Scripted Decision Node API

The scripted decision node lets you write a server-side script in JavaScript to determine the path the authentication journey takes.

These scripts have access to a number of bindings, which provide the context to help you make the decision.

The primary role of a scripted decision node is to specify the possible paths a user can take. There are two methods to define these paths within the script:

outcome

The simplest method is to assign one or more string values to the outcome variable.

if (...) {
  outcome = "true"
} else {
  outcome = "false"
}

When configuring the scripted decision node in an authentication tree, add the two outcomes true and false, and connect them to other parts of the tree, so that tree evaluation can continue.

You can specify as many outcomes as required in your scripts; for example, you might have hours, days, and months. Be sure to specify each possible outcome when designing your authentication journey.

Action

You can use the Action interface to define the script outcome and/or specify an operation to perform.

Example:

var fr = JavaImporter(
    org.forgerock.openam.auth.node.api.Action
)

if (...) {
  // Set outcome to "true", and create and populate a custom session property:
  action = fr.Action.goTo("true").putSessionProperty("customKey", "customValue").build()
}
else
{
  // Set outcome to "false". If supported by the UI, the error message is displayed:
  action = fr.Action.goTo("false").withErrorMessage("Friendly error description.").build()
}

You can also use the Action interface for other functionality:

For more information on the Action interface, see Action in the AM Javadoc.

An outcome specified as an Action takes precedence over the value set for the outcome variable:

action = Action.goTo("false").build() // Tree continues along "false" outcome.

outcome = "true" // No effect.

For more information on specifying outcomes when using the scripted decision node, see Scripted Decision Node.

The following table lists the bindings accessible to scripted decision node scripts:

Scripted Decision Node Bindings
Binding Information

auditEntryDetail

Add information to the AM audit logs.

callbacks

Request additional data from the user, by sending any of the supported callbacks.

existingSession

If the user has previously authenticated and has a session, use this variable to access the properties of that session.

The user will only have an existing session when performing a session upgrade. Any properties that may have been added by nodes earlier in the current tree will not appear on the user’s new session until the authentication tree is completed, and are therefore not available to the existingSession variable.

httpClient

Make outbound HTTP calls.

idRepository

Access the data stored in the user’s profile.

logger

Write information to the AM debug logs.

realm

Return the name of the realm to which the user is authenticating as a string.

For example, authenticating to the top-level realm returns a string value of / (forward-slash). Authenticating to a subrealm of the top level realm might return /subRealm.

requestHeaders

Access the HTTP headers provided in the login request.

requestParameters

Access the HTTP headers provided in the login request.

secrets

Access the secrets configured in an AM instance.

nodeState

Access data set by previous nodes in the tree, or store data to be used by subsequent nodes.

Accessing Request Header Data

Scripted Decision Node scripts can access the headers provided by the login request by using the methods of the requestHeaders object.

Note that the script has access to a copy of the headers. Changing their values does not affect the request itself.

Methods

String[] requestHeaders.get(String HeaderName)

Return a java.util.ArrayList of the values in the named request header, or null, if the property is not set. Note that header names are case-sensitive.

Example:

var headerName = "user-agent"

if (requestHeaders.get(headerName).get(0).indexOf("Chrome") !== -1) {
    outcome = "true"
} else {
    outcome = "false"
}

Accessing Request Parameter Data

Scripted Decision Node scripts can access any query parameters provided by the login request by using the methods of the requestParameters object.

Note that the script has access to a copy of the parameters. Changing their values does not affect the request itself.

Methods

String[] requestParameters.get(String ParameterName)

Return a java.util.ArrayList of the values in the named request parameter, or null, if the parameter is not available.

Example:

  • JavaScript

  • Groovy

var service
var authIndexType = requestParameters.get("authIndexType")

if (authIndexType && String(authIndexType.get(0)) === "service") {
    service = requestParameters.get("authIndexValue").get(0)
}
def service
def authIndexType = requestParameters.get("authIndexType")

if (authIndexType && authIndexType.get(0) == "service") {
    service = requestParameters.get("authIndexValue").get(0)
}

In JavaScript, the values stored in requestParameters have a typeof of object, and represent the java.lang.String class. Convert the value to a string in order to use strict equality comparisons.

Accessing Shared State Data

Scripted Decision Node scripts can get access to the shared state within the tree by using the nodeState object.

Methods

`JsonValue nodeState.get(`String Property Name) `

Returns the value of the named property. The value may come from the transient, secure, or shared states, in that order. For example, if the same property is available in several states, the method will return the value of the property in the transient state first.

If the property is not set, the method returns null.

Note that property names are case-sensitive.

Example:

var currentAuthLevel = nodeState.get("authLevel").asString()
var givenPassword = nodeState.get("password").asString()
nodeState nodeState.putShared(String PropertyName, String ProperyValue)

Sets the value of the named shared state property. Note that property names are case-sensitive.

Example:

try {
  var currentAuthLevel = nodeState.get("authLevel").asString()
} catch (e) {
  nodeState.putShared("errorMessage", e.toString())
}
nodeState nodeState.putTransient(String PropertyName, String ProperyValue)

Sets the value of the named transient state property. Note that property names are case-sensitive.

Example:

nodeState.putTransient("sensitiveKey", "sensitiveValue")

Accessing Profile Data

Scripted decision nodes can access profile data through the methods of the idRepository object.

Methods

Set idRepository.getAttribute(String UserName, String AttributeName)

Return the values of the named attribute for the named user.

Void idRepository.setAttribute(String UserName, String AttributeName, Array Attribute Values)

Set the named attribute as specified by the attribute value for the named user, and persist the result in the user’s profile.

Example:

  • JavaScript

  • Groovy

var username = sharedState.get("username")
var attribute = "mail"

idRepository.setAttribute(username, attribute, ["user.0@a.com", "user.0@b.com"])
def username = sharedState.get("username")
def attribute = "mail"

idRepository.setAttribute(username, attribute, ["user.0@a.com", "user.0@b.com"] as String[])
Void idRepository.addAttribute(String UserName, String AttributeName, String Attribute Value)

Add an attribute value to the list of attribute values associated with the attribute name for a particular user.

Example:

var username = sharedState.get("username")
var attribute = "mail"

// Add a value as a String.
idRepository.addAttribute(username, attribute, "user.0@c.com")
logger.error(idRepository.getAttribute(username, attribute).toString())
// > ERROR: [user.0@a.com, user.0@c.com]

// Get the first value.
logger.error(idRepository.getAttribute(username, attribute).iterator().next())
// > ERROR: user.0@a.com

// Get a value at the specified index.
logger.error(idRepository.getAttribute(username, attribute).toArray()[1])
// > ERROR: user.0@c.com

logger.error(idRepository.getAttribute(username, "non-existing-attribute").toString())
// > ERROR: []: If no attribute by this name is found, an empty Set is returned.

Setting Session Properties

Scripted Decision Node scripts can create session properties by using the Action interface. The following examples set the outcome to true, and add a custom session property:

  • JavaScript

  • Groovy

var goTo = org.forgerock.openam.auth.node.api.Action.goTo

action = goTo("true").putSessionProperty("mySessionProperty","myPropertyValue").build()
import org.forgerock.openam.auth.node.api.Action

action = Action.goTo("true").putSessionProperty("mySessionProperty","myPropertyValue").build()

Add the property name to the Whitelisted Session Property Names list in the Session Property Whitelist Service; otherwise, it will not be added to sessions. For more information on this service, see Session Property Whitelist Service.

Add the script to a scripted decision node in your authentication tree. Users that authenticate successfully using that tree will have the property added to their session, as shown in the following output when introspecting a session:

{
    "username": "15249a65-8f9a-4063-9586-a2465963cee4",
    "universalId": "id=15249a65-8f9a-4063-9586-a2465963cee4,ou=user,o=alpha,ou=services,ou=am-config",
    "realm": "/alpha",
    "latestAccessTime": "2020-10-22T15:01:14Z",
    "maxIdleExpirationTime": "2020-10-22T15:31:14Z",
    "maxSessionExpirationTime": "2020-10-22T17:01:13Z",
    "properties": {
        "AMCtxId": "dffed74d-f203-469c-9ed2-34738915baea-5255",
        "mySessionProperty": "myPropertyValue"
    }
}

Accessing Existing Session Properties

Scripted Decision Node scripts can access any existing session properties during a session upgrade request, by using the existingSession object.

The following table lists the methods of the existingSession object:

Methods

String existingSession.get(String _Property Name)

Return the string value of the named existing session property, or null, if the property is not set. Note that property names are case-sensitive.

If the current request is not a session upgrade and does not provide an existing session, the existingSession variable is not declared. Check for a declaration before attempting to access the variable.

Example:

if (typeof existingSession !== 'undefined')
{
    existingAuthLevel = existingSession.get("AuthLevel")
}
else
{
    logger.error("Variable existingSession not declared - not a session upgrade.")
}

Using Callbacks

The scripted decision node can use callbacks to provide or request additional information during the authentication process.

Example:

The following scripts use the NameCallBack callback to request a "Nickname" value from the user, and adds the returned value to the sharedState map for use elsewhere in the authentication tree:

  • Groovy

  • JavaScript

import org.forgerock.openam.auth.node.api.*
import javax.security.auth.callback.NameCallback

if (callbacks.isEmpty()) {
  action = Action.send(new NameCallback("Enter Your Nickname")).build()
} else {
  sharedState.put("Nickname", callbacks.get(0).getName())
  action = Action.goTo("true").build()
}
var fr = JavaImporter(
  org.forgerock.openam.auth.node.api,
  javax.security.auth.callback.NameCallback
)

with (fr) {
  if (callbacks.isEmpty()) {
    action = Action.send(new NameCallback("Enter Your Nickname")).build()
  } else {
    sharedState.put("Nickname", callbacks.get(0).getName())
    action = Action.goTo("true").build()
  }
}

For a list of supported callbacks, see Supported Callbacks.

Accessing Credentials and Secrets

Scripts used in a scripted decision node can access secrets.

For example, a script can access credentials or secrets defined in a file system secret volume in order to make outbound calls to a third-party REST service, without hard-coding those credentials in the script.

Methods

String secrets.getGenericSecret(String Secret ID)

Returns the value of the specified secret ID.

If the secret ID is defined at the realm level, its value is returned; otherwise, the script returns the value defined at the global level.

Only secret IDs that begin with the string scripted.node. are accessible to scripts.

Use the following functions to format the returned secret value:

getAsBytes()

Retrieve the secret value in byte[] format.

getAsUtf8()

Retrieve the secret value in UTF-8 format.

Example:

The following example scripts show how to get the value (passwd) from a secret ID named scripted.node.secret.id. They use the value in a basic authentication header to access the http://httpbin.org/#/Auth/get_basic_authuserpasswd[http://httpbin.org/basic-auth/user/passwd] service:

  • JavaScript

  • Groovy

var username = "demoUser"
var password = secrets.getGenericSecret("scripted.node.secret.id").getAsUtf8()

var auth = java.util.Base64.getEncoder().encodeToString(java.lang.String(username + ":" + password).getBytes())

var request = new org.forgerock.http.protocol.Request()
request.setMethod("GET")
request.setUri("http://httpbin.org/basic-auth/demoUser/passwd")
request.getHeaders().add("content-type","application/json; charset=utf-8")
request.getHeaders().add("Authorization", "Basic " + auth)

var response = httpClient.send(request).get()
var jsonResult = JSON.parse(response.getEntity().getString())
logger.error("Script result: " + JSON.stringify(jsonResult))
if (jsonResult.hasOwnProperty("authenticated")) {
    logger.error("outcome = success")
    outcome = "success"
}  else {
    logger.error("outcome = failure")
    outcome = "failure"
}
def username = "demoUser"
def password = secrets.getGenericSecret("scripted.node.secret.id").getAsUtf8()

def auth = java.util.Base64.getEncoder().encodeToString((username + ":" + password).getBytes())

def request = new org.forgerock.http.protocol.Request()
request.setMethod("GET")
request.setUri("http://httpbin.org/basic-auth/demoUser/passwd")
request.getHeaders().add("content-type","application/json; charset=utf-8")
request.getHeaders().add("Authorization", "Basic " + auth)

def response = httpClient.send(request).get()
if (response.status.successful) {
    logger.error("outcome = success")
    outcome = "success"
}  else {
    logger.error("outcome = failure")
    outcome = "failure"
}

Adding Audit Information

The scripted decision node can add information to audit log entries, by using the auditEntryDetail variable.

AM appends the value of the variable, which can be either plain text, or a JSON object, to the authentication audit logs.

Example:

The following Groovy script adds the user’s email address to the authentication.audit.json audit log file:

var currentUser = sharedState.get("username")
var attributeToRead = "mail"

auditEntryDetail="Extra Audit: " + currentUser + " email address: " +
  idRepository.getAttribute(currentUser,attributeToRead).iterator().next().toString()

outcome = "true"

The code above adds the information to the auditInfo element in the audit log entry:

{
  "_id":"f036618e-e318-4134-ac2a-13e860396103-545013",
  "timestamp":"2020-08-13T18:20:25.202Z",
  "eventName":"AM-NODE-LOGIN-COMPLETED",
  "transactionId":"f036618e-e318-4134-ac2a-13e860396103-544998",
  "trackingIds":[
    "f036618e-e318-4134-ac2a-13e860396103-544956"
  ],
  "principal":[
    "demo"
  ],
  "entries":[
    {
      "info":{
        "nodeOutcome":"true",
        "treeName":"Example",
        "displayName":"Audit Entry",
        "nodeType":"ScriptedDecisionNode",
        "nodeId":"13d40add-137c-4564-ad3c-7d98f7c180c1",
        "authLevel":"0",
        "nodeExtraLogging":{
          "auditInfo":"Extra Audit: demo email address: demo@example.com"
        }
      }
    }
  ]
}