diff --git a/wp-admin/includes/class-wp-importer.php b/wp-admin/includes/class-wp-importer.php
new file mode 100644
index 0000000000..5a7f0e47a7
--- /dev/null
+++ b/wp-admin/includes/class-wp-importer.php
@@ -0,0 +1,310 @@
+<?php
+/**
+ * WP_Importer base class
+ */
+class WP_Importer {
+	/**
+	 * Class Constructor
+	 *
+	 * @return void
+	 */
+	function __construct() {}
+
+	function WP_Importer() {
+		$this->__construct();
+	}
+
+	/**
+	 * Returns array with imported permalinks from WordPress database
+	 *
+	 * @param string $bid
+	 * @return array
+	 */
+	function get_imported_posts( $importer_name, $bid ) {
+		global $wpdb;
+
+		$hashtable = array();
+
+		$limit = 100;
+		$offset = 0;
+
+		// Grab all posts in chunks
+		do {
+			$meta_key = $importer_name . '_' . $bid . '_permalink';
+			$sql = $wpdb->prepare( "SELECT post_id, meta_value FROM $wpdb->postmeta WHERE meta_key = '%s' LIMIT %d,%d", $meta_key, $offset, $limit );
+			$results = $wpdb->get_results( $sql );
+
+			// Increment offset
+			$offset = ( $limit + $offset );
+
+			if ( !empty( $results ) ) {
+				foreach ( $results as $r ) {
+					// Set permalinks into array
+					$hashtable[$r->meta_value] = intval( $r->post_id );
+				}
+			}
+		} while ( count( $results ) == $limit );
+
+		// unset to save memory
+		unset( $results, $r );
+
+		return $hashtable;
+	}
+
+	/**
+	 * Return count of imported permalinks from WordPress database
+	 *
+	 * @param string $bid
+	 * @return int
+	 */
+	function count_imported_posts( $importer_name, $bid ) {
+		global $wpdb;
+
+		$count = 0;
+
+		// Get count of permalinks
+		$meta_key = $importer_name . '_' . $bid . '_permalink';
+		$sql = $wpdb->prepare( "SELECT COUNT( post_id ) AS cnt FROM $wpdb->postmeta WHERE meta_key = '%s'", $meta_key );
+
+		$result = $wpdb->get_results( $sql );
+
+		if ( !empty( $result ) )
+			$count = intval( $result[0]->cnt );
+
+		// unset to save memory
+		unset( $results );
+
+		return $count;
+	}
+
+	/**
+	 * Set array with imported comments from WordPress database
+	 *
+	 * @param string $bid
+	 * @return array
+	 */
+	function get_imported_comments( $bid ) {
+		global $wpdb;
+
+		$hashtable = array();
+
+		$limit = 100;
+		$offset = 0;
+
+		// Grab all comments in chunks
+		do {
+			$sql = $wpdb->prepare( "SELECT comment_ID, comment_agent FROM $wpdb->comments LIMIT %d,%d", $offset, $limit );
+			$results = $wpdb->get_results( $sql );
+
+			// Increment offset
+			$offset = ( $limit + $offset );
+
+			if ( !empty( $results ) ) {
+				foreach ( $results as $r ) {
+					// Explode comment_agent key
+					list ( $ca_bid, $source_comment_id ) = explode( '-', $r->comment_agent );
+					$source_comment_id = intval( $source_comment_id );
+
+					// Check if this comment came from this blog
+					if ( $bid == $ca_bid ) {
+						$hashtable[$source_comment_id] = intval( $r->comment_ID );
+					}
+				}
+			}
+		} while ( count( $results ) == $limit );
+
+		// unset to save memory
+		unset( $results, $r );
+
+		return $hashtable;
+	}
+
+	function set_blog( $blog_id ) {
+		if ( is_numeric( $blog_id ) ) {
+			$blog_id = (int) $blog_id;
+		} else {
+			$blog = 'http://' . preg_replace( '#^https?://#', '', $blog_id );
+			if ( ( !$parsed = parse_url( $blog ) ) || empty( $parsed['host'] ) ) {
+				fwrite( STDERR, "Error: can not determine blog_id from $blog_id\n" );
+				exit();
+			}
+			if ( empty( $parsed['path'] ) )
+				$parsed['path'] = '/';
+			if ( !$blog = get_blog_info( $parsed['host'], $parsed['path'] ) ) {
+				fwrite( STDERR, "Error: Could not find blog\n" );
+				exit();
+			}
+			$blog_id = (int) $blog->blog_id;
+			// Restore global $current_blog
+			global $current_blog;
+			$current_blog = $blog;
+		}
+
+		if ( function_exists( 'is_multisite' ) ) {
+			if ( is_multisite() )
+				switch_to_blog( $blog_id );
+		}
+
+		return $blog_id;
+	}
+
+	function set_user( $user_id ) {
+		if ( is_numeric( $user_id ) ) {
+			$user_id = (int) $user_id;
+		} else {
+			$user_id = (int) username_exists( $user_id );
+		}
+
+		if ( !$user_id || !wp_set_current_user( $user_id ) ) {
+			fwrite( STDERR, "Error: can not find user\n" );
+			exit();
+		}
+
+		return $user_id;
+	}
+
+	/**
+	 * Sort by strlen, longest string first
+	 *
+	 * @param string $a
+	 * @param string $b
+	 * @return int
+	 */
+	function cmpr_strlen( $a, $b ) {
+		return strlen( $b ) - strlen( $a );
+	}
+
+	/**
+	 * GET URL
+	 *
+	 * @param string $url
+	 * @param string $username
+	 * @param string $password
+	 * @param bool $head
+	 * @return array
+	 */
+	function get_page( $url, $username = '', $password = '', $head = false ) {
+		// Increase the timeout
+		add_filter( 'http_request_timeout', array( &$this, 'bump_request_timeout' ) );
+
+		$headers = array();
+		$args = array();
+		if ( true === $head )
+			$args['method'] = 'HEAD';
+		if ( !empty( $username ) && !empty( $password ) )
+			$headers['Authorization'] = 'Basic ' . base64_encode( "$username:$password" );
+
+		$args['headers'] = $headers;
+
+		return wp_remote_request( $url, $args );
+	}
+
+	/**
+	 * Bump up the request timeout for http requests
+	 *
+	 * @param int $val
+	 * @return int
+	 */
+	function bump_request_timeout( $val ) {
+		return 60;
+	}
+
+	/**
+	 * Check if user has exceeded disk quota
+	 *
+	 * @return bool
+	 */
+	function is_user_over_quota() {
+		global $current_user, $current_blog;
+
+		if ( function_exists( 'upload_is_user_over_quota' ) ) {
+			if ( upload_is_user_over_quota( 1 ) ) {
+				echo "Sorry, you have used your upload quota.\n";
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	 * Replace newlines, tabs, and multiple spaces with a single space
+	 *
+	 * @param string $string
+	 * @return string
+	 */
+	function min_whitespace( $string ) {
+		return preg_replace( '|[\r\n\t ]+|', ' ', $string );
+	}
+
+	/**
+	 * Reset global variables that grow out of control during imports
+	 *
+	 * @return void
+	 */
+	function stop_the_insanity() {
+		global $wpdb, $wp_actions;
+		// Or define( 'WP_IMPORTING', true );
+		$wpdb->queries = array();
+		// Reset $wp_actions to keep it from growing out of control
+		$wp_actions = array();
+	}
+}
+
+/**
+ * Returns value of command line params.
+ * Exits when a required param is not set.
+ *
+ * @param string $param
+ * @param bool $required
+ * @return mixed
+ */
+function get_cli_args( $param, $required = false ) {
+	$args = $_SERVER['argv'];
+
+	$out = array();
+
+	$last_arg = null;
+	$return = null;
+
+	$il = sizeof( $args );
+
+	for ( $i = 1, $il; $i < $il; $i++ ) {
+		if ( (bool) preg_match( "/^--(.+)/", $args[$i], $match ) ) {
+			$parts = explode( "=", $match[1] );
+			$key = preg_replace( "/[^a-z0-9]+/", "", $parts[0] );
+
+			if ( isset( $parts[1] ) ) {
+				$out[$key] = $parts[1];
+			} else {
+				$out[$key] = true;
+			}
+
+			$last_arg = $key;
+		} else if ( (bool) preg_match( "/^-([a-zA-Z0-9]+)/", $args[$i], $match ) ) {
+			for ( $j = 0, $jl = strlen( $match[1] ); $j < $jl; $j++ ) {
+				$key = $match[1]{$j};
+				$out[$key] = true;
+			}
+
+			$last_arg = $key;
+		} else if ( $last_arg !== null ) {
+			$out[$last_arg] = $args[$i];
+		}
+	}
+
+	// Check array for specified param
+	if ( isset( $out[$param] ) ) {
+		// Set return value
+		$return = $out[$param];
+	}
+
+	// Check for missing required param
+	if ( !isset( $out[$param] ) && $required ) {
+		// Display message and exit
+		echo "\"$param\" parameter is required but was not specified\n";
+		exit();
+	}
+
+	return $return;
+}