处理 text NULL 字段

api/graphql.go

@@ -1,9 +1,11 @@
 package api
 
 import (
+	"encoding/json"
 	"fmt"
 	"log"
 	"reflect"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -351,6 +353,7 @@ func NewSchema(config Config) (graphql.Schema, error) {
 				},
 			}),
 			Args: graphql.FieldConfigArgument{
+				"follower":      &graphql.ArgumentConfig{Type: graphql.Int, Description: "获取指定ID用户的关注列表发布的图像"},
 				"interest":      &graphql.ArgumentConfig{Type: graphql.Int, Description: "获取指定ID用户的兴趣推荐图像"},
 				"similar":       &graphql.ArgumentConfig{Type: graphql.Int, Description: "获取与指定ID图像相似的图像"},
 				"id":            &graphql.ArgumentConfig{Type: graphql.Int, Description: "获取指定ID的图像"},
@@ -384,6 +387,7 @@ func NewSchema(config Config) (graphql.Schema, error) {
 					Text     string
 					Interest int
 					Similar  int
+					Follower int
 				}
 				mapstructure.Decode(p.Args, &args)
 
@@ -471,6 +475,49 @@ func NewSchema(config Config) (graphql.Schema, error) {
 					fmt.Println("Interest:", args.Interest)
 				}
 
+				// 筛选: 关注列表
+				if args.Follower != 0 {
+					// 返回JSON数组(2.5秒)
+					var item string
+					if err := db.Raw(`
+						SELECT JSON_ARRAYAGG(web_images.id) AS json_result
+						FROM web_fans
+						INNER JOIN web_images ON web_images.user_id = web_fans.blogger_id
+						WHERE web_fans.follower_id = ?
+					`, args.Follower).Scan(&item).Error; err != nil {
+						fmt.Println("获取关注列表失败", err)
+						return nil, err
+					}
+
+					var ids []int
+					json.Unmarshal([]byte(item), &ids)
+
+					sort.Slice(ids, func(i, j int) bool {
+						return ids[i] > ids[j] // 按照降序排列
+					})
+
+					id_list = append(id_list, ids)
+
+					//fmt.Println(item)
+
+					// 返回所有结果(7秒)
+					//var item []int
+					//if err := db.Table("web_fans").Select("web_images.id").Limit(10).Joins("inner join web_images on web_images.user_id = web_fans.blogger_id").Where("web_fans.follower_id = ?", 46).Pluck("id", &item).Error; err != nil {
+					//	fmt.Println("获取关注列表失败", err)
+					//	return nil, err
+					//}
+					// id_list = append(id_list, item)
+
+					// 直接出结果(最快)
+					//var q = db.Table("web_fans").Select("web_images.*").Limit(10)
+					//q = q.Joins("inner join web_images on web_images.user_id = web_fans.blogger_id")
+					//q = q.Where("web_fans.follower_id = ?", 46).Preload("User").Preload("Article").Find(&images)
+					//return map[string]interface{}{
+					//	"list":  images,
+					//	"total": len(images),
+					//}, nil
+				}
+
 				// 排序
 
 				// 截取:取交集

api/struct.go

@@ -87,6 +87,11 @@ type TextList []struct {
 }
 
 func (a *TextList) Scan(value interface{}) error {
+	// 如果数据库中的值为NULL，则返回nil
+	if value == nil || len(value.([]byte)) == 0 {
+		*a = TextList{}
+		return nil
+	}
 	return json.Unmarshal(value.([]byte), a)
 }