type listContext struct {
	Collection string
	Keys       []string
	Error      string
}

func (c *collectionTopic) handleCollection(w http.ResponseWriter, _ *http.Request, collection string) {
	k, err := c.listCollection(collection)
	context := listContext{}
	if err == nil {
		context.Collection = collection
		context.Keys = k
	} else {
		context.Error = err.Error()
	}
	fw.RenderHTML(w, c.listTmpl, context)
}