Bind form-data request with nested structures

[Ganitzsh]

Hi,

I have an struct StructA which contains another struct StructB as an attribute, like this:

type StructB struct {
    FieldB string  `form:"fieldB"`
}

type StructA struct {
    NestedStruct *StructB
    FieldA string `form:"fieldA"`
    ...
}

In my handler I'm Binding the request content to an StructA object:

func MyHandler(c *gin.Context) {
    var tmp StructA
    ...
    c.Bind(&tmp)
    ...
}

My form contains the field fieldA as well as fieldB, but NestedStruct stays <nil> after the Bind call.
Is manual binding the only way to achieve this at the time? Or am I missing something?

Thanks

[misekm]

Please is there any solution for this? I would like to use nested structs too. Thanks.

[Ganitzsh]

I found a trick, using reflection, you can wrap the Bind function. I will provide a sample later.

[misekm]

Could you please show any sample code?

[qw4n7y]

any progress?

[thinkerou]

Hi @Ganitzsh @qw4n7y @misekm , gin supports the follow not POINTER:

type StructB struct {
    FieldB string  `form:"fieldB"`
}

type StructA struct {
    NestedStruct StructB
    FieldA string `form:"fieldA"`
    // ...
}

OR

type StructA struct {
    NestedStruct *StructB
    FieldA string `form:"fieldA"`
    // ...
}

[appleboy]

See the readme: https://github.com/gin-gonic/gin#bind-form-data-request-with-custom-struct

[nicolasvasquez]

I think that assign multiple names for different nested struct is tedious. For example:

type StructB struct {
    Id  int  `form:"structb_id" json:"id"`
    Name  string  `form:"structb_name"  json:"name"`
}
type StructA struct {
    Id  string  `form:"structa_id" json:"id"`
    Name  string  `form:"structa_name" json:"name"`
    NestedStruct *StructB `form:"fieldB" json:"structb"`
}

The json bind for nested struct is more easily than form way. Is possible work with form as the json way and send only like structb.name for assign the name of the second struct??