Calling Force.com SOAP API on behalf of a portal user

portalauth.php

<?php
require_once ('soapclient/SforcePartnerClient.php');

function get_resource($url, $access_token) {
    $curl = curl_init($url);
    curl_setopt($curl, CURLOPT_HEADER, false);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($curl, CURLOPT_HTTPHEADER,
            array("Authorization: OAuth $access_token"));
    curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);

    $json_response = curl_exec($curl);
    if (curl_getinfo($curl, CURLINFO_HTTP_CODE) != 200) {
        echo "URL is $url\n";
        echo "Status is " . curl_getinfo($curl, CURLINFO_HTTP_CODE) . 
                " curl_errno() " .curl_errno($curl).
                ", curl_error() ".curl_error($curl).
                ", response ".$json_response."\n";      
    }

    curl_close($curl);

    return json_decode($json_response, true);
}

define("SF_USERNAME", getenv("USERNAME"));
define("SF_PASSWORD", getenv("PASSWORD"));
define("SF_ORGID", getenv("ORGID"));
define("SF_PORTALID", getenv("PORTALID"));

$mySforceConnection = new SforcePartnerClient();
$mySforceConnection->createConnection("soapclient/partner.wsdl.xml");

$mySforceConnection->setLoginScopeHeader(new LoginScopeHeader(SF_ORGID, SF_PORTALID));

$login = $mySforceConnection->login(SF_USERNAME, SF_PASSWORD);
echo "Login result:\n";
print_r($login);

// Get info on me
$identityServiceUrl = 'https://login.salesforce.com/id/'.$login->userInfo->organizationId.'/'.$login->userInfo->userId.'?version=latest';
$id = get_resource($identityServiceUrl, $login->sessionId);
echo "My id:\n";
print_r($id);

$query = "SELECT Subject FROM Case WHERE OwnerId = '".$login->userInfo->userId."'";

// Get my cases via the SOAP API
$response = $mySforceConnection->query($query);
echo "My cases via SOAP:\n";
print_r($response);

// Get my cases via the REST API
$queryUrl = $id["urls"]["rest"]."query?q=".urlencode($query);
$response = get_resource($queryUrl, $login->sessionId);
echo "My cases via REST:\n";
print_r($response);
?>

sample output

$ php portalauth.php 
Login result:
stdClass Object
(
    [metadataServerUrl] => https://na14-api.salesforce.com/services/Soap/m/20.0/00Dd0000000aaaa
    [passwordExpired] => 
    [sandbox] => 
    [serverUrl] => https://na14-api.salesforce.com/services/Soap/u/20.0/00Dd0000000aaaa
    [sessionId] => 00Dd0000000aaaa!123456789012345678901234567890123456789012345678901234567890123456789012345678901234
    [userId] => 005d0000000AAAAAA
    [userInfo] => stdClass Object
        (
            [accessibilityMode] => 
            [currencySymbol] => $
            [orgDefaultCurrencyIsoCode] => USD
            [orgDisallowHtmlAttachments] => 
            [orgHasPersonAccounts] => 
            [organizationId] => 00Dd0000000aaaaAAA
            [organizationMultiCurrency] => 
            [organizationName] => Devorg
            [profileId] => 00ed0000000BBBBBBB
            [roleId] => 
            [userDefaultCurrencyIsoCode] => 
            [userEmail] => user@example.com
            [userFullName] => Pat Patterson
            [userId] => 005d0000000AAAAAA
            [userLanguage] => en_US
            [userLocale] => en_US
            [userName] => user@example.com
            [userTimeZone] => America/Los_Angeles
            [userType] => CSPLitePortal
            [userUiSkin] => PortalDefault
        )

)
My id:
Array
(
    [id] => https://login.salesforce.com/id/00Dd0000000aaaaAAA/005d0000000AAAAAA
    [asserted_user] => 1
    [user_id] => 005d0000000AAAAAA
    [organization_id] => 00Dd0000000aaaaAAA
    [username] => user@example.com
    [nick_name] => user
    [display_name] => Pat Patterson
    [email] => user@example.com
    [first_name] => Pat
    [last_name] => Patterson
    [status] => Array
        (
            [created_date] => 
            [body] => 
        )

    [photos] => Array
        (
            [picture] => https://na14.salesforce.com/img/userprofile/default_profile_200.png
            [thumbnail] => https://na14.salesforce.com/img/userprofile/default_profile_45.png
        )

    [urls] => Array
        (
            [enterprise] => https://na14.salesforce.com/services/Soap/c/24.0/00Dd0000000aaaa
            [metadata] => https://na14.salesforce.com/services/Soap/m/24.0/00Dd0000000aaaa
            [partner] => https://na14.salesforce.com/services/Soap/u/24.0/00Dd0000000aaaa
            [rest] => https://na14.salesforce.com/services/data/v24.0/
            [sobjects] => https://na14.salesforce.com/services/data/v24.0/sobjects/
            [search] => https://na14.salesforce.com/services/data/v24.0/search/
            [query] => https://na14.salesforce.com/services/data/v24.0/query/
            [recent] => https://na14.salesforce.com/services/data/v24.0/recent/
            [profile] => https://na14.salesforce.com/005d0000000AAAAAA
            [feeds] => https://na14.salesforce.com/services/data/v24.0/chatter/feeds
            [groups] => https://na14.salesforce.com/services/data/v24.0/chatter/groups
            [users] => https://na14.salesforce.com/services/data/v24.0/chatter/users
            [feed_items] => https://na14.salesforce.com/services/data/v24.0/chatter/feed-items
        )

    [active] => 1
    [user_type] => CSP_LITE_PORTAL
    [language] => en_US
    [locale] => en_US
    [utcOffset] => -28800000
    [last_modified_date] => 2012-05-24T19:41:50.000+0000
)
My cases via SOAP:
QueryResult Object
(
    [queryLocator] => 
    [done] => 1
    [records] => Array
        (
            [0] => SObject Object
                (
                    [type] => Case
                    [fields] => stdClass Object
                        (
                            [Subject] => Are we nearly there yet?
                        )

                )

        )

    [size] => 1
)
My cases via REST:
Array
(
    [totalSize] => 1
    [done] => 1
    [records] => Array
        (
            [0] => Array
                (
                    [attributes] => Array
                        (
                            [type] => Case
                            [url] => /services/data/v24.0/sobjects/Case/500d0000003QWB7AAO
                        )

                    [Subject] => Are we nearly there yet?
                )

        )

)