<?php
/** Writes every product below $rootNodeID as one JSON line each. Run as a service account with content/read. */
function myIntegrationExportProducts( $rootNodeID, $outFile )
{
    $out = fopen( $outFile, 'w' );
    $params = array( 'ClassFilterType' => 'include',
                     'ClassFilterArray' => array( 'product' ),
                     'SortBy' => array( 'node_id', true ),
                     'Limit' => 200,
                     'LoadDataMap' => true );
    $offset = 0;
    do
    {
        $params['Offset'] = $offset;
        $nodes = eZContentObjectTreeNode::subTreeByNodeID( $params, $rootNodeID );
        foreach ( (array)$nodes as $node )
        {
            fwrite( $out, json_encode( myIntegrationPayload( $node->object() ) ) . "\n" );
        }
        $offset += 200;
        eZContentObject::clearCache();
    }
    while ( is_array( $nodes ) && count( $nodes ) === 200 );
    fclose( $out );
}

<?php
/** Sends up to 100 pending rows; a failed row stays pending and is retried with a growing delay. */
function myIntegrationSendOutbox( myIntegrationHubClient $client )
{
    $db = eZDB::instance();
    $now = time();
    $rows = $db->arrayQuery( 'SELECT id, object_id, attempts FROM myintegration_outbox'
                           . ' WHERE sent = 0 AND next_try <= ' . $now . ' ORDER BY id', array( 'limit' => 100 ) );
    foreach ( $rows as $row )
    {
        $object = eZContentObject::fetch( (int)$row['object_id'] );
        $payload = $object instanceof eZContentObject
            ? myIntegrationPayload( $object )
            : array( 'remote_id' => null, 'object_id' => (int)$row['object_id'], 'deleted' => true );
        if ( $client->send( $payload, 'outbox-' . (int)$row['id'] ) )
        {
            $db->query( 'UPDATE myintegration_outbox SET sent = ' . $now . ' WHERE id = ' . (int)$row['id'] );
        }
        else
        {
            $attempts = (int)$row['attempts'] + 1;
            $delay = min( 3600, 60 * ( 2 ** $attempts ) );   // 2, 4, 8 ... minutes, at most an hour
            $db->query( 'UPDATE myintegration_outbox SET attempts = ' . $attempts . ', next_try = ' . ( $now + $delay )
                      . ' WHERE id = ' . (int)$row['id'] );
            eZDebug::writeWarning( "Outbox row {$row['id']} failed (attempt $attempts)", __METHOD__ );
        }
    }
}

<?php
function myIntegrationPayload( eZContentObject $object )
{
    $dataMap = $object->dataMap();
    $node = $object->mainNode();
    return array(
        'remote_id'  => $object->attribute( 'remote_id' ),
        'object_id'  => (int)$object->attribute( 'id' ),
        'class'      => $object->attribute( 'class_identifier' ),
        'name'       => $object->attribute( 'name' ),
        'modified'   => (int)$object->attribute( 'modified' ),
        'url'        => $node ? $node->urlAlias() : null,
        'sku'        => isset( $dataMap['sku'] ) ? $dataMap['sku']->toString() : null,
    );
}