Hi Keerthan,
On Tue, Mar 31, 2009 at 1:21 AM, Keerthan MUTHURASA <
muthurasa.keerthan(a)gmail.com> wrote:
  Hello,
 Many thanks for all these helpfull details.
 2009/3/30 Guillaume Lerouge <guillaume(a)xwiki.com>
  Hi Keerthan,
 thanks for your interest in XWiki & the GSoC. I'll try answering some of
 your questions below. 
  On Sat, Mar 28, 2009 at 9:30 PM, Keerthan
MUTHURASA <
 muthurasa.keerthan(a)gmail.com> wrote:
  Hello,
 I am Keerthan Muthurasa , Msc Software Engineering student at Oxford
 Brookes
 University , I am interested on
 doing a project for xwiki.
 I would like to discuss about my ideas for the "Import Export from any
 other
 Wiki Project" and if you could in return give me your opinions
 that would be really helpfull for me.
 This is the project requirement :
 
 
____________________________________________________________________________________________________________
   Import
Export from any other
 Wiki<
 
  
http://dev.xwiki.org/xwiki/bin/view/GoogleSummerOfCode/ImportExportfromanyo…
  > >
 >
 >  Create a extensible framework to import export data between wikis. 
 This
   should
handle converting the data in the pages including
 links between pages and metadata as well as direct access to the data
 through either a web service (prefered) or database or the
 file system
 The system should at least for MediaWiki and Confluence in import mode
 
  
____________________________________________________________________________________________________________
 
 I will begin with some questions:
 * What does it mean when talking about converting links between pages ( 
 we
 > are talking about converting internal links in the source wiki isn it 
  ?,
 
That's mean when importing or exporting data we should think about
 exporting
 or importing the linked data as well in order to keep an integrity). 
 Indeed. Most of the time, the use case will be to import a full wiki 
  rather
  than subparts, thus links would be preserved. If
you want to let users
 import/export only subarts of a wiki (such as a space or a single page),
 you
 should provide them with a warning that some links will be broken rather
 than trying to import all pages that are linked to. Or you could make
 importing liked to pages an option. It could result in surprised users if
 someone tries to export / import one page and ends up with the 76 pages
 that
 page linked / was linked to ;-) 
 I understand, I will keep in mind these details.
 Since the most common use case is to import a full wiki, it shouldn't be
 much of an issue.
 > * What does it mean when talking about exporting metadata ,direct 
 access
  to
  data through either a web service or database or
file system ? 
 Some metadata can be conserved across systems. For instance, the date 
 when
  the page was created, its edition date and its
previous versions might 
 need
  to be preserved (if that's technically
feasible). Thus it basically means
 taking care of all the information associated with the page other than 
 its
  content.
  Here my idea for the project , if I can have some
feedback it would be
 helpfull for me:
       When exporting or importing data from a given wiki to a 
 destionation
 > one
 >        Setp 1: get rid of all specific synthax proper to the source 
 wiki
  > and retrieve data,metadata, and other
usefull information.This can be
 > achieved
 >                   using a kind of parser whose job is to scan the 
 source
  > page and reconize  the specific synthax and
only retrieve proper
 > data.Concerning encountered links ,we should
 >                   convert theses pages as well but we have to be 
 carefull
  > when cross linked ( for instance we are
converting page A and A links 
 to
  B
  but when
                   converting B ,B links to A). 
 You could start by looking at the XWiki 2.0 syntax and see everything it
 allows. I think that when trying to convert pages from other wikis
 (specifically Confluence) you will run in the following issue: some pages
 use macros that are defined elsewhere on the system and won't work
 correctly
 when imported in XWiki. 
 I already had a look at Xwiki 2.0 syntax.
  For pure content, you should be able to import it
all in XWiki without 
 much
  of a problem. For content generated by a script,
you could try to 
 identify
  it and then issue warnings in your output such as
"this is specific 
 content
  that couldn't be converted".
 See my answer above about retrieving the content of linked to pages. 
 I had a look at some of the previous threads in the mailling list regarding
 import / export feature.
        Step 2: adopt a datacentric approach  to
properly store data in a
 such a way that is easy to retrieve them.We have to be carefull when
 storing
 data
                  since they have to keep the original pages structure. 
 Have you already looked at the content of a MediaWiki, Confluence and 
  XWiki
  export file? 
 Nop, I did not but I had a litle idea about the format since several
 parsers  ( XWikiParser , MediaWikiParser ...) are dealing with DOM.
 Where Can I get these differents exported files ? What is the usual case
 when getting this files ? Are we using any export utilities from the source
 wiki in order to get an xml format file ? I will investigate on that for
 MediaWiki and Confluence.
 You can download Confluence from this page:
install it locally and play with it a bit. You could specifically give
a
look to 
 .
Similar documentation is probably available from MediaWiki as well but
you'll have to look it up by yourself ;-)
   In XWiki's
case, data is stored in a XML format. It might be
 the same for Confluence & MediaWiki. If it is, you might be able to use
 XSLT
 to convert one XML format to another.
 
 I had a look at some of your previous discussion concerning the export /
 import feactures.
 If I properly understood:
 XWikiParser  => Transform XWiki format text into a DOM representation
 MediaWikiRenderer => Render a MediaWiki format text from a DOM
 representation
 MediaWikiParser => Transform MediaWiki format text into a DOM
 representation
 XWikiRenderer => Render a XWiki format text from a DOM representation
 Using the same idea it's  possible to do the same think for any other wikis
 if we aware of this wiki's syntax.
 Within the wikiModel I found some references to
     org.wikimodel.wem.xwiki.XWikiParser
     org.wikimodel.wem.mediawiki.MediaWikiParser
     org.wikimodel.wem.jspwiki.JspWikiParser
     org.wikimodel.wem.creole.CreoleWikiParser
 Where can I find the source code for these elements ? 
 
  There were some issues concerning incompatible syntax
between wikis in the
 discussion.Specially
 issues concerning syntax that can exist in some wiki and does not exist on
 other.(Example of confluence that is quite restrictive ,macro problem as
 refered by Guillaume). Are they any solutions found for this kind of issues
 or should you just warn that some information will be ommited ? 
I think that trying to convert everything is too idealistic. In the case of
the Office Importer, content that cannot be converted properly is stripped
and warnings are issued for unsupported macros for instance. I'll let Asiri
tell you more about the Office Importer conversion behavior if needed.
  As far as I can see there are works already done for
export / import
 feature
 so what's wrong with the existing work ? There are a lot of changes
 betweeen
 xWiki 1.0 and 2.0 syntax.I guess XWikiParser and XWikiRenderer has been
 modified according to these changes ? 
XWiki 1.0 syntax was using the Radeox parser while XWiki 2.0 syntax is using
WikiModel. You would definitely be working with WikiModel a lot, improving
WikiModel's Confluence & MediaWiki syntax parsers so that they can
eventually issue XDOM elements.
  To finish with my long list of questions ( sorry about
that , I am just
 trying to understand the existing work), Can I have an use case for
 importing data from Confluence to xWiki ? ( from getting input data file to
 expected result in xWiki). 
You can get an input file from the Confluence instance you will have
installed on your machine. You can also give a look to XE 1.8 default XAR
(available to download from 
  Many thanks again for your answer.
 Best regards,
 Keerthan Muthurasa
 Msc Software Engineering,
 School of Technology,
 Oxford Brookes University
 >       Step 3: use previously retrieved data to create the result page 
 in
   the
destination wiki using the wiki specific synthax for destination 
 wiki.
 See my answer above.
 > I am having a look at wikiModel that seems to contain a parser.I am 
  also
   trying to
understand Plexus.
 A Many thanks for your advices. 
 Hope this helps,
 Guillaume
  Regards,
 Keerthan Muthurasa
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http://guillaumelerouge.com/
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