})
 }
 
+func TestRawMessage(t *testing.T) {
+	runTests(t, dsn, func(dbt *DBTest) {
+		v1 := json.RawMessage("{}")
+		v2 := json.RawMessage("[]")
+		rows := dbt.mustQuery("SELECT ?, ?", v1, v2)
+		defer rows.Close()
+		if rows.Next() {
+			var o1, o2 json.RawMessage
+			if err := rows.Scan(&o1, &o2); err != nil {
+				dbt.Errorf("Got error: %v", err)
+			}
+			if !bytes.Equal(v1, o1) {
+				dbt.Errorf("expected %v, got %v", v1, o1)
+			}
+			if !bytes.Equal(v2, o2) {
+				dbt.Errorf("expected %v, got %v", v2, o2)
+			}
+		} else {
+			dbt.Errorf("no data")
+		}
+	})
+}
+
 type testValuer struct {
 	value string
 }

packets.go

@@ -13,6 +13,7 @@ import (
 	"crypto/tls"
 	"database/sql/driver"
 	"encoding/binary"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -1003,6 +1004,9 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
 				continue
 			}
 
+			if v, ok := arg.(json.RawMessage); ok {
+				arg = []byte(v)
+			}
 			// cache types and values
 			switch v := arg.(type) {
 			case int64:

statement.go

@@ -10,6 +10,7 @@ package mysql
 
 import (
 	"database/sql/driver"
+	"encoding/json"
 	"fmt"
 	"io"
 	"reflect"
@@ -129,6 +130,8 @@ func (stmt *mysqlStmt) query(args []driver.Value) (*binaryRows, error) {
 	return rows, err
 }
 
+var jsonType = reflect.TypeOf(json.RawMessage{})
+
 type converter struct{}
 
 // ConvertValue mirrors the reference/default converter in database/sql/driver
@@ -151,7 +154,6 @@ func (c converter) ConvertValue(v interface{}) (driver.Value, error) {
 		}
 		return sv, nil
 	}
-
 	rv := reflect.ValueOf(v)
 	switch rv.Kind() {
 	case reflect.Ptr:
@@ -170,11 +172,14 @@ func (c converter) ConvertValue(v interface{}) (driver.Value, error) {
 	case reflect.Bool:
 		return rv.Bool(), nil
 	case reflect.Slice:
-		ek := rv.Type().Elem().Kind()
-		if ek == reflect.Uint8 {
+		switch t := rv.Type(); {
+		case t == jsonType:
+			return v, nil
+		case t.Elem().Kind() == reflect.Uint8:
 			return rv.Bytes(), nil
+		default:
+			return nil, fmt.Errorf("unsupported type %T, a slice of %s", v, t.Elem().Kind())
 		}
-		return nil, fmt.Errorf("unsupported type %T, a slice of %s", v, ek)
 	case reflect.String:
 		return rv.String(), nil
 	}

statement_test.go

@@ -10,6 +10,7 @@ package mysql
 
 import (
 	"bytes"
+	"encoding/json"
 	"testing"
 )
 
@@ -124,3 +125,17 @@ func TestConvertUnsignedIntegers(t *testing.T) {
 		t.Fatalf("uint64 high-bit converted, got %#v %T", output, output)
 	}
 }
+
+func TestConvertJSON(t *testing.T) {
+	raw := json.RawMessage("{}")
+
+	out, err := converter{}.ConvertValue(raw)
+
+	if err != nil {
+		t.Fatal("json.RawMessage was failed in convert", err)
+	}
+
+	if _, ok := out.(json.RawMessage); !ok {
+		t.Fatalf("json.RawMessage converted, got %#v %T", out, out)
+	}
+}