我的餐厅评论应用程序在Localhost中运行但是当我在heroku上尝试这个并点击链接以显示我得到的评论时我们很抱歉，但出了点问题。 heroku日志显示以下信息，错误为 ActionView :: Template :: Error（未定义方法`大写＆＃39;对于nil：NilClass）：
2014-08-20T09:32:49.175203+00:00 app[web.1]: 46: <h4>
2014-08-20T09:32:49.175221+00:00 app[web.1]: 49: <p><%= review.created_at.strftime("%-m/%-d/%y") %></p>
2014-08-20T09:32:49.175223+00:00 app[web.1]: 50: </td>
2014-08-20T09:32:49.175225+00:00 app[web.1]: app/views/restaurants/show.html.erb:47:in `block in _app_views_restaurants_show_html_erb__3540437068917616550_70094864076860'
2014-08-20T09:32:49.175226+00:00 app[web.1]: app/views/restaurants/show.html.erb:43:in `_app_views_restaurants_show_html_erb__3540437068917616550_70094864076860'
2014-08-20T09:32:49.175303+00:00 app[web.1]: 48: </h4>
2014-08-20T09:32:49.175229+00:00 app[web.1]:
2014-08-20T09:32:49.175284+00:00 app[web.1]: ActionView::Template::Error (undefined method `capitalize' for nil:NilClass):
2014-08-20T09:32:49.175307+00:00 app[web.1]: app/views/restaurants/show.h
tml.erb:47:in `block in _app_views_restaurants_show_html_erb__3540437068917616550_70094864076860'
2014-08-20T09:32:49.175298+00:00 app[web.1]: 45: <td>
2014-08-20T09:32:49.175199+00:00 app[web.1]: ActionView::Template::Error (undefined method `capitalize' for nil:NilClass):
2014-08-20T09:32:49.175282+00:00 app[web.1]:
2014-08-20T09:32:49.175304+00:00 app[web.1]: 49: <p><%= review.created_at.strftime("%-m/%-d/%y") %></p>
2014-08-20T09:32:49.175309+00:00 app[web.1]: app/views/restaurants/show.html.erb:43:in `_app_views_restaurants_show_html_erb__3540437068917616550_70094864076860'
2014-08-20T09:32:49.175300+00:00 app[web.1]: 46: <h4>
2014-08-20T09:32:49.175218+00:00 app[web.1]: 47: <%= "#{review.user.first_name.capitalize} #{review.user.last_name.capitalize[0]}." %>
2014-08-20T09:32:49.175301+00:00 app[web.1]: 47: <%= "#{review.user.first_name.capitalize} #{review.user.last_name.capitalize[0]}." %>
2014-08-20T09:32:49.175310+00:00 app[web.1]:
2014-08-20T09:32:49.175305+00:00 app[web.1]: 50: </td>
2014-08-20T09:32:49.175312+00:00 app[web.1]:
2014-08-20T09:32:49.626763+00:00 heroku[router]: at=info method=GET path="/restaurants/5" host=yelpdemo2014.herokuapp.com request_id=76387447-eb34-431b-9fcf-785a901e95ee fwd="185.30.24.132" dyno=web.1 connect=1ms service=58ms status=500 bytes=1030
2014-08-20T09:32:49.580600+00:00 app[web.1]: Parameters: {"id"=>"5"}
2014-08-20T09:32:49.580595+00:00 app[web.1]: Parameters: {"id"=>"5"}
2014-08-20T09:32:49.617957+00:00 app[web.1]: Rendered restaurants/show.html.erb within layouts/application (20.7ms)
2014-08-20T09:32:49.617970+00:00 app[web.1]: Rendered restaurants/show.html.erb within layouts/application (20.7ms)
2014-08-20T09:32:49.620207+00:00 app[web.1]: Completed 500 Internal Server Error in 37ms
2014-08-20T09:32:49.622252+00:00 app[web.1]: ActionView::Template::Error (undefined method `capitalize' for nil:NilClass):
2014-08-20T09:32:49.580536+00:00 app[web.1]: Processing by RestaurantsController#show as HTML
2014-08-20T09:32:49.620214+00:00 app[web.1]: Completed 500 Internal Server Error in 37ms
2014-0
show.html
div class="row">
<div class="col-md-3">
<%= image_tag @restaurant.image_url %>
<h2>
<%= @restaurant.name %>
</h2>
<div class="star-rating" data-score= <%= @avg_rating %> ></div>
<p><%= "#{@reviews.length} reviews" %></p>
<p>
<strong>Address:</strong>
<%= @restaurant.address %>
</p>
<p>
<strong>Phone:</strong>
<%= @restaurant.phone %>
</p>
<p>
<strong>Website:</strong>
<%= link_to @restaurant.website, @restaurant.website %>
</p>
<%= link_to 'Write a review', new_restaurant_review_path(@restaurant), class: "btn btn-primary" %>
</div>
<div class="col-md-9">
<% if @reviews.blank? %>
<h3>No reviews yet, be the first to write one!</h3>
<% else %>
<table class="table">
<thead>
<tr>
<th class="col-md-3"></th>
<th class="col-md-9"></th>
</tr>
</thead>
<tbody>
<% @reviews.each do |review| %>
<tr>
<td>
<h4>
<%= "#{review.user.first_name.capitalize} #{review.user.last_name.capitalize[0]}." %>
</h4>
<p><%= review.created_at.strftime("%-m/%-d/%y") %></p>
</td>
<td>
<div class="star-rating" data-score= <%= review.rating %> ></div>
<p><%= h(review.comment).gsub(/\n/, '<br/>').html_safe %></p>
</td>
</tr>
<% end %>
</tbody>
</table>
<% end %>
</div>
</div>
<%= link_to 'Edit', edit_restaurant_path(@restaurant), class: "btn btn-link" %> |
<%= link_to 'Back', restaurants_path, class: "btn btn-link" %>
<script>
$('.star-rating').raty({
path: 'https://s3-eu-west-1.amazonaws.com/yelpdemoneil/stars',
readOnly: true,
score: function() {
return $(this).attr('data-score');
}
});
</script>
餐厅控制员
class RestaurantsController < ApplicationController
before_action :set_restaurant, only: [:show, :edit, :update, :destroy]
# GET /restaurants
# GET /restaurants.json
def index
@restaurants = Restaurant.all
end
# GET /restaurants/1
# GET /restaurants/1.json
def show
@reviews = Review.where(restaurant_id: @restaurant.id).order("created_at DESC")
if @reviews.blank?
@avg_rating = 0
else
@avg_rating = @reviews.average(:rating).round(2)
end
end
# GET /restaurants/new
def new
@restaurant = Restaurant.new
end
# GET /restaurants/1/edit
def edit
end
# POST /restaurants
# POST /restaurants.json
def create
@restaurant = Restaurant.new(restaurant_params)
respond_to do |format|
if @restaurant.save
format.html { redirect_to @restaurant, notice: 'Restaurant was successfully created.' }
format.json { render action: 'show', status: :created, location: @restaurant }
else
format.html { render action: 'new' }
format.json { render json: @restaurant.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /restaurants/1
# PATCH/PUT /restaurants/1.json
def update
respond_to do |format|
if @restaurant.update(restaurant_params)
format.html { redirect_to @restaurant, notice: 'Restaurant was successfully updated.' }
format.json { head :no_content }
else
format.html { render action: 'edit' }
format.json { render json: @restaurant.errors, status: :unprocessable_entity }
end
end
end
# DELETE /restaurants/1
# DELETE /restaurants/1.json
def destroy
@restaurant.destroy
respond_to do |format|
format.html { redirect_to restaurants_url }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_restaurant
@restaurant = Restaurant.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def restaurant_params
params.require(:restaurant).permit(:name, :address, :phone, :website, :image)
end
end
答案 0 :(得分：1)
<强>无
错误在于：
ActionView::Template::Error (undefined method `capitalize' for nil:NilClass)
问题是您在variable / object上调用了未设置的方法。正如你所提到的，它只在Heroku上显示，我会说这是由于你没有在数据库中拥有所需的记录而引起的
对此的修复非常简单：
<% if @reviews.any? %>
<% @reviews.each do |review| %>
...
<% end %>
<% end %>
-
数据
最重要的是，您需要在数据库中包含数据，以便填充您希望在应用程序中显示的各种变量/对象
很多人的问题是Heroku没有与本地系统保持相同的数据库，因此如果您希望数据存在，并且没有，那么您的系统将调用您的异常看到
最重要的是，您需要进行一些验证（以确定您所需的数据是否存在），或者您需要seed your production database以及您的应用所需的记录
答案 1 :(得分：1)
我同意Rich，这是另一种解决方法：
我使用try作为可选属性，例如＆＃34;名字＆＃34;因为我不想强迫用户通过验证来提交它们：
<%= "#{review.user.first_name.try(:capitalize)} #{review.user.last_name.try(:capitalize)}." %>
这样就不应该抛出异常天气或者没有属性