DRY way for setting document.domain from Rails

问题

I have a Rails app that is using two subdomains which would like to communicate in JavaScript. What would be the most DRY way to effectively set document.domain = mydomain.com?

Conditions that make it less than straight forward

1. This should not be a problem in the development or test environments where the domain is localhost.
2. This needs to also be set on certain pages which don't load the main JavaScript file

Condition 1 leads me to think I either want to rely on a Regex that parses the root domain out of location.host or do the switching in erb.

Condition 2 makes me feel it would be best to write this once and put it in the asset pipeline and include it where necessary.

Best Potential Solution

Create a file like domain_setter.js.erb (contents below), add it to precompile list, and include it in all necessary places (either \\= require domain_setter in manifests or javascript_include_tag 'domain_setter' for pages without manifests).

<%- if Rails.env.production? %>
  document.domain = 'mydomain.com';
<%- end %>

Updated Current Solution

This solution is more dynamic and doesn't require hardcoding a domain. Still not the best but it's working ... mostly :-/

(function() {
  var domain = /^(?:https?\:\/\/)?.*?([^.]+\.[^.]+?)(?:\:\d+)?$/.exec(location.host);

  if (domain == null) {
    document.domain = 'localhost';
  } else {
    document.domain = domain[1];
  }
})();

tl;dr

What's a DRY way to set mulitple pages' document.domain working with Rails?

回答1:

I think you're looking for Cross-Origin Resource Sharing (CORS). This allows javascript to make AJAX $.get/post requests across different domains.

Here's a rails library to get you started: https://github.com/cyu/rack-cors#rails

You'll want to set the origins property to be yoursubdomain.herokuapp.com

来源：https://stackoverflow.com/questions/35705950/dry-way-for-setting-document-domain-from-rails