[FEATURE REQUEST] Log when I18n Translation Fails?

[AlbinoGeek]

Summary

A call to ctx.Tr() with an invalid or mistyped key might go unnoticed if it does not log the "key not found" somewhere.

There are many reasons this could happen:

• Perhaps something new was added in one language, but not in another?
• Perhaps someone simply fat-fingered or typo'd a translation key name.
• Maybe you were using dynamic key assembly in a template.
• Maybe the end-user had access to the translation files (a CRM)

[kataras]

Hello @AlbinoGeek, I pushed a commit which gives you a lot of info and you are able to both log and inject a value there too. Example:

iris/_examples/i18n/main.go

Lines 28 to 51 in a491cdf

	// Use DefaultMessageFunc to customize the return value of a not found key or lang.
	// All language inputs fallback to the default locale if not matched.
	// This is why this one accepts both input and matched languages,
	// so the caller can be more expressful knowing those.
	// Defaults to nil.
	app.I18n.DefaultMessageFunc = func(langInput, langMatched, key string, args ...interface{}) string {
	msg := fmt.Sprintf("user language input: %s: matched as: %s: not found key: %s: args: %v", langInput, langMatched, key, args)
	app.Logger().Warn(msg)
	return msg
	}
	// Load i18n when customizations are set in place.
	//
	// First parameter: Glob filpath patern,
	// Second variadic parameter: Optional language tags, the first one is the default/fallback one.
	err := app.I18n.Load("./locales/*/*.ini", "en-US", "el-GR", "zh-CN")
	if err != nil {
	panic(err)
	}
	app.Get("/not-matched", func(ctx iris.Context) {
	text := ctx.Tr("not_found_key", "some", "values", 42)
	ctx.WriteString(text)
	// user language input: en-gb: matched as: en-US: not found key: not_found_key: args: [some values 42]
	})

[AlbinoGeek]

That's awesome, I would say that Resolved this request, as I now have control to log or dynamically generate if required.