Ruby on Rails：創建一個按鈕，如果在db中存在一行

我正在創建一個twitter副本（只是爲了學習Rails）。我有一個用戶頁面，列出所有用戶。在用戶名旁邊，我想創建一個按鈕，如果您沒有關注此用戶，請點擊「關注」，如果您不關注，請點擊「取消關注」。Ruby on Rails：創建一個按鈕，如果在db中存在一行

我已經在PHP中完成了它，我認爲我可以在Rails中做類似的事情，但我不知道如何。

followBtn.php - 包含在每個用戶之後。

$subsTable  = new Table('Sub'); 
if($user != $currentUser) { 
     $follows = $subsTable->checkFollow($currentUserID, $userID); 

     if($follows) { 
      echo "<form action='src/php/main.php' autocomplete='on' method='post'>"; 
      echo "<input type='hidden' name='page' value='unfollow'>"; 
      echo "<input type='hidden' name='followID' value='$userID'>"; 
      echo "<input type='submit' value='Unfollow' id='unfollowBtn'>"; 
      echo "</form>"; 
     } 
     if(!$follows) { 
      echo "<form action='src/php/main.php' autocomplete='on' method='post'>"; 
      echo "<input type='hidden' name='page' value='follow'>"; 
      echo "<input type='hidden' name='followID' value='$userID'>"; 
      echo "<input type='submit' value='Follow' id='followBtn'>"; 
      echo "</form>"; 
     } 
    }

Table.php

public function checkFollow($user, $follower) { 
      $table  = (string)self::$table; 

      $query = " 
       SELECT 
        * 
       FROM 
        $table 
       WHERE 
        $table.userID = '$user' 
       AND 
        $table.followID = '$follower' 
        ;"; 

      $database = Database::getInstance(); 

      $result = $database->fetch_assoc($query); 

      return $result; 
     }

這是我的Rails代碼到目前爲止，我已經得到了。我知道這不起作用，但也許並不是那麼錯。

index.html.erb

<h2>All users</h2> 

<table> 
    <tr> 
     <th>Username</th> 
     <th>Email</th> 
    </tr> 

    <% @user.each do |u| %> 
     <tr> 
      <td><%= u.username %></td> 
      <td><%= u.email %></td> 
      <% if(u.username != @current_user.username) %> 
       <% if @following %> 
        <% @temp_user = u %> 
        <%= form_for(:subscription, :url => { :controller => "subscriptions", :action => "unsubscribe" }) do |s| %> 
         <%= s.hidden_field(:userID, :value => @current_user.id) %> 
         <%= s.hidden_field(:followingID, :value => u.id) %> 
         <td><%= s.submit "Unsubscribe" %></td> 
        <% end %> 
       <% else %> 
        <%= form_for(:subscription, :url => { :controller => "subscriptions", :action => "subscribe" }) do |s| %> 
         <%= s.hidden_field(:userID, :value => @current_user.id) %> 
         <%= s.hidden_field(:followingID, :value => u.id) %> 
         <td><%= s.submit "Subscribe" %></td> 
        <% end %> 
       <% end %> 
      <% end %> 
     </tr> 
    <% end %> 
</table>

user_controller.rb

class UsersController < ApplicationController 

    before_filter :save_login_state, :only => [:new, :create] 

    def index 
    @user = User.all 
    @current_user = User.find session[:user_id] 
    @following = true if Subscriptions.find_by_sql("SELECT * FROM subscriptions WHERE userID = '{@current_user.id}' AND followingID = '{@temp_user.id}';") 
    end 
end

錯誤

NameError in UsersController#index 

uninitialized constant UsersController::Subscriptions

來源

2013-04-26 Alexander

你看到了什麼錯誤？ – shishirmk 2013-04-26 18:45:01

添加了該錯誤。 @shishirmk – Alexander 2013-04-26 19:05:49

型號名稱一般都是單數。所以我認爲這應該工作

@following = true if Subscription.find_by_sql("SELECT * FROM subscriptions WHERE userID = '{@current_user.id}' AND followingID = '{@temp_user.id}';")

來源

2013-04-26 22:51:11 shishirmk

Ruby on Rails：創建一個按鈕，如果在db中存在一行

回答

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