Rails: Using Ajax - ruby-on-rails

Question

Problem: Trying to implement "like" function on my blog
PostIndex:
<% #posts.each do |post| %>
<tr>
<td><%= post.name %></td>
<td><%= link_to post.content, post %></td>
<td><%= post.created_at.strftime("%Y/%m/%d, %I:%M%p") %></td>
<td><%= post.view %></td>
<td><%= post.like %></td>
<td><%= post.hate %></td>
<td><%= link_to 'like', like_post_path(post), :remote => true %></td>
</tr>
<% end %>
PostController:
def like
#post = Post.find(params[:id])
#post.like += 1
#post.save
respond_to do |format|
format.js
end
end
app/views/posts/like.js.erb
$('#post').html("<%=j #post.like %>");
Question:
I believe I'm not correctly pointing at the post I'm looking at in like.js.erb.
In the index file, Simply doing <%= #post.view %> worked. But how do you do it in like.js.erb?

Answer 1

You need some identifier for post's like count in your html when you want to update it after ajax call
PostIndex:
<% #posts.each do |post| %>
<tr>
<td><%= post.name %></td>
<td><%= link_to post.content, post %></td>
<td><%= post.created_at.strftime("%Y/%m/%d, %I:%M%p") %></td>
<td><%= post.view %></td>
<td id= "post<%= post.id %>_like"><%= post.like %></td> <!-- set id (identifier) here -->
<td><%= post.hate %></td>
<td><%= link_to 'like', like_post_path(post), :remote => true %></td>
</tr>
<% end %>
then in your app/views/posts/like.js.erb,
<% if #post.errors.blank? %>
$("#post<%= #post.id %>_like").html("<%=j #post.like %>");
<% end %>

Answer 2

Complete Way of Using Ajax to Fix a Table Row:
In your show.html (or index.html) file, you probably have a table already.
<tr>
<td>row 1</td>
<td>row 2</td>
<td>row 3</td>
</tr>
Let's pretend the rows represent some kind of variable. Then the table above would be like,
<tr>
<td><%= #variableA %></td>
<td><%= #variableB %></td>
<td><%= #variableC %></td>
</tr>
I want to change variableA without reloading the whole page. So I use Ajax.
My method:
def fixvar
#variableA = 2
end
You have to add one component to use Ajax.
def fixvar
#variableA = 2
end
respond_to do |format|
format.js
end
And wherever you want, you will have a link that will invoke the change via ajax.
<%= link_to 'change variable A', URLof_fixvar(#variableA), :remote => true %>
By using the option :remote => true, you're using an ajax component in your link_to method. You have to set URLof_fixvar in config/routes.rb accordingly. routing
Let's specify where to update in the table.
<tr>
<td id="variable_change_<%= #variableA.id %>><%= #variableA %></td>
<td><%= #variableB %></td>
<td><%= #variableC %></td>
</tr>
We did as above to specify the row that we're trying to update. For example, the row is now defined as variable_change_1. (assuming variableA.id is 1)
Now, you need to go to the related views folder, and create a .js.erb file that relates to the defined method above. For example, I had "like" method defined in my PostController, so I created
app/views/posts/like.js.erb
In here, you only need one line of code:
$("#variable_change_<%= #variable.id %>").html("<%= #variableA %>");
The first part before .html is pointing at the specified row, and the part after is the value that we want to update. Done!