Created VFS System (markdown)

VFS-System.md

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+### VFS Classes
+Virtual File System.
+The new VFS Classes are realized via Stream Wrappers.
+Most documentation is done in the classes itself.
+
+The class is class.iface_stream_wrapper.inc.php
+* instatiated class 
+* and static functions.
+
+### Classes 
+* iface_stream_wrapper
+* oldvfs_stream_wrapper
+* vfs_stream_wrapper
+* sqlfs_stream_wrapper
+* egw_vfs
+
+oldvfs_stream_wrapper instantiates the iface_stream_wrapper
+all methods must be implemented (since the iface_stream_wrapper is defined as php5 interface)
+Some more functions are implemented with the derived classes (touch, chown, chmod, etc).
+
+main thing is, that there is a whole lot of stats for all possible actions regarding files and dirs, these will 
+be cached in a stat-cache, that improves performance for that request.
+
+vfs_stream_wrapper does implement a new class/style sqlfs with fstab and the possibility of mounting any allowed
+vfs path. The path is resolved first thing before accessing the URL given by the request.
+a call may be:
+```php
+./cli.php ls -l vfs://ralf:PASSWORD@default
+./cli.php ls -l vfs://root_USER:PASSWORD@default where USER is the Config or headeradmin user and PASSSWORD its password.
+./cli.php ls -l oldvfs://ralf:PASSWORD@default
+```
+Security is realized via a user concept. Mounts or any access must be realized using a existing user.
+A concept of a root user is implemented, as known for most Linux/Unix users. This user is specified 
+by prepending root_ before the USER:PASSWORD Sequence.
+
+We make extensive use of the new find function, since it gives the possibility of recursively accessing 
+the mounted path. the find function allowes for a callback of the desired functionality.
+
+SQLFS implements Groupfolders with inheritance of user rights of from top to childs, that way files
+can be accessed by all groupmembers. Even if a file is created only with userrights.
+If you have only readrights in a folder, you see only the objects you are allowed to see/access.
+
+The native StreamWrapper uses the WebServer User to determine readability and writeablity. 
+The derived classes do use virtual users/group rights derived from known eGroupware users/groups.
+
+### Consequences/Benefits 
+|| oldvfs || stream wrapper interface ||
+|| all in memory || done all in chunks ||
+|| || filter/encoding possible while reading/writing ||
+|| || SqlFS uses the php pdo interface to access blobs of all possible  databases via stream reading/writing (you need to install the pdo extension for php)||
+
+
+### Commandline Interface 
+Commandline interface must be run with root or webserver rights.
+```
+[root@farm01 inc]# ../../filemanager/cli.php                                                                      
+Usage:  cli.php ls [-r|--recursive] URL [URL2 ...]                                                                
+        cli.php cat URL [URL2 ...]                                                                                
+        cli.php cp [-r|--recursive] [-p|--perms] URL-from URL-to                                                  
+        cli.php cp [-r|--recursive] [-p|--perms] URL-from [URL-from2 ...] URL-to-directory                        
+        cli.php rm [-r|--recursive] URL [URL2 ...]                                                                
+        cli.php mkdir [-p|--parents] URL [URL2 ...]                                                               
+        cli.php rmdir URL [URL2 ...]                                                                              
+        cli.php touch [-r|--recursive] [-d|--date time] URL [URL2 ...]                                            
+        cli.php chmod [-r|--recursive] mode=[ugoa]*[+-=][rwx]+,... URL [URL2 ...]                                 
+        cli.php chown [-r|--recursive] user URL [URL2 ...]                                                        
+        cli.php chgrp [-r|--recursive] group URL [URL2 ...]                                                       
+        cli.php find URL [URL2 ...] [-type (d|f)][-dirs_last][-mime type[/sub]][-name pattern][-path pattern]
+           [-uid id][-user name][-nouser][-gid id][-group name][-nogroup][-size N][-cmin N][-ctime N][-mmin N]
+           [-mtime N] (N: +n --> >n, -n --> <n, n --> =n)                                                                                        
+        cli.php mount URL [path] (without path prints out the mounts)                                             
+        cli.php umount URL|path                                                                                   
+                                                                                                                  
+URL: {vfs|sqlfs|oldvfs}://user:password@domain/home/user/file, /dir/file, ...                                     
+                                                                                                                  
+Use root_{header-admin|config-user} as user and according password for root access (no user specific access control and chown).                                                                                                     
+
+```
+
+### Example Calls 
+An example call for a readonly mount, given that the setup user name is "admin" with "adminPassword":
+```
+./filemanager/cli.php mount 'filesystem://root_admin:adminPassword@default/home/user?user=groupwareUser&mode=005' /home/groupwareUser/harddrive
+```
+Note that the user given in the "user=" option must exist in eGroupware. It defaults to "root". Usually the option "user=root" will not work because "root" is not a valid egroupware user but just a name for the superuser (setup user).
+
+An example for a mount list:
+```
+./filemanager/cli.php mount --user root_admin --password adminPassword
+```
+
+More options for the URL syntax can be found in the [http://svn.stylite.de/viewvc/egroupware/trunk/phpgwapi/inc/class.filesystem_stream_wrapper.inc.php?view=markup Stream Wrapper Source Code].