rails将来自外部url的元数据插入表中

Question

I have a table for storing links. I'm trying to use the pismo gem for grabbing meta data from a url, and saving that to the table.

In my link controller I have a before filter :

  def pismo_grab_meta_data
    doc = Pismo::Document.new("http://google.com/")
    @link_title = doc.title
  end

Which gets called in the new and create action. In my view I pass the instance variable in a hidden field.

  <%= f.hidden_field :name, :value => @link_title %>   

This works when hard code the url as a string (like the above google example), but fails when I pass it the url params, like so:

doc = Pismo::Document.new(params[:url])

Error: undefined method `gsub!' for nil:NilClass

Pretty new to rails, so I assume I'm doing something stupid here. Any help is very welcome!

<%= form_for(@link, :html => { "data-behavior" => "submit-form"}) do |f| %>
  <% if @link.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@link.errors.count, "error") %> 
        prohibited this link from being saved:
      </h2>
      <ul>
      <% @link.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>
  <%= f.hidden_field :name, :value => @link_title %>
  <div class="field urlsaver">
    <%= f.label :url %><br />
      <% if params[:link].present? %>
        <%= f.text_field :url, :value => params[:link] %>
      <% else %>
        <%= f.text_field :url %>
      <% end %>
  </div>
  <div class="actions">
    <%= f.submit 'Save', :class => 'btn' %>
  </div>
<% end %>

Answer 1

The value you are looking for should be in params[:link][:url]. Change the line to :

doc = Pismo::Document.new(params[:link][:url])