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Version: 2.8.x

Introduction​

Mainly used for embedding into user-defined structs, and through the form of tags to attach custom tag content (metadata) to the struct of the gmeta package, and dynamically retrieve these custom tag contents at runtime through specific methods.

Usage:

import "github.com/gogf/gf/v2/util/gmeta"

API Documentation:

https://pkg.go.dev/github.com/gogf/gf/v2/util/gmeta

Method List:

func Data(object interface{}) map[string]interface{}
func Get(object interface{}, key string) *gvar.Var

Usage Example​

Data Method​

The Data method is used to obtain the metadata tags of a specified struct object and return them as a map.

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/frame/g"
    "github.com/gogf/gf/v2/util/gmeta"
)

func main() {
    type User struct {
        g.Meta `orm:"user" db:"mysql"`
        Id         int
        Name       string
    }
    g.Dump(gmeta.Data(User{}))
}
tip

Most of the time, in struct definitions, we use the alias g.Meta for gmeta.Meta.

After execution, the terminal outputs:

{
    "db": "mysql",
    "orm": "user"
}

Get Method​

The Get method is used to retrieve metadata tag information of a specified name from a specified struct object.

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/util/gmeta"
)

func main() {
    type User struct {
        g.Meta `orm:"user" db:"mysql"`
        Id         int
        Name       string
    }
    user := User{}
    fmt.Println(gmeta.Get(user, "orm").String())
    fmt.Println(gmeta.Get(user, "db").String())
}

After execution, the terminal outputs:

user
mysql