wp/wp-admin/includes/file.php
changeset 5 5e2f62d02dcd
parent 0 d970ebf37754
child 7 cf61fcea0001
--- a/wp/wp-admin/includes/file.php	Mon Jun 08 16:11:51 2015 +0000
+++ b/wp/wp-admin/includes/file.php	Tue Jun 09 03:35:32 2015 +0200
@@ -50,7 +50,6 @@
  *
  * @since 1.5.0
  *
- * @uses _cleanup_header_comment
  * @uses $wp_file_descriptions
  * @param string $file Filesystem path or filename
  * @return string Description of file from $wp_file_descriptions or basename of $file if description doesn't exist
@@ -75,12 +74,11 @@
  *
  * @since 1.5.0
  *
- * @uses get_option
  * @return string Full filesystem path to the root of the WordPress installation
  */
 function get_home_path() {
-	$home = get_option( 'home' );
-	$siteurl = get_option( 'siteurl' );
+	$home    = set_url_scheme( get_option( 'home' ), 'http' );
+	$siteurl = set_url_scheme( get_option( 'siteurl' ), 'http' );
 	if ( ! empty( $home ) && 0 !== strcasecmp( $home, $siteurl ) ) {
 		$wp_path_rel_to_home = str_ireplace( $home, '', $siteurl ); /* $siteurl - $home */
 		$pos = strripos( str_replace( '\\', '/', $_SERVER['SCRIPT_FILENAME'] ), trailingslashit( $wp_path_rel_to_home ) );
@@ -99,8 +97,8 @@
  *
  * @since 2.6.0
  *
- * @param string $folder Full path to folder
- * @param int $levels (optional) Levels of folders to follow, Default: 100 (PHP Loop limit).
+ * @param string $folder Optional. Full path to folder. Default empty.
+ * @param int    $levels Optional. Levels of folders to follow, Default 100 (PHP Loop limit).
  * @return bool|array False on failure, Else array of files
  */
 function list_files( $folder = '', $levels = 100 ) {
@@ -139,21 +137,33 @@
  *
  * @since 2.6.0
  *
- * @param string $filename (optional) Filename to base the Unique file off
- * @param string $dir (optional) Directory to store the file in
+ * @param string $filename Optional. Filename to base the Unique file off. Default empty.
+ * @param string $dir      Optional. Directory to store the file in. Default empty.
  * @return string a writable filename
  */
-function wp_tempnam($filename = '', $dir = '') {
-	if ( empty($dir) )
+function wp_tempnam( $filename = '', $dir = '' ) {
+	if ( empty( $dir ) ) {
 		$dir = get_temp_dir();
-	$filename = basename($filename);
-	if ( empty($filename) )
+	}
+
+	if ( empty( $filename ) || '.' == $filename || '/' == $filename ) {
 		$filename = time();
+	}
 
-	$filename = preg_replace('|\..*$|', '.tmp', $filename);
-	$filename = $dir . wp_unique_filename($dir, $filename);
-	touch($filename);
-	return $filename;
+	// Use the basename of the given file without the extension as the name for the temporary directory
+	$temp_filename = basename( $filename );
+	$temp_filename = preg_replace( '|\.[^.]*$|', '', $temp_filename );
+
+	// If the folder is falsey, use it's parent directory name instead
+	if ( ! $temp_filename ) {
+		return wp_tempnam( dirname( $filename ), $dir );
+	}
+
+	$temp_filename .= '.tmp';
+	$temp_filename = $dir . wp_unique_filename( $dir, $temp_filename );
+	touch( $temp_filename );
+
+	return $temp_filename;
 }
 
 /**
@@ -163,11 +173,9 @@
  *
  * @since 1.5.0
  *
- * @uses wp_die
- * @uses validate_file
  * @param string $file file the users is attempting to edit
  * @param array $allowed_files Array of allowed files to edit, $file must match an entry exactly
- * @return null
+ * @return string|null
  */
 function validate_file_to_edit( $file, $allowed_files = '' ) {
 	$code = validate_file( $file, $allowed_files );
@@ -177,13 +185,13 @@
 
 	switch ( $code ) {
 		case 1 :
-			wp_die( __('Sorry, can’t edit files with “..” in the name. If you are trying to edit a file in your WordPress home directory, you can just type the name of the file in.' ));
+			wp_die( __( 'Sorry, that file cannot be edited.' ) );
 
-		//case 2 :
-		//	wp_die( __('Sorry, can’t call files with their real path.' ));
+		// case 2 :
+		// wp_die( __('Sorry, can’t call files with their real path.' ));
 
 		case 3 :
-			wp_die( __('Sorry, that file cannot be edited.' ));
+			wp_die( __( 'Sorry, that file cannot be edited.' ) );
 	}
 }
 
@@ -191,268 +199,245 @@
  * Handle PHP uploads in WordPress, sanitizing file names, checking extensions for mime type,
  * and moving the file to the appropriate directory within the uploads directory.
  *
- * @since 2.0
+ * @since 4.0.0
+ *
+ * @see wp_handle_upload_error
  *
- * @uses wp_handle_upload_error
- * @uses apply_filters
- * @uses is_multisite
- * @uses wp_check_filetype_and_ext
- * @uses current_user_can
- * @uses wp_upload_dir
- * @uses wp_unique_filename
- * @uses delete_transient
- * @param array $file Reference to a single element of $_FILES. Call the function once for each uploaded file.
- * @param array $overrides Optional. An associative array of names=>values to override default variables with extract( $overrides, EXTR_OVERWRITE ).
- * @param string $time Optional. Time formatted in 'yyyy/mm'.
- * @return array On success, returns an associative array of file attributes. On failure, returns $overrides['upload_error_handler'](&$file, $message ) or array( 'error'=>$message ).
- */
-function wp_handle_upload( &$file, $overrides = false, $time = null ) {
+ * @param array       $file      Reference to a single element of $_FILES. Call the function once for each uploaded file.
+ * @param array|false $overrides An associative array of names => values to override default variables. Default false.
+ * @param string      $time      Time formatted in 'yyyy/mm'.
+ * @param string      $action    Expected value for $_POST['action'].
+ * @return array On success, returns an associative array of file attributes. On failure, returns
+ *               $overrides['upload_error_handler'](&$file, $message ) or array( 'error'=>$message ).
+*/
+function _wp_handle_upload( &$file, $overrides, $time, $action ) {
 	// The default error handler.
 	if ( ! function_exists( 'wp_handle_upload_error' ) ) {
 		function wp_handle_upload_error( &$file, $message ) {
-			return array( 'error'=>$message );
+			return array( 'error' => $message );
 		}
 	}
 
-	$file = apply_filters( 'wp_handle_upload_prefilter', $file );
+	/**
+	 * Filter the data for a file before it is uploaded to WordPress.
+	 *
+	 * The dynamic portion of the hook name, `$action`, refers to the post action.
+	 *
+	 * @since 2.9.0 as 'wp_handle_upload_prefilter'.
+	 * @since 4.0.0 Converted to a dynamic hook with `$action`.
+	 *
+	 * @param array $file An array of data for a single file.
+	 */
+	$file = apply_filters( "{$action}_prefilter", $file );
 
 	// You may define your own function and pass the name in $overrides['upload_error_handler']
 	$upload_error_handler = 'wp_handle_upload_error';
+	if ( isset( $overrides['upload_error_handler'] ) ) {
+		$upload_error_handler = $overrides['upload_error_handler'];
+	}
 
 	// You may have had one or more 'wp_handle_upload_prefilter' functions error out the file. Handle that gracefully.
-	if ( isset( $file['error'] ) && !is_numeric( $file['error'] ) && $file['error'] )
+	if ( isset( $file['error'] ) && ! is_numeric( $file['error'] ) && $file['error'] ) {
 		return $upload_error_handler( $file, $file['error'] );
+	}
+
+	// Install user overrides. Did we mention that this voids your warranty?
 
 	// You may define your own function and pass the name in $overrides['unique_filename_callback']
 	$unique_filename_callback = null;
-
-	// $_POST['action'] must be set and its value must equal $overrides['action'] or this:
-	$action = 'wp_handle_upload';
+	if ( isset( $overrides['unique_filename_callback'] ) ) {
+		$unique_filename_callback = $overrides['unique_filename_callback'];
+	}
 
-	// Courtesy of php.net, the strings that describe the error indicated in $_FILES[{form field}]['error'].
-	$upload_error_strings = array( false,
-		__( "The uploaded file exceeds the upload_max_filesize directive in php.ini." ),
-		__( "The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form." ),
-		__( "The uploaded file was only partially uploaded." ),
-		__( "No file was uploaded." ),
-		'',
-		__( "Missing a temporary folder." ),
-		__( "Failed to write file to disk." ),
-		__( "File upload stopped by extension." ));
+	/*
+	 * This may not have orignially been intended to be overrideable,
+	 * but historically has been.
+	 */
+	if ( isset( $overrides['upload_error_strings'] ) ) {
+		$upload_error_strings = $overrides['upload_error_strings'];
+	} else {
+		// Courtesy of php.net, the strings that describe the error indicated in $_FILES[{form field}]['error'].
+		$upload_error_strings = array(
+			false,
+			__( 'The uploaded file exceeds the upload_max_filesize directive in php.ini.' ),
+			__( 'The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form.' ),
+			__( 'The uploaded file was only partially uploaded.' ),
+			__( 'No file was uploaded.' ),
+			'',
+			__( 'Missing a temporary folder.' ),
+			__( 'Failed to write file to disk.' ),
+			__( 'File upload stopped by extension.' )
+		);
+	}
 
 	// All tests are on by default. Most can be turned off by $overrides[{test_name}] = false;
-	$test_form = true;
-	$test_size = true;
-	$test_upload = true;
+	$test_form = isset( $overrides['test_form'] ) ? $overrides['test_form'] : true;
+	$test_size = isset( $overrides['test_size'] ) ? $overrides['test_size'] : true;
 
-	// If you override this, you must provide $ext and $type!!!!
-	$test_type = true;
-	$mimes = false;
-
-	// Install user overrides. Did we mention that this voids your warranty?
-	if ( is_array( $overrides ) )
-		extract( $overrides, EXTR_OVERWRITE );
+	// If you override this, you must provide $ext and $type!!
+	$test_type = isset( $overrides['test_type'] ) ? $overrides['test_type'] : true;
+	$mimes = isset( $overrides['mimes'] ) ? $overrides['mimes'] : false;
 
 	// A correct form post will pass this test.
-	if ( $test_form && (!isset( $_POST['action'] ) || ($_POST['action'] != $action ) ) )
-		return call_user_func($upload_error_handler, $file, __( 'Invalid form submission.' ));
-
+	if ( $test_form && ( ! isset( $_POST['action'] ) || ( $_POST['action'] != $action ) ) ) {
+		return call_user_func( $upload_error_handler, $file, __( 'Invalid form submission.' ) );
+	}
 	// A successful upload will pass this test. It makes no sense to override this one.
-	if ( $file['error'] > 0 )
-		return call_user_func($upload_error_handler, $file, $upload_error_strings[$file['error']] );
+	if ( isset( $file['error'] ) && $file['error'] > 0 ) {
+		return call_user_func( $upload_error_handler, $file, $upload_error_strings[ $file['error'] ] );
+	}
 
+	$test_file_size = 'wp_handle_upload' === $action ? $file['size'] : filesize( $file['tmp_name'] );
 	// A non-empty file will pass this test.
-	if ( $test_size && !($file['size'] > 0 ) ) {
-		if ( is_multisite() )
+	if ( $test_size && ! ( $test_file_size > 0 ) ) {
+		if ( is_multisite() ) {
 			$error_msg = __( 'File is empty. Please upload something more substantial.' );
-		else
+		} else {
 			$error_msg = __( 'File is empty. Please upload something more substantial. This error could also be caused by uploads being disabled in your php.ini or by post_max_size being defined as smaller than upload_max_filesize in php.ini.' );
-		return call_user_func($upload_error_handler, $file, $error_msg);
+		}
+		return call_user_func( $upload_error_handler, $file, $error_msg );
 	}
 
 	// A properly uploaded file will pass this test. There should be no reason to override this one.
-	if ( $test_upload && ! @ is_uploaded_file( $file['tmp_name'] ) )
-		return call_user_func($upload_error_handler, $file, __( 'Specified file failed upload test.' ));
+	$test_uploaded_file = 'wp_handle_upload' === $action ? @ is_uploaded_file( $file['tmp_name'] ) : @ is_file( $file['tmp_name'] );
+	if ( ! $test_uploaded_file ) {
+		return call_user_func( $upload_error_handler, $file, __( 'Specified file failed upload test.' ) );
+	}
 
 	// A correct MIME type will pass this test. Override $mimes or use the upload_mimes filter.
 	if ( $test_type ) {
 		$wp_filetype = wp_check_filetype_and_ext( $file['tmp_name'], $file['name'], $mimes );
-
-		extract( $wp_filetype );
+		$ext = empty( $wp_filetype['ext'] ) ? '' : $wp_filetype['ext'];
+		$type = empty( $wp_filetype['type'] ) ? '' : $wp_filetype['type'];
+		$proper_filename = empty( $wp_filetype['proper_filename'] ) ? '' : $wp_filetype['proper_filename'];
 
 		// Check to see if wp_check_filetype_and_ext() determined the filename was incorrect
-		if ( $proper_filename )
+		if ( $proper_filename ) {
 			$file['name'] = $proper_filename;
-
-		if ( ( !$type || !$ext ) && !current_user_can( 'unfiltered_upload' ) )
-			return call_user_func($upload_error_handler, $file, __( 'Sorry, this file type is not permitted for security reasons.' ));
-
-		if ( !$ext )
-			$ext = ltrim(strrchr($file['name'], '.'), '.');
-
-		if ( !$type )
+		}
+		if ( ( ! $type || !$ext ) && ! current_user_can( 'unfiltered_upload' ) ) {
+			return call_user_func( $upload_error_handler, $file, __( 'Sorry, this file type is not permitted for security reasons.' ) );
+		}
+		if ( ! $type ) {
 			$type = $file['type'];
+		}
 	} else {
 		$type = '';
 	}
 
-	// A writable uploads dir will pass this test. Again, there's no point overriding this one.
-	if ( ! ( ( $uploads = wp_upload_dir($time) ) && false === $uploads['error'] ) )
-		return call_user_func($upload_error_handler, $file, $uploads['error'] );
+	/*
+	 * A writable uploads dir will pass this test. Again, there's no point
+	 * overriding this one.
+	 */
+	if ( ! ( ( $uploads = wp_upload_dir( $time ) ) && false === $uploads['error'] ) ) {
+		return call_user_func( $upload_error_handler, $file, $uploads['error'] );
+	}
 
 	$filename = wp_unique_filename( $uploads['path'], $file['name'], $unique_filename_callback );
 
-	// Move the file to the uploads dir
+	// Move the file to the uploads dir.
 	$new_file = $uploads['path'] . "/$filename";
-	if ( false === @ move_uploaded_file( $file['tmp_name'], $new_file ) ) {
-		if ( 0 === strpos( $uploads['basedir'], ABSPATH ) )
+	if ( 'wp_handle_upload' === $action ) {
+		$move_new_file = @ move_uploaded_file( $file['tmp_name'], $new_file );
+	} else {
+		$move_new_file = @ rename( $file['tmp_name'], $new_file );
+	}
+
+	if ( false === $move_new_file ) {
+		if ( 0 === strpos( $uploads['basedir'], ABSPATH ) ) {
 			$error_path = str_replace( ABSPATH, '', $uploads['basedir'] ) . $uploads['subdir'];
-		else
+		} else {
 			$error_path = basename( $uploads['basedir'] ) . $uploads['subdir'];
-
+		}
 		return $upload_error_handler( $file, sprintf( __('The uploaded file could not be moved to %s.' ), $error_path ) );
 	}
 
-	// Set correct file permissions
+	// Set correct file permissions.
 	$stat = stat( dirname( $new_file ));
 	$perms = $stat['mode'] & 0000666;
 	@ chmod( $new_file, $perms );
 
-	// Compute the URL
+	// Compute the URL.
 	$url = $uploads['url'] . "/$filename";
 
-	if ( is_multisite() )
+	if ( is_multisite() ) {
 		delete_transient( 'dirsize_cache' );
+	}
 
-	return apply_filters( 'wp_handle_upload', array( 'file' => $new_file, 'url' => $url, 'type' => $type ), 'upload' );
+	/**
+	 * Filter the data array for the uploaded file.
+	 *
+	 * @since 2.1.0
+	 *
+	 * @param array  $upload {
+	 *     Array of upload data.
+	 *
+	 *     @type string $file Filename of the newly-uploaded file.
+	 *     @type string $url  URL of the uploaded file.
+	 *     @type string $type File type.
+	 * }
+	 * @param string $context The type of upload action. Values include 'upload' or 'sideload'.
+	 */
+	return apply_filters( 'wp_handle_upload', array(
+		'file' => $new_file,
+		'url'  => $url,
+		'type' => $type
+	), 'wp_handle_sideload' === $action ? 'sideload' : 'upload' ); }
+
+/**
+ * Wrapper for _wp_handle_upload(), passes 'wp_handle_upload' action.
+ *
+ * @since 2.0.0
+ *
+ * @see _wp_handle_upload()
+ *
+ * @param array      $file      Reference to a single element of $_FILES. Call the function once for
+ *                              each uploaded file.
+ * @param array|bool $overrides Optional. An associative array of names=>values to override default
+ *                              variables. Default false.
+ * @param string     $time      Optional. Time formatted in 'yyyy/mm'. Default null.
+ * @return array On success, returns an associative array of file attributes. On failure, returns
+ *               $overrides['upload_error_handler'](&$file, $message ) or array( 'error'=>$message ).
+ */
+function wp_handle_upload( &$file, $overrides = false, $time = null ) {
+	/*
+	 *  $_POST['action'] must be set and its value must equal $overrides['action']
+	 *  or this:
+	 */
+	$action = 'wp_handle_upload';
+	if ( isset( $overrides['action'] ) ) {
+		$action = $overrides['action'];
+	}
+
+	return _wp_handle_upload( $file, $overrides, $time, $action );
 }
 
 /**
- * Handle sideloads, which is the process of retrieving a media item from another server instead of
- * a traditional media upload. This process involves sanitizing the filename, checking extensions
- * for mime type, and moving the file to the appropriate directory within the uploads directory.
+ * Wrapper for _wp_handle_upload(), passes 'wp_handle_sideload' action
  *
  * @since 2.6.0
  *
- * @uses wp_handle_upload_error
- * @uses apply_filters
- * @uses wp_check_filetype_and_ext
- * @uses current_user_can
- * @uses wp_upload_dir
- * @uses wp_unique_filename
- * @param array $file an array similar to that of a PHP $_FILES POST array
- * @param array $overrides Optional. An associative array of names=>values to override default variables with extract( $overrides, EXTR_OVERWRITE ).
- * @param string $time Optional. Time formatted in 'yyyy/mm'.
- * @return array On success, returns an associative array of file attributes. On failure, returns $overrides['upload_error_handler'](&$file, $message ) or array( 'error'=>$message ).
+ * @see _wp_handle_upload()
+ *
+ * @param array      $file      An array similar to that of a PHP $_FILES POST array
+ * @param array|bool $overrides Optional. An associative array of names=>values to override default
+ *                              variables. Default false.
+ * @param string     $time      Optional. Time formatted in 'yyyy/mm'. Default null.
+ * @return array On success, returns an associative array of file attributes. On failure, returns
+ *               $overrides['upload_error_handler'](&$file, $message ) or array( 'error'=>$message ).
  */
 function wp_handle_sideload( &$file, $overrides = false, $time = null ) {
-	// The default error handler.
-	if (! function_exists( 'wp_handle_upload_error' ) ) {
-		function wp_handle_upload_error( &$file, $message ) {
-			return array( 'error'=>$message );
-		}
-	}
-
-	// You may define your own function and pass the name in $overrides['upload_error_handler']
-	$upload_error_handler = 'wp_handle_upload_error';
-
-	// You may define your own function and pass the name in $overrides['unique_filename_callback']
-	$unique_filename_callback = null;
-
-	// $_POST['action'] must be set and its value must equal $overrides['action'] or this:
+	/*
+	 *  $_POST['action'] must be set and its value must equal $overrides['action']
+	 *  or this:
+	 */
 	$action = 'wp_handle_sideload';
-
-	// Courtesy of php.net, the strings that describe the error indicated in $_FILES[{form field}]['error'].
-	$upload_error_strings = array( false,
-		__( "The uploaded file exceeds the <code>upload_max_filesize</code> directive in <code>php.ini</code>." ),
-		__( "The uploaded file exceeds the <em>MAX_FILE_SIZE</em> directive that was specified in the HTML form." ),
-		__( "The uploaded file was only partially uploaded." ),
-		__( "No file was uploaded." ),
-		'',
-		__( "Missing a temporary folder." ),
-		__( "Failed to write file to disk." ),
-		__( "File upload stopped by extension." ));
-
-	// All tests are on by default. Most can be turned off by $overrides[{test_name}] = false;
-	$test_form = true;
-	$test_size = true;
-
-	// If you override this, you must provide $ext and $type!!!!
-	$test_type = true;
-	$mimes = false;
-
-	// Install user overrides. Did we mention that this voids your warranty?
-	if ( is_array( $overrides ) )
-		extract( $overrides, EXTR_OVERWRITE );
-
-	// A correct form post will pass this test.
-	if ( $test_form && (!isset( $_POST['action'] ) || ($_POST['action'] != $action ) ) )
-		return $upload_error_handler( $file, __( 'Invalid form submission.' ));
-
-	// A successful upload will pass this test. It makes no sense to override this one.
-	if ( ! empty( $file['error'] ) )
-		return $upload_error_handler( $file, $upload_error_strings[$file['error']] );
-
-	// A non-empty file will pass this test.
-	if ( $test_size && !(filesize($file['tmp_name']) > 0 ) )
-		return $upload_error_handler( $file, __( 'File is empty. Please upload something more substantial. This error could also be caused by uploads being disabled in your php.ini.' ));
+	if ( isset( $overrides['action'] ) ) {
+		$action = $overrides['action'];
+	}
+	return _wp_handle_upload( $file, $overrides, $time, $action );
+}
 
-	// A properly uploaded file will pass this test. There should be no reason to override this one.
-	if (! @ is_file( $file['tmp_name'] ) )
-		return $upload_error_handler( $file, __( 'Specified file does not exist.' ));
-
-	// A correct MIME type will pass this test. Override $mimes or use the upload_mimes filter.
-	if ( $test_type ) {
-		$wp_filetype = wp_check_filetype_and_ext( $file['tmp_name'], $file['name'], $mimes );
-
-		extract( $wp_filetype );
-
-		// Check to see if wp_check_filetype_and_ext() determined the filename was incorrect
-		if ( $proper_filename )
-			$file['name'] = $proper_filename;
-
-		if ( ( !$type || !$ext ) && !current_user_can( 'unfiltered_upload' ) )
-			return $upload_error_handler( $file, __( 'Sorry, this file type is not permitted for security reasons.' ));
-
-		if ( !$ext )
-			$ext = ltrim(strrchr($file['name'], '.'), '.');
-
-		if ( !$type )
-			$type = $file['type'];
-	}
-
-	// A writable uploads dir will pass this test. Again, there's no point overriding this one.
-	if ( ! ( ( $uploads = wp_upload_dir( $time ) ) && false === $uploads['error'] ) )
-		return $upload_error_handler( $file, $uploads['error'] );
-
-	$filename = wp_unique_filename( $uploads['path'], $file['name'], $unique_filename_callback );
-
-	// Strip the query strings.
-	$filename = str_replace('?','-', $filename);
-	$filename = str_replace('&','-', $filename);
-
-	// Move the file to the uploads dir
-	$new_file = $uploads['path'] . "/$filename";
-	if ( false === @ rename( $file['tmp_name'], $new_file ) ) {
-		if ( 0 === strpos( $uploads['basedir'], ABSPATH ) )
-			$error_path = str_replace( ABSPATH, '', $uploads['basedir'] ) . $uploads['subdir'];
-		else
-			$error_path = basename( $uploads['basedir'] ) . $uploads['subdir'];
-		return $upload_error_handler( $file, sprintf( __('The uploaded file could not be moved to %s.' ), $error_path ) );
-	}
-
-	// Set correct file permissions
-	$stat = stat( dirname( $new_file ));
-	$perms = $stat['mode'] & 0000666;
-	@ chmod( $new_file, $perms );
-
-	// Compute the URL
-	$url = $uploads['url'] . "/$filename";
-
-	$return = apply_filters( 'wp_handle_upload', array( 'file' => $new_file, 'url' => $url, 'type' => $type ), 'sideload' );
-
-	return $return;
-}
 
 /**
  * Downloads a url to a local temporary file using the WordPress HTTP Class.
@@ -498,7 +483,7 @@
 }
 
 /**
- * Calculates and compares the MD5 of a file to it's expected value.
+ * Calculates and compares the MD5 of a file to its expected value.
  *
  * @since 3.7.0
  *
@@ -542,6 +527,7 @@
 		return new WP_Error('fs_unavailable', __('Could not access filesystem.'));
 
 	// Unzip can use a lot of memory, but not this much hopefully
+	/** This filter is documented in wp-admin/admin.php */
 	@ini_set( 'memory_limit', apply_filters( 'admin_memory_limit', WP_MAX_MEMORY_LIMIT ) );
 
 	$needed_dirs = array();
@@ -565,7 +551,14 @@
 		}
 	}
 
-	if ( class_exists('ZipArchive') && apply_filters('unzip_file_use_ziparchive', true ) ) {
+	/**
+	 * Filter whether to use ZipArchive to unzip archives.
+	 *
+	 * @since 3.0.0
+	 *
+	 * @param bool $ziparchive Whether to use ZipArchive. Default true.
+	 */
+	if ( class_exists( 'ZipArchive' ) && apply_filters( 'unzip_file_use_ziparchive', true ) ) {
 		$result = _unzip_file_ziparchive($file, $to, $needed_dirs);
 		if ( true === $result ) {
 			return $result;
@@ -646,8 +639,10 @@
 
 	// Create those directories if need be:
 	foreach ( $needed_dirs as $_dir ) {
-		if ( ! $wp_filesystem->mkdir($_dir, FS_CHMOD_DIR) && ! $wp_filesystem->is_dir($_dir) ) // Only check to see if the Dir exists upon creation failure. Less I/O this way.
+		// Only check to see if the Dir exists upon creation failure. Less I/O this way.
+		if ( ! $wp_filesystem->mkdir( $_dir, FS_CHMOD_DIR ) && ! $wp_filesystem->is_dir( $_dir ) ) {
 			return new WP_Error( 'mkdir_failed_ziparchive', __( 'Could not create directory.' ), substr( $_dir, strlen( $to ) ) );
+		}
 	}
 	unset($needed_dirs);
 
@@ -823,26 +818,43 @@
  * Initialises and connects the WordPress Filesystem Abstraction classes.
  * This function will include the chosen transport and attempt connecting.
  *
- * Plugins may add extra transports, And force WordPress to use them by returning the filename via the 'filesystem_method_file' filter.
+ * Plugins may add extra transports, And force WordPress to use them by returning
+ * the filename via the {@see 'filesystem_method_file'} filter.
  *
  * @since 2.5.0
  *
- * @param array $args (optional) Connection args, These are passed directly to the WP_Filesystem_*() classes.
- * @param string $context (optional) Context for get_filesystem_method(), See function declaration for more information.
- * @return boolean false on failure, true on success
+ * @param array  $args                         Optional. Connection args, These are passed directly to
+ *                                             the `WP_Filesystem_*()` classes. Default false.
+ * @param string $context                      Optional. Context for {@see get_filesystem_method()}.
+ *                                             Default false.
+ * @param bool   $allow_relaxed_file_ownership Optional. Whether to allow Group/World writable.
+ *                                             Default false.
+ * @return null|boolean false on failure, true on success.
  */
-function WP_Filesystem( $args = false, $context = false ) {
+function WP_Filesystem( $args = false, $context = false, $allow_relaxed_file_ownership = false ) {
 	global $wp_filesystem;
 
 	require_once(ABSPATH . 'wp-admin/includes/class-wp-filesystem-base.php');
 
-	$method = get_filesystem_method($args, $context);
+	$method = get_filesystem_method( $args, $context, $allow_relaxed_file_ownership );
 
 	if ( ! $method )
 		return false;
 
 	if ( ! class_exists("WP_Filesystem_$method") ) {
-		$abstraction_file = apply_filters('filesystem_method_file', ABSPATH . 'wp-admin/includes/class-wp-filesystem-' . $method . '.php', $method);
+
+		/**
+		 * Filter the path for a specific filesystem method class file.
+		 *
+		 * @since 2.6.0
+		 *
+		 * @see get_filesystem_method()
+		 *
+		 * @param string $path   Path to the specific filesystem method class file.
+		 * @param string $method The filesystem method to use.
+		 */
+		$abstraction_file = apply_filters( 'filesystem_method_file', ABSPATH . 'wp-admin/includes/class-wp-filesystem-' . $method . '.php', $method );
+
 		if ( ! file_exists($abstraction_file) )
 			return;
 
@@ -874,38 +886,68 @@
 }
 
 /**
- * Determines which Filesystem Method to use.
- * The priority of the Transports are: Direct, SSH2, FTP PHP Extension, FTP Sockets (Via Sockets class, or fsockopen())
+ * Determines which method to use for reading, writing, modifying, or deleting
+ * files on the filesystem.
+ *
+ * The priority of the transports are: Direct, SSH2, FTP PHP Extension, FTP Sockets
+ * (Via Sockets class, or `fsockopen()`). Valid values for these are: 'direct', 'ssh2',
+ * 'ftpext' or 'ftpsockets'.
  *
- * Note that the return value of this function can be overridden in 2 ways
- *  - By defining FS_METHOD in your <code>wp-config.php</code> file
- *  - By using the filesystem_method filter
- * Valid values for these are: 'direct', 'ssh', 'ftpext' or 'ftpsockets'
- * Plugins may also define a custom transport handler, See the WP_Filesystem function for more information.
+ * The return value can be overridden by defining the `FS_METHOD` constant in `wp-config.php`,
+ * or filtering via {@see 'filesystem_method'}.
+ *
+ * @link https://codex.wordpress.org/Editing_wp-config.php#WordPress_Upgrade_Constants
+ *
+ * Plugins may define a custom transport handler, See WP_Filesystem().
  *
  * @since 2.5.0
  *
- * @param array $args Connection details.
- * @param string $context Full path to the directory that is tested for being writable.
+ * @param array  $args                         Optional. Connection details. Default empty array.
+ * @param string $context                      Optional. Full path to the directory that is tested
+ *                                             for being writable. Default false.
+ * @param bool   $allow_relaxed_file_ownership Optional. Whether to allow Group/World writable.
+ *                                             Default false.
  * @return string The transport to use, see description for valid return values.
  */
-function get_filesystem_method($args = array(), $context = false) {
-	$method = defined('FS_METHOD') ? FS_METHOD : false; //Please ensure that this is either 'direct', 'ssh', 'ftpext' or 'ftpsockets'
+function get_filesystem_method( $args = array(), $context = false, $allow_relaxed_file_ownership = false ) {
+	$method = defined('FS_METHOD') ? FS_METHOD : false; // Please ensure that this is either 'direct', 'ssh2', 'ftpext' or 'ftpsockets'
+
+	if ( ! $context ) {
+		$context = WP_CONTENT_DIR;
+	}
 
-	if ( ! $method && function_exists('getmyuid') && function_exists('fileowner') ){
-		if ( !$context )
-			$context = WP_CONTENT_DIR;
+	// If the directory doesn't exist (wp-content/languages) then use the parent directory as we'll create it.
+	if ( WP_LANG_DIR == $context && ! is_dir( $context ) ) {
+		$context = dirname( $context );
+	}
 
-		// If the directory doesn't exist (wp-content/languages) then use the parent directory as we'll create it.
-		if ( WP_LANG_DIR == $context && ! is_dir( $context ) )
-			$context = dirname( $context );
+	$context = trailingslashit( $context );
 
-		$context = trailingslashit($context);
+	if ( ! $method ) {
+
 		$temp_file_name = $context . 'temp-write-test-' . time();
 		$temp_handle = @fopen($temp_file_name, 'w');
 		if ( $temp_handle ) {
-			if ( getmyuid() == @fileowner($temp_file_name) )
+
+			// Attempt to determine the file owner of the WordPress files, and that of newly created files
+			$wp_file_owner = $temp_file_owner = false;
+			if ( function_exists('fileowner') ) {
+				$wp_file_owner = @fileowner( __FILE__ );
+				$temp_file_owner = @fileowner( $temp_file_name );
+			}
+
+			if ( $wp_file_owner !== false && $wp_file_owner === $temp_file_owner ) {
+				// WordPress is creating files as the same owner as the WordPress files,
+				// this means it's safe to modify & create new files via PHP.
 				$method = 'direct';
+				$GLOBALS['_wp_filesystem_direct_method'] = 'file_owner';
+			} elseif ( $allow_relaxed_file_ownership ) {
+				// The $context directory is writable, and $allow_relaxed_file_ownership is set, this means we can modify files
+				// safely in this directory. This mode doesn't create new files, only alter existing ones.
+				$method = 'direct';
+				$GLOBALS['_wp_filesystem_direct_method'] = 'relaxed_ownership';
+			}
+
 			@fclose($temp_handle);
 			@unlink($temp_file_name);
 		}
@@ -914,33 +956,71 @@
 	if ( ! $method && isset($args['connection_type']) && 'ssh' == $args['connection_type'] && extension_loaded('ssh2') && function_exists('stream_get_contents') ) $method = 'ssh2';
 	if ( ! $method && extension_loaded('ftp') ) $method = 'ftpext';
 	if ( ! $method && ( extension_loaded('sockets') || function_exists('fsockopen') ) ) $method = 'ftpsockets'; //Sockets: Socket extension; PHP Mode: FSockopen / fwrite / fread
-	return apply_filters('filesystem_method', $method, $args);
+
+	/**
+	 * Filter the filesystem method to use.
+	 *
+	 * @since 2.6.0
+	 *
+	 * @param string $method  Filesystem method to return.
+	 * @param array  $args    An array of connection details for the method.
+	 * @param string $context Full path to the directory that is tested for being writable.
+	 * @param bool   $allow_relaxed_file_ownership Whether to allow Group/World writable.
+	 */
+	return apply_filters( 'filesystem_method', $method, $args, $context, $allow_relaxed_file_ownership );
 }
 
 /**
- * Displays a form to the user to request for their FTP/SSH details in order to connect to the filesystem.
+ * Displays a form to the user to request for their FTP/SSH details in order
+ * to connect to the filesystem.
+ *
  * All chosen/entered details are saved, Excluding the Password.
  *
- * Hostnames may be in the form of hostname:portnumber (eg: wordpress.org:2467) to specify an alternate FTP/SSH port.
+ * Hostnames may be in the form of hostname:portnumber (eg: wordpress.org:2467)
+ * to specify an alternate FTP/SSH port.
  *
- * Plugins may override this form by returning true|false via the <code>request_filesystem_credentials</code> filter.
+ * Plugins may override this form by returning true|false via the
+ * {@see 'request_filesystem_credentials'} filter.
  *
- * @since 2.5.0
+ * @since 2.5.
+ *
+ * @todo Properly mark optional arguments as such
  *
  * @param string $form_post the URL to post the form to
  * @param string $type the chosen Filesystem method in use
  * @param boolean $error if the current request has failed to connect
  * @param string $context The directory which is needed access to, The write-test will be performed on this directory by get_filesystem_method()
- * @param string $extra_fields Extra POST fields which should be checked for to be included in the post.
+ * @param array $extra_fields Extra POST fields which should be checked for to be included in the post.
+ * @param bool $allow_relaxed_file_ownership Whether to allow Group/World writable.
  * @return boolean False on failure. True on success.
  */
-function request_filesystem_credentials($form_post, $type = '', $error = false, $context = false, $extra_fields = null) {
-	$req_cred = apply_filters( 'request_filesystem_credentials', '', $form_post, $type, $error, $context, $extra_fields );
+function request_filesystem_credentials($form_post, $type = '', $error = false, $context = false, $extra_fields = null, $allow_relaxed_file_ownership = false ) {
+
+	/**
+	 * Filter the filesystem credentials form output.
+	 *
+	 * Returning anything other than an empty string will effectively short-circuit
+	 * output of the filesystem credentials form, returning that value instead.
+	 *
+	 * @since 2.5.0
+	 *
+	 * @param mixed  $output       Form output to return instead. Default empty.
+	 * @param string $form_post    URL to POST the form to.
+	 * @param string $type         Chosen type of filesystem.
+	 * @param bool   $error        Whether the current request has failed to connect.
+	 *                             Default false.
+	 * @param string $context      Full path to the directory that is tested for
+	 *                             being writable.
+	 * @param bool $allow_relaxed_file_ownership Whether to allow Group/World writable.
+	 * @param array  $extra_fields Extra POST fields.
+	 */
+	$req_cred = apply_filters( 'request_filesystem_credentials', '', $form_post, $type, $error, $context, $extra_fields, $allow_relaxed_file_ownership );
 	if ( '' !== $req_cred )
 		return $req_cred;
 
-	if ( empty($type) )
-		$type = get_filesystem_method(array(), $context);
+	if ( empty($type) ) {
+		$type = get_filesystem_method( array(), $context, $allow_relaxed_file_ownership );
+	}
 
 	if ( 'direct' == $type )
 		return true;
@@ -959,7 +1039,7 @@
 	$credentials['public_key'] = defined('FTP_PUBKEY') ? FTP_PUBKEY : (!empty($_POST['public_key']) ? wp_unslash( $_POST['public_key'] ) : '');
 	$credentials['private_key'] = defined('FTP_PRIKEY') ? FTP_PRIKEY : (!empty($_POST['private_key']) ? wp_unslash( $_POST['private_key'] ) : '');
 
-	//sanitize the hostname, Some people might pass in odd-data:
+	// Sanitize the hostname, Some people might pass in odd-data:
 	$credentials['hostname'] = preg_replace('|\w+://|', '', $credentials['hostname']); //Strip any schemes off
 
 	if ( strpos($credentials['hostname'], ':') ) {
@@ -970,15 +1050,15 @@
 		unset($credentials['port']);
 	}
 
-	if ( (defined('FTP_SSH') && FTP_SSH) || (defined('FS_METHOD') && 'ssh' == FS_METHOD) )
+	if ( ( defined( 'FTP_SSH' ) && FTP_SSH ) || ( defined( 'FS_METHOD' ) && 'ssh2' == FS_METHOD ) ) {
 		$credentials['connection_type'] = 'ssh';
-	else if ( (defined('FTP_SSL') && FTP_SSL) && 'ftpext' == $type ) //Only the FTP Extension understands SSL
+	} elseif ( ( defined( 'FTP_SSL' ) && FTP_SSL ) && 'ftpext' == $type ) { //Only the FTP Extension understands SSL
 		$credentials['connection_type'] = 'ftps';
-	else if ( !empty($_POST['connection_type']) )
+	} elseif ( ! empty( $_POST['connection_type'] ) ) {
 		$credentials['connection_type'] = wp_unslash( $_POST['connection_type'] );
-	else if ( !isset($credentials['connection_type']) ) //All else fails (And it's not defaulted to something else saved), Default to FTP
+	} elseif ( ! isset( $credentials['connection_type'] ) ) { //All else fails (And it's not defaulted to something else saved), Default to FTP
 		$credentials['connection_type'] = 'ftp';
-
+	}
 	if ( ! $error &&
 			(
 				( !empty($credentials['password']) && !empty($credentials['username']) && !empty($credentials['hostname']) ) ||
@@ -989,15 +1069,18 @@
 			$stored_credentials['hostname'] .= ':' . $stored_credentials['port'];
 
 		unset($stored_credentials['password'], $stored_credentials['port'], $stored_credentials['private_key'], $stored_credentials['public_key']);
-		update_option('ftp_credentials', $stored_credentials);
+		if ( ! defined( 'WP_INSTALLING' ) ) {
+			update_option( 'ftp_credentials', $stored_credentials );
+		}
 		return $credentials;
 	}
-	$hostname = '';
-	$username = '';
-	$password = '';
-	$connection_type = '';
-	if ( !empty($credentials) )
-		extract($credentials, EXTR_OVERWRITE);
+	$hostname = isset( $credentials['hostname'] ) ? $credentials['hostname'] : '';
+	$username = isset( $credentials['username'] ) ? $credentials['username'] : '';
+	$public_key = isset( $credentials['public_key'] ) ? $credentials['public_key'] : '';
+	$private_key = isset( $credentials['private_key'] ) ? $credentials['private_key'] : '';
+	$port = isset( $credentials['port'] ) ? $credentials['port'] : '';
+	$connection_type = isset( $credentials['connection_type'] ) ? $credentials['connection_type'] : '';
+
 	if ( $error ) {
 		$error_string = __('<strong>ERROR:</strong> There was an error connecting to the server, Please verify the settings are correct.');
 		if ( is_wp_error($error) )
@@ -1013,7 +1096,19 @@
 	if ( extension_loaded('ssh2') && function_exists('stream_get_contents') )
 		$types[ 'ssh' ] = __('SSH2');
 
-	$types = apply_filters('fs_ftp_connection_types', $types, $credentials, $type, $error, $context);
+	/**
+	 * Filter the connection types to output to the filesystem credentials form.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param array  $types       Types of connections.
+	 * @param array  $credentials Credentials to connect with.
+	 * @param string $type        Chosen filesystem method.
+	 * @param object $error       Error object.
+	 * @param string $context     Full path to the directory that is tested
+	 *                            for being writable.
+	 */
+	$types = apply_filters( 'fs_ftp_connection_types', $types, $credentials, $type, $error, $context );
 
 ?>
 <script type="text/javascript">
@@ -1025,14 +1120,14 @@
 	jQuery("#ftp, #ftps").click(function () {
 		jQuery("#ssh_keys").hide();
 	});
-	jQuery('form input[value=""]:first').focus();
+	jQuery('#request-filesystem-credentials-form input[value=""]:first').focus();
 });
 -->
 </script>
 <form action="<?php echo esc_url( $form_post ) ?>" method="post">
-<div>
-<h3><?php _e('Connection Information') ?></h3>
-<p><?php
+<div id="request-filesystem-credentials-form" class="request-filesystem-credentials-form">
+<h3 id="request-filesystem-credentials-title"><?php _e( 'Connection Information' ) ?></h3>
+<p id="request-filesystem-credentials-desc"><?php
 	$label_user = __('Username');
 	$label_pass = __('Password');
 	_e('To perform the requested action, WordPress needs to access your web server.');
@@ -1051,38 +1146,36 @@
 	}
 	_e('If you do not remember your credentials, you should contact your web host.');
 ?></p>
-<table class="form-table">
-<tr valign="top">
-<th scope="row"><label for="hostname"><?php _e('Hostname') ?></label></th>
-<td><input name="hostname" type="text" id="hostname" value="<?php echo esc_attr($hostname); if ( !empty($port) ) echo ":$port"; ?>"<?php disabled( defined('FTP_HOST') ); ?> size="40" /></td>
-</tr>
-
-<tr valign="top">
-<th scope="row"><label for="username"><?php echo $label_user; ?></label></th>
-<td><input name="username" type="text" id="username" value="<?php echo esc_attr($username) ?>"<?php disabled( defined('FTP_USER') ); ?> size="40" /></td>
-</tr>
-
-<tr valign="top">
-<th scope="row"><label for="password"><?php echo $label_pass; ?></label></th>
-<td><div><input name="password" type="password" id="password" value="<?php if ( defined('FTP_PASS') ) echo '*****'; ?>"<?php disabled( defined('FTP_PASS') ); ?> size="40" /></div>
-<div><em><?php if ( ! defined('FTP_PASS') ) _e( 'This password will not be stored on the server.' ); ?></em></div></td>
-</tr>
-
+<label for="hostname">
+	<span class="field-title"><?php _e( 'Hostname' ) ?></span>
+	<input name="hostname" type="text" id="hostname" aria-describedby="request-filesystem-credentials-desc" class="code" placeholder="<?php esc_attr_e( 'example: www.wordpress.org' ) ?>" value="<?php echo esc_attr($hostname); if ( !empty($port) ) echo ":$port"; ?>"<?php disabled( defined('FTP_HOST') ); ?> />
+</label>
+<div class="ftp-username">
+	<label for="username">
+		<span class="field-title"><?php echo $label_user; ?></span>
+		<input name="username" type="text" id="username" value="<?php echo esc_attr($username) ?>"<?php disabled( defined('FTP_USER') ); ?> />
+	</label>
+</div>
+<div class="ftp-password">
+	<label for="password">
+		<span class="field-title"><?php echo $label_pass; ?></span>
+		<input name="password" type="password" id="password" value="<?php if ( defined('FTP_PASS') ) echo '*****'; ?>"<?php disabled( defined('FTP_PASS') ); ?> />
+		<em><?php if ( ! defined('FTP_PASS') ) _e( 'This password will not be stored on the server.' ); ?></em>
+	</label>
+</div>
 <?php if ( isset($types['ssh']) ) : ?>
-<tr id="ssh_keys" valign="top" style="<?php if ( 'ssh' != $connection_type ) echo 'display:none' ?>">
-<th scope="row"><?php _e('Authentication Keys') ?>
-<div class="key-labels textright">
-<label for="public_key"><?php _e('Public Key:') ?></label ><br />
-<label for="private_key"><?php _e('Private Key:') ?></label>
-</div></th>
-<td><br /><input name="public_key" type="text" id="public_key" value="<?php echo esc_attr($public_key) ?>"<?php disabled( defined('FTP_PUBKEY') ); ?> size="40" /><br /><input name="private_key" type="text" id="private_key" value="<?php echo esc_attr($private_key) ?>"<?php disabled( defined('FTP_PRIKEY') ); ?> size="40" />
-<div><?php _e('Enter the location on the server where the keys are located. If a passphrase is needed, enter that in the password field above.') ?></div></td>
-</tr>
+<h4><?php _e('Authentication Keys') ?></h4>
+<label for="public_key">
+	<span class="field-title"><?php _e('Public Key:') ?></span>
+	<input name="public_key" type="text" id="public_key" aria-describedby="auth-keys-desc" value="<?php echo esc_attr($public_key) ?>"<?php disabled( defined('FTP_PUBKEY') ); ?> />
+</label>
+<label for="private_key">
+	<span class="field-title"><?php _e('Private Key:') ?></span>
+	<input name="private_key" type="text" id="private_key" value="<?php echo esc_attr($private_key) ?>"<?php disabled( defined('FTP_PRIKEY') ); ?> />
+</label>
+<span id="auth-keys-desc"><?php _e('Enter the location on the server where the public and private keys are located. If a passphrase is needed, enter that in the password field above.') ?></span>
 <?php endif; ?>
-
-<tr valign="top">
-<th scope="row"><?php _e('Connection Type') ?></th>
-<td>
+<h4><?php _e('Connection Type') ?></h4>
 <fieldset><legend class="screen-reader-text"><span><?php _e('Connection Type') ?></span></legend>
 <?php
 	$disabled = disabled( (defined('FTP_SSL') && FTP_SSL) || (defined('FTP_SSH') && FTP_SSH), true, false );
@@ -1093,19 +1186,44 @@
 	</label>
 	<?php endforeach; ?>
 </fieldset>
-</td>
-</tr>
-</table>
-
 <?php
 foreach ( (array) $extra_fields as $field ) {
 	if ( isset( $_POST[ $field ] ) )
 		echo '<input type="hidden" name="' . esc_attr( $field ) . '" value="' . esc_attr( wp_unslash( $_POST[ $field ] ) ) . '" />';
 }
-submit_button( __( 'Proceed' ), 'button', 'upgrade' );
 ?>
+	<p class="request-filesystem-credentials-action-buttons">
+		<button class="button cancel-button" data-js-action="close" type="button"><?php _e( 'Cancel' ); ?></button>
+		<?php submit_button( __( 'Proceed' ), 'button', 'upgrade', false ); ?>
+	</p>
 </div>
 </form>
 <?php
 	return false;
 }
+
+/**
+ * Print the filesystem credentials modal when needed.
+ *
+ * @since 4.2.0
+ */
+function wp_print_request_filesystem_credentials_modal() {
+	$filesystem_method = get_filesystem_method();
+	ob_start();
+	$filesystem_credentials_are_stored = request_filesystem_credentials( self_admin_url() );
+	ob_end_clean();
+	$request_filesystem_credentials = ( $filesystem_method != 'direct' && ! $filesystem_credentials_are_stored );
+	if ( ! $request_filesystem_credentials ) {
+		return;
+	}
+	?>
+	<div id="request-filesystem-credentials-dialog" class="notification-dialog-wrap request-filesystem-credentials-dialog">
+		<div class="notification-dialog-background"></div>
+		<div class="notification-dialog" role="dialog" aria-labelledby="request-filesystem-credentials-title" tabindex="0">
+			<div class="request-filesystem-credentials-dialog-content">
+				<?php request_filesystem_credentials( site_url() ); ?>
+			<div>
+		</div>
+	</div>
+	<?php
+}