Call a Struct and it's method with the string name?
nvcnvn
*******************************************
type MyStruct struct {...............}
func (p *MyStruct) MyMethod {
println("My statement.");
}
CallFunc("MyStruct", "MyMethod");
//print out My statement."
*******************************************
Can some one show me somes ideas :)
P/s:
My aim is...build an simple MVC web application with GO (like ASP.NET
MVC or CodeIgniter in PHP....).
So my app will parse the URL (example.com/Structname/Methodname....)
in to separate strings ("Structname", "Methodname",..) after that put
it in to CallFunc().
If my plan is not efficient, can you give me the better way :D
Thanks all of you!
Anschel Schaffer-Cohen
nvcnvn
an variable with MyStruct typed or not?
Eg:
type MyStruct struct {...............}
func (p *MyStruct) MyMethod {
println("My statement.");
}
{
var mys = MyStruct{};
mys.MyMethod();//print out
}
*******************************************
Not so sure but I thing that I can call MyMethod() with MethodByName()
only when "var mys = MyStruct{};" is it true?
Is there anything like StructByName()?
nvcnvn
On Nov 12, 10:10 am, Anschel Schaffer-Cohen <ansche...@gmail.com>
wrote:
nvcnvn
On 12 Tháng Mười Một, 10:10, Anschel Schaffer-Cohen
Kyle Lemons
Can you give me an example of using that function?
DEXTER
Hi,
Can you help me with the similar, but I would like to pass struct to the function
ex:
//
type Person struct {
Name string
Age int
}
c = &Person{"Dexter",37}
How do I access the attributes of Person in the called function and how do I call the function MethodByName, with extra arguments?
Thanks
Dexter
ajventi
type methodMap map[string]func () string
var methods = methodMap{
"index": func () { ....},
DEXTER
André Moraes
> Name string
> Age int
> }
> func main() {
> i := Integer(0)
> i.Add(1)
> c = &Person{"Dexter",37}
> fmt.Println(i)
> add := reflect.ValueOf(&i).MethodByName("Add")
> add.Call(c)
> }
>
> How do I access the attributes of Person in the called function and how do I
From the called function point of view, it's just another call. No
special treatment here. So you don't have to do nothing special in the
Add function.
This works because you called MethodByName on a reflect.Value and not
in a reflect.Type, this way, the receiver is already defined.
> call the function MethodByName, with extra arguments?
You don't.
The MethodByName return the pointer to the function (bound to the &i object).
You pass the parameters in the add.Call method.
See: http://weekly.golang.org/pkg/reflect/#Value.Call
For each argument you need to pass, you add them to a []reflect.Value
slice and them pass the slice to add.Call
pseudo-code:
add := reflect.ValueOf(&i).MethodByName("Add")
a := int(0)
params := make([]reflect.Value,0)
params = append(params, reflect.ValueOf(a))
add.Call(params)
This will call the Add method passing the int "a" to it
--
André Moraes
http://andredevchannel.blogspot.com/
DEXTER
The below code works without any errors, but when I try to pass a pointer to a function, it throws up errors
Any help?
package main
import "fmt"
import "reflect"
type T struct {}
func (t *T) Foo() {
fmt.Println("foo")
}
type MyStruct struct {
id int
}
func (t *T) Bar() {
fmt.Println("foo")
}
func main() {
var t T
reflect.ValueOf(&t).MethodByName("Foo").Call([]reflect.Value{})
}
/modified main () that throws errors
func main() {
var t T
bar := reflect.ValueOf(&t).MethodByName("Bar")
ms := &MyStruct{5}
params := make([]reflect.Value,0)
params = append(params, reflect.ValueOf(ms))
bar.Call(params)
}
DEXTER
Now I could get it to work with any errors
package main
import "fmt"
import "reflect"
type T struct {}
func (t *T) Foo() {
fmt.Println("foo")
}
type MyStruct struct {
id int
}
Name string
Age int
}
fmt.Println("foo", ms.id, p.Name, p.Age)
}
func main() {
var t T
reflect.ValueOf(&t).MethodByName("Foo").Call([]reflect.Value{})
}
DEXTER
How do I create instance of Struct from string
I am trying something similar to zend controller /action
In my handler function, I have 2 strings, controller name & action.
Can some one point me to code to create instance of struct from a string
Dexter
chris dollin
> Hi,
> How do I create instance of Struct from string
> I am trying something similar to zend controller /action
> In my handler function, I have 2 strings, controller name & action.
> Can some one point me to code to create instance of struct from a string
Why not just set up a map from strings to constructor functions and
use that?
Chris
(Yes, one could use reflection and seach for things of the right type and
go through the reflection API and and and and ... but why not go the
utterly straightforward route?)
Chris
--
Chris "allusive" Dollin
André Moraes
> Hi,
> How do I create instance of Struct from string
> I am trying something similar to zend controller /action
I already did something similar to that in one of my projects.
I can sent you the source code when I get home for lunch.
But the road is:
Get access to the type of the handler, the easy way is to pass a
zero-value of the hadler &MyHandler{} and find the type using reflect.
Associate the Type object with an String inside a Map.
Then, when receiving the request, create a new instace of the Type and
call the desired Method.
André Moraes
>> How do I create instance of Struct from string
>> I am trying something similar to zend controller /action
>
> I already did something similar to that in one of my projects.
// this method return a function that any time is called (with
http.Request and ResponseWriter)
// will create a new instance with the same type as "sample" parameter
// and invoke the "method"
func RestDispatchMeth(sample interface{}, method string) http.HandlerFunc {
t := reflect.ValueOf(sample).Type()
return func(w http.ResponseWriter, req *http.Request) {
v := reflect.New(t)
log.Printf("Controller: %v", t.Name())
callControllerMethod(method, v, w, req)
}
}
// this function receiveis the controler "cont" and the "methodName" parameters
// together with the ResponseWriter and Request
// If it is able to find the method it call's the method.
func callControllerMethod(methodName string, cont reflect.Value, w
http.ResponseWriter, req *http.Request) {
// check if the method is valid
if method := cont.MethodByName(methodName); method.IsValid() {
vw := reflect.ValueOf(w)
vreq := reflect.ValueOf(req)
log.Printf("Method: %v", methodName)
// call it with the rigth parameters.
method.Call([]reflect.Value{0: vw, 1: vreq})
// Calls the after request handler
// If one is defined
if AfterRequest != nil {
AfterRequest.ServeHTTP(w, req)
}
} else {
log.Printf("Unable to find method: %v", methodName)