veekun_pokedex/pokedex/lookup.py
2011-03-13 15:10:11 -07:00

605 lines
22 KiB
Python

# encoding: utf8
import os, os.path
import random
import re
import shutil
import unicodedata
from sqlalchemy.sql import func
import whoosh
import whoosh.filedb.filestore
import whoosh.filedb.fileindex
import whoosh.index
from whoosh.qparser import QueryParser
import whoosh.scoring
import whoosh.spelling
from pokedex.util import namedtuple
from pokedex.db import connect
import pokedex.db.tables as tables
from pokedex.roomaji import romanize
from pokedex.defaults import get_default_index_dir
__all__ = ['PokedexLookup']
rx_is_number = re.compile('^\d+$')
LookupResult = namedtuple('LookupResult', [
'object', 'indexed_name', 'name', 'language', 'iso639', 'iso3166', 'exact',
])
class UninitializedIndex(object):
class UninitializedIndexError(Exception):
pass
def __nonzero__(self):
"""Dummy object should identify itself as False."""
return False
def __bool__(self):
"""Python 3000 version of the above. Future-proofing rules!"""
return False
def __getattr__(self, *args, **kwargs):
raise self.UninitializedIndexError(
"The lookup index does not exist. Please use `pokedex setup` "
"or lookup.rebuild_index() to create it."
)
class LanguageWeighting(whoosh.scoring.Weighting):
"""A scoring class that forces otherwise-equal English results to come
before foreign results.
"""
def __init__(self, extra_weights={}, *args, **kwargs):
"""`extra_weights` may be a dictionary of weights which will be
factored in.
Intended for use with spelling corrections, which come along with their
own weightings.
"""
self.extra_weights = extra_weights
super(LanguageWeighting, self).__init__(*args, **kwargs)
def score(self, searcher, fieldnum, text, docnum, weight, QTF=1):
doc = searcher.stored_fields(docnum)
# Apply extra weight
weight = weight * self.extra_weights.get(text, 1.0)
language = doc.get('language')
if language is None:
# English (well, "default"); leave it at 1
return weight
elif language == u'Roomaji':
# Give Roomaji a little boost; it's most likely to be searched
return weight * 0.9
else:
# Everything else can drop down the totem pole
return weight * 0.8
class PokedexLookup(object):
MAX_FUZZY_RESULTS = 10
MAX_EXACT_RESULTS = 43
INTERMEDIATE_FACTOR = 2
# The speller only checks how much the input matches a word; there can be
# all manner of extra unmatched junk, and it won't affect the weighting.
# To compensate, greatly boost the weighting of matches at the beginning
# and end, so nearly-full-word-matches are much better
SPELLER_OPTIONS = dict(booststart=10.0, boostend=9.0)
# Dictionary of table name => table class.
# Need the table name so we can get the class from the table name after we
# retrieve something from the index
indexed_tables = dict(
(cls.__tablename__, cls)
for cls in (
tables.Ability,
tables.Item,
tables.Location,
tables.Move,
tables.Nature,
tables.Pokemon,
tables.PokemonForm,
tables.Type,
)
)
def __init__(self, directory=None, session=None):
"""Opens the whoosh index stored in the named directory. If the index
doesn't already exist, it will be created.
`directory`
Directory containing the index. Defaults to a location within the
`pokedex` egg directory.
`session`
Used for creating the index and retrieving objects. Defaults to an
attempt to connect to the default SQLite database installed by
`pokedex setup`.
"""
# By the time this returns, self.index, self.speller, and self.session
# must be set
# If a directory was not given, use the default
if directory is None:
directory = get_default_index_dir()
self.directory = directory
if session:
self.session = session
else:
self.session = connect()
# Attempt to open or create the index
if not os.path.exists(directory) or not os.listdir(directory):
# Directory doesn't exist OR is empty; caller needs to use
# rebuild_index before doing anything. Provide a dummy object that
# complains when used
self.index = UninitializedIndex()
self.speller = UninitializedIndex()
return
# Otherwise, already exists; should be an index! Bam, done.
# Note that this will explode if the directory exists but doesn't
# contain an index; that's a feature
try:
self.index = whoosh.index.open_dir(directory, indexname='MAIN')
except whoosh.index.EmptyIndexError:
raise IOError(
"The index directory already contains files. "
"Please use a dedicated directory for the lookup index."
)
# Create speller, and done
spell_store = whoosh.filedb.filestore.FileStorage(directory)
self.speller = whoosh.spelling.SpellChecker(spell_store,
**self.SPELLER_OPTIONS)
def rebuild_index(self):
"""Creates the index from scratch."""
schema = whoosh.fields.Schema(
name=whoosh.fields.ID(stored=True),
table=whoosh.fields.ID(stored=True),
row_id=whoosh.fields.ID(stored=True),
language=whoosh.fields.STORED,
iso639=whoosh.fields.ID(stored=True),
iso3166=whoosh.fields.ID(stored=True),
display_name=whoosh.fields.STORED, # non-lowercased name
)
if os.path.exists(self.directory):
# create_in() isn't totally reliable, so just nuke whatever's there
# manually. Try to be careful about this...
for f in os.listdir(self.directory):
if re.match('^_?(MAIN|SPELL)_', f):
os.remove(os.path.join(self.directory, f))
else:
os.mkdir(self.directory)
self.index = whoosh.index.create_in(self.directory, schema=schema,
indexname='MAIN')
writer = self.index.writer()
# Index every name in all our tables of interest
speller_entries = set()
for cls in self.indexed_tables.values():
q = self.session.query(cls)
for row in q.yield_per(5):
row_key = dict(table=unicode(cls.__tablename__),
row_id=unicode(row.id))
def add(name, language, iso639, iso3166):
normalized_name = self.normalize_name(name)
writer.add_document(
name=normalized_name, display_name=name,
language=language, iso639=iso639, iso3166=iso3166,
**row_key
)
speller_entries.add(normalized_name)
# Add the basic English name to the index
if cls == tables.Pokemon:
# Don't re-add alternate forms of the same Pokémon; they'll
# be added as Pokémon forms instead
if not row.is_base_form:
continue
elif cls == tables.PokemonForm:
if row.name:
add(row.pokemon_name, None, u'en', u'us')
continue
# Some things also have other languages' names
# XXX other language form names..?
seen = set()
for language, name in getattr(row, 'names', []).items():
if name in seen:
# Don't add the name again as a different
# language; no point and it makes spell results
# confusing
continue
seen.add(name)
add(name, language.name,
language.iso639,
language.iso3166)
# Add Roomaji too
if language.identifier == 'ja':
roomaji = romanize(name)
add(roomaji, u'Roomaji', u'ja', u'jp')
writer.commit()
# Construct and populate a spell-checker index. Quicker to do it all
# at once, as every call to add_* does a commit(), and those seem to be
# expensive
self.speller = whoosh.spelling.SpellChecker(self.index.storage, mingram=2,
**self.SPELLER_OPTIONS)
self.speller.add_words(speller_entries)
def normalize_name(self, name):
"""Strips irrelevant formatting junk from name input.
Specifically: everything is lowercased, and accents are removed.
"""
# http://stackoverflow.com/questions/517923/what-is-the-best-way-to-remove-accents-in-a-python-unicode-string
# Makes sense to me. Decompose by Unicode rules, then remove combining
# characters, then recombine. I'm explicitly doing it this way instead
# of testing combining() because Korean characters apparently
# decompose! But the results are considered letters, not combining
# characters, so testing for Mn works well, and combining them again
# makes them look right.
nkfd_form = unicodedata.normalize('NFKD', unicode(name))
name = u"".join(c for c in nkfd_form
if unicodedata.category(c) != 'Mn')
name = unicodedata.normalize('NFC', name)
name = name.strip()
name = name.lower()
return name
def _apply_valid_types(self, name, valid_types):
"""Combines the enforced `valid_types` with any from the search string
itself and updates the query.
For example, a name of 'a,b:foo' and valid_types of b,c will search for
only `b`s named "foo".
Returns `(name, merged_valid_types, term)`, where `name` has had any type
prefix stripped, `merged_valid_types` combines the original
`valid_types` with the type prefix, and `term` is a query term for
limited to just the allowed types. If there are no type restrictions
at all, `term` will be None.
"""
# Remove any type prefix (pokemon:133) first
user_valid_types = []
if ':' in name:
prefix_chunk, name = name.split(':', 1)
name = name.strip()
prefixes = prefix_chunk.split(',')
user_valid_types = []
for prefix in prefixes:
prefix = prefix.strip()
if prefix:
user_valid_types.append(prefix)
# Merge the valid types together. Only types that appear in BOTH lists
# may be used.
# As a special case, if the user asked for types that are explicitly
# forbidden, completely ignore what the user requested.
# And, just to complicate matters: "type" and language need to be
# considered separately.
def merge_requirements(func):
user = filter(func, user_valid_types)
system = filter(func, valid_types)
if user and system:
merged = list(set(user) & set(system))
if merged:
return merged
else:
# No overlap; use the system restrictions
return system
else:
# One or the other is blank; use the one that's not
return user or system
# @foo means language must be foo; otherwise it's a table name
lang_requirements = merge_requirements(lambda req: req[0] == u'@')
type_requirements = merge_requirements(lambda req: req[0] != u'@')
all_requirements = lang_requirements + type_requirements
# Construct the term
lang_terms = []
for lang in lang_requirements:
# Allow for either country or language codes
lang_code = lang[1:]
lang_terms.append(whoosh.query.Term(u'iso639', lang_code))
lang_terms.append(whoosh.query.Term(u'iso3166', lang_code))
type_terms = []
for type in type_requirements:
table_name = self._parse_table_name(type)
# Quietly ignore bogus valid_types; more likely to DTRT
if table_name:
type_terms.append(whoosh.query.Term(u'table', table_name))
# Combine both kinds of restriction
all_terms = []
if type_terms:
all_terms.append(whoosh.query.Or(type_terms))
if lang_terms:
all_terms.append(whoosh.query.Or(lang_terms))
return name, all_requirements, whoosh.query.And(all_terms)
def _parse_table_name(self, name):
"""Takes a singular table name, table name, or table object and returns
the table name.
Returns None for a bogus name.
"""
# Table object
if hasattr(name, '__tablename__'):
return getattr(name, '__tablename__')
# Table name
for table in self.indexed_tables.values():
if name in (table.__tablename__, table.__singlename__):
return table.__tablename__
# Bogus. Be nice and return dummy
return None
def _whoosh_records_to_results(self, records, exact=True):
"""Converts a list of whoosh's indexed records to LookupResult tuples
containing database objects.
"""
# XXX this 'exact' thing is getting kinda leaky. would like a better
# way to handle it, since only lookup() cares about fuzzy results
seen = {}
results = []
for record in records:
# Skip dupes
seen_key = record['table'], record['row_id']
if seen_key in seen:
continue
seen[seen_key] = True
cls = self.indexed_tables[record['table']]
obj = self.session.query(cls).get(record['row_id'])
results.append(LookupResult(object=obj,
indexed_name=record['name'],
name=record['display_name'],
language=record.get('language'),
iso639=record['iso639'],
iso3166=record['iso3166'],
exact=exact))
return results
def lookup(self, input, valid_types=[], exact_only=False):
"""Attempts to find some sort of object, given a name.
Returns a list of named (object, name, language, iso639, iso3166,
exact) tuples. `object` is a database object, `name` is the name under
which the object was found, `language` and the two isos are the name
and country codes of the language in which the name was found, and
`exact` is True iff this was an exact match.
This function currently ONLY does fuzzy matching if there are no exact
matches.
Formes are not returned unless requested; "Shaymin" will return only
grass Shaymin.
Extraneous whitespace is removed with extreme prejudice.
Recognizes:
- Names: "Eevee", "Surf", "Run Away", "Payapa Berry", etc.
- Foreign names: "Iibui", "Eivui"
- Fuzzy names in whatever language: "Evee", "Ibui"
- IDs: "133", "192", "250"
Also:
- Type restrictions. "type:psychic" will only return the type. This
is how to make ID lookup useful. Multiple type specs can be entered
with commas, as "move,item:1".
- Language restrictions. "@fr:charge" will only return Tackle, which
is called "Charge" in French. These can be combined with type
restrictions, e.g., "@fr,move:charge".
- Alternate formes can be specified merely like "wash rotom".
`input`
Name of the thing to look for.
`valid_types`
A list of type or language restrictions, e.g., `['pokemon',
'@ja']`. If this is provided, only results in one of the given
tables will be returned.
`exact_only`
If True, only exact matches are returned. If set to False (the
default), and the provided `name` doesn't match anything exactly,
spelling correction will be attempted.
"""
name = self.normalize_name(input)
exact = True
form = None
# Pop off any type prefix and merge with valid_types
name, merged_valid_types, type_term = \
self._apply_valid_types(name, valid_types)
# Random lookup
if name == 'random':
return self.random_lookup(valid_types=merged_valid_types)
# Do different things depending what the query looks like
# Note: Term objects do an exact match, so we don't have to worry about
# a query parser tripping on weird characters in the input
try:
# Let Python try to convert to a number, so 0xff works
name_as_number = int(name, base=0)
except ValueError:
# Oh well
name_as_number = None
if '*' in name or '?' in name:
exact_only = True
query = whoosh.query.Wildcard(u'name', name)
elif name_as_number is not None:
# Don't spell-check numbers!
exact_only = True
query = whoosh.query.Term(u'row_id', unicode(name_as_number))
else:
# Not an integer
query = whoosh.query.Term(u'name', name)
if type_term:
query = query & type_term
### Actual searching
# Limits; result limits are constants, and intermediate results (before
# duplicate items are stripped out) are capped at the result limit
# times another constant.
# Fuzzy are capped at 10, beyond which something is probably very
# wrong. Exact matches -- that is, wildcards and ids -- are far less
# constrained.
# Also, exact matches are sorted by name, since weight doesn't matter.
sort_by = dict()
if exact_only:
max_results = self.MAX_EXACT_RESULTS
sort_by['sortedby'] = (u'table', u'name')
else:
max_results = self.MAX_FUZZY_RESULTS
searcher = self.index.searcher(weighting=LanguageWeighting())
results = searcher.search(
query,
limit=int(max_results * self.INTERMEDIATE_FACTOR),
**sort_by
)
# Look for some fuzzy matches if necessary
if not exact_only and not results:
exact = False
results = []
fuzzy_query_parts = []
fuzzy_weights = {}
min_weight = [None]
for suggestion, _, weight in self.speller.suggestions_and_scores(name):
# Only allow the top 50% of scores; otherwise there will always
# be a lot of trailing junk
if min_weight[0] is None:
min_weight[0] = weight * 0.5
elif weight < min_weight[0]:
break
fuzzy_query_parts.append(whoosh.query.Term('name', suggestion))
fuzzy_weights[suggestion] = weight
if not fuzzy_query_parts:
# Nothing at all; don't try querying
return []
fuzzy_query = whoosh.query.Or(fuzzy_query_parts)
if type_term:
fuzzy_query = fuzzy_query & type_term
searcher.weighting = LanguageWeighting(extra_weights=fuzzy_weights)
results = searcher.search(fuzzy_query)
### Convert results to db objects
objects = self._whoosh_records_to_results(results, exact=exact)
# Truncate and return
return objects[:max_results]
def random_lookup(self, valid_types=[]):
"""Returns a random lookup result from one of the provided
`valid_types`.
"""
table_names = []
for valid_type in valid_types:
table_name = self._parse_table_name(valid_type)
# Skip anything not recognized. Could be, say, a language code.
# XXX The vast majority of Pokémon forms are unnamed and unindexed,
# which can produce blank results. So skip them too for now.
if table_name and table_name != 'pokemon_forms':
table_names.append(table_name)
if not table_names:
# n.b.: It's possible we got a list of valid_types and none of them
# were valid, but this function is guaranteed to return
# *something*, so it politely selects from the entire index instead
table_names = self.indexed_tables.keys()
table_names.remove('pokemon_forms')
# Rather than create an array of many hundred items and pick randomly
# from it, just pick a number up to the total number of potential
# items, then pick randomly from that, and partition the whole range
# into chunks. This also avoids the slight problem that the index
# contains more rows (for languages) for some items than others.
# XXX ought to cache this (in the index?) if possible
total = 0
partitions = []
for table_name in table_names:
count = self.session.query(self.indexed_tables[table_name]).count()
total += count
partitions.append((table_name, count))
n = random.randint(1, total)
while n > partitions[0][1]:
n -= partitions[0][1]
partitions.pop(0)
return self.lookup(unicode(n), valid_types=[ partitions[0][0] ])
def prefix_lookup(self, prefix, valid_types=[]):
"""Returns terms starting with the given exact prefix.
Type prefixes are recognized, but no other name munging is done.
"""
# Pop off any type prefix and merge with valid_types
prefix, merged_valid_types, type_term = \
self._apply_valid_types(prefix, valid_types)
query = whoosh.query.Prefix(u'name', self.normalize_name(prefix))
if type_term:
query = query & type_term
searcher = self.index.searcher()
searcher.weighting = LanguageWeighting()
results = searcher.search(query) # XXX , limit=self.MAX_LOOKUP_RESULTS)
return self._whoosh_records_to_results(results)