2
我是nodejs开发人员，我通常使用一个结构来存放配置包/对象，该对象包含对我经常使用的库和配置选项的引用。通常这个配置对象也保存我的数据库连接，并且它可以通过我的应用程序到达。运行时错误：无效内存地址或无指针在公共指针中的解除引用
我试图建立类似于这样的去和可怕的失败。
我的计划是建立一个公共变量，它保存了我的配置结构的引用。但是，当我尝试打电话给我Config.Database我得到这样的恐慌：
2017/02/19 14:05:44 http: panic serving 127.0.0.1:53554: runtime error: invalid memory address or nil pointer dereference
goroutine 50 [running]:
net/http.(*conn).serve.func1(0xc42027c000)
/usr/local/go/src/net/http/server.go:1491 +0x12a
panic(0x9f45c0, 0xc42000c100)
/usr/local/go/src/runtime/panic.go:458 +0x243
main.SignUp(0xc4202780e0)
/home/attila/dev/gopath/src/github.com/attilasatan/helloiris/handlers.go:31 +0x258
github.com/kataras/iris.HandlerFunc.Serve(0xafaf00, 0xc4202780e0)
/home/attila/dev/gopath/src/github.com/kataras/iris/http.go:211 +0x30
github.com/kataras/iris.(*Context).Do(0xc4202780e0)
/home/attila/dev/gopath/src/github.com/kataras/iris/context.go:152 +0x4d
github.com/kataras/iris.(*serveMux).BuildHandler.func1(0xc4202780e0)
/home/attila/dev/gopath/src/github.com/kataras/iris/http.go:1059 +0x6ea
github.com/kataras/iris.(*Framework).Build.func1.1(0xd87e20, 0xc4202701a0, 0xc420284000)
/home/attila/dev/gopath/src/github.com/kataras/iris/iris.go:411 +0x72
net/http.HandlerFunc.ServeHTTP(0xc420235080, 0xd87e20, 0xc4202701a0, 0xc420284000)
/usr/local/go/src/net/http/server.go:1726 +0x44
net/http.serverHandler.ServeHTTP(0xc420089f80, 0xd87e20, 0xc4202701a0, 0xc420284000)
/usr/local/go/src/net/http/server.go:2202 +0x7d
net/http.(*conn).serve(0xc42027c000, 0xd88820, 0xc42015c200)
/usr/local/go/src/net/http/server.go:1579 +0x4b7
created by net/http.(*Server).Serve
/usr/local/go/src/net/http/server.go:2293 +0x44d
2017/02/19 14:05:44 http: panic serving 127.0.0.1:53560: runtime error: invalid memory address or nil pointer dereference
goroutine 51 [running]:
net/http.(*conn).serve.func1(0xc42027c180)
/usr/local/go/src/net/http/server.go:1491 +0x12a
panic(0x9f45c0, 0xc42000c100)
/usr/local/go/src/runtime/panic.go:458 +0x243
main.SignUp(0xc4202ac070)
/home/attila/dev/gopath/src/github.com/attilasatan/helloiris/handlers.go:31 +0x258
github.com/kataras/iris.HandlerFunc.Serve(0xafaf00, 0xc4202ac070)
/home/attila/dev/gopath/src/github.com/kataras/iris/http.go:211 +0x30
github.com/kataras/iris.(*Context).Do(0xc4202ac070)
/home/attila/dev/gopath/src/github.com/kataras/iris/context.go:152 +0x4d
github.com/kataras/iris.(*serveMux).BuildHandler.func1(0xc4202ac070)
/home/attila/dev/gopath/src/github.com/kataras/iris/http.go:1059 +0x6ea
github.com/kataras/iris.(*Framework).Build.func1.1(0xd87e20, 0xc4202a60d0, 0xc4202840f0)
/home/attila/dev/gopath/src/github.com/kataras/iris/iris.go:411 +0x72
net/http.HandlerFunc.ServeHTTP(0xc420235080, 0xd87e20, 0xc4202a60d0, 0xc4202840f0)
/usr/local/go/src/net/http/server.go:1726 +0x44
net/http.serverHandler.ServeHTTP(0xc420089f80, 0xd87e20, 0xc4202a60d0, 0xc4202840f0)
/usr/local/go/src/net/http/server.go:2202 +0x7d
net/http.(*conn).serve(0xc42027c180, 0xd88820, 0xc42015c480)
/usr/local/go/src/net/http/server.go:1579 +0x4b7
created by net/http.(*Server).Serve
这是我的配置文件。正如你可以看到我使用tideland/golib/redis进行redis连接。
configure.go
package main
import (
"fmt"
"strconv"
"time"
"github.com/tideland/golib/redis"
)
/*Configuration is the main type of app configuration */
type Configuration struct {
Database *redis.Connection
}
/*Config is app configuration holder */
var Config *Configuration
/*Configure handles database connection */
func Configure() (*Configuration, error) {
db, err := redis.Open(redis.TcpConnection("127.0.0.1:6379", 30*time.Second))
if err != nil {
fmt.Printf("Database connection error")
return nil, err
}
conn, err := db.Connection()
n, _ := conn.DoInt("INCR", "IDIDID")
fmt.Printf(strconv.Itoa(n))
if err != nil {
fmt.Printf("Database connection error")
return nil, err
}
/*Config is the main configuration object*/
Config := &Configuration{conn}
return Config, err
}
而且这里是我使用Config.Database。
handlers.go
func SignUp(ctx *iris.Context) {
mail := ctx.FormValue("email")
password := ctx.FormValue("password")
passwordConfirm := ctx.FormValue("password-confirm")
if password != passwordConfirm {
ctx.RenderWithStatus(iris.StatusBadRequest, "400.html", ErrorPageData{"passwords dont match"})
} else {
user := User{mail, password, 0}
db := Config.Database
userID, err := db.DoInt("INCR", "HELLOIRIS:ID")
if err != nil {
ctx.RenderWithStatus(iris.StatusBadRequest, "400.html", ErrorPageData{"passwords dont match"})
} else {
user.ID = userID
fmt.Printf("SAVED")
ctx.Render("signup-success.html", nil)
}
ctx.JSON(200, user)
}
}
在此之后失败我改变Configure功能是这样的：
configure.go
func Configure() (Config *Configuration, err error) {
if Config != nil {
return
}
}
，我在处理
改变用途handlers.go
config, err := Configure()
if err != nil {
ctx.RenderWithStatus(iris.StatusBadRequest, "400.html", ErrorPageData{"try again later"})
return
}
user := User{mail, password, 0}
db := config.Database
...一切开始正常工作。
我的问题是我简直不明白为什么......当我使用公共指针时为什么会出现这种恐慌，为什么当我从函数返回相同的指针时为什么没有得到？