我只使用 Ruby 工作了很短的时间,今天我在处理日历以提出请求时遇到了瓶颈。我花时间在 stackoverflow、ruby 指南等上搜索不同的未定义方法错误文档,并研究了 strftime。我找到了一个使用 try 部分解决我的问题的解决方案,但现在它实际上并没有通过 strftime 来显示请求,即使 rails 服务器在帖子中拾取它。我可以正常访问我的日历,然后点击新请求按钮,填写表格,但是当我去发布该表格时,浏览器会给我这个:
undefined method `strftime' for nil:NilClass
Extracted source (around line #3):
1: <h1><%= @vacationrequest.request_name %></h1>
2:
3: <p class="info">Requested For <%= @vacationrequest.request_date.strftime("%B %e, %Y") %></p>
4:
5: <%= simple_format @vacationrequest.message %>
6:
我在 Rails 服务器上收到此错误:
Started GET "/vacationrequests/1" for 127.0.0.1 at 2012-10-17 15:18:14 -0400
Processing by VacationrequestsController#show as HTML
Parameters: {"id"=>"1"}
←[1m←[35mVacationrequest Load (0.0ms)←[0m SELECT "vacationrequests".* FROM "v
acationrequests" WHERE "vacationrequests"."id" = ? LIMIT 1 [["id", "1"]]
Rendered vacationrequests/show.html.erb within layouts/application (15.6ms)
Completed 500 Internal Server Error in 31ms
ActionView::Template::Error (undefined method strftime' for nil:NilClass):
1: <h1><%= @vacationrequest.request_date %></h1>
2:
3: <p class="info">Requested For <%= @vacationrequest.request_date.strftime(
"%B %e, %Y") %></p>
4:
5: <%= simple_format @vacationrequest.message %>
6:
app/views/vacationrequests/show.html.erb:3:inapp_views_vacationrequests_sho
w_html_erb_217743956_18446544'
这是我的展示 View :
<h1><%= @vacationrequest.request_name %></h1>
<p class="info">Requested For <%= @vacationrequest.request_date.strftime("%B %e, %Y") %></p>
<%= simple_format @vacationrequest.message %>
<p>
<%= link_to "Edit Request", edit_vacationrequest_path(@vacationrequest) %> |
<%= link_to "Back to Requests", vacationrequests_path %>
</p>
这是用户将请求信息放入的_form:
<%= form_for @vacationrequest do |f| %>
<% if @vacationrequest.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(@vacationrequest.errors.count, "error") %> prohibited this request from being saved: if this continue to happens please email the error to alex@allsafeindustries.com</h2>
<ul>
<% @vacationrequest.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :request_name %><br />
<%= f.text_field :request_name %>
</div>
<div class="field">
<%= f.label :request_date %><br />
<%= f.text_field :request_date %>
</div>
<div class="field">
<%= f.label :message %><br />
<%= f.text_area :message %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
最后是我的 Controller 中的 show 和 index 方法:
def index
@vacationrequests = Vacationrequest.all
@vacationrequests_by_date = @vacationrequests.group_by(&:request_date)
@date = params[:date] ? Date.parse(params[:date]) : Date.today
end
def show
@vacationrequest = Vacationrequest.find(params[:id])
end
任何人都可以告诉我哪里不合适或者为什么这是零吗?谢谢。
响应这里的答案是我现在从服务器得到的:
Started POST "/vacationrequests" for 127.0.0.1 at 2012-10-17 20:18:00 -0400
Processing by VacationrequestsController#create as HTML
Parameters: {"utf8"=>"√", "authenticity_token"=>"E1+xXP0pAIQpwMZruswxIZIrTZB3b
c3NlW3iRv9OLqU=", "vacationrequest"=>{"request_name"=>"One more time", "request_
date"=>"10/31/2012", "message"=>"Lucky number 7?"}, "commit"=>"Create Vacationre
quest"}
←[1m←[35m (0.0ms)←[0m begin transaction
←[1m←[36mSQL (15.6ms)←[0m ←[1mINSERT INTO "vacationrequests" ("created_at", "
message", "request_date", "request_name", "updated_at") VALUES (?, ?, ?, ?, ?)←[
0m [["created_at", Thu, 18 Oct 2012 00:18:00 UTC +00:00], ["message", "Lucky nu
mber 7?"], ["request_date", nil], ["request_name", "One more time"], ["updated_a
t", Thu, 18 Oct 2012 00:18:00 UTC +00:00]]
←[1m←[35m (109.2ms)←[0m commit transaction
Redirected to http://localhost:3000/vacationrequests/7
Completed 302 Found in 125ms (ActiveRecord: 124.8ms)
Started GET "/vacationrequests/7" for 127.0.0.1 at 2012-10-17 20:18:01 -0400
Processing by VacationrequestsController#show as HTML
Parameters: {"id"=>"7"}
←[1m←[36mVacationrequest Load (0.0ms)←[0m ←[1mSELECT "vacationrequests".* FRO
M "vacationrequests" WHERE "vacationrequests"."id" = ? LIMIT 1←[0m [["id", "7"]
]
Rendered vacationrequests/show.html.erb within layouts/application (15.6ms)
Completed 500 Internal Server Error in 16ms
ActionView::Template::Error (undefined method `strftime' for nil:NilClass):
1: <h1><%= @vacationrequest.request_name %></h1>
2: <%= debug @vacationrequest %>
3: <p class="info">Requested For <%= @vacationrequest.request_date.strftime(
"%B %e, %Y") %></p>
4:
5: <%= simple_format @vacationrequest.message %>
6:
app/views/vacationrequests/show.html.erb:3:in `_app_views_vacationrequests_sho
w_html_erb___377763931_36688344'
我还使用了 View 调试并检查了我的方案,所有属性似乎都正确排列。
至于这里评论中的请求是我的 Vacationrequest 模型:
class Vacationrequest < ActiveRecord::Base
attr_accessible :message, :request_name, :request_date
end
再一次感谢您的帮助。
这是架构:
ActiveRecord::Schema.define(:version => 20121016194123) do
create_table "vacationrequests", :force => true do |t|
t.string "request_name"
t.date "request_date"
t.text "message"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
end
和创建 Controller 操作代码:
def create
@vacationrequest = Vacationrequest.new(params[:vacationrequest])
if @vacationrequest.save
redirect_to @vacationrequest, notice: "Created Request!"
else
render :new
end
end
当我看到这个时,问题的一部分是我的模式是复数而我的 Controller 是单数吗?再次感谢。
最佳答案
First you have to make sure if there is 'request_date' filled before you create a record by applying ActiveRecord validations.
Secondly, you can use ruby's try method to avoid such exceptions
<%= @vacationrequest.try(:request_date).try(:strftime, '%B %e, %Y') %>
编码愉快!
更新
在较新版本的 Ruby 中,您可以使用 &.
-> lonely operator
代替上述解决方案。它也被称为安全导航运算符。
<%= @vacationrequest&.request_date&.strftime('%B %e, %Y') %>
关于ruby-on-rails - Ruby 未定义方法 `strftime' 为 nil :NilClass,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12943362/