如果URL包含字符串？

Question

如果:name传递给_form，而如果:name未传递，我该如何使用条件做一件事？

随着:name通过：

Started GET "/inspirations/new?inspiration%5Bname%5D=Always+trust+yourself+more+than+you+doubt+yourself" for 127.0.0.1 at 2016-11-08 01:00:44 -0500 
Processing by InspirationsController#new as HTML 
    Parameters: {"inspiration"=>{"name"=>"Always trust yourself more than you doubt yourself"}} 

没有:name通过：

Started GET "/inspirations/new" for 127.0.0.1 at 2016-11-08 01:16:18 -0500 
Processing by InspirationsController#new as */* 
    User Load (0.3ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT 1 [["id", 1]] 
    CACHE (0.0ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT 1 [["id", 1]] 
    Inspiration Load (0.4ms) SELECT "inspirations".* FROM "inspirations" WHERE "inspirations"."id" IS NULL LIMIT 1 
    Rendered inspirations/_form.html.erb (4.1ms) 
    Rendered inspirations/new.html.erb within layouts/modal (5.9ms) 
Completed 200 OK in 49ms (Views: 41.9ms | ActiveRecord: 0.7ms) 

_form

<%= simple_form_for(@inspiration) do |f| %> 
    <%= f.text_area :name %> 
    <% if params[:name].nil? %> # Should Be Triggered If No :name Is Present in URL 
    etc... 
    <% end %> 
<% end %> 

因此，例如，当一个URL包含字符串：

http://www.livetochallenge.com/inspirations/new?inspiration%5Bname%5D=Life+would+be+easier+if+I+had+the+source+code.

但我经常使用URL缩短器。

没有为我工作：

• Is there a way to check if part of the URL contains a certain string
• including url parameters in if statement

Answer 1

试试这个：

<%= simple_form_for(@inspiration) do |f| %> 
    <%= f.text_area :name %> 
    <% if params[:inspiration].try(:[], :name).nil? %> # Should Be Triggered If No :name Is Present in URL 
    etc... 
    <% end %> 
<% end %> 

这将检查：名字里PARAMS [：灵感]只如果后者在场。所以，不应该发生错误。

Answer 2

您可以使用fetch来避免错误。

<%= simple_form_for(@inspiration) do |f| %> 
    <%= f.text_area :name %> 
    <%= f.text_area :name %> 
    <% name = params.fetch(:inspiration, {}).fetch(:name, nil) %> 
    <% if name.nil? %> 
    etc... 
    <% end %> 
<% end %>