Ii. Use the data check function provided by rails3.0 to check input data

Next, go to the previous article and open the app/models/product. rb file.

1 class Product < ActiveRecord::Base
2 end

In this file, you can add some statements to restrict the input data.

validates :title, :description, :image_url, :presence => true

This statement indicates that the constraints for opening fields are non-empty. In this case, check whether the title, description, image_url, and these fields are non-empty,

Come,

validates :price, :numericality => {:greater_than_or_equal_to => 0.01}

This statement requires that the price value is greater than or equal to 0.01,

Come back

validates :title, :uniqueness => true

This statement verifies that the title field cannot be repeated,

1 validates :image_url, :format => {
2     :with    => %r{\.(gif|jpg|png)$}i,
3     :message => 'must be a URL for GIF, JPG or PNG image.'
4   }

Finally, this is to constrain image_url and process it through a regular expression. The format must be gif/jpg/png. The criterion is that the last decimal point must be the extension,

OK, I'm done, so the complete code should be like this.

class Product < ActiveRecord::Base  validates :title, :description, :image_url, :presence => true  validates :price, :numericality => {:greater_than_or_equal_to => 0.01}  validates :title, :uniqueness => true  validates :image_url, :format => {    :with    => %r{\.(gif|jpg|png)$}i,    :message => 'must be a URL for GIF, JPG or PNG image.'  }end

You can try to open the http: // localhost: 3000/products Page and directly press submit? Haha