UnboundID Server SDK

Ping Identity
UnboundID Server SDK Documentation

ExamplePolicyInformationProvider.java

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package com.unboundid.directory.sdk.examples;

import com.unboundid.directory.sdk.broker.api.PolicyInformationProvider;
import com.unboundid.directory.sdk.broker.config.
    PolicyInformationProviderConfig;
import com.unboundid.directory.sdk.broker.types.BrokerContext;
import com.unboundid.directory.sdk.broker.types.RequestAttribute;
import com.unboundid.directory.sdk.broker.types.RequestContext;
import com.unboundid.util.args.ArgumentException;
import com.unboundid.util.args.ArgumentParser;
import com.unboundid.util.args.FileArgument;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

/**
 * Example of a third-party Policy Information Provider.  This example
 * implementation retrieves named attributes from a Java properties file, and
 * can retrieve other JSON content from a additional files.
 */
public class ExamplePolicyInformationProvider
    extends PolicyInformationProvider
{

  /**
   * The name of the argument that will be used to specify the directory
   * containing 'attributes.txt' and/or JSON content files.
   */
  private static final String ARG_NAME_CONTENT_DIR = "content-directory";

  /**
   * The name of the file that contains named attributes.
   */
  private static final String ATTRIBUTES_FILE_NAME = "attributes.txt";


  /**
   * The directory containing 'attributes.txt' and any JSON content
   * files.
   */
  private File contentDirectory;

  private Properties properties;
  private Set<String> supportedAttributes = new HashSet<String>();

  /**
   * Character used to delimit subject id from attribute id in the
   * name portion of each java property line.
   */
  public static final Character PROPERTY_NAME_DELIMITER = '$';


  /**
   * Creates a new instance of this policy information provider.  All policy
   * information provider implementations must include a default constructor,
   * but any initialization should generally be performed in the
   * {@code initializePolicyInformationProvider} method.
   */
  public ExamplePolicyInformationProvider()
  {
  }


  /**
   * Retrieves a human-readable name for this extension.
   * @return extension name
   */
  @Override
  public String getExtensionName()
  {
    return "Example Policy Information Provider";
  }


  /**
   * Retrieves a human-readable description of this extension.
   * @return text description string
   */
  @Override
  public String[] getExtensionDescription()
  {
    return new String[]
    {
      "This Policy Information Provider serves as an example that may" +
          " be used to demonstrate the process for creating a third-party" +
          " policy information provider.  This example provider reads" +
          " attribute data from text files.  The extension attribute with" +
          " name " + ARG_NAME_CONTENT_DIR + " specifies the directory in" +
          " which these text files are located.  The example provider"+
          " supports both Attribute Descriptors and Attribute Selectors. " +
          " For Attribute Descriptors, it reads values from a Java properties"+
          " file named 'attributes.txt' from the content directory.  For"+
          " Attribute Selectors, the XACML Category Id is interpreted as the" +
          " file name within the content directory from which to retrieve" +
          " JSON content."
    };
  }


  /**
   * Updates the provided argument parser to define any configuration arguments
   * which may be used by this policy information provider. The argument parser
   * may also be updated to define relationships between arguments (e.g., to
   * specify required, exclusive, or dependent argument sets).
   *
   * @param  parser  The argument parser to be updated with the configuration
   *                 arguments which may be used by this provider.
   *
   * @throws  ArgumentException  If a problem is encountered while updating the
   *                             provided argument parser.
   */
  @Override
  public void defineConfigArguments(final ArgumentParser parser)
      throws ArgumentException
  {

    // add argument used to specify the path to a properties file
    Character shortIdentifier = null;
    String longIdentifier = ARG_NAME_CONTENT_DIR;
    boolean required = true;
    int maxOccurrences = 1;
    String    placeholder     = "{path}";
    String    description     = "The directory containing the java properties"+
        " file 'attributes.txt' and zero or more JSON content files." +
        " 'attributes.txt' is a file containing name-value pairs.  Each"+
        " name-value pair must be in the" +
        " following format:  <subjectName>" + PROPERTY_NAME_DELIMITER +
        "<xacmlAttributeId>=value where subjectName = subject property from" +
        " the request context and xacmlAttributeId = the XACML attribute Id" +
        " being requested.  (Example: 'applicationX$urn:myorganization" +
        PROPERTY_NAME_DELIMITER + "myattribute=myvalue'.)";
    boolean   fileMustExist   = true;
    boolean   parentMustExist = true;
    boolean   mustBeFile      = false;
    boolean   mustBeDirectory = true;

    parser.addArgument(new FileArgument(shortIdentifier, longIdentifier,
        required, maxOccurrences, placeholder, description, fileMustExist,
        parentMustExist, mustBeFile, mustBeDirectory));
  }


  /**
   * Initialize this Policy Information Provider.  Sets the directory containing
   * attribute files and loads the named attribute properties file if it exists.
   *
   * @param  serverContext  A handle to the server context for the server in
   *                        which this extension is running.
   * @param  config         The general configuration for this policy
   *                        information provider.
   * @param  parser         The argument parser which has been initialized from
   *                        the configuration for this policy information
   *                        provider.
   *
   * @throws IOException if an error occurs reading the properties file
   */
  @Override
  public void initializePolicyInformationProvider(
      final BrokerContext serverContext,
      final PolicyInformationProviderConfig config,
      final ArgumentParser parser) throws IOException
  {
    contentDirectory = ((FileArgument)parser.getNamedArgument(
        ARG_NAME_CONTENT_DIR)).getValue();
    properties = new Properties();
    File attributesFile = new File(contentDirectory.getPath() +
        File.separator + ATTRIBUTES_FILE_NAME);
    if (attributesFile.exists()) {
      FileInputStream stream = new FileInputStream(attributesFile);
      properties.load(stream);

      // get list of supported attributes
      for (Object key : properties.keySet()) {
        String s = (String)key;
        int pos = s.indexOf(PROPERTY_NAME_DELIMITER);
        if (pos > 0) {
          String attributeUrn = s.substring(pos + 1);
          supportedAttributes.add(attributeUrn);

        }
      }
    }
  }


  /**
   * Retrieve an attribute value from the data store, which in the case of
   * this example is a java properties file.
   * @param categoryId XACML category identifier
   * @param attributeId XACML attribute identifier
   * @param context request context, can be used to retrieve other
   *                attributes from the request that may be needed
   *                in order to evaluate the requested attribute
   * @return RequestAttribute object
   * @throws Exception if an error occurs retrieving the attribute
   */
  @Override
  public RequestAttribute getAttribute(
      final String categoryId,
      final String attributeId,
      final RequestContext context) throws Exception
  {
    // construct key using both subject and attribute Id
    StringBuilder key = new StringBuilder(context.getSubject());
    key.append(PROPERTY_NAME_DELIMITER);
    key.append(attributeId);
    String value = properties.getProperty(key.toString());
    if (value == null)
    {
      throw new Exception(String.format(
          "attribute %s not found for subject %s",
          attributeId, context.getSubject()));
    }
    return new RequestAttribute("http://www.w3.org/2001/XMLSchema#string",
        Arrays.asList(value));
  }


  /**
   * Retrieve JSON-formatted content from the specified attributes category,
   * which in the case of this example is retrieved from a file whose name
   * is the same as the category name.
   * @param categoryId XACML category identifier.  This is the category Id
   *                   specified by the AttributeSelector element in the
   *                   policy that is requesting this attribute.
   * @param context request context, can be used to retrieve other
   *                attributes from the request that may be needed
   *                in order to retrieve the requested content
   * @return JSON-encoded string
   * @throws Exception if an error occurs retrieving the content
   */
  @Override
  public String getJsonContent(
      final String categoryId,
      final RequestContext context)
      throws Exception {

    // assume that content files are small
    Path p = Paths.get(contentDirectory.getPath(), categoryId);
    return new String(Files.readAllBytes(p), StandardCharsets.UTF_8);
  }


  /**
   * Determine whether this example provider can get the specified
   * attribute.
   *
   * @param categoryId XACML category identifier.  This is the category Id
   *                   specified by the AttributeDesignator element in the
   *                   policy that is requesting this attribute.
   * @param attributeId XACML attribute identifier as specified in the
   *                   AttributeDesignator element in the policy that is
   *                   requesting the attribute.
   * @param context request context
   * @return True if the attribute is served by this provider.
   */
  @Override
  public boolean canGetAttribute(
      final String categoryId,
      final String attributeId,
      final RequestContext context) {
    return supportedAttributes.contains(attributeId);
  }

  /**
   * Determine whether this example provider can get JSON content for the
   * specified attributes category.
   *
   * @param categoryId XACML category identifier.  This is the category Id
   *                   specified by the AttributeSelector element in the
   *                   policy that is requesting this attribute.
   * @param contextSelectorId optional ContextSelectorId.  This is the
   *                   context selector string specified in the
   *                   AttributeSelector.
   * @param context request context
   * @return True if the attributes category / context selector can be served
   * by this provider.
   */
  @Override
  public boolean canGetJsonContent(
      final String categoryId,
      final String contextSelectorId,
      final RequestContext context) {
    Path p = Paths.get(contentDirectory.getPath(), categoryId);
    return Files.exists(p);
  }

  /**
   * Retrieves a map containing examples of configurations that may be used for
   * this extension.  The map key should be a list of sample arguments, and the
   * corresponding value should be a description of the behavior that will be
   * exhibited by the extension when used with that configuration.
   *
   * @return  A map containing examples of configurations that may be used for
   *          this extension.  It may be {@code null} or empty if there should
   *          not be any example argument sets.
   */
  @Override()
  public Map<List<String>,String> getExamplesArgumentSets()
  {
    final LinkedHashMap<List<String>,String> exampleMap =
        new LinkedHashMap<List<String>,String>(1);

    exampleMap.put(
        Arrays.asList(ARG_NAME_CONTENT_DIR + "=/var/xacmlContent"),
        "Retrieve attribute data from file(s) in the directory" +
            " /var/xacmlContent.");

    return exampleMap;
  }
}