Improving authentication performance when using the session

When using the session, it is often desirable to take advantage of the fact that the authenticated state of the user is kept in the session and not create and initialize the other filters (which might slow things down on every request).

The application can be structured like this:

1. <?php
2. $session = new ezcAuthenticationSession();
3. $session->start();
5. $credentials = new ezcAuthenticationPasswordCredentials( $user, $pass );
7. $authenticated = false;
8. if ( !$session->isValid( $credentials ) )
9. {
10. // create the authentication object
11. $authentication = new ezcAuthentication( $credentials );
12. $authentication->session = $session;
14. // create filters and add them to the authentication object
15. $authentication->addFilter( new ezcAuthenticationOpenidFilter() );
17. // run the authentication object
18. if ( !$authentication->run() )
19. {
20. $status = $authentication->getStatus();
21. // build an error message based on $status
22. }
23. else
24. {
25. $authenticated = true;
26. }
27. }
28. else
29. {
30. $authenticated = true;
31. }
33. if ( $authenticated )
34. {
35. // the authentication succeeded and the user can see his content
36. }
37. else
38. {
39. // inform the user that the authentication failed (with the error
40. // message that was created earlier)
41. }
42. ?>

In this way, the creation and initialization of the authentication filters is not performed if the credentials are stored in the session.

Multiple credentials

To be able to use multiple credentials for authentication (each filter with its own credentials), you must enable the multipleCredentials option for ezcAuthenticationGroupFilter.

The following example demonstrates how to use multiple credentials.

1. <?php
2. require_once 'tutorial_autoload.php';
4. $credentials1 = new ezcAuthenticationPasswordCredentials( 'jan.modaal', 'b1b3773a05c0ed0176787a4f1574ff0075f7521e' ); // incorrect password
5. $credentials2 = new ezcAuthenticationPasswordCredentials( 'john.doe', 'wpeE20wyWHnLE' ); // correct username + password
7. $options = new ezcAuthenticationGroupOptions();
8. $options->multipleCredentials = true;
9. $options->mode = ezcAuthenticationGroupFilter::MODE_AND;
10. $group = new ezcAuthenticationGroupFilter( array(), $options );
12. $group->addFilter( new ezcAuthenticationHtpasswdFilter( '../../tests/filters/htpasswd/data/htpasswd' ), $credentials1 );
13. $group->addFilter( new ezcAuthenticationHtpasswdFilter( '../../tests/filters/htpasswd/data/htpasswd' ), $credentials2 );
15. $authentication = new ezcAuthentication( $credentials1 );
16. $authentication->addFilter( $group );
17. // add more filters if needed
19. if ( !$authentication->run() )
20. {
21. // authentication did not succeed, so inform the user
22. $status = $authentication->getStatus();
24. $err = array(
25. array( 'ezcAuthenticationHtpasswdFilter' => array(
26. ezcAuthenticationHtpasswdFilter::STATUS_OK => '',
27. ezcAuthenticationHtpasswdFilter::STATUS_USERNAME_INCORRECT => 'Incorrect username ' . $credentials1->id,
28. ezcAuthenticationHtpasswdFilter::STATUS_PASSWORD_INCORRECT => 'Incorrect password for ' . $credentials1->id
29. ) ),
31. array( 'ezcAuthenticationHtpasswdFilter' => array(
32. ezcAuthenticationHtpasswdFilter::STATUS_OK => '',
33. ezcAuthenticationHtpasswdFilter::STATUS_USERNAME_INCORRECT => 'Incorrect username ' . $credentials2->id,
34. ezcAuthenticationHtpasswdFilter::STATUS_PASSWORD_INCORRECT => 'Incorrect password for ' . $credentials2->id
35. ) )
36. );
38. foreach ( $status as $line => $error )
39. {
40. list( $key, $value ) = each( $error );
41. echo $err[$line][$key][$value] . "\n";
42. }
43. }
44. else
45. {
46. // authentication succeeded, so allow the user to see his content
47. }
48. ?>

First, two credentials objects are created.

A Group filter is created with the multipleCredentials option enabled.

Two Htpasswd filters are added to the Group filter, each with their own credentials.

An Authentication object is created with a default credentials (which would have been used for other filters outside the Group filter, and to save the authenticated state in the session).

The Group filter is then added to the Authentication object.

After running the authentication (line 19), if the usernames and the passwords do not pass through the htpasswd filters, then the credentials are incorrect and the user must be informed. The getStatus() method is used for this. The values in the status returned must be cycled through and for each value a response is created for the user ("Username incorrect john.doe", "Password incorrect for john.doe", etc).

If run() returned true (line 44) then the user is logged-in and he can see his content.

The above example will output:

Incorrect password for jan.modaal

Fetch extra data during LDAP authentication

Any data that is defined for an acount can be fetched. Before running the authentication process (before calling run(), register which data needs to be fetched. Example:

// $filter is an ezcAuthenticationLdapFilter object
$filter->registerFetchData( array( 'name', 'company', 'mobile' ) );

After the authentication process is finished (after run()), retrieve the data that was registered:

// $filter is an ezcAuthenticationLdapFilter object
$data = $filter->fetchData();

For the previous example, the $data array will be something like this:

array( 'name' => array( 'Dr. No' ),
       'company' => array( 'SPECTRE' ),
       'mobile' => array( '555-7732873' )
     );

OpenID "dumb" (stateless) mode

The following example shows how to authenticate against OpenID in "dumb" (stateless) mode.

1. <?php
2. require_once 'tutorial_autoload.php';
4. // no headers should be sent before calling $session->start()
5. $session = new ezcAuthenticationSession();
6. $session->start();
8. $url = isset( $_GET['openid_identifier'] ) ? $_GET['openid_identifier'] : $session->load();
9. $action = isset( $_GET['action'] ) ? strtolower( $_GET['action'] ) : null;
11. $credentials = new ezcAuthenticationIdCredentials( $url );
12. $authentication = new ezcAuthentication( $credentials );
13. $authentication->session = $session;
15. if ( $action === 'logout' )
16. {
17. $session->destroy();
18. }
19. else
20. {
21. $filter = new ezcAuthenticationOpenidFilter();
22. $authentication->addFilter( $filter );
23. }
25. if ( !$authentication->run() )
26. {
27. // authentication did not succeed, so inform the user
28. $status = $authentication->getStatus();
29. $err = array(
30. 'ezcAuthenticationOpenidFilter' => array(
31. ezcAuthenticationOpenidFilter::STATUS_SIGNATURE_INCORRECT => 'OpenID said the provided identifier was incorrect',
32. ezcAuthenticationOpenidFilter::STATUS_CANCELLED => 'The OpenID authentication was cancelled',
33. ezcAuthenticationOpenidFilter::STATUS_URL_INCORRECT => 'The identifier you provided is invalid'
34. ),
35. 'ezcAuthenticationSession' => array(
36. ezcAuthenticationSession::STATUS_EMPTY => '',
37. ezcAuthenticationSession::STATUS_EXPIRED => 'Session expired'
38. )
39. );
40. foreach ( $status as $line )
41. {
42. list( $key, $value ) = each( $line );
43. echo $err[$key][$value] . "\n";
44. }
45. ?>
46. Please login with your OpenID identifier (an URL, eg. www.example.com or http://www.example.com):
47. <form method="GET" action="">
48. <input type="hidden" name="action" value="login" />
49. <img src="http://openid.net/login-bg.gif" /> <input type="text" name="openid_identifier" />
50. <input type="submit" value="Login" />
51. </form>
53. <?php
54. }
55. else
56. {
57. ?>
59. You are logged-in as <b><?php echo $url; ?></b> | <a href="?action=logout">Logout</a>
61. <?php
62. }
63. ?>

A session class is created and used to start the PHP session. The OpenID identifier (provided by the user through a GET form) is fetched and used to create a credentials object. On subsequent requests to the page, the token is loaded from session instead of the GET form. OpenID specifications recommend the name 'openid_identifier' for the text field of the form in which users type their OpenID identifier (so that browser can prefill the field if user chooses this).

An authentication object is created using the credentials object, and the session handler is added to it.

If the user is at logout (line 15), then the session is destroyed, which means the user will see the login form.

If the user is not at logout (line 19), then an OpenID filter is created with the credentials object.

After running the authentication (line 25), if the OpenID server did not authorize the identifier, then the credentials are incorrect and the user must be informed. The getStatus() method is used for this. The values in the status returned must be cycled through and for each value a response is created for the user ("Signature incorrect", "Session expired"). At line 46 a simple HTML form is displayed, as example. The form displays the OpenID logo (as suggested by the OpenID specifications).

If run() returned true (line 55) then the user is logged-in and he can see his content. Line 59 contains an example of how to implement a logout option for the application.

OpenID "smart" (stateful) mode

The following example shows how to authenticate against OpenID in "smart" (stateful) mode.

1. <?php
2. require_once 'tutorial_autoload.php';
4. // no headers should be sent before calling $session->start()
5. $session = new ezcAuthenticationSession();
6. $session->start();
8. $url = isset( $_GET['openid_identifier'] ) ? $_GET['openid_identifier'] : $session->load();
9. $action = isset( $_GET['action'] ) ? strtolower( $_GET['action'] ) : null;
11. $credentials = new ezcAuthenticationIdCredentials( $url );
12. $authentication = new ezcAuthentication( $credentials );
13. $authentication->session = $session;
15. if ( $action === 'logout' )
16. {
17. $session->destroy();
18. }
19. else
20. {
21. $options = new ezcAuthenticationOpenidOptions();
22. $options->mode = ezcAuthenticationOpenidFilter::MODE_SMART;
24. // define a file store
25. $options->store = new ezcAuthenticationOpenidFileStore( '/tmp/store' );
27. $filter = new ezcAuthenticationOpenidFilter( $options );
28. $authentication->addFilter( $filter );
29. }
31. if ( !$authentication->run() )
32. {
33. // authentication did not succeed, so inform the user
34. $status = $authentication->getStatus();
35. $err = array(
36. 'ezcAuthenticationOpenidFilter' => array(
37. ezcAuthenticationOpenidFilter::STATUS_SIGNATURE_INCORRECT => 'OpenID said the provided identifier was incorrect',
38. ezcAuthenticationOpenidFilter::STATUS_CANCELLED => 'The OpenID authentication was cancelled',
39. ezcAuthenticationOpenidFilter::STATUS_URL_INCORRECT => 'The identifier you provided is invalid'
40. ),
41. 'ezcAuthenticationSession' => array(
42. ezcAuthenticationSession::STATUS_EMPTY => '',
43. ezcAuthenticationSession::STATUS_EXPIRED => 'Session expired'
44. )
45. );
46. foreach ( $status as $line )
47. {
48. list( $key, $value ) = each( $line );
49. echo $err[$key][$value] . "\n";
50. }
51. ?>
52. Please login with your OpenID identifier (an URL, eg. www.example.com or http://www.example.com):
53. <form method="GET" action="">
54. <input type="hidden" name="action" value="login" />
55. <img src="http://openid.net/login-bg.gif" /> <input type="text" name="openid_identifier" />
56. <input type="submit" value="Login" />
57. </form>
59. <?php
60. }
61. else
62. {
63. ?>
65. You are logged-in as <b><?php echo $url; ?></b> | <a href="?action=logout">Logout</a>
67. <?php
68. }
69. ?>

The only differences between this example and the one in the previous section is defining the mode of the OpenID filter, and defining a store (file store in this example or database store as shown in the OpenID example in AuthenticationDatabaseTiein) which will hold the associations. In addition the store will also hold the nonces which are used to prevent replay attacks.

OpenID immediate mode

The OpenID request checkid_immediate is supported, which allows for user authentication in a pop-up window or iframe (or similar techniques). Instead of redirecting the user agent as in the checkid_setup step, the developer has the possibility to open a pop-up/iframe for the user to authenticate with the OpenID provider.

A more detailed description of the process: when using checkid_immediate, the OpenID provider is asked if the user can be authenticated on the spot, with no redirection of the user agent. If the user cannot be authenticated, the provider sends back a setup URL, which the application can use in a pop-up window or iframe to display to the user so that he can authenticate himself to the OpenID provider. After user enters his OpenID username and password at this page and accepts the originating site, the pop-up window or iframe is redirected to the return URL value (which should be a different page than the page which opens the pop-up window). The return URL page will then inform the main page of success or failure through JavaScript, and the main page can do the action that it needs to perform based on the outcome in the pop-up page.

The checkid_immediate mode is enabled by setting the option immediate to true.

Note: retrieval of extra data during authentication (fullname, email, etc) is not possible at the moment when using the immediate mode.

For example, this is one simple way of implementing checkid_immediate:

• the main page contains the OpenID login form (where the user types in his OpenID identifier). This page contains also a hidded form value which specifies to which page to return to in the pop-up window. The Enter key and the submit button should be disabled on the form. When user clicks on the Login button, the main page should employ AJAX to request the return URL. When the return URL finishes loading, the main page will read from the return URL page the setup URL and it will open it in a pop-up/iframe.
• the return URL page enables the option immediate to the OpenID filter, and runs the filter. It gets back the setup URL and it echoes it to be picked-up by the main page once the return URL page will finish loading. The setup URL should be the only thing that the return URL page is echoing, to not interfere with the main page.
• in the pop-up/iframe the setup URL will load, which basically depends on the OpenID provider how it is handled by the user. After the user enters his credentials on the setup URL page, he will be redirected to the return URL, which should detect this, and which should inform the main page that the user was authenticated to the OpenID provider.

A rudimentary source code example is provided below. It does not contain code to inform the user that the session expired or the errors experienced during the authentication process. The code has been tested on some browsers (Firefox 1.5, Konqueror 3.5, Internet Explorer 6.0), but it is possible that some browsers might have issues with the JavaScript code.

The main page:

1. <?php
2. require_once 'tutorial_autoload.php';
4. // no headers should be sent before calling $session->start()
5. $options = new ezcAuthenticationSessionOptions();
7. // setting 60 seconds timeout for session for testing purposes only
8. $options->validity = 60;
10. $session = new ezcAuthenticationSession( $options );
11. $session->start();
13. $identity = $session->load();
15. $url = isset( $_GET['openid_identifier'] ) ? $_GET['openid_identifier'] : $identity;
16. $action = isset( $_GET['action'] ) ? strtolower( $_GET['action'] ) : null;
18. $credentials = new ezcAuthenticationIdCredentials( $url );
19. $authentication = new ezcAuthentication( $credentials );
20. $authentication->session = $session;
22. if ( $action === 'logout' )
23. {
24. $session->destroy();
25. }
27. if ( !$authentication->run() )
28. {
29. // authentication did not succeed, so inform the user
31. ?>
33. <script language="JavaScript">
34. var xmlhttp = false;
36. /*@cc_on @*/
37. /*@if ( @_jscript_version >= 5 )
38. try
39. {
40. xmlhttp = new ActiveXObject( "Msxml2.XMLHTTP" );
41. }
42. catch ( e )
43. {
44. try
45. {
46. xmlhttp = new ActiveXObject( "Microsoft.XMLHTTP" );
47. }
48. catch ( E )
49. {
50. xmlhttp = false;
51. }
52. }
53. @end @*/
55. if ( !xmlhttp && typeof XMLHttpRequest != 'undefined' )
56. {
57. try
58. {
59. xmlhttp = new XMLHttpRequest();
60. }
61. catch ( e )
62. {
63. xmlhttp = false;
64. }
65. }
67. if ( !xmlhttp && window.createRequest )
68. {
69. try
70. {
71. xmlhttp = window.createRequest();
72. }
73. catch ( e )
74. {
75. xmlhttp = false;
76. }
77. }
78. </script>
80. <script language="JavaScript">
81. function disableEnterKey( e )
82. {
83. var key;
84. key = ( window.event ) ? window.event.keyCode : e.which;
86. return ( key != 13 );
87. }
89. function login()
90. {
91. var url;
92. var form1;
93. var setupUrl;
95. form1 = document.form1;
97. url = form1.url.value + '?openid_identifier=' + escape( form1.openid_identifier.value ) +
98. '&action=login&immediate=true';
100. xmlhttp.open( "GET", url, true );
101. xmlhttp.onreadystatechange = function()
102. {
103. if ( xmlhttp.readyState == 4 )
104. {
105. setupUrl = xmlhttp.responseText;
106. hwnd = window.open( setupUrl, 'Login' );
107. if ( hwnd.opener == null )
108. {
109. hwnd.opener = self;
110. }
111. }
112. }
113. xmlhttp.send( null );
114. }
115. </script>
116. Please login with your OpenID identifier (an URL, eg. www.example.com or http://www.example.com):
117. <form method="GET" name="form1">
118. <input type="hidden" name="url" value="http://localhost/openid/openid_immediate.php" />
119. <input type="hidden" name="action" value="login" />
120. <img src="http://openid.net/login-bg.gif" /> <input type="text" name="openid_identifier" onKeyPress="return disableEnterKey( event )" />
121. <input type="button" onclick="javascript: login();" value="Login" />
122. <div name="status" id="status"></div>
123. </form>
125. <?php
126. }
127. else
128. {
129. ?>
131. You are logged-in as <b><?php echo $url; ?></b> | <a href="?action=logout">Logout</a>
133. <?php
134. }
135. ?>

This page handles the session, and contains JavaScript code to read from the return URL page the setup URL, and to open a pop-up page with that setup URL.

The pop-up page (also return URL):

1. <?php
2. require_once 'tutorial_autoload.php';
4. // no headers should be sent before calling $session->start()
5. $options = new ezcAuthenticationSessionOptions();
6. // setting 10 seconds timeout for session for testing purposes only
7. $options->validity = 60;
9. $session = new ezcAuthenticationSession( $options );
10. $session->start();
12. $setupUrl = isset( $_GET['openid_user_setup_url'] ) ? $_GET['openid_user_setup_url'] : null;
13. $immediate = isset( $_GET['immediate'] ) ? $_GET['immediate'] : false;
15. if ( $setupUrl !== null )
16. {
17. $urlParts = parse_url( $setupUrl );
18. parse_str( $urlParts['query'], $parts );
19. $identity = $parts['openid_identity'];
20. }
21. else
22. {
23. $identity = $session->load();
24. }
26. $url = isset( $_GET['openid_identifier'] ) ? $_GET['openid_identifier'] : $identity;
27. $action = isset( $_GET['action'] ) ? strtolower( $_GET['action'] ) : null;
29. $credentials = new ezcAuthenticationIdCredentials( $url );
30. $authentication = new ezcAuthentication( $credentials );
31. $authentication->session = $session;
33. if ( $action === 'logout' )
34. {
35. $session->destroy();
36. }
37. else
38. {
39. $options = new ezcAuthenticationOpenidOptions();
41. // for checkid_immediate
42. if ( $immediate !== false )
43. {
44. $options->immediate = true;
45. }
47. $filter = new ezcAuthenticationOpenidFilter( $options );
49. // it seems that fetching extra data does not work with checkid_immediate
50. $filter->registerFetchData( array( 'fullname', 'gender', 'country', 'language' ) );
51. $authentication->addFilter( $filter );
52. }
54. if ( !$authentication->run() )
55. {
56. $setupUrl = $filter->getSetupUrl();
57. if ( !empty( $setupUrl ) )
58. {
59. // the setup URL will be read by the main window
60. echo $setupUrl;
61. }
62. else
63. {
64. echo 'Authentication did not succeed.';
65. }
66. }
67. else
68. {
69. ?>
70. <script language="JavaScript">
71. // inform the parent window that authentication was successful
72. top.opener.window.document.getElementById( 'status' ).innerHTML = '<b style="color: #009900;">logged-in</b> | <a href="openid_ajax.php?action=logout">Logout</a>';
73. window.close();
74. </script>
75. <?
76. }
77. ?>

This page also contains code to handle the session, in addition to handling the OpenID authentication. It will be called 2 times:

• first by the main page, with the immediate=true query parameter. A connection to the OpenID provider is created, and a setup URL is fetched, which will be echoed to be picked up by the main page. The main page then opens the setup URL in a pop-up window.
• second, by the setup URL, as the openid.return_to query parameter is set to redirect back to this page. The OpenID filter is called again, this time to check the signature in the return URL, and if it authenticates successfully, the main page is informed of this (line 80) and the pop-up window is closed. Other methods can be employed to inform the main page, and the main page can do other actions instead of just displaying a message.

Fetch extra data during OpenID authentication

Any data that is defined for an acount can be fetched. Before running the authentication process (before calling run(), register which data needs to be fetched. Example:

// $filter is an ezcAuthenticationOpenidFilter object
$filter->registerFetchData( array( 'fullname', 'gender', 'country',
'language' ) );

After the authentication process is finished (after run()), retrieve the data that was registered:

// $filter is an ezcAuthenticationOpenidFilter object
$data = $filter->fetchData();

For the previous example, the $data array will be something like this:

array( 'fullname' => array( 'John Doe' ),
       'gender' => array( 'M' ),
       'country' => array( 'US' ),
       'language' => array( 'FR' )
     );

Note: when using the immediate OpenID mode (by setting the option immediate to true), extra data cannot be fetched during authentication.