Flickr Tags

I just migrated from a flickr account to a new G2 installation after i realized how sucky the flickr free account is.

One thing the G2 needs is the flickr tags, and it sounds like a lot of other people agree.

Has anyone started on a new module to accomplish this? If not can anyone with general G2 knowledge offer some design hints? I'm thinking i might take this on.

eg. opinions on things like:
--is it better to add a new table, that stores entity id and tag name. Thus one entity to many tag rows relationship. Or is it better to just add a col to the entity table (guessing there is one) and lists all the tags for the given entity?
--how should the user add tags? add an item to the drop down like when want to edit/delete a pic.

etc
--Matthias

cool. thanks
i read that thread you referenced. The Q posed there is more of making Flickr be an external File System. I think that's kind of a silly idea. Seems like implementing a WebDav module would be more useful in that case.

As for the other links i've read them before, but there seems to be some good info there anyways. So i think i'll probably start this. I'm guessing "customfield module" would be a good starting point... i'll look this up.

Here are my current ideas. Lots are stolen from Flickr, b/c they do it very well (quick/simple)
--user can set tags during upload.
--user can change using the drop down in album (like delete image)
--user can pick any tags (ie there is not a list of approved tags).
--user enter's tags into text box, separated by spaces, this is inserted into a tags table (as Valiant described)... do it quick/simple!.
--make a tag view (don't need search func for now). This would look like http://www.flickr.com/photos/thias_l/tags/

that should be a good start.
If anyone has any ideas/requests, please holler. This is an RFC.

--matthias

This was what you recommended in your first reply. I'd argue that this is overkill. The tags table is not needed only the TagMapping table. I agree with you that the relationship should be one entity to many TagMappings, otherwise getting a list of entities that have a specific tag requires a LIKE in the WHERE clause (slow, and not ideal). Also doing a select count(*) from tagsMapping is really a pain in the butt.

I think we are on the same page on this one.

one clarification: when i say that the user enters the tags using one text field i mean that the code will tokenize this and insert one row into the TagMappings table for each token. Thus easy to use, easy to add new tags, easy to search, a little bit hard to write the SQL... Hence easy for the user.

Anything more?
--Matthias

yeah i see your point... i'll mark that as an enhancement. Right now i just want to get something simple working...

@inc:
yes, inc as in includes i guess.

right, but it's also used for more. module.inc tells G2 a lot of things about your module.

yes and no.
"painting the header" is not an event. so your definition of an event in G2 may be wrong.
there's an event when an entity is saved / deleted, there's an event when a user logs in / out, there's an event when permissions get changed and that's about it. you can register your module as a event handler, see albumselect as an example. but i don't think you need to register any event handler in your module.

@performFactoryRegistrations:
only needed if you e.g. register a search plugin or event handlers. or if you register a new entity type.

@getItemLinks:
these links are shown in the sidebar in the item actions list, so "Add Tag to this image" would appear in the same list as "Edit photo" etc.
$params['view'] = 'tags.AddTag'; tells G2 that it should load the GalleryView modules/tags/AddTag.inc when someone clicks on this link.

see my explanations about views / controllers in the link i mentioned in the second post of this topic.

maybe you want to add your tags list on the edit photo -> general page or in a separate tab. then you should look at itemEditOptions and ItemEditPlugins. grep the existing modules for such occurrences.

creating a new codex page = just enter a new address in the browser.
http://codex.gallery2.org/index.php/Gallery2:Module_Development_Tutorial would show a new page which can be edited.

btw: on http://gallery.menalto.com/dev
there's also a link to:
http://txtdump.com/g2dev/

well, the tutorial is very incomplete and only touches very few aspects of module making. feel free to extend it ;)

yes. you need to change the xml instructions in the Tag.class too though.
these are all comment lines that start with @g2, e.g.
* @g2 <class-name>GalleryItem</class-name>
* @g2 <parent-class-name>GalleryFileSystemEntity</parent-class-name>
* @g2 <schema>
* @g2 <schema-major>1</schema-major>
* @g2 <schema-minor>0</schema-minor>
* @g2 </schema>
* @g2 <requires-id/>

use maps when you map something together.
use non-maps if you're dealing with objects / things. e.g. a Tag is an object, it has attributes.
a tag has a name, a description, ...

but when you're tagging, you're mapping a tag with an item.
so you'll certainly need a map to map tagId with itemId.
and i'd also recommend using additionally a tags table just to have a single list of all registered tags and you could then easily add attributes like "description" to each tag, in a normalized (SQL-sense of normalization) manner.

the SQL CREATE TABLE stuff is generated with gmake.
the table is generated in your database when installing the module.

- yes, the @g2 comment lines are parsed by lib/tools/bin/extractClassXml.pl (therefore our current perl requirement when generating interface and sql files). this is valid XML, the corresponding dtd is in lib/tools/dtd/ . the resulting xml is validated and then used to generate the interfaces (which add setter and getter methods for object/entity classes and add, update, remove map entry methods for map classes), and it generates the create table SQL for all database management systems (currently DB2, mysql, oracle, postgresql).
- yes the example is from GalleryItem.class
-- yes, the <class-name> must be the same as the class name which must be the same as the file name
-- the <parent-class-name> is only required if your class extends another class
-- schema major / minor are the version of the class / table. here i made it 1,0. all first versions of a class / table should be 1,0.
the purpose is: when you later have to change the table, you'll change the class and increment the schema to 1,1. and our upgrade code will check if the existing db tables must be upgraded or no.
but the upgrade table code must still be written manually in such a case (modules/*/classes/GalleryStorage/DatabaseStorage/schema/xml-src/ A_ for alter, R_ for remove table. T_ is a special case for our T as in Test that we use in the installer.

that would be great!

to clarify:
G2 has two types of db tables:
- Maps
- Entities
(the rest; Lock, Schema and Sequences are for internal use)

if you use
GalleryCoreApi::newFactoryInstance('GalleryEntity', 'GalleryTag');
then you have to declare a GalleryTag to a GalleryEntity.
(GalleryEntities are generic objects, you'll get created, modified since timestampts and some other attributes).
i'd say, yeah, why not, make your Tags to be Entities.

see modules/comment/classes/GalleryComment.class
it's defined to be a ChildEntity. Do you need a parent / child relationship for tags? can tags be categorized hierarchically? i'd say no. what you want are flickr style tags and AFAIK, they are all on the same level, flat.

so you want
class GalleryTag extends GalleryEntity {
and you want:
* @g2 <class-name>GalleryTag</class-name>
* @g2 <parent-class-name>GalleryEntity</parent-class-name>
* @g2 <schema>
* @g2 <schema-major>1</schema-major>
* @g2 <schema-minor>0</schema-minor>
* @g2 </schema>
* @g2 <requires-id/>

and finally you need to register your entity:
in module.inc:

    function performFactoryRegistrations() {
        $ret = GalleryCoreApi::registerFactoryImplementation(
            'GalleryEntity', 'GalleryTag', 'GalleryTag',
            'modules/tag/classes/GalleryTag.class', 'tag', null);
        if ($ret->isError()) {
            return $ret->wrap(__FILE__, __LINE__);
        }

        return GalleryStatus::success();
    }

am i right to assume that if you extend a GalleryChildEntity G2 handles the entry into the ChildEntity table, and thus when you delete the Entity a trigger is fired that helps clean up the extended class? e.g. a Comment is added to a picture, if you delete the picture do all the comments get dumped too?

seems like this is what we want here. a Tag is like a specialized comment, that is marked across several entities.

Well i have it about 70% done. However one thing that is a real pain in the butt is that you have to edit the tags for each entity by itself. This is not ideal. I've read that G2 has a problem in that batch changes can't be done (at least not now). Have you seen/know of any way to do a batch edit?

ideas?
--Matthias

are you using a separate table rather than the existing keywords so each tag is in its own row in the table? (ie don't need to use LIKE in queries) will lots of people say "hey, I already keyworded all my items, I can't use them??"

i don't have too much time/interest in this feature, but it does get a lot of votes so here I will post a bit of code I hacked together... we'll see if it provides any ideas or leads anywhere.

the attached file include a module and small patch to modules/core/classes/GalleryTheme.class

what does work:

• enter a url in your browser like: gallery2/main.php?g2_view=keyalbum.KeywordAlbum&g2_keyword=word
  (replace "word" with keyword to search for)
• activate rewrite rule in URL Rewrite site admin and then use url like gallery2/key/word
  (again replace "word" with keyword to search for)
• in either case you can add g2_page=2 or whatever page number

caveats and what doesn't work:

• doesn't apply permissions or any sort order (comment in code for where this would go)
• uses a fake album item to pass into the theme, as our framework isn't ready to handle containers that aren't albums
• theme isn't selectable, just uses that of the root album
• though the displayed view shows the right number of pages and next/prev links, the urls on these links are incorrect

perhaps this will give bharat or others some ideas about how the framework can be adjusted to better handle non-album containers.

Interest hasn't declined here, I'd love to hear any updates...

Here's what I have done, I am a complete beginner at Gallery2, but I think this tag module is better than what's currently available (umm, nothing, that I know of). I certainly don't consider it production quality by any means, but here's the info on it if anyone else wants to use it for now or pick up where I've left off

- haven't tried it with rewrite module
- has a search component just for tags
- lists tags below the item with links to find all others with that tag and to remove tag if they have permission
- basic functions of add and delete (can't edit and make a sitewide tag change)
- only tested on mysql
- and because I don't know enough about the inner system of gallery2, the tag table is inefficient, but i based it on my original thinking that childentities were automatically efficient (i found out later my assumption was wrong)...basically...multiple tags are stored multiple times instead of the optimized way
- there's no list page that lists all entered tags
- it's based greatly off of the comment module so you will see all the php comments refer to that guy who did the main work
- it utilizes that autocomplete javascript to fill in for new tags
- can only enter one tag at a time (phrase or single word)
- it surely has bugs in it, but i haven't found any major ones in my use yet

Anyway, I like how it works for my own use and I hope someone else comes out with a better one I can use...but here's for all the other people like me. I'm just too preoccupied to continue experimenting with it and certainly want to know when an official tag module comes out
-Danny

Excellent. Thanks for sharing!

I've installed it on my test site and it seems to work fine. A couple of comments.

* After installing, be sure to add the tags to your themes. Otherwise, you won't see them. (I'm new to Gallery2 and missed this initially.)
* I must be missing a permissions thing, because as I'm using it right now only the tag author can see the tags. I'd like to make tags visible to all users of the site.
* Can more than one tag be added at a time?

Regards and thanks!

Jeremy

- when developing php applications, set error_reporting to E_ALL in php.ini

- i had to copy GNUmakefile's from the current comment module to make it work with the current nightly snapshots (the database schema has changed)

- getting: "Notice: Undefined variable: totalTags in /var/www/localhost/htdocs/clean/gallery2/modules/tag/Callbacks.inc on line 86"
if no tags have been added yet (added the show tags block to album and photo pages)

- postgres compatibility issue:
postgres7 error: [-1: ERROR: zero-length delimited identifier at or near """" at character 72] in EXECUTE(" SELECT g2_ChildEntity.g_id, g2_Tag.g_tagName, "", "", g2_ChildEntity.g_parentId FROM g2_ChildEntity, g2_Tag, g2_AccessSubscriberMap WHERE g2_ChildEntity.g_id = g2_Tag.g_id AND g2_ChildEntity.g_parentId = g2_AccessSubscriberMap.g_itemId AND g2_AccessSubscriberMap.g_accessListId IN (17,18,20,167) AND (g2_Tag.g_tagName LIKE '%door%') ORDER BY g2_Tag.g_tagName DESC, g2_ChildEntity.g_id DESC LIMIT 20")
when clicking on an existing tag (search)

the problem is this code

	$query = sprintf('
	SELECT
	  [GalleryChildEntity::id],
          [GalleryTag::tagName],
          "",
          "",
          [GalleryChildEntity::parentId]

in GalleryTagSearch.class, which doesn't make a lot of sense

- when deleting a tag, i get "Notice: Undefined index: tag in /var/www/localhost/htdocs/clean/gallery2/g2data/smarty/templates_c/%%672277621/%%38^385^385FFEDD%%Tag.tpl.php on line 4" in the delete tag view
(but deleting works)

- rewrite rules: i tested the module with url rewrite active, but the rewrite rules were not used.

@Jeremy Butler:
- @permissions, go to your top album, click "edit permissions", add the tag permissions to the everybody group
- @adding more than one tag at a time: no
- @bugs: can't reproduce what you think is a bug. just add the show tags block to album and photo pages in site admin -> themes and it does exactly what it should

what did you miss?
probably the view tags block. you must add it to photo and album pages separately.

Hey, it started working!

That is, the tags started showing up in the photo pages within an album.

I don't know if this is what did the trick, but I shifted from one theme to another and then back to the original (Matrix). After going through that process, the tags began showing up!

Jeremy Butler
www.ScreenSite.org
www.TVCrit.com
www.AllThingsAcoustic.org

this is kinda great

Sorry to bump a relatively old thread, but I was curious as to where this has gone, if anywhere?

Fingers crossed, though. It's the most requested item in the feature vote (1204624 - not counting bulk watermarking as that is done and closed now). Probably the most requested on the forums, too.
Whoever adds this essential feature is going to be a popular person!

this sourceforge message has some info on the project: http://sourceforge.net/mailarchive/message.php?msg_id=12601674

I have downloaded this module and test it with a 2.0 version. I ahve to say it really does do exactly what Tag are suppose to. Perhaps just a few more improvement and it will be exactly like how Flickr's tag work.

Can anyone try make this compatiable with 2.1?

Thanks!

I can only say I will eagerly await. My skill in coding is still too low to try modifies complex module like this. Thank you for your work so far! I love it!