diff --git a/README.md b/README.md index 89d4abd5..0b99e459 100644 --- a/README.md +++ b/README.md @@ -102,6 +102,67 @@ window.authorizations.add("key", new ApiKeyAuthorization("Authorization", "XXXX" Note! You can pass multiple header params on a single request, just use unique names for them (`key` is used in the above example). +## CORS Support + +CORS is a technique to prevent websites from doing bad things with your personal data. Most browsers + javascript toolkits not only support CORS but enforce it, which has implications for your API server which supports Swagger. + +You can read about CORS here: http://www.w3.org/TR/cors. + +There are two cases where no action is needed for CORS support: + +1. swagger-ui is hosted on the same server as the application itself (same host *and* port). +2. The application is located behind a proxy that enables the requires CORS headers. This may already be covered within your organization. + +Otherwise, CORS support needs to be enabled for: + +1. Your Swagger docs. For Swagger 2.0 it's the `swagger.json` and any externally `$ref`ed docs, and for prior version it's the `Resource Listing` and `API Declaration` files. +2. For the `Try it now` button to work, CORS needs to be enabled on your API endpoints as well. + +### Testing CORS Support + +You can verify CORS support with one of three techniques: + +- Curl your API and inspect the headers. For instance: + +```bash +$ curl -I "http://petstore.swagger.wordnik.com/api/api-docs" +HTTP/1.1 200 OK +Date: Thu, 12 Sep 2013 17:05:44 GMT +Access-Control-Allow-Origin: * +Access-Control-Allow-Methods: GET, POST, DELETE, PUT, PATCH, OPTIONS +Access-Control-Allow-Headers: Content-Type, api_key, Authorization +Content-Type: application/json +Content-Length: 0 +``` + +This tells us that the petstore resource listing supports OPTIONS, and the following headers: `Content-Type`, `api_key`, `Authorization`. + +- Try swagger-ui from your file system and look at the debug console. If CORS is not enabled, you'll see something like this: + +``` +XMLHttpRequest cannot load http://sad.server.com/v2/api-docs. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access. +``` + +Swagger-UI cannot easily show this error state. + +- Using the http://www.test-cors.org website. Keep in mind this will show a successful result even if `Access-Control-Allow-Headers` is not available, which is still required for Swagger-UI to function properly. + +### Enabling CORS + +The method of enabling CORS depends on the server and/or framework you use to host your application. http://enable-cors.org provides information on how to enable CORS in some common web servers. + +Other servers/frameworks may provide you information on how to enable it specifically in their use case. + +### CORS and Header Parameters + +Swagger lets you easily send headers as parameters to requests. The name of these headers *MUST* be supported in your CORS configuration as well. From our example above: + +``` +Access-Control-Allow-Headers: Content-Type, api_key, Authorization +``` + +Only headers with these names will be allowed to be sent by Swagger-UI. + ## How to Improve It Create your own fork of [swagger-api/swagger-ui](https://github.com/swagger-api/swagger-ui)