Golang NullString.Scan方法代碼示例

// Scan implements the Scanner interface.
func (ns *ByteSlice) Scan(value interface{}) error {
	n := sql.NullString{String: base64.StdEncoding.EncodeToString(ns.ByteSlice)}
	err := n.Scan(value)
	//ns.Float32, ns.Valid = float32(n.Float64), n.Valid
	ns.ByteSlice, err = base64.StdEncoding.DecodeString(n.String)
	ns.Valid = n.Valid
	return err
}

func (this *ERole) Scan(value interface{}) error {
	var x sql.NullString
	err := x.Scan(value)
	if !x.Valid || err != nil {
		return err
	}

	*this = ERole(x.String)
	return nil
}

func (this *Str) Scan(value interface{}) error {
	var s sql.NullString
	err := s.Scan(value)
	if !s.Valid || err != nil {
		return err
	}

	*this = Str(s.String)
	return nil
}

func main() {
	db, err := sqlx.Connect("mysql", "root:[email protected](localhost:3306)/bookszilla?parseTime=true")
	if err != nil {
		log.Fatalln(err)
	}
	db.Ping()

	for i := 1; i <= 1000; i++ {
		url := "http://wmate.ru/ebooks/book" + strconv.Itoa(i) + ".html"
		response, err := http.Get(url)
		println(url + " " + response.Status)

		if err != nil {
			fmt.Printf("%s", err)
			// os.Exit(1)
		} else if response.StatusCode == 200 {
			defer response.Body.Close()

			doc, err := goquery.NewDocumentFromResponse(response)
			if err != nil {
				log.Fatal(err)
			}

			doc.Find("article.post").Each(func(i int, s *goquery.Selection) {
				title := s.Find("h1").Text()
				println(title)

				// author := s.Find("ul.info li").Eq(2).Find("em").Text()
				// println(author)

				var desctiption sql.NullString
				desc := ""
				s.Find("p").Each(func(j int, sp *goquery.Selection) {
					desc += strings.TrimSpace(sp.Text()) + "\n"
				})

				if len(desc) > 0 {
					desctiption.Scan(desc)
				}

				// println(desctiption)

				sql := "INSERT INTO `books` (`name`, `description`) VALUES (?, ?);"
				db.Exec(sql, title, desctiption)
			})
		}
	}
}

// Input: email string, password string
// Output:
// - Success: session string
// - Failed: {}
func Login(w http.ResponseWriter, r *http.Request) {
	var email sql.NullString
	email.Scan(r.FormValue("email"))
	password := r.FormValue("password")

	user := models.User{Email: email, Password: password}

	if !repository.Login(&user) {
		w.WriteHeader(http.StatusForbidden)
		w.Write([]byte(`{"error":"Mat khau hoac email khong dung"}`))
		return
	}

	createUserToken(&user)
	repository.UpdateUser(&user)

	json.NewEncoder(w).Encode(user)
}

func TestNullTypeString(t *testing.T) {
	var b Sqlizer
	var name sql.NullString

	b = Eq{"name": name}
	sql, args, err := b.ToSql()

	assert.NoError(t, err)
	assert.Empty(t, args)
	assert.Equal(t, "name IS NULL", sql)

	name.Scan("Name")
	b = Eq{"name": name}
	sql, args, err = b.ToSql()

	assert.NoError(t, err)
	assert.Equal(t, []interface{}{"Name"}, args)
	assert.Equal(t, "name = ?", sql)
}

func (s *scanner) Scan(src interface{}) error {
	var err error

	switch s.value.Type().Kind() {
	case reflect.Struct:
		nt := mysql.NullTime{}
		err := nt.Scan(src)
		if err != nil {
			return err
		}
		s.value.Set(reflect.ValueOf(nt.Time))
	case reflect.Bool:
		nb := sql.NullBool{}
		err := nb.Scan(src)
		if err != nil {
			return err
		}
		s.value.SetBool(nb.Bool)
	case reflect.String:
		ns := sql.NullString{}
		err = ns.Scan(src)
		if err != nil {
			return err
		}
		s.value.SetString(ns.String)
	case reflect.Int64:
		ni := sql.NullInt64{}
		err = ni.Scan(src)
		if err != nil {
			return err
		}
		s.value.SetInt(ni.Int64)
	case reflect.Float64:
		ni := sql.NullFloat64{}
		err = ni.Scan(src)
		if err != nil {
			return err
		}
		s.value.SetFloat(ni.Float64)
	}
	return nil
}

func fetchResult(itemT reflect.Type, rows *sql.Rows, columns []string) (reflect.Value, error) {
	var item reflect.Value
	var err error

	switch itemT.Kind() {
	case reflect.Map:
		item = reflect.MakeMap(itemT)
	case reflect.Struct:
		item = reflect.New(itemT)
	default:
		return item, db.ErrExpectingMapOrStruct
	}

	expecting := len(columns)

	// Allocating results.
	values := make([]*sql.RawBytes, expecting)
	scanArgs := make([]interface{}, expecting)

	for i := range columns {
		scanArgs[i] = &values[i]
	}

	if err = rows.Scan(scanArgs...); err != nil {
		return item, err
	}

	// Range over row values.
	for i, value := range values {

		if value != nil {
			// Real column name
			column := columns[i]

			// Value as string.
			svalue := string(*value)

			var cv reflect.Value

			v, _ := to.Convert(svalue, reflect.String)
			cv = reflect.ValueOf(v)

			switch itemT.Kind() {
			// Destination is a map.
			case reflect.Map:
				if cv.Type() != itemT.Elem() {
					if itemT.Elem().Kind() == reflect.Interface {
						cv, _ = util.StringToType(svalue, cv.Type())
					} else {
						cv, _ = util.StringToType(svalue, itemT.Elem())
					}
				}
				if cv.IsValid() {
					item.SetMapIndex(reflect.ValueOf(column), cv)
				}
			// Destionation is a struct.
			case reflect.Struct:

				index := util.GetStructFieldIndex(itemT, column)

				if index == nil {
					continue
				} else {

					// Destination field.
					destf := item.Elem().FieldByIndex(index)

					if destf.IsValid() {

						if cv.Type() != destf.Type() {

							if destf.Type().Kind() != reflect.Interface {

								switch destf.Type() {
								case nullFloat64Type:
									nullFloat64 := sql.NullFloat64{}
									if svalue != `` {
										nullFloat64.Scan(svalue)
									}
									cv = reflect.ValueOf(nullFloat64)
								case nullInt64Type:
									nullInt64 := sql.NullInt64{}
									if svalue != `` {
										nullInt64.Scan(svalue)
									}
									cv = reflect.ValueOf(nullInt64)
								case nullBoolType:
									nullBool := sql.NullBool{}
									if svalue != `` {
										nullBool.Scan(svalue)
									}
									cv = reflect.ValueOf(nullBool)
								case nullStringType:
									nullString := sql.NullString{}
									nullString.Scan(svalue)
									cv = reflect.ValueOf(nullString)
								default:
									var decodingNull bool

									if svalue == "" {
//.........這裏部分代碼省略.........

	// "fmt"
	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
	"github.com/triitvn/instagram-go/api/models/repository"
	"net/url"
	"strconv"
)

var _ = Describe("User", func() {
	var params = url.Values{}
	params.Add("displayName", "Foo")
	params.Add("email", "[email protected]")
	params.Add("password", "123456")

	var email sql.NullString
	email.Scan("[email protected]")

	repository.DeleteUserByEmail(email)

	var userId string

	Describe("Register", func() {
		Context("Register Success", func() {
			It("should have ID", func() {

				response := Request("POST", "/user?"+params.Encode(), "")

				objmap := JsonStrToMap(response.Body)

				userId = strconv.Itoa(int(objmap["Id"].(float64)))

// Scan implements the Scanner interface.
func (ns *String) Scan(value interface{}) error {
	n := sql.NullString{String: ns.String}
	err := n.Scan(value)
	ns.String, ns.Valid = n.String, n.Valid
	return err
}