How can I use Rails routes to redirect from one domain to another?

Question

My app used to run on foo.tld but now it runs on bar.tld. Requests will still come in for foo.tld, I want to redirect them to bar.tld.

How can I do this in rails routes?

Answer 1

This works in Rails 3.2.3

constraints(:host => /foo.tld/) do
  match "/(*path)" => redirect {|params, req| "http://bar.tld/#{params[:path]}"}
end

This works in Rails 4.0

constraints(:host => /foo.tld/) do
  match "/(*path)" => redirect {|params, req| "http://bar.tld/#{params[:path]}"},  via: [:get, :post]
end

Answer 2

This does the job of the other answer. Though in addition, it preserves query strings as well. (Rails 4):

# http://foo.tld?x=y redirects to http://bar.tld?x=y
constraints(:host => /foo.tld/) do
  match '/(*path)' => redirect { |params, req|
    query_params = req.params.except(:path)
    "http://bar.tld/#{params[:path]}#{query_params.keys.any? ? "?" + query_params.to_query : ""}"
  }, via: [:get, :post]
end

Note: If you're dealing with full domains instead of just subdomains, use :domain instead of :host.

Answer 3

The following solution redirects multiple domains on GET and HEAD requests while returning http 400 on all other requests (as per this comment in a similar question).

/lib/constraints/domain_redirect_constraint.rb:

module Constraints
  class DomainRedirectConstraint
    def matches?(request)
      request_host = request.host.downcase
      return request_host == "foo.tld1" || \
             request_host == "foo.tld2" || \
             request_host == "foo.tld3"
    end
  end
end

/config/routes.rb:

require 'constraints/domain_redirect_constraint'

Rails.application.routes.draw do
  match "/(*path)", to: redirect {|p, req| "//bar.tld#{req.fullpath}"}, via: [:get, :head], constraints: Constraints::DomainRedirectConstraint.new
  match "/(*path)", to: proc { [400, {}, ['']] }, via: :all, constraints: Constraints::DomainRedirectConstraint.new

  ...
end

For some reason constraints Constraints::DomainRedirectConstraint.new do didn't work for me on heroku but constraints: Constraints::DomainRedirectConstraint.new worked fine.

Answer 4

Bit more modern approach:

constraints(host: 'www.mydomain.com') do
    get '/:param' => redirect('https://www.mynewurl.com/:param')
end