CORS Support

This section describes CORS (Cross-Origin Resource Sharing), a standard mechanism to enable cross-origin requests.

Why do I need CORS support?

By default, many browsers implement a same origin policy, which prevents making requests to a resource on an origin that’s different from the source origin.

For example, a request originating from a page served from http://www.opennms.com to a resource on http://www.adventuresinoss.com would be considered a cross-origin request.

For further details, see:

How can I enable CORS support?

Enable CORS support for the REST interface (or any other part of the Web UI) as follows:

  1. Open '${OPENNMS_HOME}/jetty-webapps/opennms/WEB-INF/web.xml' for editing.

  2. Apply the CORS filter to the '/rest/' path by removing the comments around the <filter-mapping> definition. The result should look like:

      <!-- Uncomment this to enable CORS support -->
  <filter-mapping>
    <filter-name>CORS Filter</filter-name>
    <url-pattern>/rest/*</url-pattern>
  </filter-mapping>

  3. Restart Horizon.

How can I configure CORS support?

The org.ebaysf.web.cors.CORSFilter servlet filter provides CORS support.

Configure parameters by modifying the filter definition in the 'web.xml' file referenced above.

By default, the allowed origins parameter is set to '*'.

The complete list of parameters supported are available from: