On Tue, 2006-10-24 at 21:33 +0100, Jamie McCracken wrote: > >> Next up we would define the basic metadata or properties of the object > >> (EG Contact.FirstName, Contact.Surname, Contact.EmailAddress etc along > >> with their types) and add these to the metadata types table > > > > $ grep EVC_ e-vcard.h| wc -l > > 61 > > > > Two of those are false positives, but that means that there are > > currently 59 defined keys in EDS. The version in Maemo adds another > > three keys, but vCards allow arbitrary keys. Does Tracker handle this > > programatically? If I add a vCard that has a number of custom fields, > > can they be stored and indexed? > > you would need to define each metadata field individually that you want > indexed > > if fields dont need to be indexed then they can be stored as blobs > either separately or as one big blob This limitation means that I'm not sure Tracker is suitable for storing contacts in a general manner. The Nokia 770 addressbook application adds several custom fields and parameters to fields to the contacts, which is a no-op as far as EDS is concerned as the data store doesn't care. Evolution also adds some custom fields and parameters over the vCard specification. Then again, as it doesn't store vCards, if Tracker were used as a backend for EDS it could examine the vCards, check all of the used fields are registered with Tracker, registering the ones that are not as required before populating object. How efficient this turns out to be remains to be seen. > >> Metadata is stored in a separate table according to its data type (IE > >> string, numeric, Date etc). We use a composite primary key (ServiceID, > >> MetaDataID) and the value itself is indexed. Is there a list type? Some vCard types are list-of-string and this needs to be handled to be searched correctly. > > Would I be able to search for all contacts that have an X-JABBER field > > where TYPE contains HOME (so FOOHOMEBAR won't match)? A real-world > > example from the Nokia 770: give me all contacts with an X-JABBER field > > where the X-OSSO-BOUND parameter is "ross burtonini com". > > You would need to completely flatten the metadata as > Contact.HomeJabberID, Contact.WorkJabberID etc so that all metadata is > mapped 1:1 Eek. Explosion of metadata. Oh, can a single metadata type have multiple occurrences in an object? Can a Contact object have multiple Contact.JabberID fields? The Contact object representing me would have three email addresses, four Jabber accounts, and two web pages. > It would be nice as tracker is a freedesktop thingie to avoid evolution > specific naming and also to make it clean and easy for other software to > use. Contacts also have relevance to Emails and instant messaging so > that kind of software might wanna use these contact objects too. Yes, of course. The only Evolution-specific values currently used in Evolution-generated vCards are very Evolution-specific (such as what of the four combos an email address appears in). > A contact can only have one metadata value per type (this is a primary > key constraint) Ah, you've just answered my question above. What is the solution for my case? > > Is all of this possible with Tracker, or can tracker not efficiently > > store vCard data? > > I think it should be okay I'm not so sure. > So basically what I would need from you is a spec for the contact object > detailing what methods you need and what metadata (all flattened out > although non searchable stuff can be kept as a single blob type) they > need then I can look at implementing it. Basically if you open e-vcard.h and look at the long list of EVC_* defines at the top, you have the set of official vCard fields (N, ADR, PHONE, etc) and a set of commonly used extension fields (X-JABBER, etc). 99% of these are strings, although some might be binary (e.g. PHOTO;ENCODING=b;TYPE=PNG:[base64-encoded PNG] compared to PHOTO;TYPE=URL:http://burtonini.com/head.png). As you can see storing vCard-like contacts is a tricky proposition. Storing a custom subset that isn't as flexbily as vCard is possible, but as vCards are a standard format, is it worth the cost of loosing data on import? Tomorrow I must check out the RDFS encoding of vCard, which I'm sure I've seen somewhere. Ross -- Ross Burton mail: ross burtonini com jabber: ross burtonini com www: http://www.burtonini.com./ PGP Fingerprint: 1A21 F5B0 D8D0 CFE3 81D4 E25A 2D09 E447 D0B4 33DF
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