时间戳

首页 > 解决方案 > 尝试使用 API 时 nil:NilClass 的未定义方法“[]”

ruby-on-rails - 尝试使用 API 时 nil:NilClass 的未定义方法“[]”

问题描述

我是 ruby​​ 的新手，我正在尝试使用一个 api 并显示我从中获得的数据，但我不断收到此错误：nil:NilClass 的未定义方法“[]”。这可能是一个愚蠢的错误，但我又是新手，无法弄清楚。这是我的控制器：

class RecipeController < ApplicationController
  def Recipe
  end

  def search
    recipe = find_recipe(params[:targetCalories])
    unless recipe
      flash[:alert] = 'Recipe not found'
      return render action: :Recipe
    end
    @recipe = recipe.first
  end

  private
  def request_api(url)
    response = Excon.get(
      url,
      headers: {
        'X-RapidAPI-Host' => URI.parse(url).host,
        'X-RapidAPI-Key' => ENV.fetch('RAPIDAPI_API_KEY')
      }
    )
    return nil if response.status != 200
    JSON.parse(response.body)
  end
  def find_recipe(name)
    request_api(
      "https://spoonacular-recipe-food-nutrition-v1.p.rapidapi.com/recipes/mealplans/generate/#{URI.encode(targetCalories)}"
    )
  end

end

这是我的html：

<div class="container">
  <div class="row">
    <div class="col-lg-12 mt-5">
         <% if flash[:alert] %>
             <div class="alert alert-warning"><%= flash[:alert] %></div>
        <% end %>
      <div class="mx-auto mt-5" style="width: 400px">
        <%= form_with(url: search_path, method: 'get', local: true) do %>
          <div class="form-group">
            <%= label_tag :country, 'Type amount of calories '%>
            <%= text_field_tag :country, nil, placeholder: 'Eg. 1000', class: 'form-control' %>
          </div>
          <%= button_tag 'Search', class: 'btn btn-success btn-block' %>
        <% end %>
      </div>
    </div>
  </div>

  <div class="container">
  <div class="row mt-5">
    <div class="col-lg-6">
      <h4>Recipe info</h4>
      <dl>
        <dt>Day</dt>
        <dd><%= @recipe['day'] %></dd>
        <dt>Capital</dt>
        <dd><%= @recipe['type'] %></dd>
        <dt>Currency</dt>
        <dd><%= @recipe['value'].join(', ') %></dd>
      </dl>
    </div>

  </div>
</div>

编辑：这是完整的堆栈跟踪

app/views/recipe/Recipe.html.erb:26
actionview (6.0.2.1) lib/action_view/base.rb:274:in `_run'
actionview (6.0.2.1) lib/action_view/template.rb:185:in `block in render'
activesupport (6.0.2.1) lib/active_support/notifications.rb:182:in `instrument'
actionview (6.0.2.1) lib/action_view/template.rb:386:in `instrument_render_template'
actionview (6.0.2.1) lib/action_view/template.rb:183:in `render'
actionview (6.0.2.1) lib/action_view/renderer/template_renderer.rb:59:in `block (2 levels) in render_template'
actionview (6.0.2.1) lib/action_view/renderer/abstract_renderer.rb:89:in `block in instrument'
activesupport (6.0.2.1) lib/active_support/notifications.rb:180:in `block in instrument'
activesupport (6.0.2.1) lib/active_support/notifications/instrumenter.rb:24:in `instrument'
activesupport (6.0.2.1) lib/active_support/notifications.rb:180:in `instrument'
actionview (6.0.2.1) lib/action_view/renderer/abstract_renderer.rb:88:in `instrument'
actionview (6.0.2.1) lib/action_view/renderer/template_renderer.rb:58:in `block in render_template'
actionview (6.0.2.1) lib/action_view/renderer/template_renderer.rb:66:in `render_with_layout'
actionview (6.0.2.1) lib/action_view/renderer/template_renderer.rb:57:in `render_template'
actionview (6.0.2.1) lib/action_view/renderer/template_renderer.rb:13:in `render'
actionview (6.0.2.1) lib/action_view/renderer/renderer.rb:61:in `render_template_to_object'
actionview (6.0.2.1) lib/action_view/renderer/renderer.rb:29:in `render_to_object'
actionview (6.0.2.1) lib/action_view/rendering.rb:118:in `block in _render_template'
actionview (6.0.2.1) lib/action_view/base.rb:304:in `in_rendering_context'
actionview (6.0.2.1) lib/action_view/rendering.rb:117:in `_render_template'
actionpack (6.0.2.1) lib/action_controller/metal/streaming.rb:219:in `_render_template'
actionview (6.0.2.1) lib/action_view/rendering.rb:103:in `render_to_body'
actionpack (6.0.2.1) lib/action_controller/metal/rendering.rb:52:in `render_to_body'
actionpack (6.0.2.1) lib/action_controller/metal/renderers.rb:142:in `render_to_body'
actionpack (6.0.2.1) lib/abstract_controller/rendering.rb:25:in `render'
actionpack (6.0.2.1) lib/action_controller/metal/rendering.rb:36:in `render'
actionpack (6.0.2.1) lib/action_controller/metal/instrumentation.rb:44:in `block (2 levels) in render'
activesupport (6.0.2.1) lib/active_support/core_ext/benchmark.rb:14:in `block in ms'
C:/Ruby26-x64/lib/ruby/2.6.0/benchmark.rb:308:in `realtime'
activesupport (6.0.2.1) lib/active_support/core_ext/benchmark.rb:14:in `ms'
actionpack (6.0.2.1) lib/action_controller/metal/instrumentation.rb:44:in `block in render'
actionpack (6.0.2.1) lib/action_controller/metal/instrumentation.rb:85:in `cleanup_view_runtime'
activerecord (6.0.2.1) lib/active_record/railties/controller_runtime.rb:34:in `cleanup_view_runtime'
actionpack (6.0.2.1) lib/action_controller/metal/instrumentation.rb:43:in `render'
remotipart (1.4.4) lib/remotipart/render_overrides.rb:23:in `render'
actionpack (6.0.2.1) lib/action_controller/metal/implicit_render.rb:35:in `default_render'
actionpack (6.0.2.1) lib/action_controller/metal/basic_implicit_render.rb:6:in `block in send_action'
actionpack (6.0.2.1) lib/action_controller/metal/basic_implicit_render.rb:6:in `tap'
actionpack (6.0.2.1) lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
actionpack (6.0.2.1) lib/abstract_controller/base.rb:196:in `process_action'
actionpack (6.0.2.1) lib/action_controller/metal/rendering.rb:30:in `process_action'
actionpack (6.0.2.1) lib/abstract_controller/callbacks.rb:42:in `block in process_action'
activesupport (6.0.2.1) lib/active_support/callbacks.rb:135:in `run_callbacks'
actionpack (6.0.2.1) lib/abstract_controller/callbacks.rb:41:in `process_action'
actionpack (6.0.2.1) lib/action_controller/metal/rescue.rb:22:in `process_action'
actionpack (6.0.2.1) lib/action_controller/metal/instrumentation.rb:33:in `block in process_action'
activesupport (6.0.2.1) lib/active_support/notifications.rb:180:in `block in instrument'
activesupport (6.0.2.1) lib/active_support/notifications/instrumenter.rb:24:in `instrument'
activesupport (6.0.2.1) lib/active_support/notifications.rb:180:in `instrument'
actionpack (6.0.2.1) lib/action_controller/metal/instrumentation.rb:32:in `process_action'
actionpack (6.0.2.1) lib/action_controller/metal/params_wrapper.rb:245:in `process_action'
activerecord (6.0.2.1) lib/active_record/railties/controller_runtime.rb:27:in `process_action'
actionpack (6.0.2.1) lib/abstract_controller/base.rb:136:in `process'
actionview (6.0.2.1) lib/action_view/rendering.rb:39:in `process'
actionpack (6.0.2.1) lib/action_controller/metal.rb:191:in `dispatch'
actionpack (6.0.2.1) lib/action_controller/metal.rb:252:in `dispatch'
actionpack (6.0.2.1) lib/action_dispatch/routing/route_set.rb:51:in `dispatch'
actionpack (6.0.2.1) lib/action_dispatch/routing/route_set.rb:33:in `serve'
actionpack (6.0.2.1) lib/action_dispatch/journey/router.rb:49:in `block in serve'
actionpack (6.0.2.1) lib/action_dispatch/journey/router.rb:32:in `each'
actionpack (6.0.2.1) lib/action_dispatch/journey/router.rb:32:in `serve'
actionpack (6.0.2.1) lib/action_dispatch/routing/route_set.rb:837:in `call'
rack-pjax (1.1.0) lib/rack/pjax.rb:12:in `call'
remotipart (1.4.4) lib/remotipart/middleware.rb:32:in `call'
warden (1.2.8) lib/warden/manager.rb:36:in `block in call'
warden (1.2.8) lib/warden/manager.rb:34:in `catch'
warden (1.2.8) lib/warden/manager.rb:34:in `call'
rack (2.2.2) lib/rack/tempfile_reaper.rb:15:in `call'
rack (2.2.2) lib/rack/etag.rb:27:in `call'
rack (2.2.2) lib/rack/conditional_get.rb:27:in `call'
rack (2.2.2) lib/rack/head.rb:12:in `call'
actionpack (6.0.2.1) lib/action_dispatch/http/content_security_policy.rb:18:in `call'
rack (2.2.2) lib/rack/session/abstract/id.rb:266:in `context'
rack (2.2.2) lib/rack/session/abstract/id.rb:260:in `call'
actionpack (6.0.2.1) lib/action_dispatch/middleware/cookies.rb:648:in `call'
activerecord (6.0.2.1) lib/active_record/migration.rb:567:in `call'
actionpack (6.0.2.1) lib/action_dispatch/middleware/callbacks.rb:27:in `block in call'
activesupport (6.0.2.1) lib/active_support/callbacks.rb:101:in `run_callbacks'
actionpack (6.0.2.1) lib/action_dispatch/middleware/callbacks.rb:26:in `call'
actionpack (6.0.2.1) lib/action_dispatch/middleware/executor.rb:14:in `call'
actionpack (6.0.2.1) lib/action_dispatch/middleware/actionable_exceptions.rb:17:in `call'
actionpack (6.0.2.1) lib/action_dispatch/middleware/debug_exceptions.rb:32:in `call'
web-console (4.0.1) lib/web_console/middleware.rb:132:in `call_app'
web-console (4.0.1) lib/web_console/middleware.rb:28:in `block in call'
web-console (4.0.1) lib/web_console/middleware.rb:17:in `catch'
web-console (4.0.1) lib/web_console/middleware.rb:17:in `call'
actionpack (6.0.2.1) lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'
railties (6.0.2.1) lib/rails/rack/logger.rb:38:in `call_app'
railties (6.0.2.1) lib/rails/rack/logger.rb:26:in `block in call'
activesupport (6.0.2.1) lib/active_support/tagged_logging.rb:80:in `block in tagged'
activesupport (6.0.2.1) lib/active_support/tagged_logging.rb:28:in `tagged'
activesupport (6.0.2.1) lib/active_support/tagged_logging.rb:80:in `tagged'
railties (6.0.2.1) lib/rails/rack/logger.rb:26:in `call'
sprockets-rails (3.2.1) lib/sprockets/rails/quiet_assets.rb:13:in `call'
actionpack (6.0.2.1) lib/action_dispatch/middleware/remote_ip.rb:81:in `call'
actionpack (6.0.2.1) lib/action_dispatch/middleware/request_id.rb:27:in `call'
rack (2.2.2) lib/rack/method_override.rb:24:in `call'
rack (2.2.2) lib/rack/runtime.rb:22:in `call'
activesupport (6.0.2.1) lib/active_support/cache/strategy/local_cache_middleware.rb:29:in `call'
actionpack (6.0.2.1) lib/action_dispatch/middleware/executor.rb:14:in `call'
actionpack (6.0.2.1) lib/action_dispatch/middleware/static.rb:126:in `call'
rack (2.2.2) lib/rack/sendfile.rb:110:in `call'
actionpack (6.0.2.1) lib/action_dispatch/middleware/host_authorization.rb:83:in `call'
webpacker (4.2.2) lib/webpacker/dev_server_proxy.rb:23:in `perform_request'
rack-proxy (0.6.5) lib/rack/proxy.rb:57:in `call'
railties (6.0.2.1) lib/rails/engine.rb:526:in `call'
puma (4.3.1) lib/puma/configuration.rb:228:in `call'
puma (4.3.1) lib/puma/server.rb:681:in `handle_request'
puma (4.3.1) lib/puma/server.rb:472:in `process_client'
puma (4.3.1) lib/puma/server.rb:328:in `block in run'
puma (4.3.1) lib/puma/thread_pool.rb:134:in `block in spawn_thread'

标签： ruby-on-railsrubyrestapi

解决方案

nil:NilClass 的未定义方法“[]”在 app/views/recipe/Recipe.html.erb:26

您的@recipe实例变量为零。确保在控制器中为它分配一个值，在你的def Recipe操作中。

PS：控制器动作应该是小写的，所以def recipe.

推荐阅读