Correctly doing redirect_to :back in Ruby on Rails when referrer is not available

It is unlikely that you do have a session and don't have a referrer.

The situation that a referrer is not set isn't that uncommon and I usually rescue that expection:

def some_method
  redirect_to :back
rescue ActionController::RedirectBackError
  redirect_to root_path
end

If you do this often (which I think is a bad idea) you can wrap it in an other method like Maran suggests.

BTW I think that's a bad idea because this makes the userflow ambiguous. Only in the case of a login this is sensible.

UPDATE: As several people pointed out this no longer works with Rails 5. Instead, use redirect_back, this method also supports a fallback. The code then becomes:

def some_method
  redirect_back fallback_location: root_path
end

Here's my little redirect_to_back method:

  def redirect_to_back(default = root_url)
    if request.env["HTTP_REFERER"].present? and request.env["HTTP_REFERER"] != request.env["REQUEST_URI"]
      redirect_to :back
    else
      redirect_to default
    end
  end

You can pass an optional url to go somewhere else if http_refferrer is blank.

def store_location
  session[:return_to] = request.request_uri
end

def redirect_back_or_default(default)
  redirect_to(session[:return_to] || default)
  session[:return_to] = nil
end

Try that! (Thanks to the Authlogic plugin)

redirect_back_or_to (Rails 7+)

Rails 7 presents a new idiomatic way to redirect back or to the fallback location.

Quoting directly from the official Rails API docs:

redirect_back_or_to(fallback_location, allow_other_host: true, **args)

Redirects the browser to the page that issued the request (the referrer) if possible, otherwise redirects to the provided default fallback location.

The referrer information is pulled from the HTTP Referer (sic) header on the request. This is an optional header and its presence on the request is subject to browser security settings and user preferences. If the request is missing this header, the fallback_location will be used.

redirect_back_or_to({ action: "show", id: 5 })
redirect_back_or_to @post
redirect_back_or_to "http://www.rubyonrails.org"
redirect_back_or_to "/images/screenshot.jpg"
redirect_back_or_to posts_url
redirect_back_or_to proc { edit_post_url(@post) }
redirect_back_or_to '/', allow_other_host: false

It is also worth mentioning that
the Rails 5 way redirect_back(fallback_location: '/things/stuff')
has exactly the same behavior as newly introduced redirect_back_or_to('/things/stuff').

Sources:

• Pull Request.
• redirect_back_or_to official docs.
• redirect_back official docs.