Cross Origin Resource Sharing Filter

Filter to enable Cross Origin Resource Sharing (CORS) capabilities on Clyde API gateway, allowing to make AJAX requests from client side.

Implementation is based on cors module.

• Installation
• Configuration
  • Examples
    • Enable all CORS requests
    • Enable CORS requests only from myserver origin and on provider
  • Notes
• License

Installation

npm install clydeio-cors --save

Configuration

CORS filter bypasses the configuration options to cors module, so you can use the same options:

Next lines are copied from cors module configuration options. Follow the link for more detail.

• origin: Configures the Access-Control-Allow-Origin CORS header. Possible values:

• Boolean - set origin to true to reflect the request origin, as defined by req.header('Origin'), or set it to false to disable CORS.
• String - set origin to a specific origin. For example if you set it to "http://example.com" only requests from "http://example.com" will be allowed.
• RegExp - set origin to a regular expression pattern which will be used to test the request origin. If it's a match, the request origin will be reflected. For example the pattern /example\.com$/ will reflect any request that is coming from an origin ending with "example.com".
• Array - set origin to an array of valid origins. Each origin can be a String or a RegExp. For example ["http://example1.com", /\.example2\.com$/] will accept any request from "http://example1.com" or from a subdomain of "example2.com".
• Function - set origin to a function implementing some custom logic. The function takes the request origin as the first parameter and a callback (which expects the signature err [object], allow [bool]) as the second.

• methods: Configures the Access-Control-Allow-Methods CORS header. Expects a comma-delimited string (ex: 'GET,PUT,POST') or an array (ex: ['GET', 'PUT', 'POST']).
• allowedHeaders: Configures the Access-Control-Allow-Headers CORS header. Expects a comma-delimited string (ex: 'Content-Type,Authorization') or an array (ex: ['Content-Type', 'Authorization']). If not specified, defaults to reflecting the headers specified in the request's Access-Control-Request-Headers header.
• exposedHeaders: Configures the Access-Control-Expose-Headers CORS header. Expects a comma-delimited string (ex: 'Content-Range,X-Content-Range') or an array (ex: ['Content-Range', 'X-Content-Range']). If not specified, no custom headers are exposed.
• credentials: Configures the Access-Control-Allow-Credentials CORS header. Set to true to pass the header, otherwise it is omitted.
• maxAge: Configures the Access-Control-Allow-Max-Age CORS header. Set to an integer to pass the header, otherwise it is omitted.
• preflightContinue: Pass the CORS preflight response to the next handler.

For details on the effect of each CORS header, read this article on HTML5 Rocks.

Examples

Enable all CORS requests

{
  "prefilters": [
    {
      "id": "cors",
      "path": "clyde-cors"
    }
  ],

  "providers": [
    {
      "id": "provider",
      "context": "/provider",
      "target": "http://server"
    }
  ]
}

Enable CORS requests only from myserver origin and on provider

{
  "providers": [
    {
      "id": "provider",
      "context": "/provider",
      "target": "http://provider_server",
      "prefilters": [
        {
          "id": "cors",
          "path": "clyde-cors",
          "config": {
            "origin": "http://myserver"
          }
        }
      ]
    }
  ]
}

Notes

• It must be configured as a global or provider's prefilter. It has no sense as a postfilter.

License

The MIT License (MIT)

Copyright (c) 2015 Antonio Santiago (@acanimal)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.