我正在使用具有多个数据库的Go RESTful API应用程序.当启动服务器时,用户提供他们想要使用的数据库.
在应用程序中,我有三个函数处理连接：selectedDb.Get(),selectedDb.Add(),selectedDb.Connect().
如果有人选择MysqL,它处理MysqL的东西,如果有人选择MongoDB它处理Mongo等等.
这是我如何尝试完成这一点：
DbInterface.go
package dbinit
type Object struct {
Uuid string
Object string
Deleted bool
}
// The interface that all connectors should have
type Intfc interface {
Connect() HERE_LIES_MY_PROBLEM
Add(string,string,string) string
Get(string) (Object,bool)
}
MysqL.go
package MysqLConnector import ( ... ) type MysqL struct{} // Connect to MysqL func (f MysqL) Connect() HERE_LIES_MY_PROBLEM { client,err = sql.Open("MysqL","yourusername:yourpassword@/yourdatabase") if err != nil { panic(err.Error()) } return client } // Add item to DB func (f MysqL) Add(owner string,refType string,object string) string { // do stuff related to this DB return // a string } func (f MysqL) Get(Uuid string) (dbinit.Object,bool) { // do stuff related to this DB return // an object and a bool }
Mongo.go
package mongoConnector
import (
...
)
type Mongo struct{}
// Connect to mongo
func (f Mongo) Connect() HERE_LIES_MY_PROBLEM {
info := &mgo.DialInfo{
Addrs: []string{hosts},Timeout: 60 * time.Second,Database: database,Username: username,Password: password,}
client,err := mgo.DialWithInfo(info)
if err != nil {
panic(err)
}
return client
}
// Add item to DB
func (f Mongo) Add(owner string,object string) string {
// do stuff related to this DB
return // a string
}
func (f Mongo) Get(Uuid string) (dbinit.Object,bool) {
// do stuff related to this DB
return // an object and a bool
}
main.go
... var selectedDb dbinit.Intfc commandLineInput := "MysqL" // just for the example if commandLineInput == "MysqL" { selectedDb = MysqLConnector.MysqL{} } else if commandLineInput == "mongo" { selectedDb = mongoConnector.Mongo{} } client := selectedDb.Connect() // this runs everytime the API is called api.HandlerFoobar = foobar.handlerFunction(func(params foobar.Params) middleware.Responder { // Here I want to add something to the selected dbinit selectedDb.Get(client,addStringA,addStringB,addStringC) return // the API response }) ...
问题陈述
当我返回客户端的MysqL,它不适用于Mongo,反之亦然.
我仅在启动服务器时将数据库连接到数据库,并将客户端存储在客户端变量中.然而,问题是Mongo返回的是另一个客户端,而不是MysqL.
解决方法
如果要使用这些方法保留界面,则应该将您的界面更改为：
接口：
// The interface that all connectors should have
type Intfc interface {
// Connect to the database,if an error occur at the moment
// of connection,return the error
Connect() error
// Add returns a string,it returns an error if something occurs
Add(string,string) (string,error)
Get(string) (Object,bool)
}
MysqL的：
type MysqL struct{ conn *sql.DB // contains the connection to the DB } // Connect to MysqL func (f *MysqL) Connect() error { conn,err := sql.Open("MysqL","yourusername:yourpassword@/yourdatabase") if err != nil { return error } f.conn = conn return nil } // Add item to DB func (f *MysqL) Add(owner string,object string) (string,error) { // do something return // a string and error } func (f *MysqL) Get(Uuid string) (dbinit.Object,bool) { // do something return // an object and a bool }
蒙戈：
type Mongo struct{
session *mgo.Session
}
// Connect to mongo
func (f *Mongo) Connect() error {
info := &mgo.DialInfo{
// some data
}
session,err := mgo.DialWithInfo(info)
if err != nil {
return error
}
f.session = session
return nil
}
// Add item to DB
func (f *Mongo) Add(owner string,error) {
// do something
return // a string and error (it could be nil at success)
}
func (f *Mongo) Get(Uuid string) (dbinit.Object,bool) {
// do something
return // an object and a bool
}
主要：
var selectedDb dbinit.Intfc commandLineInput := "MysqL" if commandLineInput == "MysqL" { selectedDb = &MysqLConnector.MysqL{} } else if commandLineInput == "mongo" { selectedDb = &mongoConnector.Mongo{} } err := selectedDb.Connect() if err != nil { panic(err) } // this runs everytime the API is called api.HandlerFoobar = foobar.handlerFunction(func(params foobar.Params) middleware.Responder { data,err := selectedDb.Add(addStringA,addStringC) if err != nil { // do something } return // the API response })
但是您也可以从Intfc中删除Connect()错误方法,只需使用Add和Get即可,但应更新如下所示的软件包：
// Connect to MysqL,it could be any function name func Connect() (*MysqL,error) { connection,"yourusername:yourpassword@/yourdatabase") if err != nil { return nil,error } return &MysqL{conn: connection} }
蒙戈
// Connect to mongo,it could be any function name
func Connect() (*Mongo,error) {
info := &mgo.DialInfo{
// some data
}
s,err := mgo.DialWithInfo(info)
if err != nil {
return nil,error
}
return &Mongo{session: s}
}
主要
var selectedDb dbinit.Intfc var err error commandLineInput := "MysqL" if commandLineInput == "MysqL" { selectedDb,err = MysqLConnector.Connect() } else if commandLineInput == "mongo" { selectedDb,err = mongoConnector.Connect() } if err != nil { panic(err) }