Previous Next

Database Table Authentication

Introduction

Zend_Auth_Adapter_DbTable provides the ability to authenticate against credentials stored in a database table. Because Zend_Auth_Adapter_DbTable requires an instance of Zend_Db_Adapter_Abstract to be passed to its constructor, each instance is bound to a particular database connection. Other configuration options may be set through the constructor and through instance methods, one for each option.

The available configuration options include:

  • tableName: This is the name of the database table that contains the authentication credentials, and against which the database authentication query is performed.

  • identityColumn: This is the name of the database table column used to represent the identity. The identity column must contain unique values, such as a username or e-mail address.

  • credentialColumn: This is the name of the database table column used to represent the credential. Under a simple identity and password authentication scheme, the credential value corresponds to the password. See also the credentialTreatment option.

  • credentialTreatment: In many cases, passwords and other sensitive data are encrypted, hashed, encoded, obscured, salted or otherwise treated through some function or algorithm. By specifying a parameterized treatment string with this method, such as 'MD5(?)' or 'PASSWORD(?)', a developer may apply such arbitrary SQL upon input credential data. Since these functions are specific to the underlying RDBMS, check the database manual for the availability of such functions for your database system.

Example #1 Basic Usage

As explained in the introduction, the Zend_Auth_Adapter_DbTable constructor requires an instance of Zend_Db_Adapter_Abstract that serves as the database connection to which the authentication adapter instance is bound. First, the database connection should be created.

The following code creates an adapter for an in-memory database, creates a simple table schema, and inserts a row against which we can perform an authentication query later. This example requires the PDO SQLite extension to be available:

// Create an in-memory SQLite database connection
$dbAdapter = new Zend_Db_Adapter_Pdo_Sqlite(array('dbname' =>
                                                  ':memory:'));

// Build a simple table creation query
$sqlCreate = 'CREATE TABLE [users] ('
           . '[id] INTEGER  NOT NULL PRIMARY KEY, '
           . '[username] VARCHAR(50) UNIQUE NOT NULL, '
           . '[password] VARCHAR(32) NULL, '
           . '[real_name] VARCHAR(150) NULL)';

// Create the authentication credentials table
$dbAdapter->query($sqlCreate);

// Build a query to insert a row for which authentication may succeed
$sqlInsert = "INSERT INTO users (username, password, real_name) "
           . "VALUES ('my_username', 'my_password', 'My Real Name')";

// Insert the data
$dbAdapter->query($sqlInsert);

With the database connection and table data available, an instance of Zend_Auth_Adapter_DbTable may be created. Configuration option values may be passed to the constructor or deferred as parameters to setter methods after instantiation:

// Configure the instance with constructor parameters...
$authAdapter = new Zend_Auth_Adapter_DbTable(
    $dbAdapter,
    'users',
    'username',
    'password'
);

// ...or configure the instance with setter methods
$authAdapter = new Zend_Auth_Adapter_DbTable($dbAdapter);

$authAdapter
    ->setTableName('users')
    ->setIdentityColumn('username')
    ->setCredentialColumn('password')
;

At this point, the authentication adapter instance is ready to accept authentication queries. In order to formulate an authentication query, the input credential values are passed to the adapter prior to calling the authenticate() method:

// Set the input credential values (e.g., from a login form)
$authAdapter
    ->setIdentity('my_username')
    ->setCredential('my_password')
;

// Perform the authentication query, saving the result
$result = $authAdapter->authenticate();

In addition to the availability of the getIdentity() method upon the authentication result object, Zend_Auth_Adapter_DbTable also supports retrieving the table row upon authentication success:

// Print the identity
echo $result->getIdentity() . "\n\n";

// Print the result row
print_r($authAdapter->getResultRowObject());

/* Output:
my_username

Array
(
    [id] => 1
    [username] => my_username
    [password] => my_password
    [real_name] => My Real Name
)
*/

Since the table row contains the credential value, it is important to secure the values against unintended access.

Advanced Use: Persisting a DbTable Result Object

By default, Zend_Auth_Adapter_DbTable returns the identity supplied back to the auth object upon successful authentication. Another use case scenario, where developers want to store to the persistent storage mechanism of Zend_Auth an identity object containing other useful information, is solved by using the getResultRowObject() method to return a stdClass object. The following code snippet illustrates its use:

// authenticate with Zend_Auth_Adapter_DbTable
$result = $this->_auth->authenticate($adapter);

if ($result->isValid()) {
    // store the identity as an object where only the username and
    // real_name have been returned
    $storage = $this->_auth->getStorage();
    $storage->write($adapter->getResultRowObject(array(
        'username',
        'real_name',
    )));

    // store the identity as an object where the password column has
    // been omitted
    $storage->write($adapter->getResultRowObject(
        null,
        'password'
    ));

    /* ... */

} else {

    /* ... */

}

Advanced Usage By Example

While the primary purpose of Zend_Auth (and consequently Zend_Auth_Adapter_DbTable) is primarily authentication and not authorization, there are a few instances and problems that toe the line between which domain they fit within. Depending on how you’ve decided to explain your problem, it sometimes makes sense to solve what could look like an authorization problem within the authentication adapter.

With that bit of a disclaimer out of the way, Zend_Auth_Adapter_DbTable has some built in mechanisms that can be leveraged to add additional checks at authentication time to solve some common user problems.

// The status field value of an account is not equal to "compromised"
$adapter = new Zend_Auth_Adapter_DbTable(
    $db,
    'users',
    'username',
    'password',
    'MD5(?) AND status != "compromised"'
);

// The active field value of an account is equal to "TRUE"
$adapter = new Zend_Auth_Adapter_DbTable(
    $db,
    'users',
    'username',
    'password',
    'MD5(?) AND active = "TRUE"'
);

Another scenario can be the implementation of a salting mechanism. Salting is a term referring to a technique which can highly improve your application’s security. It’s based on the idea that concatenating a random string to every password makes it impossible to accomplish a successful brute force attack on the database using precomputed hash values from a dictionary.

Therefore we need to modify our table to store our salt string:

$sqlAlter = "ALTER TABLE [users] "
          . "ADD COLUMN [password_salt] "
          . "AFTER [password]";

$dbAdapter->query($sqlAlter);

Here’s a simple way to generate a salt string for every user at registration:

for ($i = 0; $i < 50; $i++)
{
    $dynamicSalt .= chr(rand(33, 126));
}

And now let’s build the adapter:

$adapter = new Zend_Auth_Adapter_DbTable(
    $db,
    'users',
    'username',
    'password',
    "MD5(CONCAT('"
    . Zend_Registry::get('staticSalt')
    . "', ?, password_salt))"
);

Note:

You can improve security even more by using a static salt value hardcoded into your application. In the case that your database is compromised (e. g. by an SQL injection attack) but your web server is intact your data is still unusable for the attacker.

Previous Next
Introduction to Zend Framework
Overview
Installation
Zend_Acl
Introduction
Refining Access Controls
Advanced Usage
Zend_Amf
Introduction
Zend_Amf_Server
Zend_Auth
Introduction
Database Table Authentication
Digest Authentication
HTTP Authentication Adapter
LDAP Authentication
Open ID Authentication
Zend_Cache
Introduction
The theory of caching
Zend_Cache frontends
Zend_Cache backends
Zend_Captcha
Introduction
Captcha Operation
Captcha Adapters
Zend_Config
Introduction
Theory of Operation
Zend_Config_Ini
Zend_Config_Xml
Zend_Config_Writer
Zend_Config_Writer
Zend_Console_Getopt
Introduction to Getopt
Declaring Getopt Rules
Fetching Options and Arguments
Configuring Zend_Console_Getopt
Zend_Controller
Zend_Controller Quick Start
Zend_Controller Basics
The Front Controller
The Request Object
The Standard Router
The Dispatcher
Action Controllers
Action Helpers
The Response Object
Plugins
Using a Conventional Modular Directory Structure
MVC Exceptions
Migrating from Previous Versions
Zend_Currency
Introduction to Zend_Currency
How to work with currencies
Migrating from Previous Versions
Zend_Date
Introduction
Theory of Operation
Basic Methods
Zend_Date API Overview
Creation of dates
Constants for General Date Functions
Working examples
Zend_Db
Zend_Db_Adapter
Zend_Db_Statement
Zend_Db_Profiler
Zend_Db_Select
Zend_Db_Table
Zend_Db_Table_Row
Zend_Db_Table_Rowset
Zend_Db_Table Relationships
Zend_Debug
Dumping Variables
Zend_Dojo
Introduction
Zend_Dojo_Data: dojo.data Envelopes
Dojo View Helpers
Dojo Form Elements and Decorators
Zend_Dom
Introduction
Zend_Dom_Query
Zend_Exception
Using Exceptions
Zend_Feed
Introduction
Importing Feeds
Retrieving Feeds from Web Pages
Consuming an RSS Feed
Consuming an Atom Feed
Consuming a Single Atom Entry
Modifying Feed and Entry structures
Custom Feed and Entry Classes
Zend_File
Zend_File_Transfer
Validators for Zend_File_Transfer
Filters for Zend_File_Transfer
Migrating from previous versions
Zend_Filter
Introduction
Standard Filter Classes
Filter Chains
Writing Filters
Zend_Filter_Input
Zend_Filter_Inflector
Zend_Form
Zend_Form
Zend_Form Quick Start
Creating Form Elements Using Zend_Form_Element
Creating Forms Using Zend_Form
Creating Custom Form Markup Using Zend_Form_Decorator
Standard Form Elements Shipped With Zend Framework
Standard Form Decorators Shipped With Zend Framework
Internationalization of Zend_Form
Advanced Zend_Form Usage
Zend_Gdata
Introduction to Gdata
Authenticating with AuthSub
Using the Book Search Data API
Authenticating with ClientLogin
Using Google Calendar
Using Google Documents List Data API
Using Google Health
Using Google Spreadsheets
Using Google Apps Provisioning
Using Google Base
Using Picasa Web Albums
Using the YouTube Data API
Catching Gdata Exceptions
Zend_Http
Zend_Http_Client - Introduction
Zend_Http_Client - Advanced Usage
Zend_Http_Client - Connection Adapters
Zend_Http_Cookie and Zend_Http_CookieJar
Zend_Http_Response
Zend_InfoCard
Introduction
Zend_Json
Introduction
Basic Usage
JSON Objects
XML to JSON conversion
Zend_Json_Server - JSON-RPC server
Zend_Layout
Introduction
Zend_Layout Quick Start
Zend_Layout Configuration Options
Zend_Layout Advanced Usage
Zend_Ldap
Introduction
Zend_Loader
Loading Files and Classes Dynamically
Loading Plugins
Zend_Locale
Introduction
Using Zend_Locale
Normalization and Localization
Working with Dates and Times
Supported locales
Migrating from previous versions
Zend_Log
Overview
Writers
Formatters
Filters
Zend_Mail
Introduction
Sending via SMTP
Sending Multiple Mails per SMTP Connection
Using Different Transports
HTML E-Mail
Attachments
Adding Recipients
Controlling the MIME Boundary
Additional Headers
Character Sets
Encoding
SMTP Authentication
Securing SMTP Transport
Reading Mail Messages
Zend_Measure
Introduction
Creation of Measurements
Outputting measurements
Manipulating Measurements
Types of measurements
Zend_Memory
Overview
Memory Manager
Memory Objects
Zend_Mime
Zend_Mime
Zend_Mime_Message
Zend_Mime_Part
Zend_OpenId
Introduction
Zend_OpenId_Consumer Basics
Zend_OpenId_Provider
Zend_Paginator
Introduction
Usage
Configuration
Advanced usage
Zend_Pdf
Introduction.
Creating and loading PDF documents.
Save changes to the PDF document.
Document pages.
Drawing
Document Info and Metadata.
Zend_Pdf module usage example
Zend_ProgressBar
Zend_ProgressBar
Zend_Registry
Using the Registry
Zend_Rest
Introduction
Zend_Rest_Client
Zend_Rest_Server
Zend_Search_Lucene
Overview
Building Indexes
Searching an Index
Query Language
Query Construction API
Character Set
Extensibility
Interoperating with Java Lucene
Advanced
Best Practices
Zend_Server
Introduction
Zend_Server_Reflection
Zend_Service
Introduction
Zend_Service_Akismet
Zend_Service_Amazon
Zend_Service_Audioscrobbler
Zend_Service_Delicious
Zend_Service_Flickr
Zend_Service_Nirvanix
Zend_Service_ReCaptcha
Zend_Service_Simpy
Introduction
Zend_Service_StrikeIron
Zend_Service_StrikeIron: Bundled Services
Zend_Service_StrikeIron: Advanced Uses
Zend_Service_Technorati
Zend_Service_Twitter
Zend_Service_Yahoo
Zend_Session
Introduction
Basic Usage
Advanced Usage
Global Session Management
Zend_Session_SaveHandler_DbTable
Zend_Soap
Zend_Soap_Server
Zend_Soap_Client
WSDL Accessor
AutoDiscovery
Zend_Test
Introduction
Zend_Test_PHPUnit
Zend_Text
Zend_Text_Figlet
Zend_Text_Table
Zend_TimeSync
Introduction
Working with Zend_TimeSync
Zend_Translate
Introduction
Adapters for Zend_Translate
Using Translation Adapters
Migrating from previous versions
Zend_Uri
Zend_Uri
Zend_Validate
Introduction
Standard Validation Classes
Validator Chains
Writing Validators
Zend_Version
Reading the Zend Framework Version
Zend_View
Introduction
Controller Scripts
View Scripts
View Helpers
Zend_View_Abstract
Zend_Wildfire
Zend_Wildfire
Zend_XmlRpc
Introduction
Zend_XmlRpc_Client
Zend_XmlRpc_Server
Zend Framework Requirements
PHP Version
PHP Extensions
Zend Framework Components
Zend Framework Dependencies
Zend Framework Coding Standard for PHP
Overview
PHP File Formatting
Naming Conventions
Coding Style
Zend Framework Performance Guide
Introduction
Class Loading
Internationalization (i18n) and Localization (l10n)
View Rendering
Copyright Information