fsconfig.php

Currently, LnBlog only stores data by writing it to text files on the web server.  However, it supports two methods for doing this.  One is to use standard file-writing functions and the other is to use FTP.  These are refferred to, respectively, as NativeFS and FTPFS.  Deciding between these is the first configuration step for LnBlog and is done by the fs_setup.php script.  This script creates the fsconfig.php file, which should not be present in an initial installation.

The reason for having two types of filesystem writing is that many web hosts use PHP’s safe_mode feature to provide added security.  One of the restrictions this imposes is that scripts can only read files from the disk if the owner of the file is the same as the owner of the script.  In some shared hosting environments (such as those using Mod_PHP), PHP runs and writes files as a system accout, whereas the scripts themselves would be owned by the user account of the site operator, so scripts would not be able to read any of the files they created.  This restriction can be bypassed by performing file writing via FTP, as this allows scripts to connect to the FTP server as the site owner, not a system user.  This also has the beneficial effect that the files created by the scripts will be owned by the user account, so that they can be more easily managed via an FTP client.

If you have the option, it is recommended that you use NativeFS.  It is by far the faster, more reliable, and easier to configure.  FTPFS only exists to work around security restrictions created by certain configurations.  Furthermore, note that safe_mode was deprecated in PHP 5.3 and removed from PHP 5.4, so unless you’re stuck on a very old version of PHP, it is unlikely that you will need FTPFS.

Writing to the filesystem is carried out using an abstract interface class.  This class defines the basic functions of the file-writing subsystem, such as creating directories, deleting files, and writing text data to a file.  There are NativeFS and FTPFS subclasses which implement this interface.  LnBlog writes files by using a wrapper function in the creators.php file to instantiate the correct class based on a constant defined in the fsconfig.php file.

The fsconfig.php file is a simple PHP source code file which contains only a series of constant definitions.  If necessary, these definitions can be changed by hand, although this is not recommended.  Note that which definitions are actually present depends on the type of file writing used.  If NativeFS is used, there is no extra configuration needed, but FTPFS requires various user authentication details.