Ruby on Rails：控制器中的 params[] 变量

Question

我是 Ruby（和 Rails）的新手，所以对这个基本问题表示歉意。

据我了解，控制器内部的params[...] 变量应该保存我刚刚在网页上提交的表单中的数据？我正在尝试使用以下代码根据字段是否为空白来更新模型：

@s3_destination = S3Destination.find(params[:id])

if params[:credentials_secret].to_s.empty?

    update = @s3_destination.update_attributes({
         :name => params[:name],
         :bucket => params[:bucket],
         :region => params[:region],
         :credentials_id => params[:credentials_id]
    })

    if update
        redirect_to @s3_destination
    else
        render 'edit'
    end

else

    update = @s3_destination.update_attributes({
         :name => params[:name],
         :bucket => params[:bucket],
         :region => params[:region],
         :credentials_id => params[:credentials_id],
         :credentials_secret => params[:credentials_secret],
    })

    if update
        redirect_to @s3_destination
    else
        render 'edit'
    end

end

控制器动作执行良好，但模型中现在没有数据，所以我假设我在 update_attributes 函数中设置它时做错了。

params[:name] 不应该从名为“name”的表单元素中获取值吗？还是我误解了它的目的？

编辑

回答一些问题：

我相信这是相关的日志条目，对我来说一切正常吗？

2015 年 12 月 9 日 12:40:51 +0000 为 127.0.0.1 启动 PATCH "/s3_destinations/1" 由 S3DestinationsController#update 处理为 HTML 参数：{"utf8"=>"✓", "authenticity_token"=>"a26uTf4+58v/O+pTqOYn0R7cjzGVWBnbFVdJ1OWwNnybEpUdYt2FNruOla/ikOnAFLpY3mn71Wow5oV​​ee+R3Ng==", "s3_destination"=>{"name,=>"Cogative Bucket 1" “bucket”=>“cogative-backup-01”，“region”=>“eu-west-1”，“credentials_id”=>“AKIAIZG2HJ35NR3DQYGA”，“credentials_secret”=>“12345”}，“commit”=> "保存 S3 目的地", "id"=>"1"} 用户负载 (0.1ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT 1 [["id", 1]] S3Destination 负载 (0.0ms) SELECT "s3_destinations".* FROM "s3_destinations" WHERE "s3_destinations"."id" = ?限制 1 [["id", 1]] (0.1ms) 开始交易 (0.0ms) 提交事务 重定向到 http://localhost:3000/s3_destinations/1 Completed 302 Found in 3ms (ActiveRecord: 0.2ms)

表单本身是这样生成的：

<h2>Editing AWS S3 Destination</h2>

<%= form_for :s3_destination, url: s3_destination_path(@s3_destination), method: :patch do |f| %>

    <% if @s3_destination.errors.any? %>
        <div id="error_explanation">
          <h2>
            <%= pluralize(@s3_destination.errors.count, "error") %> prohibited this source from being saved:
          </h2>
          <ul>
            <% @s3_destination.errors.full_messages.each do |msg| %>
                <li><%= msg %></li>
            <% end %>
          </ul>
        </div>
    <%end %>

    <p>
      <%= f.label :name %><br>
      <%= f.text_field :name %>
    </p>

    <p>
      <%= f.label :bucket %><br>
      <%= f.text_field :bucket %>
    </p>

    <select name="s3_destination[region]">
      <option value="us-east-1">US Standard (N. Virginia)</option>
      <option value="us-west-2">US West (Oregon)</option>
      <option value="us-west-1">US West (N. California)</option>
      <option value="eu-west-1">EU (Ireland)</option>
      <option value="eu-central-1">EU (Frankfurt)</option>
      <option value="ap-southeast-1">Asia Pacific (Singapore)</option>
      <option value="ap-southeast-2">Asia Pacific (Sydney)</option>
      <option value="ap-northeast-1">Asia Pacific (Tokyo)</option>
      <option value="sa-east-1">South America (Sao Paulo)</option>
    </select>

    <p>
      <%= f.label :credentials_id %><br>
      <%= f.text_field :credentials_id %>
    </p>

    <p>
      <%= f.label :credentials_secret %><br>
      <%= f.password_field :credentials_secret %>
    </p>

    <p>
      <%= f.submit %>
    </p>

<% end %>

Answer 1

你引用了params[:name]，但是参数都捆绑在params[:s3_destination]下，所以你需要引用params[:s3_destination][:name]等。

这样做的好处是您不需要调用要更新的每个属性。在简单的情况下，您可以

@s3_destination.update_attributes(params[:s3_destination])

为了安全（例如，我不能编辑表单来提交你不想让我编辑的属性），你应该使用strong parameters：

s3_params = params.require(:s3_destination)
  .permit(:name, :bucket, :region, :credentials_id, :credentials_secret)
@s3_destination.update_attributes(s3_params)

然后对于您的 credentials_secret 逻辑，您可以从该哈希中删除空白值：

s3_params = params.require(:s3_destination)
  .permit(:name, :bucket, :region, :credentials_id, :credentials_secret)
s3_params.delete(:credentials_secret) if s3_params[:credentials_secret].blank?
@s3_destination.update_attributes(s3_params)

blank? 将同时捕获 nil 和 ""，就像您当前对 .to_s.empty? 所做的那样。