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another "xmlfs" proposal
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From: |
gnubie10-bugsoccer |
|
Subject: |
another "xmlfs" proposal |
|
Date: |
Sat, 3 May 2008 11:53:18 -0700 (PDT) |
On Wed, 30 Apr 2008 01:11:49 +0200, antrik wrote:
> It could be possible though to pick one simple unambiguos XPath syntax
> and use it for the static representation of the document contents...
> That's why the task suggested considering the tree representation with a
> view on both DOM *and* XPath. I'm not sure what is possible here (I know
> very little about XPath), but it's certainly worth looking into.
DOM is a(n object) model for xml documents. In principle, using it or not is
not the point. I think antrik wanted to say to translate the data model of the
xml document to an directory structure so that the file _path_ resembles the
[document structure][0] (PS: example, not puting extra nodes to amend the
notation). When you use XSLT, you have to select nodes using XPath and learning
it was vary easy to me because they followed the [principle of the least
surpise][3] doing things as much compatible with unix directory naming
convention as possible and using ortogonal concepts (see attribute selection as
a node queried and as an expression) (PS: indeed, they are following their own
recomendations about resource location).
I mean: if we want an translator to create an unix directory tree that maps to
data from an xml and back again, then we should (must?) use an convention that
resembles xpath.
Take this file named 'tom_sic.xml' (indented as a [MarkDown][] codeblock):
<?xml version="1.0"?>
<libraries
xmlns:goudi='http://deux-fleurs.net/analyse-xmlfs'
xmlns:pouet='http://deux-fleurs.net/analyse-xmlfs'
>
<pouet:library goudi:name="plop">
<curious_balise>
</curious_balise>
<!--a comment-->
<book>
<author>Mark Twain</author>
<title>La case de l'oncle Tom</title>
<isbn>4242</isbn>
</book>
<book />
Here is some CDATA
<sub-library name="pikaplop">
<location>Grenoble</location>
<name>Arlequin</name>
</sub-library>
CDATA, again !
</pouet:library>
</libraries>
I made some corrections on [Charly Caulet's example][4] (PS: a good examples,
since it stresses the design). In portuguese, if you correct some quoting you
must put "(sic)" before the correction. This (PS: unnecessary) comentary is
just the unique prompt i think i will have to say to avoid saying "something et
al." (meaning "something and all"). "Al." is abbreviation to "alumni". I know
my english is bad. But if I do no correct, anybody won't correct me and I wont
learn.
See the following typescript:
> xpath tom_sic.xml "/libraries/pouet:library/book[isbn = '4242']"
Found 1 nodes:
-- NODE --
<book>
<author>Mark Twain</author>
<title>La case de l'oncle Tom</title>
<isbn>4242</isbn>
</book>
> xpath tom_sic.xml "/libraries/pouet:library/*[contains(name(),'ook')]"
Found 2 nodes:
-- NODE --
<book>
<author>Mark Twain</author>
<title>La case de l'oncle Tom</title>
<isbn>4242</isbn>
</book>-- NODE --
<book />
>
A cople of days ago i played a little with this. The Perl module XML::Directory
creates and xml representing an directory (lets bootstrap this shit!). Follows
'dir.pl':
# refer to
http://search.cpan.org/~pcimprich/XML-Directory-1.00/docs/Directory.pod
use Data::Dumper;
use XML::Directory::String;1
if (-d $ARGV[0]) { $dir = XML::Directory::String->new($ARGV[0]0,3,10) }
else { print "usage: $0 dir\n"; exit };
$dir->set_details(1);
$rc = $dir->parse_dir;
@res = $dir->get_array;
foreach $line (@res) { print "$line\n"; }
A sample result is 'foo.xml':
<?xml version="1.0" encoding="utf-8"?>
<dirtree >
<directory name="xml">
<file name=".dir.pl.swp"></file>
<file name="dir.pl"></file>
<file name="final.xml"></file>
<file name="foo.pl"></file>
<file name="foo.xml"></file>
</directory>
</dirtree>
I made by hand, as a proof of concept, this directory tree:
> find dirtree/
dirtree/
dirtree/directory
dirtree/directory/directory
dirtree/directory/directory/@name
dirtree/directory/directory/file[@name = 'foo.xml']
dirtree/directory/directory/file[@name = 'foo.xml']/@name
dirtree/directory/directory/file[@name = 'dir.pl']
dirtree/directory/directory/file[@name = 'dir.pl']/@name
dirtree/directory/directory/file[@name = 'foo.pl']
dirtree/directory/directory/file[@name = 'foo.pl']/@name
dirtree/directory/directory/file[@name = '.dir.pl.swp']
dirtree/directory/directory/file[@name = '.dir.pl.swp']/@name
dirtree/directory/directory/file[@name = 'perl5.8.8.core']
dirtree/directory/directory/file[@name = 'perl5.8.8.core']/@name
dirtree/directory/@name
> find dirtree -type f -print0 | xargs -0 grep -v "notafilename"
dirtree/directory/directory/@name:xml
dirtree/directory/directory/file[@name = 'foo.xml']/@name:foo.xml
dirtree/directory/directory/file[@name = 'dir.pl']/@name:dir.pl
dirtree/directory/directory/file[@name = 'foo.pl']/@name:foo.pl
dirtree/directory/directory/file[@name = '.dir.pl.swp']/@name:.dir.pl..swp
dirtree/directory/directory/file[@name =
'perl5.8.8.core']/@name:perl5.8.8.core
dirtree/directory/@name:hurd
> cat dirtree/directory/directory/file\[@name\ =\ \'*\]/@name
.dir.pl.swp
dir.pl
foo.pl
foo.xml
perl5.8.8.core
>
That day, i realized some facts. had to try other possibilities but take this
one just as a main part of the desired result. The interesting one is that,
like the special file with name "*" from httpfs (that i could not use yet)
which separates the local namespace and the foreing ("away", don't know, please
correct) one, using "[" and "]" to enclose the conditional expression that
selects nodes in a xpath, the XPath creators used the pattern of an array
element qualified identifier from C language. May be if we do "ls
dirtree/directory/directory/" we should get "@name file[]". This solves the
problem of having more than one node. Well, is missing the order of the nodes
and the commentary shit.
"Special file" as the unix concept. Plan9 takes the "everthing is a file"
paradigma. I don't know if this is our plan. In addition that, i don't
understand Hurd concepts to talk about then properly. But if we will create an
_unix_ diretory tree (with "/" as the relation symbol of the graph), we must
think a directory as in unix.
> hexdump xml/
0000000 ee2f 0002 000c 0104 002e 0000 0026 0000
0000010 0024 0204 2e2e 0000 ee34 0002 0018 0c08
0000020 662e 6f6f 782e 6c6d 732e 7077 8900 cf64
0000030 ee32 0002 0010 0708 6f66 2e6f 6d78 006c
0000040 f029 0002 0020 0608 6f66 2e6f 6c70 cf00
0000050 ee35 0002 0010 0708 6964 2e72 6c70 007e
0000060 ee49 0002 0018 0608 6964 2e72 6c70 cf00
0000070 6964 2e72 6c70 cf00 ee47 0002 0014 0908
0000080 6966 616e 2e6c 6d78 006c c091 ee34 0002
0000090 0028 1c08 7473 7261 6974 676e 6e2e 746f
00000a0 6f73 7974 6570 6373 6972 7470 742e 7478
00000b0 f900 cf21 ee35 0002 014c 1408 6966 696e
00000c0 6873 6e69 2e67 7974 6570 6373 6972 7470
00000d0 1800 c06f 0000 0000 0000 0000 0000 0000
00000e0 0000 0000 0000 0000 0000 0000 0000 0000
*
0000200
>
yeah! i am on an unix.
It is not trivial to select an commentary with xpath (not to me).
> xpath tom_sic.xml "/libraries/pouet:library/*[node()]"
Found 3 nodes:
-- NODE --
<curious_balise>
</curious_balise>-- NODE --
<book>
<author>Mark Twain</author>
<title>La case de l'oncle Tom</title>
<isbn>4242</isbn>
</book>-- NODE --
<sub-library name="pikaplop">
<location>Grenoble</location>
<name>Arlequin</name>
</sub-library>
> xpath tom_sic.xml "/libraries/pouet:library/*[comment()]"
No nodes found
> xpath tom_sic.xml "/libraries/pouet:library/*[commen()]"
Can't locate object method "commen" via package "XML::XPath::Function" at
/usr/local/lib/perl5/site_perl/5.8.8/XML/XPath/Function.pm line 69.
>
don't know what is happening. May be "comments" should go to
public-qt-comments@w3.org. Diging further at [w3c recommendations][1] i found
that comment() is for backward compatibility.
> xpath tom_sic.xml "/libraries/pouet:library/*[not(comment())]"
Found 4 nodes:
-- NODE --
<curious_balise>
</curious_balise>-- NODE --
<book>
<author>Mark Twain</author>
<title>La case de l'oncle Tom</title>
<isbn>4242</isbn>
</book>-- NODE --
<book />-- NODE --
<sub-library name="pikaplop">
<location>Grenoble</location>
<name>Arlequin</name>
</sub-library>
>
Nobody from w3c wants to select comment? Anybody here still wants to do so?
(Anybody here still reading?) I don't. I mean to select comment. I doesn't make
sense. Now i need to go back to the meaning of the file.
To conclude. May be an comment is not an proper node. If Hurd New Generation
needs comments, i will do so. I just seams that xpath ain't encoding the
selection. I tested with the following implementations:
> perl -e 'use XML::XPath qw(VERSION); print XML::XPath->VERSION . "\n"'
1.13
> sabcmd --version
sabcmd 1.0.3 (June 26, 2006)
copyright (C) 2000 - 2005 Ginger Alliance (www.gingerall.com)
The Sablotron XSLT Processor comes with NO WARRANTY.
It is subject to the Mozilla Public License Version 1.1.
Alternatively, you may use Sablotron under the GNU General Public License.
>
When i did that directory tree, i had to decide that the "name" attribute of
"directory" element "disambiguousate" (sorry the neologism usualy makes sence
in portuguese, please correct me) (PS: makes univocal or unequivocal; makes not
to call two or more things with the same name). We wont be using ad-hoc xml
files. It must be valid following certain constraints. I used to think the XML
document type declaration (thought the 'd' from DTD was "document") as an
separated thing. Now i see it is an optional part of the same thing. If
"curious#balise" can't be an name for an xml element, it can not be an name for
a file on an xmlfs ("xml file system" as a concept, not as an implementation).
Hence:
> xmllint dir.xml --postvalid
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE dirtree [
<!ELEMENT directory (file | directory)*>
<!ATTLIST directory name CDATA #REQUIRED>
<!ELEMENT file EMPTY>
<!ATTLIST file name CDATA #REQUIRED>
]>
<dirtree>
<directory name="xml">
<file name=".dir.pl.swp"/>
<file name="dir.pl"/>
<file/>
<file name="foo.pl"/>
<file name="foo.xml"/>
</directory>
</dirtree>
dir.xml:8: element dirtree: validity error : No declaration for element
dirtree
dir.xml:12: element file: validity error : Element file does not carry
attribute name
Document dir.xml does not validate
>
; wont setup an file system translator server. The `<!ELEMENT dirtree
(directory)>` is missing and there is a file without name.
Now, with a(n?) [well formed xml][2] "../dir.xml",
perl -e 'use XML::Simple; $x = XMLin("../dir.xml"); sub md { $n = shift;
print "mkdir -p $n->{name}; cd $n->{name}\n"; $g = $n->{file}; foreach $f (keys
%$g) { print "touch $f\n" } $g = $x->{directory}; if (defined $n->{directory})
{ md($n->{directory}) } print "cd ..\n" } md($x->{directory})' | sh
will recreate (unserialize) the directory tree (certainly I will use XSLT the
next time). I must say (again) that I don't want to put any kind of file inside
an xml. Althought it looks like possible. (PS: actually the files aren't been
serialized/unserialized)
go for it, mf! This rugby is going down...
-stty-
References:
[0]: http://www.w3.org/TR/xpath-datamodel/
"XQuery 1.0 and XPath 2.0 Data Model (XDM)",
W3C Recommendation, 23 Jan. 2007.
[1]: http://www.w3.org/TR/xpath-functions/
"XQuery 1.0 and XPath 2.0 Functions and Operators",
W3C Recommendation, 23 Jan. 2007.
[2]: http://www.w3.org/TR/REC-xml/#sec-well-formed
"Extensible Markup Language (XML) 1.0. (Third Edition)",
W3C Recommendation.
[3]: http://en.wikipedia.org/wiki/Principle_of_least_astonishment
[4]: http://deux-fleurs.net/analyse-xmlfs
"La case de l'oncle Tom"
[MarkDown]: http://daringfireball.net/projects/markdown/syntax
"Daring Fireball: Markdown Syntax Documentation"
PS:
I like this task because it ...
.... well i wont say. Just put it to eleven:
Script started on Thu May 01 15:11:53 2008
(@TRIMMED@:~) @TRIMMED@% /usr/sbin/svccfg -s apache2
svc:/network/http:apache2> listprop
httpd application
httpd/stability astring Evolving
httpd/ssl boolean false
network dependency
network/entities fmri svc:/milestone/network:default
network/grouping astring require_all
network/restart_on astring error
network/type astring service
filesystem-local dependency
filesystem-local/entities fmri
svc:/system/filesystem/local:default
filesystem-local/grouping astring require_all
filesystem-local/restart_on astring none
filesystem-local/type astring service
autofs dependency
autofs/entities fmri
svc:/system/filesystem/autofs:default
autofs/grouping astring optional_all
autofs/restart_on astring error
autofs/type astring service
startd framework
startd/ignore_error astring core,signal
general framework
general/enabled boolean true
start method
start/exec astring "/lib/svc/method/http-apache2
start"
start/timeout_seconds count 60
start/type astring method
stop method
stop/exec astring "/lib/svc/method/http-apache2
stop"
stop/timeout_seconds count 60
stop/type astring method
refresh method
refresh/exec astring "/lib/svc/method/http-apache2
refresh"
refresh/timeout_seconds count 60
refresh/type astring method
restarter framework NONPERSISTENT
restarter/transient_contract count
restarter/logfile astring
/var/svc/log/network-http:apache2.log
restarter/contract count 3909
restarter/start_pid count 24825
restarter/start_method_timestamp time 1209556078.609862000
restarter/start_method_waitstatus integer 0
restarter/auxiliary_state astring none
restarter/next_state astring none
restarter/state astring online
restarter/state_timestamp time 1209556078.612699000
restarter_actions framework NONPERSISTENT
restarter_actions/refresh integer
restarter_actions/restart integer
svc:/network/http:apache2> set prop general/enabled = false
Usage: set [-vV]
Without arguments, display current options. Otherwise set the given
options.
svc:/network/http:apache2> svc:/network/http:apache2> set prop
general/enabled = falsprop general/enabled = false
Permission denied.
svc:/network/http:apache2> help
General commands: help set repository end
Manifest commands: inventory validate import export archive
Profile commands: apply extract
Entity commands: list select unselect add delete
Snapshot commands: listsnap selectsnap revert
Property group commands: listpg addpg delpg
Property commands: listprop setprop delprop editprop
Property value commands: addpropvalue delpropvalue setenv unsetenv
svc:/network/http:apache2> help import
Usage: import file
Import a manifest into the repository.
svc:/network/http:apache2> end
(@TRIMMED@:~) @TRIMMED@% man -k manifest
bart_manifest bart_manifest (4) - system audit manifest file
inetconv inetconv (1m) - convert inetd\&.conf entries into smf service
manifests, import them into smf repository
moe moe (1) - manifest the optimal expansion of a pathname
service_bundle service_bundle (4) - service manifest file format
(@TRIMMED@:~) @TRIMMED@% man service_bundle
Reformatting page. Please Wait... done
File Formats service_bundle(4)
NAME
service_bundle - service manifest file format
SYNOPSIS
/usr/share/lib/xml/dtd/service_bundle.dtd.1
DESCRIPTION
The service management facility, described in smf(5), util-
izes an XML-based file format to marshal the description of
a set of services or service instances between systems. This
file is known as a service bundle. The primary form of a
service bundle is the inventory of services that are pro-
vided by a package, which is called a "service manifest".
The DTD describing the service_bundle is provided at
/usr/share/lib/xml/dtd/service_bundle.dtd.1. service_bundle
documents can also use the XML Inclusions (XInclude) facil-
ity to merge multiple documents into one. A service_bundle
document manipulator must therefore support the functional-
ity defined by the XInclude specification.
A complete service description consists of the following:
o A set of properties that identify the service and iden-
tify its restarter
o A set of properties that identify each instance
o A set of framework property groups that describe the
framework's understanding of each instance
o A set of method property groups as required by
svc.startd(1M), or by a delegated restarter
o Additional optional method property groups
o A set of dependency property groups
o An optional group of properties that indicate services
to which dependencies on the described service were
--More--(34%) added
o A set of application property groups or application-
specific typed property groups containing application
configuration data
o A template that describes supporting information about
this service, such as a description and links to docu-
mentation.
SunOS 5.10 Last change: 30 Aug 2004 1
File Formats service_bundle(4)
The document type definition for the service bundle provides
markup to define each of these aspects of a service descrip-
tion, as well as a number of entities that identify regular
features in describing a service, such as the
<create_default_instance> tag.
The attributes and tags are fully described in the commented
DTD. The services supplied with the operating system, stored
under /var/svc/manifest, provide examples of correctly
formed service descriptions.
Localization in the Template Element
The description tags in the template element for a service
are internationalizable. Service developers wishing to pro-
vided localized descriptions of their services can elect to
deliver a set of loctext element in the description, like
<common_name>
<loctext xml:lang="C">extended accounting<loctext>
<loctext xml:lang="fr_CA">...</loctext>
<loctext xml:lang="ja">...</loctext>
....
</common_name>
Alternatively, service developers can choose to deliver mul-
tiple manifests in the naming scheme
/var/svc/manifest/[category]/[service].[locale].xml
--More--(69%)
(@TRIMMED@:~) @TRIMMED@% ls /var/svc/manifest
application device milestone network platform site
system
(@TRIMMED@:~) @TRIMMED@% ls /var/svc/manifestls /var/svc/manifest | grep
apache2
/var/svc/manifest/network/http-apache2.xml
(@TRIMMED@:~) @TRIMMED@% cat /var/svc/manifest/network/http-apache2.xml
<?xml version="1.0"?>
<!DOCTYPE service_bundle SYSTEM
"/usr/share/lib/xml/dtd/service_bundle.dtd.1">
<!--
Copyright 2006 Sun Microsystems, Inc. All rights reserved.
Use is subject to license terms.
ident "@(#)http-apache2.xml 1.3 06/03/27 SMI"
-->
<service_bundle type='manifest' name='SUNWapch2r:apache'>
<service
name='network/http'
type='service'
version='1'>
<!--
Because we may have multiple instances of network/http
provided by different implementations, we keep dependencies
and methods within the instance.
-->
<instance name='apache2' enabled='false'>
<!--
Wait for network interfaces to be initialized.
-->
<dependency name='network'
grouping='require_all'
restart_on='error'
type='service'>
<service_fmri value='svc:/milestone/network:default'/>
</dependency>
<!--
Wait for all local filesystems to be mounted.
-->
<dependency name='filesystem-local'
grouping='require_all'
restart_on='none'
type='service'>
<service_fmri
value='svc:/system/filesystem/local:default'/>
</dependency>
<!--
Wait for automounting to be available, as we may be
serving data from home directories or other remote
filesystems.
-->
<dependency name='autofs'
grouping='optional_all'
restart_on='error'
type='service'>
<service_fmri
value='svc:/system/filesystem/autofs:default'/>
</dependency>
<exec_method
type='method'
name='start'
exec='/lib/svc/method/http-apache2 start'
timeout_seconds='60' />
<exec_method
type='method'
name='stop'
exec='/lib/svc/method/http-apache2 stop'
timeout_seconds='60' />
<exec_method
type='method'
name='refresh'
exec='/lib/svc/method/http-apache2 refresh'
timeout_seconds='60' />
<property_group name='httpd' type='application'>
<stability value='Evolving' />
<propval name='ssl' type='boolean' value='true' />
</property_group>
<property_group name='startd' type='framework'>
<!-- sub-process core dumps shouldn't restart
session -->
<propval name='ignore_error' type='astring'
value='core,signal' />
</property_group>
</instance>
<stability value='Evolving' />
<template>
<common_name>
<loctext xml:lang='C'>
Apache 2 HTTP server
</loctext>
</common_name>
<documentation>
<manpage title='httpd' section='8'
manpath='/usr/apache2/man' />
<doc_link name='apache.org'
uri='http://httpd.apache.org' />
</documentation>
</template>
</service>
</service_bundle>
(@TRIMMED@:~) @TRIMMED@% /usr/sbin/svcadm refresh apache2
svcadm: svc:/network/http:apache2: Permission denied.
(@TRIMMED@:~) @TRIMMED@% /usr/sbin/svcadm refresh apach
svcadm: svc:/network/http:apache2: Permission denied.
(@TRIMMED@:~) @TRIMMED@% /usr/sbin/s
/usr/sbin/svcs: Command not found.
(@TRIMMED@:~) @TRIMMED@% /usr/
Usage: svcs [-aHpv] [-o col[,col ... ]] [-R restarter] [-sS col] [<service>
...]
svcs -d | -D [-Hpv] [-o col[,col ... ]] [-sS col] [<service> ...]
svcs -l <service> ...
svcs -x [-v] [<service> ...]
svcs -?
(@TRIMMED@:~) @TRIMMED@% /usr/bin/svcs -x
svc:/network/http:apache2 (Apache 2 HTTP server)
State: online since Wed Apr 30 08:47:58 2008
See: httpd(8)
See: /var/svc/log/network-http:apache2.log
Impact: None.
(@TRIMMED@:~) @TRIMMED@% /usr/bin/svcs -
STATE STIME FMRI
online Apr_30 svc:/network/http:apache2
16:30:35 1000 httpd
16:30:36 1002 httpd
16:30:37 1003 httpd
16:30:37 1005 httpd
16:30:37 1006 httpd
16:30:37 1007 httpd
17:12:37 1334 httpd
17:15:19 1371 httpd
Apr_30 24831 httpd
Apr_30 24836 httpd
Apr_30 25394 httpd
(@TRIMMED@:~) @TRIMMED@% uname -a
SunOS @TRIMMED@ 5.10 Generic_120012-14 i86pc i386 i86pc
(@TRIMMED@:~) @TRIMMED@% exit
script done on Thu May 01 15:20:22 2008
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- another "xmlfs" proposal,
gnubie10-bugsoccer <=