1.1. CORS Support

1.1.1. 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.org to a resource on http://www.adventuresinoss.com would be considered a cross origin request.

CORS (Cross Origin Resource Sharing) is a standard mechanism used to enable cross origin requests.

For further details, see:

1.1.2. How can I enable CORS support?

CORS support for the REST interface (or any other part of the Web UI) can be enabled 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-name>CORS Filter</filter-name>
  3. Restart OpenNMS

1.1.3. How can I configure CORS support?

CORS support is provided by the org.ebaysf.web.cors.CORSFilter servlet filter.

Parameters can be configured 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: