Question

I'm learning how to use Sinatra. I figured out that when I pass object as locals, e.g.:

product = FetchProduct.new.call(id) #function finds exact Product instance
erb :"products/show", locals: { product: product }

I can use product object in my views with all instance methods I declared. But I can't use any class method, any attempt to do so gives me uninitialized constant error. What should I do if I want to use Product.format_price(product.price) method? Is there any way to pass class methods to Sinatra views?

Answer 1

klass = const_get( product.class )
klass.format_price

But that doesn't really make sense because you already know you want Product.format_price. So why don't you use Product.format_price?

Answer 2

在你的观点中运行这种逻辑通常是一个坏主意。最佳做法是尽可能满足其需要。

请注意您在视图中运行类方法的原因是因为您的视图中无法访问Product，而且说实话，如果您想关注，则不应该如此MVC原则。

如果它只是视图中您需要的format_price方法（特别是因为您似乎将Product的实例传递给Product.format_price这很奇怪而且大代码嗅觉），然后创建一个名为format_price的辅助方法，可以被视图访问，或者更好的是，在控制器中创建一个名为format_price的辅助方法（或者包含在你的辅助模块中）控制器）并将返回值作为本地传递

get '/' do
  product = FetchProduct.new.call(id)
  erb :'products/show', locals: { 
    product: product, 
    price: format_price(product)
  }
end

private

def format_price(product)
  # awesome formatting logic
end

Ruby, Sinatra views and class methods

2 个答案: