Ruby-on-rails 如何从 params[:something] 中删除一个字段
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How to remove a field from params[:something]
提问by providence
My registration form, which is a form for the Users model, takes a string value for company. However, I have just made a change such that users belongs_to companies. Therefore, I need to pass an object of Company to the Users model.
我的注册表单是用户模型的表单，它采用公司的字符串值。但是，我刚刚进行了更改，使用户属于公司。因此，我需要将 Company 的对象传递给 Users 模型。
I want to use the string value from the form to obtain the an object of Company:
我想使用表单中的字符串值来获取 Company 的对象：
@user.company = Company.find_by_name(params[:company])
I believe the above works, however the form is passing the :company (which is string) into the model when I call:
我相信上面的方法是有效的，但是当我调用时，表单将 :company （它是字符串）传递到模型中：
@user = User.new(params[:user])
Therefore, I want to know (and cannot find how) to remove the :company param before passing it to the User model.
因此，我想知道（并且找不到如何）在将 :company 参数传递给 User 模型之前删除它。
回答by Jeremy Ruten
Rails 4/5 - edited answer(see comments)
Rails 4/5 - 编辑的答案（见评论）
Since this question was written newer versions of Rails have added the extract!and excepteg:
由于此问题是编写的，较新版本的 Rails 已添加了摘录！和除外例如：
new_params = params.except[the one I wish to remove]
This is a safer way to 'grab' all the params you need into a copy WITHOUT destroying the original passed in params (which is NOT a good thing to do as it will make debugging and maintenance of your code very hard over time).
这是一种更安全的方法，可以将您需要的所有参数“抓取”到副本中，而不会破坏传入的原始参数（这不是一件好事，因为随着时间的推移，它会使代码的调试和维护变得非常困难）。
Or you could just pass directly without copying eg:
或者你可以直接通过而不复制，例如：
@person.update(params[:person].except(:admin))
The extract!(has the ! bang operator) will modify the original so use with more care!
该extract!（有！砰运营商）将修改原来那么更为谨慎使用！
Original Answer
原答案
You can remove a key/value pair from a Hash using Hash#delete:
您可以使用Hash#delete以下方法从哈希中删除键/值对：
params.delete :company
If it's contained in params[:user], then you'd use this:
如果它包含在 params[:user] 中，那么你可以使用这个：
params[:user].delete :company
回答by samuraisam
You should probably be using hash.except
您可能应该使用 hash.except
class MyController < ApplicationController
def explore_session_params
params[:explore_session].except(:account_id, :creator)
end
end
It accomplishes 2 things: allows you to exclude more than 1 key at a time, and doesn't modify the original hash.
它完成两件事：允许您一次排除 1 个以上的键，并且不修改原始哈希。
回答by Deepak Mahakale
The correct way to achieve this is using strong_params
实现这一目标的正确方法是使用 strong_params
class UsersController < ApplicationController
def create
@user = User.new(user_params)
end
private
def user_params
params.require(:user).permit(:name, :age)
end
end
This way you have more control over which params should be passed to model
这样您就可以更好地控制应将哪些参数传递给模型
回答by Taimoor Changaiz
respond_to do |format|
if params[:company].present?
format.html { redirect_to(:controller => :shopping, :action => :index) }
else
format.html
end
end
this will remove params from the url
这将从网址中删除参数
回答by Washington Botelho
To be possible to delete you can do a memo:
为了可以删除你可以做一个备忘录：
def parameters
@parameters ||= params.require(:root).permit(:foo, :bar)
end
Now you can do:
现在你可以这样做：
parameteres.delete(:bar)
parameters
=> <ActionController::Parameters {"foo" => "foo"} permitted: true>
