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 def parse(search_string, me):
   7     """Parses a search query, and returns a query object on Art.
   8
   9     Queries can contain:
  10     - Regular tags: foo
  11     - User relations: by:kalu, of:eevee, for:ootachi
  12     - User relations relative to some user: by:me
  13       Note that this necessitates a `me` parameter.
  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
  32             if tag == 'me':
  33                 target_user = me
  34             else:
  35                 # XXX what to do if this fails?  abort?  return empty query?
  36                 target_user = User.get_by(name=tag)
  37
  38             if prefix == 'by':
  39                 rel = ArtUserType.BY
  40             elif prefix == 'for':
  41                 rel = ArtUserType.FOR
  42             elif prefix == 'of':
  43                 rel = ArtUserType.OF
  44             else:
  45                 # Bogus tag.  Not sure what to do here, so for the moment,
  46                 # ignore it
  47                 continue
  48
  49             # Inner join to the ArtUser table
  50             q = q.join(ArtUser, aliased=True) \
  51                  .filter(ArtUser.user == target_user) \
  52                  .filter(ArtUser.type == rel)
  53
  54         else:
  55             # Regular ol' tag
  56             q = q.join(Tag, TagText, aliased=True) \
  57                  .filter(TagText.text == tag)
  58
  59     return q
  60
  61 def add_tags(art, tag_string, adding_user, me):
  62     """Takes a string that looks like a tag query, and effectively modifies the
  63     art's tags to match it.
  64     """
  65
  66     # XXX what to do with invalid tags?  just return them and let caller fix?
  67     bad_tags = []
  68     for tag_text in tag_string.split():
  69         original_tag_text = tag_text
  70         tag_text = tag_text.lower()
  71
  72         # Adding or removing a tag?
  73         if tag_text[0] == '-':
  74             add = False
  75             tag_text = tag_text[1:]
  76         else:
  77             # Allow "+foo" to mean "add foo"
  78             if tag_text[0] == '+':
  79                 tag_text = tag_text[1:]
  80             add = True
  81
  82         # Check for special namespaces
  83         prefix = None
  84         if ':' in tag_text:
  85             prefix, tag_text = tag_text.split(':', 1)
  86             if prefix not in ['by', 'for', 'of']:
  87                 # This is bogus.  Skip it.
  88                 bad_tags.append(original_tag_text)
  89                 continue
  90
  91             if prefix == 'by':
  92                 # XXX this needs supporting.  silently ignore for now
  93                 continue
  94
  95         # Must be 3-50 alphanumeric characters
  96         if not re.match('^[a-z0-9]{3,50}$', tag_text):
  97             bad_tags.append(original_tag_text)
  98             continue
  99
 100         # Do work!
 101         if prefix:
 102             if tag_text == 'me':
 103                 target_user = me
 104             else:
 105                 target_user = User.get_by(name=tag_text)
 106
 107             # Special tag; at the moment, just a relationship
 108             if prefix == 'by':
 109                 rel = ArtUserType.BY
 110             elif prefix == 'for':
 111                 rel = ArtUserType.FOR
 112             elif prefix == 'of':
 113                 rel = ArtUserType.OF
 114
 115             user_assoc_data = dict(art=art, user=target_user, type=rel)
 116             if add:
 117                 find_or_create(ArtUser, **user_assoc_data)
 118
 119             else:
 120                 # XXX this will die for nonassociations
 121                 user_assoc = ArtUser.get_by(**user_assoc_data)
 122                 user_assoc.delete()
 123
 124         else:
 125             # Regular tag
 126             if add:
 127                 tag = find_or_create(TagText, text=tag_text)
 128                 find_or_create(Tag, art=art, tagger=adding_user, tagtext=tag)
 129
 130             else:
 131                 tag = TagText.get_by(text=tag_text)
 132                 if tag:
 133                     # XXX this will die
 134                     tag_assoc = Tag.get_by(art=art, tagger=adding_user, tagtext=tag)
 135                     tag_assoc.delete()
 136
 137     elixir.session.commit()