Getting Started With RJS in Rails
def mark_complete
begin
@task = Task.find(params[:id])
@task.task_status_id = TaskStatus::COMPLETE
@task.save
rescue ActiveRecord::RecordNotFound
render :nothing => true
return
end
render_text @task.status.description
end
Adding this code in a view template is all we need to have our display automatically update:
This works great for those times when we only need to update a single DOM element on a page. What about when we need to update multiple pieces of content on the same page? One solution that has worked quite well for us is the use of RJS templates in Rails.Status: <%= @task.status.description %>
<%= link_to_remote 'Mark as Complete', :update =>, 'task-status-' + @task.id.to_s, :url => {:controller => 'task', :action => 'mark_complete', :id => @task %>
To take our simple example a bit further, let's say that when we mark a task as complete, we want to update some general task list reporting information and highlight the current task after the update occurs. Here is our status information and task listing in the view:
Completed: <%= Task.completed_count %> task(s)
Remaining: <%= Task.remaining_count %> task(s) <% for task in @tasks %>Task: <%= h task.title %>
Status: <%= task.status.description %>
<%= link_to_remote 'Mark as Complete', :url => {:controller => 'task', :action => 'mark_complete', :id => task} %> <% end %> This is where the RJS template comes into play – we'll write the Ruby code to update the display and then wire it into our action. This content will go in 'views/task/_update_tasks.rjs':page.replace_html('tasks-completed', Task.completed_count) page.replace_html('tasks-remaining', Task.remaining_count) page.replace_html('task-status-' + @task.id.to_s, @task.status.description) page.visual_effect(:highlight, 'task-item-' + @task.id.to_s, :duration => 1.0)Now, we'll go back to the action and wire it up to use our new RJS template. The 'render_text' line is all that's changed from the original example – I'll include the full sample for clarity:def mark_complete begin @task = Task.find(params[:id]) @task.task_status_id = TaskStatus::COMPLETE @task.save rescue ActiveRecord::RecordNotFound render :nothing => true return end render :partial => 'update_tasks' endThat's all there is to it, now when you flag a task as completed you'll get the feedback immediately in your browser.
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