Connection class for Saleforce.

Requirements:
PHP >= 5.1.x
Salesforce Toolkit for PHP >=5.1.x

Folder structure (To be used as an example, you can have your own structure but make sure you update the SF_SOAPCLIENT_DIR and the index require_once):

• public_html
  • sf-lib
    • toolkit (Salesforce Toolkit Folder)
    • SF_Connect.class.php
  • index.php

SF_Connect.class.php

PHP Code:

<?php
/**
 * Salesforce Connection
 *
 * Creates a connection to Salesforce
 * 
 * @author Jeremy Simkins
 * @version 0.0.1
 */
class SF_Connect {
    /**
     * Instance of Saleforce Soap Client
     * @var resource
     */
    private static $soapClient;

    /**
     * WSDL Method
     * @var string
     */
    private static $wsdlMethod;

    /**
     * Salesforce User Login
     * @var string
     */
    const SALESFORCE_USER = '**LOGIN**';

    /**
     * Salesforce User Login Password
     * @var string
     */
    const SALESFORCE_PASS = '**PASS**';

    /**
     * Salesforce Token
     * @var string
     */
    const SALESFORCE_TOKEN = '**TOKEN**';

    /**
     * Debug Mode
     * - True - Shows errors
     * - False - Emails errors
     *
     * SHOULD BE FALSE IN A LIVE ENVIRONMENT
     * @var bool
     */
    const IN_DEBUG_MODE = true;

    /**
     * Email to send errors to
     * @var STRING
     */
    const ERROR_EMAIL = '**EMAIL**';

    /**
     * Path to toolkit soapclient folder
     * @var string
     */
    const SF_SOAPCLIENT_DIR = 'sf-lib/toolkit/soapclient/';

    /**
     * Initiates the Salesforce Connection
     * @param string $wsdlMethod
     */
    public static function connect($wsdlMethod = 'partner') {
        # Prevent Stupid
        if (self::$soapClient) return;

        # Ensure we have a valid method
        if ( !$wsdlMethod || !in_array($wsdlMethod, array('partner', 'enterprise', 'metadata')) ) {
            die(((self::IN_DEBUG_MODE) ? 'Bad wsdl requested' : 'Unable to connect to salesforce.com'));
        }

        try {
            # Create client and connection
            self::$soapClient = self::getSoapClient($wsdlMethod);
            self::$soapClient->createConnection(self::SF_SOAPCLIENT_DIR . self::$wsdlMethod . '.wsdl.xml');

            # Login
            $tmpLogin = self::$soapClient->login(self::SALESFORCE_USER, self::SALESFORCE_PASS . self::SALESFORCE_TOKEN);

            # Ensure password is still valid
            if ( $tmpLogin->passwordExpired ) {
                if (self::IN_DEBUG_MODE) {
                    die('Password has expired');
                }
                return false;
            }
            return true;
        } catch ( SoapFault $e ) {
            $errorMessage = "Error: [{$e->getCode()}] {$e->getMessage()}";
            $errorMessage .= '<br />';
            $errorMessage .= "File:{$e->getFile()}<br />Line: {$e->getLine()}";
            $errorMessage .= '<br />';
            $errorMessage .= '<pre>' . print_r($e->getTrace(), true) . '</pre>';

            # While in debug we can display the error
            if ( self::IN_DEBUG_MODE ) {
                echo $errorMessage;
            } else {
                // To send HTML mail, the Content-type header must be set
                $headers = 'MIME-Version: 1.0' . "\r\n";
                $headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";

                mail(self::ERROR_EMAIL, 'Salesforce Error!', $errorMessage, $headers);
            }
            return false;
        }
    }

    /**
     * Returns proper resource for given wdsl Method
     * Also sets self::$wsdlMethod to ensure the proper soap client is initiated
     * @param string $wsdlMethod
     */
    private static function getSoapClient($wsdlMethod) {
        switch (strtolower($wsdlMethod)) {
            case 'enterprise':
                # Require Client
                require_once (self::SF_SOAPCLIENT_DIR . 'SforceEnterpriseClient.php');
                # Set method
                self::$wsdlMethod = 'enterprise';
                # Return object
                return new SforceEnterpriseClient();
                break;
            case 'metadata':
                # Require Client
                require_once (self::SF_SOAPCLIENT_DIR . 'SforceMetadataClient.php');
                # Set method
                self::$wsdlMethod = 'metadata';
                # Return object
                return new SforceMetadataClient();
                break;
            case 'partner':
                # Require Client
                require_once (self::SF_SOAPCLIENT_DIR . 'SforcePartnerClient.php');
                # Set method
                self::$wsdlMethod = 'partner';
                # Return object
                return new SforcePartnerClient();
                break;
            default:
                die(((self::IN_DEBUG_MODE) ? 'Bad client requested' : 'Unable to connect to salesforce.com'));
                break;
        }
    }

    /**
     * Logout current connection
     */
    public static function logout() {
        self::$soapClient->logout();
    }

    /**
     * Return soap client
     */
    public static function getClient() {
        return self::$soapClient;
    }
}

/**
 * This clears out your local PHP WSDL cache incase you may have been performing
 * tests against your development account or Sandbox account
 */
ini_set("soap.wsdl_cache_enabled", "0");

Test Script
index.php

PHP Code:

# Require the connection class
require_once 'sf-lib/SF_Connect.class.php';

# Initialize the connection
if ( !SF_Connect::connect() ) {
    # Connection failed, output error
    die('Unable to connect to salesforce.com');
}

/**
 * Successful connection
 *
 * Process actions here
 */

# Demo
$query = "SELECT Id, FirstName, LastName from Lead";
$queryResult = SF_Connect::getClient()->query($query);
$records = $queryResult->records;
foreach ($records as $sObject) {
    echo "Id = ".$sObject->Id;
    echo '<br />';
    echo "First Name = ".$sObject->fields->FirstName;
    echo '<br />';
    echo "Last Name = ".$sObject->fields->LastName;
    echo '<hr />';
}

# Don't forget to logout
SF_Connect::logout(); 


Defaults to partner as the default connection client.
Below are examples on how to connect to Enterprise and Metadata:
Enterprise Connection

PHP Code:

# Initialize the connection
if ( !SF_Connect::connect('enterprise') ) {
    # Connection failed, output error
    die('Unable to connect to salesforce.com');
} 


Metadata connection

PHP Code:

# Initialize the connection
if ( !SF_Connect::connect('metadata') ) {
    # Connection failed, output error
    die('Unable to connect to salesforce.com');
} 


I am working on my own library for Saleforce and plan to release more in the future.
If you have any concerns, suggestions, or updates for the connection class, please let me know.

Thanks to this post by saariko for a reference.

Hope some find this useful