使用回调和函数作为go中的类型

问题描述：

I am attempting to create a sort of function that is similar to the Express (NodeJS) route method in Go:

app.get("route/here/", func(req, res){
    res.DoStuff()
});

In this example I want "foo" (the type) to be the same as the anonymous function in the above method. Here is one of my failed attempts using Go:

type foo func(string, string)

func bar(route string, io foo) {
        log.Printf("I am inside of bar")
        // run io, maybe io() or io(param, param)?
}

func main() {
        bar("Hello", func(arg1, arg2) {
                return  arg + arg2
        })
}

How might I fix my dilemma? Should I not use a type and use something else? What are my options?

我正在尝试创建一种类似于Go中的Express（NodeJS）路由方法的函数：

app.get("route/here/“，func（req，res）{
 res.DoStuff（）
}）;  
  code>  pre> 
 
 在此示例中，我希望“ foo”（类型）与上述方法中的匿名函数相同。 这是我使用Go失败的尝试之一： p> 
 
 
  type foo func（string，string）
 
func bar（route string，io foo）{
 log.Printf  （“我在酒吧里面”）
 //运行io，也许是io（）或io（param，param）？
} 
 
func main（）{
 bar（“ Hello”，func（arg1  ，arg2）{
返回arg + arg2 
}）
} 
  code>  pre> 
 
 如何解决我的难题？ 我不应该使用类型并使用其他东西吗？ 我有什么选择？ p> 
  div>

答

You are on the right track - creating a type for a func on the context you are using it adds clearer design intent and more importantly additional type safety.

You just need to modify you example a bit for it to compile:

package main

import "log"

//the return type of the func is part of its overall type definition - specify string as it's return type to comply with example you have above
type foo func(string, string) string

func bar(route string, io foo) {

    log.Printf("I am inside of bar")
    response := io("param", "param")
    log.Println(response)

}

func main() {

    bar("Hello", func(arg1, arg2 string) string {
        return arg1 + arg2
    })

}

答

package main

import (
    "fmt"
    "log"
)

type foo func(string, string)

func bar(route string, callback foo) bool {
 //...logic

  /* you can return the callback to use the 
     parameters and also in the same way you 
     could verify the bar function
   */
    callback("param", "param")
    return true
}

func main() {
    fmt.Println("Hello, playground")

    res := bar("Hello", func(arg1, arg2 string) {
        log.Println(arg1 + "_1")
        log.Println(arg2 + "_2")
    })

    fmt.Println("bar func res: ", res)
}

使用回调和函数作为go中的类型

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