[Owncloud] App Data Migration

[Achim Bohnet]

Am Samstag, 3. März 2012, 23:06:56 schrieb Bartek Przybylski:
[...]
> 
> Tom also ask me to provide xml example for bookmarks app, so here it is :
> 
> <migration app_version="0.2">

May I suggest a data model version instead of app version.
Maybe the older app v0.4 can import data from new v0.7 as long
as the data model has not changed.

Achim

>   <db>
>     <table name = "*PREFIX*bookmarks">
>       <field name="id"/>
>       <field name="url"/>
>       <field name="title"/>
>       <field name="user_id" user_id/>
>       <field name="public"/>
>       <field name="added"/>
>       <field name="lastmodified"/>
>       <field name="clickcount"/>
>     </table>
>     <table name="*PREFIX*bookmarks_tags">
>       <field name="bookmark_id" relates_to="**PREFIX*bookmarks.id" />
>       <field name="tag" />
>     </table>
>   </db>
> <!--
>    <files>
>      <dir path="path_to_export"/>
>      <file path="file_to_export"/>
>    </files>
> -->
> </migration>
> 
> table tag doesn't have to contain all fiels, but only those to migrate
> (they must be null possible)
> in case of questions to my idea don't hesitate to comment and ask
> 
> bartek
> 
> 2012/3/3 Tom Needham <tom at owncloud.com>:
> > Could you describe this process in more details ? then we could look
> > for enhancements ;)
> > 
> > 
> > OK. Apps will provide an import and export function. See and examples for
> > the bookmarks app
> > here: http://gitorious.org/owncloud/owncloud/blobs/691103acd5aad2673b63757
> > 26ba24fb56e88451b/apps/bookmarks/lib/migrate.php
> > 
> > When ownCloud needs to export a user, it will run
> > OC_Migration::export($userid). This will then execute all of the 'export'
> > functions for apps that have registered as migration providers. Once it
> > receives data back from these functions it wraps it all up into either
> > XML,
> > JSON or something along those lines and exports it to a file. When
> > importing, its pretty much the reverse of this, except each app will be
> > passed its portion of the export file. It can then run through that and
> > add
> > items back into the database.
> > 
> > The backend will do the dirty work to make it easier for devs. For
> > example,
> > on export it will add in information from the apps info.xml file so this
> > can be accessed when importing. The backend will also pass a $uid to the
> > import functions because this may have changed from the original install
> > (because of a conflict on the new install).
> > 
> > The question is how we should export the data? XML, JSON... ? I tried
> > using
> > JSON this afternoon and it saved a lot of time because apps could just
> > pass
> > an array structure for their 'export' function and then all the backend
> > has
> > to do is merge some arrays and run json_encode(). Also creating arrays is
> > much easier than playing with DOMDocument ;)
> > 
> > Also, I found a function that will format the json output so that it is
> > still human readable.
> > 
> > Thanks,
> > Tom
> > 
> > Tom Needham
> > tom at owncloud.com
> > 
> > 
> > 
> > On 3 Mar 2012, at 20:37, Bartek Przybylski wrote:
> > 
> > Hi Tom!
> > Could you describe this process in more details ? then we could look
> > for enhancements ;)
> > 
> > bartek
> > 
> > 2012/3/3 Tom Needham <tom at owncloud.com>:
> > 
> > Hi All,
> > 
> > 
> > So I'm currently doing some work on a backend for app data migration.
> > 
> > Basically apps can register as migration providers (much like they do with
> > 
> > search) and provide and import and export function.
> > 
> > 
> > Originally I was planning to use XML as the overall output format but we
> > 
> > just had a chat in IRC and possibly JSON would be easier? Apps could just
> > 
> > provide an array structure on export and be given the same one on import.
> > 
> > The backend will do all the hard work of mashing all the arrays together,
> > 
> > and adding in various other data (app version numbers, owncloud version
> > 
> > number..) and then just run json_encode() and export to a .json file.
> > 
> > 
> > What does everyone thing? Thought I'd get your feedback before going ahead
> > 
> > with it.
> > 
> > 
> > Cheers,
> > 
> > Tom
> > 
> > 
> > 
> > Tom Needham
> > 
> > tom at owncloud.com
> > 
> > 
> > 
> > 
> > 
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> > 
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> > 
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> > 
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> 
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