douxuanling6523 2017-09-13 23:21
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类型interface {}是没有方法的接口-Golang

I am using https://github.com/kataras/iris golang web framework. This is follow up mail from the last question asked here - Fetching Logged in User Info for display - Golang Template

I am finally using code that was mentioned in the previous post like:-

ctx.Values().Get("user")

and the value that user is set or has is "Struct" type:-

// users is struct below

var user users

// details are fetched from DB and assigned to user 
// like mentioned here http://go-database-sql.org/retrieving.html 
// Now value is set
ctx.Values().Set("user", user);

But after getting the value, When I use in different handler and print:-

user := ctx.Values().Get("user")
fmt.Println(user.ID)

I get the error:-

user.ID undefined (type interface {} is interface with no methods)

I need help in "Type assertion" for the interface. How can i "type assert" above value.

Please let me know, what is the right way to do it. Thanks

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  • duanjiu1003 2017-09-13 23:36
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    A type assertion does just that, asserts a value is a given type.

    userID := user.(users).ID
    

    Use they type name, and it should work.

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