Go language type conversion problem, solve?

This is a creation in Article, where the information may have evolved or changed.

Package IPC

Import(

  "Encoding/json"

  "FMT"

)

TypeRequeststruct{

 methodstring"method"

 paramsstring"params"

}

TypeResponsestruct{

 Codestring"code"

 bodystring"Body"

}

TypeServerinterface{

 Name ()string

 Handle (method,paramsstring)*response

}

Typeipcserverstruct{

 Server

}

Funcnewipcserver (serverserver)*ipcserver{

  return&ipcserver (server)

}

Func(server*ipcserver)Connect ()Chanstring {

 session: =make (chanstring,0)

  Gofunc (c chan string)  {

  for{

 Request: =<-c

  ifrequest= ="CLOSE"{//
    Close the connection

   break

            }

  varreqRequest

 Err: =json. Unmarshal ([]byte(request),&req)

  iferr!=nil{

 FMT. Println ("Invalidrequestformat:",request)

            }

 resp: =server. Handle (req. Method,req. Params)

 B,err: =json. Marshal (RESP)

 c<-string(b)//  return result

        }

 FMT. Println ("Sessionclosed.")

 } (session)

 FMT. Println ("Anewsessionhasbeen   createdsuccessfully. ")

  returnsession

}

return&ipcserver (server)
The program compiles this line error, say type conversion exception. I don't know how to change