英文:
Use pointer as a function's argument
问题
如何使用函数参数的方法？
func writeToInflux(c interface{}, host string, service string, state string) bool {fmt.Println(reflect.TypeOf(c), host, service)bp, e := client.NewBatchPoints(client.BatchPointsConfig{Database: database,Precision: "us",})if e != nil {log.Print(e)}tags := map[string]string{"host": host,"service": service,}fields := map[string]interface{}{"state": state,}pt, err := client.NewPoint("mon", tags, fields, time.Now())if err != nil {log.Print(err)}bp.AddPoint(pt)if err := c.Write(bp); err != nil {log.Print("write failed " + err)}return true}func handler(w http.ResponseWriter, r *http.Request) {c, err := client.NewHTTPClient(client.HTTPConfig{Addr: "http://10.x.x.x:8086",Username: username,Password: password,})if err != nil {log.Print(err)}a := strings.Split(r.URL.Path, "/")writeToInflux(c, a[3], a[4], a[5])}
在这个例子中，我无法使用c变量的参数，或者也许还有其他选项可以将c作为参数传递给函数？
英文:
How can I use methods of function arguments?
func writeToInflux(c interface{}, host string, service string, state string) bool {fmt.Println(reflect.TypeOf(c), host, service)bp, e := client.NewBatchPoints(client.BatchPointsConfig{Database: database,Precision: "us",})if e != nil {log.Print(e)}tags := map[string]string{"host": host,"service": service,}fields := map[string]interface{}{"state": state,}pt, err := client.NewPoint("mon", tags, fields, time.Now())if err != nil {log.Print(err)}bp.AddPoint(pt)if err := c.Write(bp); err != nil {log.Print("write failed " + err)}return true}func handler(w http.ResponseWriter, r *http.Request) {c, err := client.NewHTTPClient(client.HTTPConfig{Addr: "http://10.x.x.x:8086",Username: username,Password: password,})if err != nil {log.Print(err)}a := strings.Split(r.URL.Path, "/")writeToInflux(c, a[3], a[4], a[5])}
In this example i can't use parameters of c variable, or maybe there is another options to use c as parameter to function?
答案1
得分: 1
在writeToInflux函数中，c interface{}没有指定任何c应该实现的方法。你应该使用InfluxWriter接口，这样你就可以调用c.Write方法：
type InfluxWriter interface {Write(bp client.BatchPoints) (*client.Response, error)}
另外，writeToInflux函数可以接受一个client.Client参数，这样你就可以访问它的所有方法。
英文:
In writeToInflux, the c interface{} doesn't specify any methods c should implement. You should use sine InfluxWriter interface so you can call c.Write:
type InfluxWriter {Write(bp client.BatchPoints) (*client.Response, error)}
Alternatively, writeToInflux can accept a client.Client, giving you access to all its methods.
答案2
得分: -1
"c"是一个interface{}类型，在函数参数中使用接口，可以将任何结构体或任何数据类型传递给它。
在你的情况下，你想让c使用write函数
如果 err := c.Write(bp); err != nil {
log.Print("write failed " + err)
}
编译器不知道c的类型，所以你需要进行类型断言。
尝试这样做，它会起作用
newC, ok := c.(c的类型) c的类型 -> 一个结构体或任何具有write方法的类型
if ok {
if err := newC.Write(bp); err != nil {
log.Print("write failed " + err)
}
}
或者像这样更改你的函数
func writeToInflux(c client.Client, host string, service string, state string) bool
英文:
"c" is an interface{} type, Having an interface in function parameter, you can able to pass any struct or any data types into it.
In your case you want c to use the function writeif err := c.Write(bp); err != nil {log.Print("write failed " + err)}
The compiler doesn't know the type of c, so you need to type assert it.
Try this, It will work
newC,ok:= c.(type of c) type of C -> a struct or any type which has a method writeif ok {if err := newC.Write(bp); err != nil {log.Print("write failed " + err)}}
Or Change your function like this
func writeToInflux(c client.Client, host string, service string, state string) bool
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