veekun_pokedex/pokedex/lookup.py

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Python
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# encoding: utf8
import os, os.path
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import random
import re
import shutil
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import unicodedata
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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
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from pokedex.util import namedtuple
from pokedex.db import connect
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import pokedex.db.tables as tables
from pokedex.roomaji import romanize
from pokedex.defaults import get_default_index_dir
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__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,
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tables.Location,
tables.Move,
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tables.Nature,
tables.Pokemon,
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
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# If a directory was not given, use the default
if directory is None:
directory = get_default_index_dir()
self.directory = directory
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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():
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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:
# Pokémon need their form name added
# XXX kinda kludgy
add(row.full_name, None, u'en', u'us')
# If this is a default form, ALSO add the unadorned name,
# so 'Deoxys' alone will still do the right thing
if row.forme_name and not row.forme_base_pokemon_id:
add(row.name, None, u'en', u'us')
else:
add(row.name, None, u'en', u'us')
# Some things also have other languages' names
# XXX other language form names..?
for foreign_name in getattr(row, 'foreign_names', []):
moonspeak = foreign_name.name
if row.name == moonspeak:
# Don't add the English name again as a different
# language; no point and it makes spell results
# confusing
continue
add(moonspeak, foreign_name.language.name,
foreign_name.language.iso639,
foreign_name.language.iso3166)
# Add Roomaji too
if foreign_name.language.name == 'Japanese':
roomaji = romanize(foreign_name.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(',')
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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
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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
if table_name:
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()
# 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)