It not possible to DisallowUnknownFields() during echo.Context.Bind()

[Vadym-Kupriyanchuk]

It will be useful to be able to setup a custom JSON decoder for the request body.

[aldas]

If you are only concerned about body (json) then you do not need to use echo bind at all.

Using plain json.decoder has less side-effects

if err := json.NewDecoder(c.Request().Body).Decode(&payload); err != nil {
	return err
}

// or for DisallowUnknownFields() wrapped in your custom func
decoder := json.NewDecoder(c.Request().Body)
decoder.DisallowUnknownFields()
if err := decoder.Decode(&payload); err != nil {
	return err
}

If you mean returning error when request payload has fields that are not in bindable struct - you are making that endpoint more brittle.

I personally would advice creating two separate structs for binding and passing to business logic and mapping them in handler. In that way you would not expose fields accidentally to binding See this and think about that IsAdmin - what happens when you have implemented that handler and some time later someone adds that field on your struct that you are reusing in transport layer and business layer.

[Vadym-Kupriyanchuk]

The first case is definitely my situation, Thanks for the help.

[therox]

If you have to collect data not only from the request body, but path and/or query then you have to write too much code instead of using shiny bright e.Bind()

[aldas]

That is why we have functions. Wrap this common code into your separate package and function and call it err := mybind.Bind(c, target) instead of calling err := c.Bind(target).

Also c.Bind() calls internally c.Echo().JSONSerializer (here) so you can setup your own global JSONSerializer with settings that you need.