多级加载

api/graphql.go

@@ -17,6 +17,30 @@ import (
 	"gorm.io/gorm"
 )
 
+var db *gorm.DB
+var err error
+
+func LoadItem(requestedFields []ast.Selection) (data []string) {
+	var items = []string{"user", "article"}
+	for _, field := range requestedFields {
+		fieldAST, _ := field.(*ast.Field)
+		if funk.Contains(items, fieldAST.Name.Value) {
+			data = append(data, fieldAST.Name.Value)
+			for _, str := range LoadItem(fieldAST.SelectionSet.Selections) {
+				str = strings.ToUpper(string(str[0])) + str[1:]
+				data = append(data, fieldAST.Name.Value+"."+str)
+			}
+		}
+		if fieldAST.Name.Value == "list" {
+			for _, str := range LoadItem(fieldAST.SelectionSet.Selections) {
+				str = strings.ToUpper(string(str[0])) + str[1:]
+				data = append(data, str)
+			}
+		}
+	}
+	return data
+}
+
 // 自动生成 GraphQL 类型的函数
 func generateGraphQLType(model interface{}) (*graphql.Object, error) {
 	modelType := reflect.TypeOf(model)
@@ -52,7 +76,7 @@ func generateGraphQLType(model interface{}) (*graphql.Object, error) {
 
 func NewSchema(config Config) (graphql.Schema, error) {
 
-	db, err := gorm.Open(mysql.Open(fmt.Sprintf(
+	db, err = gorm.Open(mysql.Open(fmt.Sprintf(
 		"%s:%s@tcp(%s:%d)/%s?charset=utf8mb4&parseTime=True&loc=Local",
 		config.Mysql.UserName,
 		config.Mysql.Password,
@@ -88,7 +112,7 @@ func NewSchema(config Config) (graphql.Schema, error) {
 			"user_name":   &graphql.Field{Type: graphql.String, Description: "用户名"},
 			"avatar":      &graphql.Field{Type: graphql.String, Description: "用户头像"},
 			"rank":        &graphql.Field{Type: graphql.String, Description: "用户等级"},
-			"price":       &graphql.Field{Type: graphql.Float, Description: "用户金币"},
+			"price":       &graphql.Field{Type: graphql.Int, Description: "用户金币"},
 			"create_time": &graphql.Field{Type: graphql.DateTime, Description: "用户创建时间"},
 			"update_time": &graphql.Field{Type: graphql.DateTime, Description: "用户更新时间"},
 		},
@@ -190,13 +214,11 @@ func NewSchema(config Config) (graphql.Schema, error) {
 	// 将 list 中的字段提取出来用于查询
 	get_fields := func(requestedFields []ast.Selection) (fields []string) {
 		for _, field := range requestedFields {
-			fieldAST, ok := field.(*ast.Field)
+			fieldAST, _ := field.(*ast.Field)
-			if ok && fieldAST.Name.Value == "list" {
+			if fieldAST.Name.Value == "list" {
 				for _, field := range fieldAST.SelectionSet.Selections {
-					fieldAST, ok := field.(*ast.Field)
+					fieldAST, _ := field.(*ast.Field)
-					if ok {
+					fields = append(fields, fieldAST.Name.Value)
-						fields = append(fields, fieldAST.Name.Value)
-					}
 				}
 			}
 		}
@@ -380,7 +402,6 @@ func NewSchema(config Config) (graphql.Schema, error) {
 
 				var total int
 				var images []Image
-				var fields = get_fields(p.Info.FieldASTs[0].SelectionSet.Selections)
 				var query = db.Limit(limit)
 
 				// 参数映射
@@ -518,16 +539,12 @@ func NewSchema(config Config) (graphql.Schema, error) {
 					query = query.Where("id IN ?", list)
 				}
 
+				for index, item := range LoadItem(p.Info.FieldASTs[0].SelectionSet.Selections) {
+					fmt.Println(index, item)
+					query = query.Preload(item)
+				}
+
 				// 输出
-				if funk.Contains(fields, "user") {
-					query = query.Preload("User")
-					fmt.Println("加载 user")
-				}
-
-				if funk.Contains(fields, "article") {
-					query = query.Preload("Article")
-				}
-
 				if err := query.Find(&images).Error; err != nil {
 					fmt.Println("获取图像列表失败", err)
 					return nil, err

api/struct.go

@@ -92,9 +92,10 @@ func (a *TextList) Scan(value interface{}) error {
 
 type User struct {
 	ID         int       `json:"id"          db:"id" gorm:"primaryKey"`
-	UserName   *string   `json:"user_name"   db:"user_name"`
+	UserName   string    `json:"user_name"   db:"user_name"`
-	Avatar     *string   `json:"avatar"      db:"avatar"`
+	Avatar     string    `json:"avatar"      db:"avatar"`
-	Rank       *string   `json:"rank"        db:"rank"`
+	Rank       string    `json:"rank"        db:"rank"`
+	Price      int       `json:"price"       db:"price"`
 	CreateTime time.Time `json:"create_time" db:"create_time"`
 	UpdateTime time.Time `json:"update_time" db:"update_time"`
 }
@@ -108,6 +109,8 @@ type Article struct {
 	Title       string    `json:"title"       db:"title"`
 	Orientation string    `json:"orientation" db:"orientation"`
 	Tags        string    `json:"tags"        db:"tags"`
+	UserId      int       `json:"user_id"     db:"user_id"`
+	User        User      `json:"user"        gorm:"foreignKey:UserId"`
 	CreateTime  time.Time `json:"create_time" db:"create_time"`
 	UpdateTime  time.Time `json:"update_time" db:"update_time"`
 }