Rails -TypeError：无法将ActionController :: Parameters转换为文本

Question

我正在使用jQuery Preview开发一个网站，以获取任何链接的标题，描述或favction_url。

jQuery预览： https : //github.com/embedly/jquery-preview/

我的链接控制器具有以下代码：

class LinksController < ApplicationController
    before_action :find_link, :only => [:edit, :update, :destroy]

    def index
        @links = Link.all
    end

    def new
        @link = Link.new
    end

    def create
        @link = Link.new(:content => link_params, :title => params[:title], :description => params[:description], :favicon_url => params[:favicon_url])

        if @link.save
            redirect_to root_path
        else
            render :new
        end
    end

    def edit
    end

    def update

        if @link.update_attributes(link_params)
            redirect_to root_path
        else
            render :edit
        end
    end

    def destroy
        @link.destroy

        redirect_to root_path
    end

private

    def link_params
        params.require(:link).permit(:content)
    end

    def find_link
        @link = Link.find(params[:id])
    end
end

在我的views / links / new.html.erb中有以下代码：

<script>
    // Set up preview.
    $('#url').preview({key:'key'})

    // On submit add hidden inputs to the form.
    $('form').on('submit', function(){
      $(this).addInputs($('#url').data('preview'));
      return true;
    });
</script>

<h1>Share Link</h1>
<%= simple_form_for @link do |f| %>
    <%= f.input :content, :input_html => {:id => "url"} %>
    <div class="selector-wrapper"></div>
    <%= f.button :submit, :disable_with => "Submiting...", :class => "btn btn-primary btn-large" %>
<% end %>

但是，当我单击提交时，出现错误：

TypeError：无法将ActionController :: Parameters转换为文本：INSERT INTO“链接”（“内容”，“ created_at”，“描述”，“ favicon_url”，“标题”，“ updated_at”）值（？，？，？ ，？，？，？）

并标记了这行链接控制器代码：

if @link.save

谁能帮我？ 谢谢。

我得到的参数如下所示，除了content ，其他参数来自jQuery Preview：

Parameters: {"utf8"=>"✓", 

"authenticity_token"=>"NDqZbleBkEEZzshRlTM+d6GZdVEGAoO1W/mp7B68ZZ0=", 

"link"=>{"content"=>"http://stackoverflow.com/questions/20815513/rails-typeerror-cant-cast-actioncontrollerparameters-to-text/20815623?noredirect=1#20815623"}, 

"commit"=>"submit", 

"original_url"=>"http%3A//stackoverflow.com/questions/20815513/rails-typeerror-cant-cast-actioncontrollerparameters-to-text/20815623%3Fnoredirect%3D1%2320815623", 

"url"=>"http%3A//stackoverflow.com/questions/20815513/rails-typeerror-cant-cast-actioncontrollerparameters-to-text", 

"type"=>"html", 

"provider_url"=>"http%3A//stackoverflow.com", 

"provider_display"=>"stackoverflow.com", "provider_name"=>"Stackoverflow", 

"favicon_url"=>"http%3A//cdn.sstatic.net/stackoverflow/img/favicon.ico", 

"title"=>"Rails%20-TypeError%3A%20can%27t%20cast%20ActionController%3A%3AParameters%20to%20text", 

    "description"=>"I%27m%20developing%20a%20website%20using%20jQuery%20Preview%20to%20fetch%20the%20title%2C%20description%20or%20favction_url%20of%20any%20link.", 

"thumbnail_url"=>"http%3A//cdn.sstatic.net/stackoverflow/img/apple-touch-icon@2.png%3Fv%3Dfde65a5a78c6", 

"author_name"=>"", 

"author_url"=>"", 

"media_type"=>"", 

"media_html"=>"", 

"media_width"=>"", 

"media_height"=>""}

Answer 1

在您的create操作中，您试图将link_params哈希值分配为需要文本的content值。

通过对传递属性的Link.new(...)的调用，您正在批量分配属性，而使用Rails4强大的参数，您需要将所有属性添加到将要批量分配的permit列表中。

如下更新create和link_params方法定义：

# app/controllers/links_controller.rb

def create
    @link = Link.new(link_params)

    if @link.save
        redirect_to root_path
    else
        render :new
    end
end

private

def link_params
    params.require(:link).permit(:content, :title, :description, :favicon_url)
end

更新：合并参数哈希中的某些属性，并将它们合并为params[:link]

# app/controllers/links_controller

private

def link_params
  # Select parameters you need to merge
  params_to_merge = params.select { |k, v| ['title', 'description', 'favicon_url'].include?(k) }
  params.require(:link).permit(:content).merge(params_to_merge)
end