Mô hình Tabless

Thứ Tư, 22/04/2020

Tram Ho

1. Giới thiệu bài toán:

Khi làm dự án tất cả các dữ liệu sẽ được xử lý thông qua model và lưu vào trong DB, ví dụ thông tin user, sản phẩm, hoá đơn ….
Tuy nhiên cũng có 1 số dữ liệu đóng vai trò như master data của hệ thống và không cần lưu vào trong DB nhưng vẫn có nhu cầu được xử lý thông qua model, ví dụ 12 khối lớp, bảng chữ cái, ….
Hôm nay mình sẽ giới thiệu 1 số cách mà mình đã xử lý bài toán trên.

2. Tabless Actice Record Model:

Mình sẽ tạo class Letter và implement các hàm cần thiết như 1 model thật sự

<span class="token comment"># app/models/letter.rb</span>
<span class="token keyword">class</span> <span class="token class-name">Letter</span>
  <span class="token keyword">class</span> <span class="token operator">&lt;</span><span class="token operator">&lt;</span> <span class="token keyword">self</span>
    <span class="token keyword">def</span> all
      <span class="token punctuation">(</span><span class="token string">"a"</span><span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token string">"z"</span><span class="token punctuation">)</span><span class="token punctuation">.</span>map <span class="token punctuation">{</span><span class="token operator">|</span>char<span class="token operator">|</span> <span class="token constant">Letter</span><span class="token punctuation">.</span><span class="token keyword">new</span><span class="token punctuation">(</span>char<span class="token punctuation">)</span><span class="token punctuation">}</span>
    <span class="token keyword">end</span>

    <span class="token keyword">def</span> find_by params
      all<span class="token punctuation">.</span>detect <span class="token punctuation">{</span><span class="token operator">|</span>letter<span class="token operator">|</span> letter<span class="token punctuation">.</span>char <span class="token operator">==</span> params<span class="token punctuation">[</span><span class="token symbol">:char</span><span class="token punctuation">]</span> <span class="token punctuation">}</span>
    <span class="token keyword">end</span>
  <span class="token keyword">end</span>

  attr_reader <span class="token symbol">:char</span>

  <span class="token keyword">def</span> initialize char
    <span class="token variable">@char</span> <span class="token operator">=</span> char
  <span class="token keyword">end</span>

  <span class="token keyword">def</span> to_params
    char
  <span class="token keyword">end</span>

  <span class="token keyword">def</span> products
    <span class="token constant">Product</span><span class="token punctuation">.</span><span class="token function">where</span><span class="token punctuation">(</span><span class="token string">"name LIKE ?"</span><span class="token punctuation">,</span> <span class="token string">"<span class="token interpolation"><span class="token delimiter tag">#{</span>char<span class="token delimiter tag">}</span></span>%"</span><span class="token punctuation">)</span>
  <span class="token keyword">end</span>
<span class="token keyword">end</span>

# app/models/letter.rb

class Letter

class << self

def all

("a".."z").map {|char| Letter.new(char)}

end

def find_by params

all.detect {|letter| letter.char == params[:char] }

end

attr_reader :char

def initialize char

@char = char

end

def to_params

char

end

def products

Product.where("name LIKE ?", "#{char}%")

end

Ở đây mình đã implement 1 số hàm để Letter có thể được sử dụng như ActiveRecord của Rails.

<span class="token constant">Letter</span><span class="token punctuation">.</span>all
<span class="token constant">Letter</span><span class="token punctuation">.</span><span class="token function">find_by</span><span class="token punctuation">(</span>char<span class="token punctuation">:</span> <span class="token string">"a"</span><span class="token punctuation">)</span>
<span class="token constant">Letter</span><span class="token punctuation">.</span><span class="token function">find_by</span><span class="token punctuation">(</span>char<span class="token punctuation">:</span> <span class="token string">""</span><span class="token punctuation">)</span>
letter <span class="token operator">=</span> <span class="token constant">Letter</span><span class="token punctuation">.</span><span class="token keyword">new</span><span class="token punctuation">(</span><span class="token string">"a"</span><span class="token punctuation">)</span>
letter<span class="token punctuation">.</span>products

Letter.all

Letter.find_by(char: "a")

letter = Letter.new("a")

letter.products

Bạn có thể tiếp tục implement thêm các methods khác như Letter.first, Letter.last, letter.valid?, ….

Bạn cũng có thể tạo LettersController cho Letter như model bình thường

<span class="token comment"># app/controllers/letters_controller.rb</span>
<span class="token keyword">class</span> <span class="token class-name">LettersController</span> <span class="token operator">&lt;</span> <span class="token constant">ApplicationController</span>
  before_action <span class="token symbol">:load_letter</span><span class="token punctuation">,</span> only<span class="token punctuation">:</span> <span class="token symbol">:show</span>

  <span class="token keyword">def</span> index
    <span class="token variable">@letters</span> <span class="token operator">=</span> <span class="token constant">Letter</span><span class="token punctuation">.</span>all
  <span class="token keyword">end</span>

  <span class="token keyword">def</span> show
    <span class="token variable">@letters</span> <span class="token operator">=</span> <span class="token constant">Letter</span><span class="token punctuation">.</span>all
    <span class="token variable">@products</span> <span class="token operator">=</span> <span class="token variable">@letter</span><span class="token punctuation">.</span>products
  <span class="token keyword">end</span>

  <span class="token keyword">private</span>
  <span class="token keyword">def</span> load_letter
    <span class="token variable">@letter</span> <span class="token operator">=</span> <span class="token constant">Letter</span><span class="token punctuation">.</span>find_by char<span class="token punctuation">:</span> params<span class="token punctuation">[</span><span class="token symbol">:id</span><span class="token punctuation">]</span>
    <span class="token keyword">return</span> <span class="token keyword">if</span> <span class="token variable">@letter</span>

    flash<span class="token punctuation">[</span><span class="token symbol">:danger</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token string">"Letter not found"</span>
    redirect_to root_path
  <span class="token keyword">end</span>
<span class="token keyword">end</span>

# app/controllers/letters_controller.rb

class LettersController < ApplicationController

before_action :load_letter, only: :show

def index

@letters = Letter.all

end

def show

@letters = Letter.all

@products = @letter.products

end

private

def load_letter

@letter = Letter.find_by char: params[:id]

return if @letter

flash[:danger] = "Letter not found"

redirect_to root_path

end

<span class="token comment"># app/views/letters/index.html.erb</span>
<span class="token operator">&lt;</span>div <span class="token keyword">class</span><span class="token operator">=</span><span class="token string">"container"</span><span class="token operator">&gt;</span>
  <span class="token operator">&lt;</span>h3<span class="token operator">&gt;</span><span class="token constant">Letter</span> <span class="token constant">List</span><span class="token operator">&lt;</span><span class="token operator">/</span>h3<span class="token operator">&gt;</span>

  <span class="token operator">&lt;</span>ul <span class="token keyword">class</span><span class="token operator">=</span><span class="token string">"pager"</span><span class="token operator">&gt;</span>
    <span class="token operator">&lt;</span><span class="token operator">%</span> <span class="token variable">@letters</span><span class="token punctuation">.</span><span class="token keyword">each</span> <span class="token keyword">do</span> <span class="token operator">|</span>letter<span class="token operator">|</span> <span class="token string">%&gt;
      &lt;li&gt;</span><span class="token operator">&lt;</span><span class="token operator">%</span><span class="token operator">=</span> link_to letter<span class="token punctuation">.</span>char<span class="token punctuation">.</span>upcase<span class="token punctuation">,</span> <span class="token function">letter_path</span><span class="token punctuation">(</span>id<span class="token punctuation">:</span> letter<span class="token punctuation">.</span>char<span class="token punctuation">)</span> <span class="token string">%&gt;&lt;/li&gt;</span>
    <span class="token operator">&lt;</span><span class="token operator">%</span> <span class="token keyword">end</span> <span class="token string">%&gt;
  &lt;/ul&gt;</span>
<span class="token operator">&lt;</span><span class="token operator">/</span>div<span class="token operator">&gt;</span>

# app/views/letters/index.html.erb

<h3>Letter List</h3>

<% @letters.each do |letter| %>

<% end %>

</ul>

</div>

# app/views/letters/show.html.erb
 <div class="container">
 <h3>Product List</h3>
 <ul class="pager">
 <% @letters.each do |letter| %>
 <li><%= link_to letter.char.upcase, letter_path(id: letter.char), class: ("active" if params
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 Nguồn bài viết :  Viblo

Mô hình Tabless

1. Giới thiệu bài toán:

2. Tabless Actice Record Model:

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