render() method in rails is used for rendering a content to the view . Its uses are:

In Controller for rendering an action Example:

render :action => "show"

This is the most common use of render in controller . The template for show will be rendered without any redirect to the action show within the same controller.

Sometimes we need to render to the action within same controller with a custom layout. Then we do it in this way:

    render :action => "show" , layout: admin

We can do the same thing as :

    render :template => "user/show" , layout: admin

This is known as template rendering. One thing we need to care here is the path of the template should be relative to its own root directory.

Rendering partial in a view page Example:

    <%= render :partial => social_share, :locals => {blog: @blog} %>

For details on render partial go to this link .

Rendering file:

File rendering works similarly to action rendering. Here the file path is file system path and if layout is not mentioned then file is rendered without any layout.

Example:

render :file => "/home/ubuntu/Railsapp/app/views/profiles/template.erb", :layout => true, :status => 404

In the above example status 404 is sent while rendering the file with the current layout.

Render xml and json data

    render :xml => {:pin => "248001"}


If we want to pass the same as json data

    render :json => {:pin => 248001}

Rendering text If we want render text from controller then we can do it like this :

    render :text => "Hi how r u!", :layout => true

In rails 4.1 and above render :text => is deprecated . This is written as:

    render :plain => "Hi how r u!", :layout => true #content type text/plain
    render :html =>  "Hi how r u!", :layout => true #content type html/plain

Render inline

Using render inline we can render any text to a template without the physical existence of the template in the application. For example:

    def welcome
      render :inline => "Hi how r u <%= name %>!", :locals => { :name => "Jonathan" }
    end

This action has no template, but if we send a request to this action from browser then "Hi how r u Jonathan !" will be displayed in the browser. Default format of template is erb. If we want in xml format then :

    render :inline => "xml.p { 'Good to see you back!' }", :type => :builder