Method fireFallbackViewOnce

context/context.go:3849–3888

(err ErrViewNotExist)

const fallbackViewOnce = "iris.fallback.view.once"

func (ctx *Context) fireFallbackViewOnce(err ErrViewNotExist) error {
	// Note(@kataras): this is our way to keep the same View method for
	// both fallback and normal views, remember, we export the whole
	// Context functionality to the end-developer through the fallback view provider.
	if ctx.values.Get(fallbackViewOnce) != nil {
		return err
	}

	v := ctx.values.Get(ctx.app.ConfigurationReadOnly().GetFallbackViewContextKey())
	if v == nil {
		return err
	}

	providers, ok := v.([]FallbackViewProvider)
	if !ok {
		return err
	}

	ctx.values.Set(fallbackViewOnce, struct{}{})

	var pErr error
	for _, provider := range providers {
		pErr = provider.FallbackView(ctx, err)
		if pErr != nil {
			if vErr, ok := pErr.(ErrViewNotExist); ok {
				// This fallback view does not exist or it's not responsible to handle,
				// try the next.
				pErr = vErr
				continue
			}
		}

		// If OK then we found the correct fallback.
		// If the error was a parse error and not a template not found
		// then exit and report the pErr error.
		break
	}

	return pErr
}

// FallbackView registers one or more fallback views for a template or a template layout.
// When View cannot find the given filename to execute then this "provider"