connection: interpolate json.RawMessage as string (#1058)

json encoded data is represented as bytes however it should be interpolated as a string

Fixes #819

AUTHORS

@@ -13,6 +13,7 @@
 
 Aaron Hopkins <go-sql-driver at die.net>
 Achille Roussel <achille.roussel at gmail.com>
+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>

connection.go

@@ -12,6 +12,7 @@ import (
 	"context"
 	"database/sql"
 	"database/sql/driver"
+	"encoding/json"
 	"io"
 	"net"
 	"strconv"
@@ -271,6 +272,14 @@ func (mc *mysqlConn) interpolateParams(query string, args []driver.Value) (strin
 				}
 				buf = append(buf, '\'')
 			}
+		case json.RawMessage:
+			buf = append(buf, '\'')
+			if mc.status&statusNoBackslashEscapes == 0 {
+				buf = escapeBytesBackslash(buf, v)
+			} else {
+				buf = escapeBytesQuotes(buf, v)
+			}
+			buf = append(buf, '\'')
 		case []byte:
 			if v == nil {
 				buf = append(buf, "NULL"...)

connection_test.go

@@ -11,6 +11,7 @@ package mysql
 import (
 	"context"
 	"database/sql/driver"
+	"encoding/json"
 	"errors"
 	"net"
 	"testing"
@@ -36,6 +37,33 @@ func TestInterpolateParams(t *testing.T) {
 	}
 }
 
+func TestInterpolateParamsJSONRawMessage(t *testing.T) {
+	mc := &mysqlConn{
+		buf:              newBuffer(nil),
+		maxAllowedPacket: maxPacketSize,
+		cfg: &Config{
+			InterpolateParams: true,
+		},
+	}
+
+	buf, err := json.Marshal(struct {
+		Value int `json:"value"`
+	}{Value: 42})
+	if err != nil {
+		t.Errorf("Expected err=nil, got %#v", err)
+		return
+	}
+	q, err := mc.interpolateParams("SELECT ?", []driver.Value{json.RawMessage(buf)})
+	if err != nil {
+		t.Errorf("Expected err=nil, got %#v", err)
+		return
+	}
+	expected := `SELECT '{\"value\":42}'`
+	if q != expected {
+		t.Errorf("Expected: %q\nGot: %q", expected, q)
+	}
+}
+
 func TestInterpolateParamsTooManyPlaceholders(t *testing.T) {
 	mc := &mysqlConn{
 		buf:              newBuffer(nil),