floof/lib/tags.py

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