egroupware_official/phpgwapi/doc/vfs/vfs.lyx

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\layout Title
\added_space_top vfill \added_space_bottom vfill 
phpgwapi - VFS Class
\layout Author

Jason Wies
\layout Date

June 2001, February 2002
\layout Abstract

The VFS, or Virtual File System, handles all file system activity for phpGroupWa
re.
\layout Section

Introduction and Purpose
\begin_inset LatexCommand \label{sec:introduction}

\end_inset 


\layout Standard

The latest version of the VFS for phpGroupWare combines actual file system
 manipulation with fully integrated database support.
 It features nearly transparent handling of files and directories, as well
 as files inside and outside the virtual root.
 This document is intended to provide API and application developers with
 a guide to incorporating the VFS into their work.
\layout Section

Basics
\begin_inset LatexCommand \label{sec:basics}

\end_inset 


\layout Subsection

Prerequisites
\begin_inset LatexCommand \label{sec:prerequisites}

\end_inset 


\layout Standard

You must explicitly enable the VFS class.
 To do this, set 'enable_vfs_class' to True in $GLOBALS['phpgw_info']['flags'].
 An example:
\layout Verbatim

$GLOBALS['phpgw_info']['flags'] = array(
\layout Verbatim

     'currentapp' => 'phpwebhosting',
\layout Verbatim

     'noheader' => False,
\layout Verbatim

     'noappheader' => False,
\layout Verbatim

     'enable_vfs_class' => True,
\layout Verbatim

     'enable_browser_class' => True
\layout Verbatim

);
\layout Subsection

Concepts
\begin_inset LatexCommand \label{sec:concepts}

\end_inset 


\layout Standard

The VFS in located in phpgwapi/inc/class.vfs_sql.inc.php.
 You can look over it, but I don't suggest trying to understand how it works.
 It isn't necessary to know its internals to use it, but you may find the
 inline comments helpful.
 The basic things to keep in mind:
\layout Itemize

Files and directories are synonymous in almost all cases
\layout Verbatim

$GLOBALS['phpgw']->vfs->mv (array(
\layout Verbatim

     'from' => 'file1',
\layout Verbatim

     'to' => 'dir/file2'
\layout Verbatim

));
\layout Verbatim

\layout Verbatim

$GLOBALS['phpgw']->vfs->mv (array(
\layout Verbatim

     'from' => 'dir1',
\layout Verbatim

     'to' => 'dir/dir1'
\layout Verbatim

));
\layout Verbatim

\layout Verbatim

$GLOBALS['phpgw']->vfs->rm (array(
\layout Verbatim

     'string' => 'file'
\layout Verbatim

));
\layout Verbatim

\layout Verbatim

$GLOBALS['phpgw']->vfs->rm (array(
\layout Verbatim

     'string' => 'dir'
\layout Verbatim

));
\layout Standard

All work as you would except them to.
 The major exception is:
\layout Verbatim

$GLOBALS['phpgw']->vfs->touch (array(
\layout Verbatim

     'string' => 'file'
\layout Verbatim

));
\layout Standard

vs.
\layout Verbatim

$GLOBALS['phpgw']->vfs->mkdir (array(
\layout Verbatim

     'string' => 'dir'
\layout Verbatim

));
\layout Verbatim

\layout Itemize

Users and groups are synonymous
\layout Standard

As far as the actual paths are concerned, users and groups are the same.
 /home/username works the same as /home/groupname.
\layout Itemize

You should never have to know the real paths of files
\layout Standard

One of the VFS's responsibilities is to translate paths for you.
 While you certainly 
\emph on 
can
\emph default 
 operate using full paths, it is much simpler to use the virtual paths.
 For example, instead of using:
\layout Verbatim

$GLOBALS['phpgw']->vfs->cp (array(
\layout Verbatim

     'from' => '/var/www/phpgroupware/files/home/user/file1',
\layout Verbatim

     'to' => '/var/www/phpgroupware/files/home/user/file2',
\layout Verbatim

     'relatives' => array(
\layout Verbatim

          RELATIVE_NONE|VFS_REAL,
\layout Verbatim

          RELATIVE_NONE|VFS_REAL
\layout Verbatim

     )
\layout Verbatim

));
\layout Standard

you might use
\layout Verbatim

$GLOBALS['phpgw']->vfs->cp (array(
\layout Verbatim

     'from' => '/home/user/file1',
\layout Verbatim

     'to' => '/home/user/file2',
\layout Verbatim

     'relatives' => array(
\layout Verbatim

          RELATIVE_NONE,
\layout Verbatim

          RELATIVE_NONE
\layout Verbatim

     )
\layout Verbatim

));
\layout Standard

(We'll get to the RELATIVE's in a minute.)
\layout Standard

Site administrators should be able to move their files dir around on their
 system and know that everything will continue to work smoothly.
\layout Itemize

Relativity is 
\emph on 
vital
\layout Standard

Relativity is a new feature in the VFS, and its importance cannot be stressed
 enough.
 It will make your life much easier, especially for file system intensive
 applications, but it will take some getting used to.
 If something doesn't work right the first time, chances are great it has
 to do with incorrect relativity settings.
 We will deal with relativity in depth in the Relativity section.
\layout Section

Basic Functions
\begin_inset LatexCommand \label{sec:basic_functions}

\end_inset 


\layout Standard

These are two functions you'll need to know before we get into relativity.
\layout Subsection

path_parts ()
\begin_inset LatexCommand \label{sec:path_parts}

\end_inset 


\layout Standard

The job of path_parts () is to translate any given file location into its
 many component parts for any relativity.
 The values passed to path_parts () are:
\layout Verbatim

string
\layout Verbatim

relatives
\layout Verbatim

object
\layout Standard

'string' is the path you want to translate, 'relatives' is the standard
 relativity array, and 'object' specifies how you would like the return
 value: if 'object' is True, an object will be returned; if 'object' is
 False, an array will be returned.
 I think you'll find the object easier to deal with, and we'll be using
 it throughout this document.
 The most important returned values (but not all) for path_parts () are:
\layout Verbatim

fake_full_path
\layout Verbatim

fake_leading_dirs
\layout Verbatim

fake_extra_path
\layout Verbatim

fake_name
\layout Verbatim

real_full_path
\layout Verbatim

real_leading_dirs
\layout Verbatim

real_extra_path
\layout Verbatim

real_name
\layout Standard

Just like you would think, fake_full_path contains the full virtual path
 of 'string', and real_full_path contains the full real path of 'string'.
 The fake_name and real_name variables should always be the same, and contain
 the final file or directory name.
 The leading_dirs contain everything except the name, and the extra_path
 is everything from the / before 
\begin_inset Quotes eld
\end_inset 

home
\begin_inset Quotes erd
\end_inset 

 to the end of the leading_dirs.
 To better illustrate, here is an example:
\layout Verbatim

$p = $GLOBALS['phpgw']->vfs->path_parts (array(
\layout Verbatim

     'string' => '/home/jason/dir/file',
\layout Verbatim

     'relatives' => array(
\layout Verbatim

         RELATIVE_NONE
\layout Verbatim

     )
\layout Verbatim

));
\layout Itemize

$p->fake_full_path - /home/jason/dir/file
\layout Itemize

$p->fake_leading_dirs - /home/jason/dir
\layout Itemize

$p->fake_extra_path - home/jason/dir
\layout Itemize

$p->fake_name - file
\layout Itemize

$p->real_full_path - /var/www/phpgroupware/files/home/jason/dir/file
\layout Itemize

$p->real_leading_dirs - /var/www/phpgroupware/files/home/jason/dir 
\layout Itemize

$p->real_extra_path - home/jason/dir
\layout Itemize

$p->real_name - file
\layout Standard

As you can see, path_parts () is a very useful function and will save you
 from doing those darn substr ()'s yourself.
 For those of you used to the prior VFS, note that 
\emph on 
getabsolutepath () is depreciated
\emph default 
.
 getabsolutepath () still exists (albeit in a much different form), and
 is responsible for some of the path translation, but it is an 
\emph on 
internal
\emph default 
 function only.
 Applications should only use path_parts ().
 We have shown you how to use path_parts () so you can experiment with it
 using different paths and relativities as we explore relativity.
\layout Subsection

cd ()
\begin_inset LatexCommand \label{sec:cd}

\end_inset 


\layout Standard

Part of the overall goal for the VFS in phpGroupWare is to give the user
 a seamless experience during their session.
 For example, if they upload a file using a file manager to the directory
 /home/my_group/project1, and then go to download an email attachment, the
 default directory will be /home/my_group/project1.
 This is accomplished using the cd () function.
 Examples: 
\layout Verbatim

/* cd to their home directory */
\layout Verbatim

$GLOBALS['phpgw']->vfs->cd (array(
\layout Verbatim

     'string' => '/'
\layout Verbatim

));
\layout Verbatim

\layout Verbatim

/* cd to /home/jason/dir */
\layout Verbatim

$GLOBALS['phpgw']->vfs->cd (array(
\layout Verbatim

     'string' => '/home/jason/dir',
\layout Verbatim

     'relative' => False,
\layout Verbatim

     'relatives' => array(
\layout Verbatim

          RELATIVE_NONE
\layout Verbatim

     )
\layout Verbatim

));
\layout Verbatim

\layout Verbatim

/* When following the above, cd's to /home/jason/dir/dir2 */
\layout Verbatim

$GLOBALS['phpgw']->vfs->cd (array(
\layout Verbatim

     'string' => 'dir2',
\layout Verbatim

     'relative' => True
\layout Verbatim

));
\layout Standard

If 'relative' is True, the 'string' is simply appended to the current path.
 If you want to know what the current path is, use $GLOBALS['phpgw']->vfs->pwd
 ().
\layout Standard

Now you're ready for relativity.
\layout Section

Relativity
\begin_inset LatexCommand \label{sec:relativity}

\end_inset 


\layout Standard

Ok, just one last thing before we get into relativity.
 You will notice throughout the examples the use of $fakebase.
 $GLOBALS['phpgw']->vfs->fakebase is by default '/home'.
 The old VFS was hard-coded to use '/home', but the naming choice for this
 is now up to administrators.
 See the 
\begin_inset LatexCommand \ref[Fakebase directory (changing /home)]{sec:fakebase}

\end_inset 

 section for more information.
 Throughout the rest of this document, you will see $fakebase used in calls
 to the VFS, and /home used in actual paths.
 
\emph on 
You should always use $fakebase when making applications.
 
\emph default 
I suggest doing $fakebase = $GLOBALS['phpgw']->vfs->fakebase; right off
 the bat to keep things neater.
\layout Subsection

What is it and how does it work?
\layout Standard

One of the design challenges for a Virtual File System is to try to figure
 out whether the calling application is referring to a file inside or outside
 the virtual root, and if inside, exactly where.
 To solve this problem, the phpGroupWare VFS uses RELATIVE defines that
 are used in bitmasks passed to each function.
 The result is that any set of different relativities can be used in combination
 with each other.
 Let's look at a few examples.
 Say you want to move 'logo.png' from the user's home directory to the current
 directory.
 
\layout Verbatim

$GLOBALS['phpgw']->vfs->mv (array(
\layout Verbatim

    'from' => 'logo.png',
\layout Verbatim

    'to' => 'logo.png',
\layout Verbatim

    'relatives' => array(
\layout Verbatim

          RELATIVE_USER,
\layout Verbatim

          RELATIVE_ALL
\layout Verbatim

     )
\layout Verbatim

));
\layout Standard

RELATIVE_USER means relative to the user's home directory.
 RELATIVE_ALL means relative to the current directory, as set by cd () and
 as reported by pwd ().
 So if the current directory was 
\begin_inset Quotes eld
\end_inset 

$fakebase/my_group/project1
\begin_inset Quotes erd
\end_inset 

, the call to mv () would be processed as:
\layout Verbatim

MOVE 
\begin_inset Quotes eld
\end_inset 

$fakebase/jason/logo.png
\begin_inset Quotes erd
\end_inset 

 TO 
\begin_inset Quotes eld
\end_inset 

$fakebase/my_group/project1/logo.png
\begin_inset Quotes erd
\end_inset 


\layout Standard

and the actual file system call would be:
\layout Verbatim

rename ('/var/www/phpgroupware/files/home/jason/logo.php', '/var/www/phpgroupware
/files/home/my_group/project1/logo.png');
\layout Standard

Those used to the old VFS will note that you do not have to translate the
 path beforehand.
 Let's look at another example.
 Suppose you were moving an email attachment stored in phpGroupWare's temporary
 directory to the 'attachments' directory within the user's home directory
 (we're assuming the attachments directory exists).
 Note that the temporary directory is 
\emph on 
outside
\emph default 
 the virtual root.
\layout Verbatim

$GLOBALS['phpgw']->vfs->mv (array(
\layout Verbatim

     'from' => $GLOBALS['phpgw_info']['server']['temp_dir'] .
 '/' .
 $randomdir .
 '/' .
 $randomfile,
\layout Verbatim

     'to' => 'attachments/actual_name.ext',
\layout Verbatim

     'relatives' => array(
\layout Verbatim

          RELATIVE_NONE|VFS_REAL,
\layout Verbatim

          RELATIVE_USER
\layout Verbatim

     )
\layout Verbatim

));
\layout Standard

$randomdir and $randomfile are what the directory and file might be called
 before they are given a proper name by the user, which is actual_name.ext
 in this example.
 RELATIVE_NONE is the define for using full path names.
 However, RELATIVE_NONE is still relative to the virtual root, so we pass
 along VFS_REAL as well, to say that the file is 
\emph on 
outside
\emph default 
 the virtual root, somewhere else in the file system.
 Once again, RELATIVE_USER means relative to the user's home directory.
 So the actual file system call might look like this (keep in mind that
 $randomdir and $randomfile are just random strings):
\layout Verbatim

rename ('/var/www/phpgroupware/tmp/0ak5adftgh7/jX42sC9M', '/var/www/phpgroupware
/files/home/jason/attachments/actual_name.ext');
\layout Standard

Of course you don't have to know that, nor should you be concerned with
 it; you can take it for granted that the VFS will translate the paths correctly.
 Let's take a look at one more example, this time using the RELATIVE_USER_APP
 define.
 RELATIVE_USER_APP is used to store quasi-hidden application files, similar
 to the Unix convention of ~/.appname.
 It simply appends .appname to the user's home directory.
 For example, if you were making an HTML editor application named 'htmledit',
 and wanted to keep a backup file in case something goes wrong, you could
 use RELATIVE_USER_APP to store it:
\layout Verbatim

$GLOBALS['phpgw']->vfs->write (array(
\layout Verbatim

     'string' => 'file.name~',
\layout Verbatim

     'relatives' => array(
\layout Verbatim

          RELATIVE_USER_APP
\layout Verbatim

     ),
\layout Verbatim

     'content' => $contents
\layout Verbatim

));
\layout Standard

This assumes that ~/.htmledit exists of course.
 The backup file 
\begin_inset Quotes eld
\end_inset 

file.name~
\begin_inset Quotes erd
\end_inset 

 would then be written in $fakebase/jason/.htmledit/file.name~.
 Note that storing files like this might not be as good of a solution as
 storing them in the temporary directory or in the database.
 But it is there in case you need it.
\layout Subsection

Complete List
\begin_inset LatexCommand \label{sec:relatives_complete_list}

\end_inset 


\layout Standard

Here is the complete list of RELATIVE defines, and what they do:
\layout Description

RELATIVE_ROOT Don't translate the path at all.
 Just prepends a /.
 You'll probably want to use RELATIVE_NONE though, which handles both virtual
 and real files.
\layout Description

RELATIVE_USER User's home directory
\layout Description

RELATIVE_CURR_USER Current user's home directory.
 If the current directory is $fakebase/my_group/project1, this will return
 is $fakebase/my_group
\layout Description

RELATIVE_USER_APP Append .appname to the user's home directory, where appname
 is the current application's appname
\layout Description

RELATIVE_PATH DO NOT USE.
 Relative to the current directory, used in RELATIVE_ALL
\layout Description

RELATIVE_NONE Not relative to anything.
 Use this with VFS_REAL for files outside the virtual root.
 Note that using RELATIVE_NONE by itself still means relative to the virtual
 root
\layout Description

RELATIVE_CURRENT An alias for the currently set RELATIVE define, or RELATIVE_ALL
 if none is set (see the Defaults section)
\layout Description

VFS_REAL File is outside of the virtual root.
 Usually used with RELATIVE_NONE
\layout Description

RELATIVE_ALL Relative to the current directory.
 Use RELATIVE_ALL
\emph on 
 
\emph default 
instead of RELATIVE_PATH
\layout Subsection

Defaults
\begin_inset LatexCommand \label{sec:relatives_defaults}

\end_inset 


\layout Standard

You might be thinking to yourself that passing along RELATIVE defines with
 every VFS call is overkill, especially if your application always uses
 the same relativity.
 The default RELATIVE define for all VFS calls is RELATIVE_CURRENT.
 RELATIVE_CURRENT itself defaults to RELATIVE_ALL (relative to the current
 path), 
\emph on 
unless
\emph default 
 your application sets a specific relativity.
 If your application requires most of the work to be done outside of the
 virtual root, you may wish to set RELATIVE_CURRENT to RELATIVE_NONE|VFS_REAL.
 set_relative () is the function to do this.
 For example:
\layout Verbatim

$GLOBALS['phpgw']->vfs->set_relative (array(
\layout Verbatim

     'mask' => RELATIVE_NONE|VFS_REAL
\layout Verbatim

));
\layout Verbatim

\layout Verbatim

$GLOBALS['phpgw']->vfs->read (array(
\layout Verbatim

     'string' => '/etc/passwd'
\layout Verbatim

));
\layout Verbatim

\layout Verbatim

$GLOBALS['phpgw']->vfs->cp (array(
\layout Verbatim

     'from' => '/usr/include/stdio.h',
\layout Verbatim

     'to' => '/tmp/stdio.h'
\layout Verbatim

));
\layout Verbatim

\layout Verbatim

$GLOBALS['phpgw']->vfs->cp (array(
\layout Verbatim

     'from' => '/usr/share/pixmaps/yes.xpm',
\layout Verbatim

     'to' => 'icons/yes.xpm',
\layout Verbatim

     'relatives' => array(
\layout Verbatim

          RELATIVE_CURRENT,
\layout Verbatim

          RELATIVE_USER
\layout Verbatim

     )
\layout Verbatim

));
\layout Standard

You should notice that no relativity array is needed in the other calls
 that refer to files outside the virtual root, but one is needed for calls
 that include files inside the virtual root.
 Any RELATIVE define can be set as the default and works in the same fashion.
 To retrieve the currently set define, use get_relative ().
 Note that the relativity is reset after each page request; that is, it's
 good only for the life of the current page loading, and is not stored in
 session management.
\layout Section

Function reference
\begin_inset LatexCommand \label{sec:function_reference}

\end_inset 


\layout Standard

To view the function reference for the VFS, use the doc/inlinedocparser.php
 script that comes with phpGroupWare, ie 
\begin_inset LatexCommand \url[http://localhost/doc/inlinedocparser.php?fn=class.vfs_sql.inc.php]{http://localhost/doc/inlinedocparser.php?fn=class.vfs_sql.inc.php}

\end_inset 

.
\layout Section

Notes
\begin_inset LatexCommand \label{sec:notes}

\end_inset 


\layout Subsection

Database
\begin_inset LatexCommand \label{sec:database}

\end_inset 


\layout Standard

Data about the files and directories within the virtual root is kept in
 the SQL database.
 Currently, this information includes:
\layout Itemize

File ID (used internally, primary key for table)
\layout Itemize

Owner ID (phpGW account_id)
\layout Itemize

Created by ID (phpGW account_id)
\layout Itemize

Modified by ID (phpGW account_id)
\layout Itemize

Created (date)
\layout Itemize

Modified (date)
\layout Itemize

Size (bytes)
\layout Itemize

MIME type
\layout Itemize

Deleteable (Y/N/Other?)
\layout Itemize

Comment
\layout Itemize

App (appname of application that created the file)
\layout Itemize

Directory (directory the file or directory is in)
\layout Itemize

Name (name of file or directory)
\layout Itemize

Link directory (if the file or directory is linked, what the actual directory
 is)
\layout Itemize

Link name (if the file or directory is linked, what the actual name is)
\layout Itemize

Version (numeric version of the file)
\layout Standard

The internal names of these (the database column names) are stored in the
 $GLOBALS['phpgw']->vfs->attributes array, which is useful for loops, and
 is guaranteed to be up-to-date.
\layout Standard

Note that no information is kept about files outside the virtual root.
 If a file is moved outside, all records of it are deleted from the database
 (other than the journaling records).
 If a file is moved into the virtual root, some information, specifically
 MIME-type, is not always stored in the database.
 The vital information has defaults: owner is based on where the file is
 being stored; size is correctly read; deleteable is set to Y.
\layout Subsection

ACL support
\begin_inset LatexCommand \label{sec:acl_support}

\end_inset 


\layout Standard

ACL support is built into the VFS.
 vfs->acl_check () does the actual checking, and is called from all VFS
 functions as needed.
 If the file or directory sent to acl_check () doesn't exist, the permissions
 for the parent directory are used to determine access.
 ACL checking can be overridden at any time by setting vfs->override_acl.
 For example:
\layout Verbatim

$GLOBALS['phpgw']->vfs->override_acl = 1;
\layout Verbatim

$GLOBALS['phpgw']->vfs->mkdir (array(
\layout Verbatim

     'string' => $GLOBALS['fakebase'].
 '/' .
 $group_array['account_name'],
\layout Verbatim

     'relatives' => array(
\layout Verbatim

          RELATIVE_NONE
\layout Verbatim

     )
\layout Verbatim

));
\layout Verbatim

$GLOBALS['phpgw']->vfs->override_acl = 0;
\layout Subsection

Function aliases
\begin_inset LatexCommand \label{sec:function_aliases}

\end_inset 


\layout Standard

You might have noticed there are some functions that just pass the arguments
 on to other functions.
 These are provided in part because of legacy and in part for convenience.
 You can use either.
 Here is the list (alias -> actual):
\layout Itemize

copy -> cp
\layout Itemize

move -> rm
\layout Itemize

delete -> rm
\layout Itemize

dir -> ls
\layout Subsection

Fakebase directory (changing /home)
\begin_inset LatexCommand \label{sec:fakebase}

\end_inset 


\layout Standard

The old VFS was hard-coded to use '/home' as the fake base directory, even
 though the user never saw it.
 With the new system, crafty administrators may wish to change '/home' to
 something else, say '/users' or '/public_html'.
 The fake base directory name is stored in $GLOBALS['phpgw']->vfs->fakebase,
 and changing it will transparently change it throughout the VFS and all
 applications.
 However, this must be done 
\emph on 
before
\emph default 
 any data is in the VFS database.
 If you wish to change it afterwords, you'll have to manually update the
 database, replacing the old value with the new value.
 
\emph on 
Application programmers need to recognize that /home is not absolute, and
 use $GLOBALS['phpgw']->vfs->fakebase instead
\emph default 
.
 I suggest setting $fakebase = $GLOBALS['phpgw']->vfs->fakebase; right off
 the bat to keep things neater.
\layout Section

About this Document
\layout Subsection

Copyright and License
\layout Standard

Copyright (c) 2001, 2002 Jason Wies
\layout Standard

Permission is granted to copy, distribute and/or modify this document under
 the terms of the GNU Free Documentation License, Version 1.1 or any later
 version published by the Free Software Foundation; with no Invarient Sections,
 with no Front-Cover Texts, and no Back-Cover Texts.
\layout Standard

A copy of the license is available at 
\begin_inset LatexCommand \url[http://www.gnu.org/copyleft/fdl.html]{http://www.gnu.org/copyleft/fdl.html}

\end_inset 

.
\layout Subsection

History
\layout Standard

Original document released in June 2001 by Jason Wies.
\layout Standard

Updated February 2002 to include arrayized parameters, single quotes, and
 GLOBALS.
\layout Subsection

Contributing
\layout Standard

Contributions are always welcome.
 Please send to the current maintainer, Jason Wies, 
\begin_inset LatexCommand \url[zone@phpgroupware.org]{mailto:zone@phpgroupware.org}

\end_inset 

.
\the_end