floof/lib/tags.py

   1 from floof.model import Art, ArtUser, ArtUserType, Tag, TagText, User
   2 import elixir
   3 from dbhelpers import find_or_create
   4 import re
   5
   6 from pylons import c
   7
   8 def parse(search_string):
   9     """Parses a search query, and returns a query object on Art.
  10
  11     Queries can contain:
  12     - Regular tags: foo
  13     - User relations: by:kalu, of:eevee, for:ootachi
  14
  15     Later:
  16     - Negative versions of anything above: -by:eevee, -dongs
  17     """
  18
  19     # XXX doesn't do negative querying yet.
  20     # XXX could use some sane limits.
  21
  22     # We'll be building this as we go.
  23     q = Art.query
  24
  25     terms = search_string.split()
  26     for tag in terms:
  27         if ':' in tag:
  28             # This is a special tag; at the moment, by/for/of to indicate
  29             # related users
  30             prefix, tag = tag.split(':', 1)
  31             if tag == 'me':
  32                 tag = c.user.name
  33
  34             # XXX what to do if this fails?  abort?  return empty query?
  35             target_user = User.get_by(name=tag)
  36
  37             if prefix == 'by':
  38                 rel = ArtUserType.BY
  39             elif prefix == 'for':
  40                 rel = ArtUserType.FOR
  41             elif prefix == 'of':
  42                 rel = ArtUserType.OF
  43             else:
  44                 # Bogus tag.  Not sure what to do here, so for the moment,
  45                 # ignore it
  46                 continue
  47
  48             # Inner join to the ArtUser table
  49             q = q.join(ArtUser, aliased=True) \
  50                  .filter(ArtUser.user == target_user) \
  51                  .filter(ArtUser.type == rel)
  52
  53         else:
  54             # Regular ol' tag
  55             q = q.join(Tag, TagText, aliased=True) \
  56                  .filter(TagText.text == tag)
  57
  58     return q
  59
  60 def add_tags(art, tag_string, user):
  61     """Takes a string that looks like a tag query, and effectively modifies the
  62     art's tags to match it.
  63     """
  64
  65     # XXX what to do with invalid tags?  just return them and let caller fix?
  66     bad_tags = []
  67     for tag_text in tag_string.split():
  68         original_tag_text = tag_text
  69         tag_text = tag_text.lower()
  70
  71         # Adding or removing a tag?
  72         if tag_text[0] == '-':
  73             add = False
  74             tag_text = tag_text[1:]
  75         else:
  76             # Allow "+foo" to mean "add foo"
  77             if tag_text[0] == '+':
  78                 tag_text = tag_text[1:]
  79             add = True
  80
  81         # Check for special namespaces
  82         prefix = None
  83         if ':' in tag_text:
  84             prefix, tag_text = tag_text.split(':', 1)
  85             if prefix not in ['by', 'for', 'of']:
  86                 # This is bogus.  Skip it.
  87                 bad_tags.append(original_tag_text)
  88                 continue
  89
  90             if prefix == 'by':
  91                 # XXX this needs supporting.  silently ignore for now
  92                 continue
  93
  94         # Must be 3-50 alphanumeric characters
  95         if not re.match('^[a-z0-9]{3,50}$', tag_text):
  96             bad_tags.append(original_tag_text)
  97             continue
  98
  99         # Do work!
 100         if prefix:
 101             target_user = User.get_by(name=tag_text)
 102
 103             # Special tag; at the moment, just a relationship
 104             if prefix == 'by':
 105                 rel = ArtUserType.BY
 106             elif prefix == 'for':
 107                 rel = ArtUserType.FOR
 108             elif prefix == 'of':
 109                 rel = ArtUserType.OF
 110
 111             user_assoc_data = dict(art=art, user=target_user, type=rel)
 112             if add:
 113                 find_or_create(ArtUser, **user_assoc_data)
 114
 115             else:
 116                 # XXX this will die for nonassociations
 117                 user_assoc = ArtUser.get_by(art=art, **user_assoc_data)
 118                 user_assoc.delete()
 119
 120         else:
 121             # Regular tag
 122             if add:
 123                 tag = find_or_create(TagText, text=tag_text)
 124                 find_or_create(Tag, art=art, tagger=user, tagtext=tag)
 125
 126             else:
 127                 tag = TagText.get_by(text=tag_text)
 128                 if tag:
 129                     # XXX this will die
 130                     tag_assoc = Tag.get_by(art=art, tagger=user, tagtext=tag)
 131                     tag_assoc.delete()
 132
 133     elixir.session.commit()