templates/twirp_validate

import (
  "github.com/twitchtv/twirp"
)

{{ $decorator := (or .Vars.DecoratorName (printf "%sWithTwirpValidation" .Interface.Name)) }}

// {{$decorator}} implements {{.Interface.Type}} interface instrumented with arguments validation
type {{$decorator}} struct {
  {{.Interface.Type}}
}

// New{{$decorator}} returns {{$decorator}}
func New{{$decorator}} (base {{.Interface.Type}}) {{$decorator}} {
  return {{$decorator}} {
    {{.Interface.Name}}: base,
  }
}

{{range $method := .Interface.Methods}}
  // {{$method.Name}} implements {{$.Interface.Type}}
  func (_d {{$decorator}}) {{$method.Declaration}} {
    {{- if $method.ReturnsError}}
      {{range $param := $method.Params}}
        {{if not ( and $method.AcceptsContext (eq $param.Name "ctx")) }}
          if _v, _ok := interface{}({{$param.Name}}).(interface{ Validate() error}); _ok {
            if err = _v.Validate(); err != nil {
              err = twirp.NewError(twirp.InvalidArgument, err.Error())
              return
            }
          }
        {{end}}
      {{end}}
    {{end}}
    {{$method.Pass (printf "_d.%s." $.Interface.Name) }}
  }
{{end}}