Rails：参数数量错误（给定 1，预期 0）

Question

我在 posts 索引页上收到此错误：

此型号：

class Post < ApplicationRecord

  include Filterable

  belongs_to :region
  belongs_to :category
  belongs_to :topic
  validates :title, presence: true, length: { maximum: 500 }
  validates :content, presence: true
  validates :published_at, presence: true
  translates :title, :content, :slug, touch: true, fallbacks_for_empty_translations: true
  has_attached_file :image, styles: { thumb: "100x70#", featured: "1560x868#", small: "760x868#", big: ">1600x1600" }
  validates_attachment :image, content_type: { content_type: ["image/jpeg", "image/gif", "image/png"] }
  validates_attachment_presence :image

  scope :published, -> (published) { where(published: (['true', true].include? published)).order(featured: :desc, published_at: :desc) }
  scope :published_until_now, -> { where("published_at < ?", Time.now).merge(Post.published(true)) }
  scope :topic, -> (topic_id) {
    joins(:topic).where('topic_id = ?', topic_id) }
  scope :category, -> (post_category) {
    joins(:category).where('category_id = ?', post_category) }
  scope :match, -> (search_term) {
    with_translations(I18n.locale).where('content like ? or title like ?', "%#{search_term}%", "%#{search_term}%") }

  self.per_page = 10

  after_save :unfeature_older_posts, if: Proc.new { |post| post.featured? }

  extend FriendlyId
  friendly_id :title, use: :globalize

  def unfeature_older_posts
    featured_posts = Post.where(featured: true).where.not(id: id).order(published_at: :desc)
    if featured_posts.size == 1
      featured_posts.last.update(featured: false)
    end
  end

end

这个控制器：

class PostsController < ApplicationController

  before_action :get_pages_tree, :get_privacy_policy, only: [:index, :show]

  def index
    @filters = params.slice(:topic, :category)
    @posts = Post.published_until_now
      .filter(@filters)
      .paginate(:page => params[:page], per_page: 11)
  end

  def show
    @post = Post.friendly.find(params[:id])
  end
end

和filter定义在这里：

module Filterable
  extend ActiveSupport::Concern

  module ClassMethods
    def filter(filtering_params)
      results = self.where(nil)
      filtering_params.each do |key, value|
        results = results.public_send(key, value) if value.present?
      end
      results
    end
  end
end

我不确定从这里到哪里去。我最近在Rails5和Ruby2.7.0升级到Ruby，不知道有没有关系。

Answer 1

尝试将 module ClassMethods 替换为 class_methods do。

如果有效，请记住：

filter 方法来自 Ruby。它在 Array 中定义。正如您在 doc 中看到的那样，Array 上的 filter 方法没有参数。这是您看到的错误的直接原因。

在 Rails 中，当在 ActiveRecord 对象（在您的情况下为 Post.published_until_now）上调用 Array 上的方法并且在模型上找不到方法时，它会自动将自己转换为 Array。因此，它在 Array 上调用 filter 方法。通常，您不想定义诸如 filter 这样令人困惑的方法。

Rails：参数数量错误（给定 1，预期 0）

Rails : Wrong number of arguments (given 1, expected 0)

ruby

arguments

ruby-on-rails

ruby-on-rails-5