Ruby/Datamapper创建或更新问题 - 不可改变的错误

Question

我有一个用户类，可以选择有一个帐单地址。当我发布付款表格时，假设用户表示他们希望保存其帐单地址详细信息，我想要创建一个新的地址记录或更新原始地址记录。

我已经尝试了很多事情，但我可以向工作代码最接近的是...

class User 
    include DataMapper::Resource 
    property :id,   Serial 
    property :provider, String, :length => 100 
    property :identifier, String, :length => 100 
    property :username, String, :length => 100 
    property :remember_billing, Boolean 
    has 1, :billing_address 
end 

class BillingAddress 
    include DataMapper::Resource 
    property :first,  String, :length => 20 
    property :surname,  String, :length => 20 
    property :address1, String, :length => 50 
    property :address2, String, :length => 50 
    property :towncity, String, :length => 40 
    property :state,  String, :length => 2 
    property :postcode, String, :length => 20 
    property :country,  String, :length => 2 
    property :deleted_at, ParanoidDateTime 
    belongs_to :user, :key => true 
end 

post "/pay" do 
    @post = params[:post] 
    @addr = params[:addr] 
    if @addr == nil 
    @addr = Hash.new 
    end 

    user = User.first(:identifier => session["vya.user"]) 
    user.remember_billing = [email protected]["remember"] 

    if user.remember_billing 
    user.billing_address = BillingAddress.first_or_create({ :user => user }, @addr) 
    end 
    user.save 
    ... 

时，没有记录工作正常。但是，如果已经有记录，它会保留原始值。

我看到了一个类似的帖子 但如果我改变代码是

user.billing_address = BillingAddress.first_or_create(:user => user).update(@addr) 

我得到的错误

DataMapper::ImmutableError at /pay 
Immutable resource cannot be modified 

任何帮助非常赞赏

Answer 1

你链接很多东西在一起，那里。如何：

billing = BillingAddress.first_or_new(:user => user, @addr) #don't update, send the hash as second parameter 
billing.saved? ? billing.update(@addr) : billing.save 
raise "Billing is not saved for some reason: #{billing.errors.inspect}" unless billing && billing.saved? 
user.billing_address = billing 
user.save