Gin binding.Default return Bindding

Description

When I was using data binding, I found that the second time I fetched the value after ShouldBind, the value became EOF. I found that I could use ShouldBindBodyWith, but when using this method, I needed to use different Bindding depending on the Content-Type.when using different Bindding eg.

b := binding.Default(c.Request.Method, c.ContentType())
err := c.ShouldBindBodyWith(&body,b)

But binding.Default returns Binding. but the values returned are all implementations of BindingBody. if you use the return value of BindingBody,so that this function can be used.

How to reproduce

// fix return Binding change to BindingBody
func Default(method, contentType string) BindingBody {
    if method == http.MethodGet {
        return Form
    }

    switch contentType {
    case MIMEJSON:
        return JSON
    case MIMEXML, MIMEXML2:
        return XML
    case MIMEPROTOBUF:
        return ProtoBuf
    case MIMEMSGPACK, MIMEMSGPACK2:
        return MsgPack
    case MIMEYAML:
        return YAML
    case MIMEMultipartPOSTForm:
        return FormMultipart
    default: // case MIMEPOSTForm:
        return Form
    }
}

b := binding.Default(c.Request.Method, c.ContentType())
err := c.ShouldBindBodyWith(&body,b)

Environment

• go version: go version go1.16.9 darwin/amd64
• gin version: 1.7.7
• operating system: Mac OS