DispatchHandler

When a request is handled, the first condition in the list of conditions is evaluated. If the condition expression yields true, the request is dispatched to the associated handler with no further processing. Otherwise, the next condition in the list is evaluated.

Usage

{
  "name": string,
  "type": "DispatchHandler",
  "config": {
    "bindings": [
      {
        "condition": runtime expression<boolean>,
        "handler": Handler reference,
        "baseURI": runtime expression<url>,
      }, ...
    ]
  }
}

Properties

"bindings": array of objects, required

One or more condition and handler bindings.

"condition": runtime expression<boolean>, optional

A flag to indicate that a condition is met. The condition can be based on the request, context, or IG runtime environment, such as system properties or environment variables.

Conditions are defined using IG expressions, as described in Expressions, and are evaluated as follows:

true: The request is dispatched to the associated handler.
false: The next condition in the list is evaluated.

For example conditions and requests that match them, see Example conditions and requests.

Default: ${true}

"handler": Handler reference, required

A Handler to dispatch the request to if the associated condition yields true.

"baseURI": runtime expression<url>,optional

A base URI that overrides the existing request URI. Only scheme, host, and port are used in the supplied URI.

The result of the expression must be a string that represents a valid URI, but is not a real java.net.URI object. For example, it would be incorrect to use ${request.uri}, which is not a String but a MutableUri.

In the following example, the binding condition looks up the hostname of the request. If it finds a match, the value is used for the baseURI. Otherwise, the default value is used:

{
  "properties": {
    "uris": {
      "app1.example.com": {
        "baseURI": "http://backend1:8080/"
      },
      "app2.example.com": {
        "baseURI": "http://backend2:8080/"
      },
      "default": {
        "baseURI": "http://backend3:8080/"
      }
    }
  },
  "handler": {
    "type": "DispatchHandler",
    "config": {
      "bindings": [
        {
          "condition": "${not empty uris[contexts.router.originalUri.host]}",
          "baseURI": "${uris[contexts.router.originalUri.host].baseURI}",
          "handler": "ReverseProxyHandler"
        },
        {
          "baseURI": "${uris['default'].baseURI}",
          "handler": "ReverseProxyHandler"
        }
      ]
    }
  }
}

Default: No change to the base URI

Example

The following sample is from a SAML 2.0 federation configuration:

If the incoming URI matches /saml, then IG dispatches to a SamlFederationHandler without further processing.
If the previous condition is not met, and the user name is not set in the session context, then IG dispatches the request to a SPInitiatedSSORedirectHandler.

In this case, the user has not authenticated with the SAML 2.0 Identity Provider, so the SPInitiatedSSORedirectHandler initiates SAML 2.0 SSO from the Service Provider, which is IG.
If neither of the previous conditions are met, the request goes through a LoginChain handler.

{
    "name": "DispatchHandler",
    "type": "DispatchHandler",
    "config": {
        "bindings": [
            {
                "condition": "${find(request.uri.path, '^/saml')}",
                "handler": "SamlFederationHandler"
            },
            {
                "condition": "${empty session.username}",
                "handler": "SPInitiatedSSORedirectHandler",
                "baseURI": "http://www.example.com:8081"
            },
            {
                "handler": "LoginChain",
                "baseURI": "http://www.example.com:8081"
            }
        ]
    }
}

More information

org.forgerock.openig.handler.DispatchHandler

Expressions

Identity Gateway 7.2

DispatchHandler

Usage

Properties

Example

More information