Merge pull request #7 from flycash/dev

sql: 支持 JsonColumn

.CHANGELOG.md

@@ -1,2 +1,3 @@
 # 开发中
-[ekit: add ToPtr function](https://github.com/gotomicro/ekit/pull/6)
+[ekit: add ToPtr function](https://github.com/gotomicro/ekit/pull/6)
+[sql: 支持 JsonColumn](https://github.com/gotomicro/ekit/pull/7)

sql/json.go

@@ -0,0 +1,65 @@
+// Copyright 2021 gotomicro
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sql
+
+import (
+	"database/sql"
+	"database/sql/driver"
+	"encoding/json"
+	"fmt"
+)
+
+// JsonColumn 代表存储字段的 json 类型
+// 主要用于没有提供默认 json 类型的数据库
+// T 可以是结构体，也可以是切片或者 map
+// 一切可以被 json 库所处理的类型都能被用作 T
+type JsonColumn[T any] struct {
+	Val   T
+	Valid bool
+}
+
+// Value 返回一个 json 串。类型是 []byte
+func (j JsonColumn[T]) Value() (driver.Value, error) {
+	if !j.Valid {
+		return nil, nil
+	}
+	return json.Marshal(j.Val)
+}
+
+// Scan 将 src 转化为对象
+// src 的类型必须是 []byte, *[]byte, string, sql.RawBytes, *sql.RawBytes 之一
+func (j *JsonColumn[T]) Scan(src any) error {
+	var bs []byte
+	switch val := src.(type) {
+	case []byte:
+		bs = val
+	case *[]byte:
+		bs = *val
+	case string:
+		bs = []byte(val)
+	case sql.RawBytes:
+		bs = val
+	case *sql.RawBytes:
+		bs = *val
+	default:
+		return fmt.Errorf("ekit：JsonColumn.Scan 不支持 src 类型 %v", src)
+	}
+
+	if err := json.Unmarshal(bs, &j.Val); err != nil {
+		return err
+	}
+	j.Valid = true
+	return nil
+}

sql/json_test.go

@@ -0,0 +1,141 @@
+// Copyright 2021 gotomicro
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sql
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestJsonColumn_Value(t *testing.T) {
+	js := JsonColumn[User]{Valid: true, Val: User{Name: "Tom"}}
+	value, err := js.Value()
+	assert.Nil(t, err)
+	assert.Equal(t, []byte(`{"Name":"Tom"}`), value)
+	js = JsonColumn[User]{}
+	value, err = js.Value()
+	assert.Nil(t, err)
+	assert.Nil(t, value)
+}
+
+func TestJsonColumn_Scan(t *testing.T) {
+	testCases := []struct {
+		name    string
+		src     any
+		wantErr error
+		wantVal User
+	}{
+		{
+			name:    "nil",
+			wantErr: errors.New("ekit：JsonColumn.Scan 不支持 src 类型 <nil>"),
+		},
+		{
+			name:    "string",
+			src:     `{"Name":"Tom"}`,
+			wantVal: User{Name: "Tom"},
+		},
+		{
+			name: "string pointer",
+			src: func() string {
+				return `{"Name":"Tom"}`
+			}(),
+			wantVal: User{Name: "Tom"},
+		},
+		{
+			name:    "bytes",
+			src:     []byte(`{"Name":"Tom"}`),
+			wantVal: User{Name: "Tom"},
+		},
+		{
+			name: "bytes pointer",
+			src: func() *[]byte {
+				res := []byte(`{"Name":"Tom"}`)
+				return &res
+			}(),
+			wantVal: User{Name: "Tom"},
+		},
+		{
+			name:    "sql.RawBytes",
+			src:     sql.RawBytes(`{"Name":"Tom"}`),
+			wantVal: User{Name: "Tom"},
+		},
+		{
+			name: "sql.RawBytes pointer",
+			src: func() *sql.RawBytes {
+				res := sql.RawBytes(`{"Name":"Tom"}`)
+				return &res
+			}(),
+			wantVal: User{Name: "Tom"},
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			js := &JsonColumn[User]{}
+			err := js.Scan(tc.src)
+			assert.Equal(t, tc.wantErr, err)
+			if err != nil {
+				return
+			}
+			assert.Equal(t, tc.wantVal, js.Val)
+			assert.True(t, js.Valid)
+		})
+	}
+}
+
+func TestJsonColumn_ScanTypes(t *testing.T) {
+	jsSlice := JsonColumn[[]string]{}
+	err := jsSlice.Scan(`["a", "b", "c"]`)
+	assert.Nil(t, err)
+	assert.Equal(t, []string{"a", "b", "c"}, jsSlice.Val)
+	val, err := jsSlice.Value()
+	assert.Nil(t, err)
+	assert.Equal(t, []byte(`["a","b","c"]`), val)
+
+	jsMap := JsonColumn[map[string]string]{}
+	err = jsMap.Scan(`{"a":"a value"}`)
+	assert.Nil(t, err)
+	val, err = jsMap.Value()
+	assert.Nil(t, err)
+	assert.Equal(t, []byte(`{"a":"a value"}`), val)
+}
+
+type User struct {
+	Name string
+}
+
+func ExampleJsonColumn_Value() {
+	js := JsonColumn[User]{Valid: true, Val: User{Name: "Tom"}}
+	value, err := js.Value()
+	if err != nil {
+		fmt.Println(err)
+	}
+	fmt.Print(string(value.([]byte)))
+	// Output:
+	// {"Name":"Tom"}
+}
+
+func ExampleJsonColumn_Scan() {
+	js := JsonColumn[User]{}
+	err := js.Scan(`{"Name":"Tom"}`)
+	if err != nil {
+		fmt.Println(err)
+	}
+	fmt.Print(js.Val)
+	// Output:
+	// {Tom}
+}