获取数据追加字段
1. 前言
前面小节介绍了数据库操作，本小节介绍如何在数据模型中指定追加字段，追加字段的目的主要是用于对某些字段的特殊处理或需要在返回数据的时候返回某些特性情况的字段，这样的处理对接口的使用者来说更加友好，对于开发者来说可以减少代码量和工作量。
2. 应用场景
下面返回的数据可以看到创建时间字段 created_at 是时间戳，这种就需要转化成可读的日期格式，这个时候就可以用到 ThinkPHP 提供的数据模型的字段追加功能，它可以在原有字段的基础上追加出想要的其他字段数据。之前获取学生列表接口的时候返回数据如下:
{
"total": 200,
"per_page": 10,
"current_page": 2,
"last_page": 20,
"data": [
{
"id": 12,
"name": "孙空",
"age": 20,
"id_number": "420117201005127996",
"created_at": 1603617951,
"update_at": 0,
"status": 1
},
{
"id": 1,
"name": "赵四",
"age": 24,
"id_number": "420117201005124146",
"created_at": 1603617951,
"update_at": 0,
"status": 1
},
{
"id": 10,
"name": "孙空",
"age": 21,
"id_number": "420117201005124671",
"created_at": 1603617951,
"update_at": 0,
"status": 1
},
{
"id": 9,
"name": "钱学",
"age": 19,
"id_number": "420117201005121149",
"created_at": 1603617951,
"update_at": 0,
"status": 1
},
{
"id": 8,
"name": "吴小明",
"age": 21,
"id_number": "420117201005123197",
"created_at": 1603617951,
"update_at": 0,
"status": 1
},
{
"id": 7,
"name": "张红",
"age": 19,
"id_number": "420117201005123721",
"created_at": 1603617951,
"update_at": 0,
"status": 1
},
{
"id": 6,
"name": "王五",
"age": 25,
"id_number": "420117201005123617",
"created_at": 1603617951,
"update_at": 0,
"status": 1
},
{
"id": 5,
"name": "钱学",
"age": 23,
"id_number": "420117201005123085",
"created_at": 1603617951,
"update_at": 0,
"status": 1
},
{
"id": 4,
"name": "赵四",
"age": 20,
"id_number": "420117201005128637",
"created_at": 1603617951,
"update_at": 0,
"status": 1
},
{
"id": 3,
"name": "赵四",
"age": 18,
"id_number": "420117201005125711",
"created_at": 1603617951,
"update_at": 0,
"status": 1
}
]
}
3. 设置追加字段
这里还是以之前第 10 小节学生列表为例，可以在 app\Models\Study\StudentModel 中增加属性 $append，然后想要追加什么字段可以初始化 $append，如下图所示:
此时再去请求之前的分页列表接口，会出现如下 created_at_text 字段，因为没有处理该值，所以显示的是 null：
{
"total": 400,
"per_page": 15,
"current_page": 1,
"last_page": 27,
"data": [
{
"id": 205,
"name": "吴小明",
"age": 21,
"id_number": "420117201005129466",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 212,
"name": "孙空",
"age": 18,
"id_number": "420117201005127426",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 208,
"name": "张红",
"age": 22,
"id_number": "420117201005126184",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 206,
"name": "王五",
"age": 21,
"id_number": "420117201005124940",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 215,
"name": "赵四",
"age": 20,
"id_number": "420117201005122353",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 213,
"name": "张红",
"age": 20,
"id_number": "420117201005126460",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 204,
"name": "吴小明",
"age": 19,
"id_number": "420117201005124822",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 209,
"name": "李珍",
"age": 19,
"id_number": "420117201005122985",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 207,
"name": "钱学",
"age": 24,
"id_number": "420117201005123220",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 203,
"name": "孙空",
"age": 19,
"id_number": "420117201005129634",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 211,
"name": "张红",
"age": 22,
"id_number": "420117201005129909",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 400,
"name": "孙空",
"age": 23,
"id_number": "420117201005129673",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 214,
"name": "王五",
"age": 20,
"id_number": "420117201005126275",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 210,
"name": "钱学",
"age": 18,
"id_number": "420117201005125767",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
},
{
"id": 202,
"name": "李珍",
"age": 20,
"id_number": "420117201005125731",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": null
}
]
}
如下图所示：
4.定义追加字段赋值方法
可以在 StudentModel 中创建如下方法处理追加字段值：
public function getCreatedAtTextAttr()
{
return date('Y-m-d H:i',$this->created_at);
}
如下图所示：
Tips： 追加字段处理的方法命名格式为
getAaaBbbAttr()这种格式，其中AaaBbb是追加字段按照大驼峰命名书写的。
5. 请求数据查看
在 postman 请求学生列表接口，可以查看到数据中已有可读的 created_at_text 字段：
{
"total": 400,
"per_page": 15,
"current_page": 1,
"last_page": 27,
"data": [
{
"id": 205,
"name": "吴小明",
"age": 21,
"id_number": "420117201005129466",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 212,
"name": "孙空",
"age": 18,
"id_number": "420117201005127426",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 208,
"name": "张红",
"age": 22,
"id_number": "420117201005126184",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 206,
"name": "王五",
"age": 21,
"id_number": "420117201005124940",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 215,
"name": "赵四",
"age": 20,
"id_number": "420117201005122353",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 213,
"name": "张红",
"age": 20,
"id_number": "420117201005126460",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 204,
"name": "吴小明",
"age": 19,
"id_number": "420117201005124822",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 209,
"name": "李珍",
"age": 19,
"id_number": "420117201005122985",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 207,
"name": "钱学",
"age": 24,
"id_number": "420117201005123220",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 203,
"name": "孙空",
"age": 19,
"id_number": "420117201005129634",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 211,
"name": "张红",
"age": 22,
"id_number": "420117201005129909",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 400,
"name": "孙空",
"age": 23,
"id_number": "420117201005129673",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 214,
"name": "王五",
"age": 20,
"id_number": "420117201005126275",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 210,
"name": "钱学",
"age": 18,
"id_number": "420117201005125767",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
},
{
"id": 202,
"name": "李珍",
"age": 20,
"id_number": "420117201005125731",
"created_at": 1605286706,
"update_at": 0,
"status": 1,
"created_at_text": "2020-11-14 00:58"
}
]
}
如下图所示：
6. 小结
本小节主要介绍如何在模型中追加字段，只需要在模型设置 protected $append 字段属性即可，需要追加的字段需要定义对应的 getAaBbAttr() 方法对字段赋值，通过追加字段的方式可以很方便的处理某些特定的字段。
Tips： 代码仓库：https://gitee.com/love-for-poetry/tp6