Skip to main content
Version: 2.2.x

自定义回调处理是最常见的接口开发实现,开发中只需要对接口中的部分方法进行替换与修改,在驱动默认实现逻辑中注入自定义逻辑。所有的 SQL 语句执行必定会通过 DoQuery 或者 DoExec 或者 DoFilter 接口,根据需求在自定义的驱动中实现并覆盖相关接口方法实现所需功能即可。

我们来看一个自定义回调处理的示例,现需要将所有执行的 SQL 语句记录到 monitor 表中,以方便于进行 SQL 审计。为简化示例编写,以下代码实现了一个自定义的 MySQL 驱动,该驱动继承于 driversmysql 模块内已经实现的 Driver

package driver

import (
"context"

"github.com/gogf/gf/contrib/drivers/mysql/v2"
"github.com/gogf/gf/v2/database/gdb"
"github.com/gogf/gf/v2/os/gtime"
)

// MyDriver is a custom database driver, which is used for testing only.
// For simplifying the unit testing case purpose, MyDriver struct inherits the mysql driver
// gdb.Driver and overwrites its functions DoQuery and DoExec.
// So if there's any sql execution, it goes through MyDriver.DoQuery/MyDriver.DoExec firstly
// and then gdb.Driver.DoQuery/gdb.Driver.DoExec.
// You can call it sql "HOOK" or "HiJack" as your will.
type MyDriver struct {
*mysql.Driver
}

var (
// customDriverName is my driver name, which is used for registering.
customDriverName = "MyDriver"
)

func init() {
// It here registers my custom driver in package initialization function "init".
// You can later use this type in the database configuration.
if err := gdb.Register(customDriverName, &MyDriver{}); err != nil {
panic(err)
}
}

// New creates and returns a database object for mysql.
// It implements the interface of gdb.Driver for extra database driver installation.
func (d *MyDriver) New(core *gdb.Core, node *gdb.ConfigNode) (gdb.DB, error) {
return &MyDriver{
&mysql.Driver{
Core: core,
},
}, nil
}

// DoCommit commits current sql and arguments to underlying sql driver.
func (d *MyDriver) DoCommit(ctx context.Context, in gdb.DoCommitInput) (out gdb.DoCommitOutput, err error) {
tsMilliStart := gtime.TimestampMilli()
out, err = d.Core.DoCommit(ctx, in)
tsMilliFinished := gtime.TimestampMilli()
_, _ = in.Link.ExecContext(ctx,
"INSERT INTO `monitor`(`sql`,`cost`,`time`,`error`) VALUES(?,?,?,?)",
gdb.FormatSqlWithArgs(in.Sql, in.Args),
tsMilliFinished-tsMilliStart,
gtime.Now(),
err,
)
return
}

我们看到,这里在包初始化方法 init 中使用了 gdb.Register("MyDriver", &MyDriver{}) 来注册了了一个自定义名称的驱动。我们也可以通过 gdb.Register("mysql", &MyDriver{}) 来覆盖已有的框架 mysql 驱动为自己的驱动。

驱动名称 mysql 为框架默认的 DriverMysql 驱动的名称。

由于这里我们使用了一个新的驱动名称 MyDriver,因此在 gdb 配置中的 type 数据库类型时,需要填写该驱动名称。以下是一个使用配置的示例:

database:
default:
- link: "MyDriver:root:12345678@tcp(127.0.0.1:3306)/user"