source: trunk/www.guidonia.net/wp/wp-content/plugins/contact-form-7/modules/file.php@ 44

<?php
/**
** A base module for [file] and [file*]
**/

function wpcf7_file_shortcode_handler( $tag ) {
        global $wpcf7_contact_form;

        if ( ! is_array( $tag ) )
                return '';

        $type = $tag['type'];
        $name = $tag['name'];
        $options = (array) $tag['options'];
        $values = (array) $tag['values'];

        if ( empty( $name ) )
                return '';

        $atts = '';
        $id_att = '';
        $class_att = '';

        if ( 'file*' == $type )
                $class_att .= ' wpcf7-validates-as-required';

        foreach ( $options as $option ) {
                if ( preg_match( '%^id:([-0-9a-zA-Z_]+)$%', $option, $matches ) ) {
                        $id_att = $matches[1];

                } elseif ( preg_match( '%^class:([-0-9a-zA-Z_]+)$%', $option, $matches ) ) {
                        $class_att .= ' ' . $matches[1];

                }
        }

        if ( $id_att )
                $atts .= ' id="' . trim( $id_att ) . '"';

        if ( $class_att )
                $atts .= ' class="' . trim( $class_att ) . '"';

        $html = '<input type="file" name="' . $name . '"' . $atts . ' value="1" />';

        $validation_error = '';
        if ( is_a( $wpcf7_contact_form, 'WPCF7_ContactForm' ) )
                $validation_error = $wpcf7_contact_form->validation_error( $name );

        $html = '<span class="wpcf7-form-control-wrap ' . $name . '">' . $html . $validation_error . '</span>';

        return $html;
}

wpcf7_add_shortcode( 'file', 'wpcf7_file_shortcode_handler', true );
wpcf7_add_shortcode( 'file*', 'wpcf7_file_shortcode_handler', true );


/* Encode type filter */

function wpcf7_file_form_enctype_filter( $enctype ) {
        global $wpcf7_contact_form;

        $multipart = (bool) $wpcf7_contact_form->form_scan_shortcode(
                array( 'type' => array( 'file', 'file*' ) ) );

        if ( $multipart )
                $enctype = ' enctype="multipart/form-data"';

        return $enctype;
}

add_filter( 'wpcf7_form_enctype', 'wpcf7_file_form_enctype_filter' );


/* Validation + upload handling filter */

function wpcf7_file_validation_filter( $result, $tag ) {
        global $wpcf7_contact_form;

        $type = $tag['type'];
        $name = $tag['name'];
        $options = (array) $tag['options'];

        $file = $_FILES[$name];

        if ( $file['error'] ) {
                $result['valid'] = false;
                $result['reason'][$name] = $wpcf7_contact_form->message( 'upload_failed_php_error' );
                return $result;
        }

        if ( empty( $file['tmp_name'] ) && 'file*' == $type ) {
                $result['valid'] = false;
                $result['reason'][$name] = $wpcf7_contact_form->message( 'invalid_required' );
                return $result;
        }

        if ( ! is_uploaded_file( $file['tmp_name'] ) )
                return $result;

        $file_type_pattern = '';
        $allowed_size = 1048576; // default size 1 MB

        foreach ( $options as $option ) {
                if ( preg_match( '%^filetypes:(.+)$%', $option, $matches ) ) {
                        $file_types = explode( '|', $matches[1] );
                        foreach ( $file_types as $file_type ) {
                                $file_type = trim( $file_type, '.' );
                                $file_type = str_replace(
                                        array( '.', '+', '*', '?' ), array( '\.', '\+', '\*', '\?' ), $file_type );
                                $file_type_pattern .= '|' . $file_type;
                        }

                } elseif ( preg_match( '/^limit:([1-9][0-9]*)([kKmM]?[bB])?$/', $option, $matches ) ) {
                        $allowed_size = (int) $matches[1];

                        $kbmb = strtolower( $matches[2] );
                        if ( 'kb' == $kbmb ) {
                                $allowed_size *= 1024;
                        } elseif ( 'mb' == $kbmb ) {
                                $allowed_size *= 1024 * 1024;
                        }

                }
        }

        /* File type validation */

        // Default file-type restriction
        if ( '' == $file_type_pattern )
                $file_type_pattern = 'jpg|jpeg|png|gif|pdf|doc|docx|ppt|pptx|odt|avi|ogg|m4a|mov|mp3|mp4|mpg|wav|wmv';

        $file_type_pattern = trim( $file_type_pattern, '|' );
        $file_type_pattern = '(' . $file_type_pattern . ')';
        $file_type_pattern = '/\.' . $file_type_pattern . '$/i';

        if ( ! preg_match( $file_type_pattern, $file['name'] ) ) {
                $result['valid'] = false;
                $result['reason'][$name] = $wpcf7_contact_form->message( 'upload_file_type_invalid' );
                return $result;
        }

        /* File size validation */

        if ( $file['size'] > $allowed_size ) {
                $result['valid'] = false;
                $result['reason'][$name] = $wpcf7_contact_form->message( 'upload_file_too_large' );
                return $result;
        }

        $uploads_dir = wpcf7_upload_tmp_dir();
        wpcf7_init_uploads(); // Confirm upload dir

        $filename = wp_unique_filename( $uploads_dir, $file['name'] );

        // If you get script file, it's a danger. Make it TXT file.
        if ( preg_match( '/\.(php|pl|py|rb|cgi)\d?$/', $filename ) )
                $filename .= '.txt';

        $new_file = trailingslashit( $uploads_dir ) . $filename;

        if ( false === @move_uploaded_file( $file['tmp_name'], $new_file ) ) {
                $result['valid'] = false;
                $result['reason'][$name] = $wpcf7_contact_form->message( 'upload_failed' );
                return $result;
        }

        // Make sure the uploaded file is only readable for the owner process
        @chmod( $new_file, 0400 );

        $wpcf7_contact_form->uploaded_files[$name] = $new_file;

        return $result;
}

add_filter( 'wpcf7_validate_file', 'wpcf7_file_validation_filter', 10, 2 );
add_filter( 'wpcf7_validate_file*', 'wpcf7_file_validation_filter', 10, 2 );


/* File uploading functions */

function wpcf7_init_uploads() {
        $dir = wpcf7_upload_tmp_dir();
        wp_mkdir_p( trailingslashit( $dir ) );
        @chmod( $dir, 0733 );

        $htaccess_file = trailingslashit( $dir ) . '.htaccess';
        if ( file_exists( $htaccess_file ) )
                return;

        if ( $handle = @fopen( $htaccess_file, 'w' ) ) {
                fwrite( $handle, "Deny from all\n" );
                fclose( $handle );
        }
}

function wpcf7_cleanup_upload_files() {
        $dir = trailingslashit( wpcf7_upload_tmp_dir() );

        if ( ! is_dir( $dir ) )
                return false;
        if ( ! is_readable( $dir ) )
                return false;
        if ( ! is_writable( $dir ) )
                return false;

        if ( $handle = @opendir( $dir ) ) {
                while ( false !== ( $file = readdir( $handle ) ) ) {
                        if ( $file == "." || $file == ".." || $file == ".htaccess" )
                                continue;

                        $stat = stat( $dir . $file );
                        if ( $stat['mtime'] + 60 < time() ) // 60 secs
                                @unlink( $dir . $file );
                }
                closedir( $handle );
        }
}

if ( ! is_admin() && 'GET' == $_SERVER['REQUEST_METHOD'] )
        wpcf7_cleanup_upload_files();

?>