Algorithm for Labels like in Gmail

[Gerard Flanagan]

rhcarvalho at gmail.com wrote:
> Hello there!
>
> I'm trying to make a simple Contact Manager using python (console
> only), however i'm having trouble implementing a division by "Groups"
> or "Labels" just like in Gmail. I don't have any real code to post
> because all i got now is a raw TXT file holding the names and phones of
> my contacts.
>
> The only idea I could figure out until now seems too weak, so that's
> why i'm asking for help. I thought of making a separate list (in a text
> file) holding all the possible groups, where each group hold the names
> of the contacts. Then if i access a group, i'll be able to see all
> contacts related to that group. On the other hand, i'll also need to
> attach to the contact instance a list of every group it is present.
> I think it's a bad idea because it seems to be very easy to get things
> messed up. Like I can get things corrupted or bad linked, and i'll
> always need to run functions to check all the realations between
> contact names and groups...
>
> I like the way i can "label" emails on Gmail, does anyone know how I
> can implement such kind of feature? What's the best/broadly used
> algorithm?
>
> Sorry for the long message, and thanks in advance
>
> Rodolfo Carvalho

There's a program called 'buzhug' (http://buzhug.sourceforge.net/)
which is described as "a pure-Python database engine, using a Pythonic,
no-SQL syntax".  I think it's in its early stages of development but it
might be suitable for your project.  I spent the morning playing about
with it using your example of a (Very Simple) Contact Manager, and
there's some runnable but unfinished code below.  It only implements a
'Many-to-one' relationship between Contacts and Groups  - in other
words, a Contact can only belong to one Group.  There's probably a lot
I haven't considered, it will break easily, and the docstrings are in
the post, but there you go.

Have fun!

Gerard

(also - http://groups.google.com/group/buzhug)
------------------------------------------------------------

print

from buzhug import Base
import os

def get_bases():
    if os.path.exists('data'):
        return Base('data/dt_groups'), Base('data/dt_contacts')
    else:
        #Bases don't exist, so create them
        os.mkdir('data')
        groups = Base('data/dt_groups')
        groups.create( ('name', str) )
        groups.insert( 'Family' )
        groups.insert( 'Friends' )
        groups.commit()

        contacts = Base('data/dt_contacts')
        contacts.create( ('group', groups), ('first_name', str),
('last_name', str), ('email', str) )
        contacts.insert( groups[0], 'Jack', 'Jones', 'jj at abcd.com' )
        contacts.insert( groups[0], 'John', 'Jones', 'jj at wxyz.com' )

        contacts.insert( groups[1], 'James', 'diGriz',
'digriz at stainless.com' )
        contacts.insert( groups[1], 'Dirk', 'Gently',
'dirk at dogstoerd.com' )
        contacts.commit()
    return groups, contacts

def usage():
    print '''
    ADD  - Add a Contact
        eg. ADD Family, Susan, Smith, suzie at hatmail.com
        eg. ADD Work, Jason, Jones, jj at mywork.com
    DEL  - Delete a Contact or Group
        eg. DEL firstname=Susan, lastname=Smith
        eg. DEL group=Family
    FIND - Search for contacts
        eg. FIND lastname=Smith
        eg. FIND group=Family
    EXIT - End the program
          '''

def intro():
    print '\n' * 5
    print '#' * 52
    print '#' * 20, ' CONTACTS ', '#' * 20
    print '#' * 52
    usage()
    print '\n' * 2


def get_input(prompt):
    s = raw_input(prompt).strip()
    if s.upper() == 'EXIT':
        raise EOFError
    return s

def ADD(groupname, firstname, lastname, email):
    groups, contacts = get_bases()
    try:
        groups.open()
        #see if a group with this name exists
        records = [ g for g in groups if g.name == groupname ]
        if len(records) == 0:
            #no group with this name, so create it
            gid = groups.insert( name=groupname.strip() )
            group = groups[gid]
        else:
            group = records[0]
    finally:
        groups.commit()
    try:
        contacts.open()
        contacts.insert(group, firstname.strip(), lastname.strip(),
email.strip())
    finally:
        contacts.commit()

def test():
    groups, contacts = get_bases()
    try:
        contacts.open()
        for contact in contacts:
            print contact.group.name, contact.first_name,
contact.last_name
    finally:
        contacts.commit()

if __name__ == '__main__':

    intro()
    while True:
        try:
            s = get_input('-> ')
            if s[0] == '?':
                usage()
            elif s == 'test':
                test()
            elif s[:4] == 'ADD ':
                grp, fname, lname, email = s[4:].split(',')
                try:
                    ADD(grp, fname, lname, email)
                except Exception, e:
                    print e
        except EOFError:
            break
    print '\nbye'

--------------------------------------------------------------------