pokedex/lookup.py

   1 # encoding: utf8
   2 from collections import namedtuple
   3 import os, os.path
   4 import pkg_resources
   5 import random
   6 import re
   7 import shutil
   8 import unicodedata
   9
  10 from sqlalchemy.sql import func
  11 import whoosh
  12 import whoosh.filedb.filestore
  13 import whoosh.filedb.fileindex
  14 import whoosh.index
  15 from whoosh.qparser import QueryParser
  16 import whoosh.scoring
  17 import whoosh.spelling
  18
  19 from pokedex.db import connect
  20 import pokedex.db.tables as tables
  21 from pokedex.roomaji import romanize
  22
  23 __all__ = ['PokedexLookup']
  24
  25
  26 rx_is_number = re.compile('^\d+$')
  27
  28 LookupResult = namedtuple('LookupResult',
  29     ['object', 'indexed_name', 'name', 'language', 'iso3166', 'exact'])
  30
  31 class LanguageWeighting(whoosh.scoring.Weighting):
  32     """A scoring class that forces otherwise-equal English results to come
  33     before foreign results.
  34     """
  35
  36     def score(self, searcher, fieldnum, text, docnum, weight, QTF=1):
  37         doc = searcher.stored_fields(docnum)
  38         if doc['language'] == None:
  39             # English (well, "default"); leave it at 1
  40             return weight
  41         elif doc['language'] == u'Roomaji':
  42             # Give Roomaji a little boost; it's most likely to be searched
  43             return weight * 0.95
  44         else:
  45             # Everything else can drop down the totem pole
  46             return weight * 0.9
  47
  48
  49 class PokedexLookup(object):
  50     INTERMEDIATE_LOOKUP_RESULTS = 25
  51     MAX_LOOKUP_RESULTS = 10
  52
  53     # Dictionary of table name => table class.
  54     # Need the table name so we can get the class from the table name after we
  55     # retrieve something from the index
  56     indexed_tables = dict(
  57         (cls.__tablename__, cls)
  58         for cls in (
  59             tables.Ability,
  60             tables.Item,
  61             tables.Location,
  62             tables.Move,
  63             tables.Nature,
  64             tables.Pokemon,
  65             tables.Type,
  66         )
  67     )
  68
  69
  70     def __init__(self, directory=None, session=None, recreate=False):
  71         """Opens the whoosh index stored in the named directory.  If the index
  72         doesn't already exist, it will be created.
  73
  74         `directory`
  75             Directory containing the index.  Defaults to a location within the
  76             `pokedex` egg directory.
  77
  78         `session`
  79             If the index needs to be created, this database session will be
  80             used.  Defaults to an attempt to connect to the default SQLite
  81             database installed by `pokedex setup`.
  82
  83         `recreate`
  84             If set to True, the whoosh index will be created even if it already
  85             exists.
  86         """
  87
  88         # By the time this returns, self.index, self.speller, and self.session
  89         # must be set
  90
  91         # Defaults
  92         if not directory:
  93             directory = pkg_resources.resource_filename('pokedex',
  94                                                         'data/whoosh-index')
  95
  96         if session:
  97             self.session = session
  98         else:
  99             self.session = connect()
 100
 101         # Attempt to open or create the index
 102         directory_exists = os.path.exists(directory)
 103         if directory_exists and not recreate:
 104             # Already exists; should be an index!  Bam, done.
 105             try:
 106                 self.index = whoosh.index.open_dir(directory, indexname='MAIN')
 107                 spell_store = whoosh.filedb.filestore.FileStorage(directory)
 108                 self.speller = whoosh.spelling.SpellChecker(spell_store)
 109                 return
 110             except whoosh.index.EmptyIndexError as e:
 111                 # Apparently not a real index.  Fall out and create it
 112                 pass
 113
 114         # Delete and start over if we're going to bail anyway.
 115         if directory_exists and recreate:
 116             # Be safe and only delete if it looks like a whoosh index, i.e.,
 117             # everything starts with _
 118             if all(f[0] == '_' for f in os.listdir(directory)):
 119                 shutil.rmtree(directory)
 120                 directory_exists = False
 121
 122         if not directory_exists:
 123             os.mkdir(directory)
 124
 125
 126         ### Create index
 127         schema = whoosh.fields.Schema(
 128             name=whoosh.fields.ID(stored=True),
 129             table=whoosh.fields.ID(stored=True),
 130             row_id=whoosh.fields.ID(stored=True),
 131             language=whoosh.fields.STORED,
 132             iso3166=whoosh.fields.STORED,
 133             display_name=whoosh.fields.STORED,  # non-lowercased name
 134         )
 135
 136         self.index = whoosh.index.create_in(directory, schema=schema,
 137                                             indexname='MAIN')
 138         writer = self.index.writer()
 139
 140         # Index every name in all our tables of interest
 141         # speller_entries becomes a list of (word, score) tuples; the score is
 142         # 2 for English names, 1.5 for Roomaji, and 1 for everything else.  I
 143         # think this biases the results in the direction most people expect,
 144         # especially when e.g. German names are very similar to English names
 145         speller_entries = []
 146         for cls in self.indexed_tables.values():
 147             q = self.session.query(cls)
 148
 149             for row in q.yield_per(5):
 150                 row_key = dict(table=unicode(cls.__tablename__),
 151                                row_id=unicode(row.id))
 152
 153                 def add(name, language, iso3166, score):
 154                     normalized_name = self.normalize_name(name)
 155
 156                     writer.add_document(
 157                         name=normalized_name, display_name=name,
 158                         language=language, iso3166=iso3166,
 159                         **row_key
 160                     )
 161
 162                     speller_entries.append((normalized_name, score))
 163
 164
 165                 # Add the basic English name to the index
 166                 if cls == tables.Pokemon:
 167                     # Pokémon need their form name added
 168                     # XXX kinda kludgy
 169                     add(row.full_name, None, u'us', 1)
 170
 171                     # If this is a default form, ALSO add the unadorned name,
 172                     # so 'Deoxys' alone will still do the right thing
 173                     if row.forme_name and not row.forme_base_pokemon_id:
 174                         add(row.name, None, u'us', 1)
 175                 else:
 176                     add(row.name, None, u'us', 1)
 177
 178                 # Some things also have other languages' names
 179                 # XXX other language form names..?
 180                 for foreign_name in getattr(row, 'foreign_names', []):
 181                     moonspeak = foreign_name.name
 182                     if row.name == moonspeak:
 183                         # Don't add the English name again as a different
 184                         # language; no point and it makes spell results
 185                         # confusing
 186                         continue
 187
 188                     add(moonspeak, foreign_name.language.name,
 189                                    foreign_name.language.iso3166,
 190                                    3)
 191
 192                     # Add Roomaji too
 193                     if foreign_name.language.name == 'Japanese':
 194                         roomaji = romanize(foreign_name.name)
 195                         add(roomaji, u'Roomaji', u'jp', 8)
 196
 197         writer.commit()
 198
 199         # Construct and populate a spell-checker index.  Quicker to do it all
 200         # at once, as every call to add_* does a commit(), and those seem to be
 201         # expensive
 202         self.speller = whoosh.spelling.SpellChecker(self.index.storage)
 203         self.speller.add_scored_words(speller_entries)
 204
 205
 206     def normalize_name(self, name):
 207         """Strips irrelevant formatting junk from name input.
 208
 209         Specifically: everything is lowercased, and accents are removed.
 210         """
 211         # http://stackoverflow.com/questions/517923/what-is-the-best-way-to-remove-accents-in-a-python-unicode-string
 212         # Makes sense to me.  Decompose by Unicode rules, then remove combining
 213         # characters, then recombine.  I'm explicitly doing it this way instead
 214         # of testing combining() because Korean characters apparently
 215         # decompose!  But the results are considered letters, not combining
 216         # characters, so testing for Mn works well, and combining them again
 217         # makes them look right.
 218         nkfd_form = unicodedata.normalize('NFKD', unicode(name))
 219         name = u"".join(c for c in nkfd_form
 220                         if unicodedata.category(c) != 'Mn')
 221         name = unicodedata.normalize('NFC', name)
 222
 223         name = name.strip()
 224         name = name.lower()
 225
 226         return name
 227
 228
 229     def _apply_valid_types(self, name, valid_types):
 230         """Combines the enforced `valid_types` with any from the search string
 231         itself and updates the query.
 232
 233         For example, a name of 'a,b:foo' and valid_types of b,c will search for
 234         only `b`s named "foo".
 235
 236         Returns `(name, merged_valid_types, term)`, where `name` has had any type
 237         prefix stripped, `merged_valid_types` combines the original
 238         `valid_types` with the type prefix, and `term` is a query term for
 239         limited to just the allowed types.  If there are no type restrictions
 240         at all, `term` will be None.
 241         """
 242
 243         # Remove any type prefix (pokemon:133) first
 244         user_valid_types = []
 245         if ':' in name:
 246             prefix_chunk, name = name.split(':', 1)
 247             name = name.strip()
 248
 249             prefixes = prefix_chunk.split(',')
 250             user_valid_types = [_.strip() for _ in prefixes]
 251
 252         # Merge the valid types together.  Only types that appear in BOTH lists
 253         # may be used.
 254         # As a special case, if the user asked for types that are explicitly
 255         # forbidden, completely ignore what the user requested
 256         combined_valid_types = []
 257         if user_valid_types and valid_types:
 258             combined_valid_types = list(
 259                 set(user_valid_types) & set(combined_valid_types)
 260             )
 261
 262             if not combined_valid_types:
 263                 # No overlap!  Just use the enforced ones
 264                 combined_valid_types = valid_types
 265         else:
 266             # One list or the other was blank, so just use the one that isn't
 267             combined_valid_types = valid_types + user_valid_types
 268
 269         if not combined_valid_types:
 270             # No restrictions
 271             return name, [], None
 272
 273         # Construct the term
 274         type_terms = []
 275         final_valid_types = []
 276         for valid_type in combined_valid_types:
 277             table_name = self._parse_table_name(valid_type)
 278
 279             # Quietly ignore bogus valid_types; more likely to DTRT
 280             if table_name:
 281                 final_valid_types.append(valid_type)
 282                 type_terms.append(whoosh.query.Term(u'table', table_name))
 283
 284         return name, final_valid_types, whoosh.query.Or(type_terms)
 285
 286
 287     def _parse_table_name(self, name):
 288         """Takes a singular table name, table name, or table object and returns
 289         the table name.
 290
 291         Returns None for a bogus name.
 292         """
 293         if hasattr(name, '__tablename__'):
 294             return getattr(name, '__tablename__')
 295         elif name in self.indexed_tables:
 296             return name
 297         elif name + 's' in self.indexed_tables:
 298             return name + 's'
 299         else:
 300             # Bogus.  Be nice and return dummy
 301             return None
 302
 303     def _whoosh_records_to_results(self, records, exact=True):
 304         """Converts a list of whoosh's indexed records to LookupResult tuples
 305         containing database objects.
 306         """
 307         # XXX this 'exact' thing is getting kinda leaky.  would like a better
 308         # way to handle it, since only lookup() cares about fuzzy results
 309         seen = {}
 310         results = []
 311         for record in records:
 312             # Skip dupes
 313             seen_key = record['table'], record['row_id']
 314             if seen_key in seen:
 315                 continue
 316             seen[seen_key] = True
 317
 318             cls = self.indexed_tables[record['table']]
 319             obj = self.session.query(cls).get(record['row_id'])
 320
 321             results.append(LookupResult(object=obj,
 322                                         indexed_name=record['name'],
 323                                         name=record['display_name'],
 324                                         language=record['language'],
 325                                         iso3166=record['iso3166'],
 326                                         exact=exact))
 327
 328         return results
 329
 330
 331     def lookup(self, input, valid_types=[], exact_only=False):
 332         """Attempts to find some sort of object, given a name.
 333
 334         Returns a list of named (object, name, language, iso3166, exact)
 335         tuples.  `object` is a database object, `name` is the name under which
 336         the object was found, `language` and `iso3166` are the name and country
 337         code of the language in which the name was found, and `exact` is True
 338         iff this was an
 339         exact match.
 340
 341         This function currently ONLY does fuzzy matching if there are no exact
 342         matches.
 343
 344         Formes are not returned unless requested; "Shaymin" will return only
 345         grass Shaymin.
 346
 347         Extraneous whitespace is removed with extreme prejudice.
 348
 349         Recognizes:
 350         - Names: "Eevee", "Surf", "Run Away", "Payapa Berry", etc.
 351         - Foreign names: "Iibui", "Eivui"
 352         - Fuzzy names in whatever language: "Evee", "Ibui"
 353         - IDs: "133", "192", "250"
 354         Also:
 355         - Type restrictions.  "type:psychic" will only return the type.  This
 356           is how to make ID lookup useful.  Multiple type specs can be entered
 357           with commas, as "move,item:1".  If `valid_types` are provided, any
 358           type prefix will be ignored.
 359         - Alternate formes can be specified merely like "wash rotom".
 360
 361         `input`
 362             Name of the thing to look for.
 363
 364         `valid_types`
 365             A list of table objects or names, e.g., `['pokemon', 'moves']`.  If
 366             this is provided, only results in one of the given tables will be
 367             returned.
 368
 369         `exact_only`
 370             If True, only exact matches are returned.  If set to False (the
 371             default), and the provided `name` doesn't match anything exactly,
 372             spelling correction will be attempted.
 373         """
 374
 375         name = self.normalize_name(input)
 376         exact = True
 377         form = None
 378
 379         # Pop off any type prefix and merge with valid_types
 380         name, merged_valid_types, type_term = \
 381             self._apply_valid_types(name, valid_types)
 382
 383         # Random lookup
 384         if name == 'random':
 385             return self.random_lookup(valid_types=merged_valid_types)
 386
 387         # Do different things depending what the query looks like
 388         # Note: Term objects do an exact match, so we don't have to worry about
 389         # a query parser tripping on weird characters in the input
 390         try:
 391             # Let Python try to convert to a number, so 0xff works
 392             name_as_number = int(name, base=0)
 393         except ValueError:
 394             # Oh well
 395             name_as_number = None
 396
 397         if '*' in name or '?' in name:
 398             exact_only = True
 399             query = whoosh.query.Wildcard(u'name', name)
 400         elif name_as_number is not None:
 401             # Don't spell-check numbers!
 402             exact_only = True
 403             query = whoosh.query.Term(u'row_id', unicode(name_as_number))
 404         else:
 405             # Not an integer
 406             query = whoosh.query.Term(u'name', name)
 407
 408         if type_term:
 409             query = query & type_term
 410
 411
 412         ### Actual searching
 413         searcher = self.index.searcher()
 414         # XXX is this kosher?  docs say search() takes a weighting arg, but it
 415         # certainly does not
 416         searcher.weighting = LanguageWeighting()
 417         results = searcher.search(query,
 418                                   limit=self.INTERMEDIATE_LOOKUP_RESULTS)
 419
 420         # Look for some fuzzy matches if necessary
 421         if not exact_only and not results:
 422             exact = False
 423             results = []
 424
 425             for suggestion in self.speller.suggest(
 426                 name, self.INTERMEDIATE_LOOKUP_RESULTS):
 427
 428                 query = whoosh.query.Term('name', suggestion)
 429                 results.extend(searcher.search(query))
 430
 431         ### Convert results to db objects
 432         objects = self._whoosh_records_to_results(results, exact=exact)
 433
 434         # Only return up to 10 matches; beyond that, something is wrong.  We
 435         # strip out duplicate entries above, so it's remotely possible that we
 436         # should have more than 10 here and lost a few.  The speller returns 25
 437         # to give us some padding, and should avoid that problem.  Not a big
 438         # deal if we lose the 25th-most-likely match anyway.
 439         return objects[:self.MAX_LOOKUP_RESULTS]
 440
 441
 442     def random_lookup(self, valid_types=[]):
 443         """Returns a random lookup result from one of the provided
 444         `valid_types`.
 445         """
 446
 447         tables = []
 448         for valid_type in valid_types:
 449             table_name = self._parse_table_name(valid_type)
 450             if table_name:
 451                 tables.append(self.indexed_tables[table_name])
 452
 453         if not tables:
 454             # n.b.: It's possible we got a list of valid_types and none of them
 455             # were valid, but this function is guaranteed to return
 456             # *something*, so it politely selects from the entire index isntead
 457             tables = self.indexed_tables.values()
 458
 459         # Rather than create an array of many hundred items and pick randomly
 460         # from it, just pick a number up to the total number of potential
 461         # items, then pick randomly from that, and partition the whole range
 462         # into chunks.  This also avoids the slight problem that the index
 463         # contains more rows (for languages) for some items than others.
 464         # XXX ought to cache this (in the index?) if possible
 465         total = 0
 466         partitions = []
 467         for table in tables:
 468             count = self.session.query(table).count()
 469             total += count
 470             partitions.append((table, count))
 471
 472         n = random.randint(1, total)
 473         while n > partitions[0][1]:
 474             n -= partitions[0][1]
 475             partitions.pop(0)
 476
 477         return self.lookup(unicode(n), valid_types=[ partitions[0][0] ])
 478
 479     def prefix_lookup(self, prefix, valid_types=[]):
 480         """Returns terms starting with the given exact prefix.
 481
 482         Type prefixes are recognized, but no other name munging is done.
 483         """
 484
 485         # Pop off any type prefix and merge with valid_types
 486         prefix, merged_valid_types, type_term = \
 487             self._apply_valid_types(prefix, valid_types)
 488
 489         query = whoosh.query.Prefix(u'name', self.normalize_name(prefix))
 490
 491         if type_term:
 492             query = query & type_term
 493
 494         searcher = self.index.searcher()
 495         searcher.weighting = LanguageWeighting()
 496         results = searcher.search(query)  # XXX , limit=self.MAX_LOOKUP_RESULTS)
 497
 498         return self._whoosh_records_to_results(results)