veekun_pokedex/pokedex/lookup.py

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# encoding: utf8
from collections import namedtuple
import os, os.path
import pkg_resources
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import random
import re
import shutil
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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.db import connect
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import pokedex.db.tables as tables
from pokedex.roomaji import romanize
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__all__ = ['open_index', 'lookup', 'random_lookup']
INTERMEDIATE_LOOKUP_RESULTS = 25
MAX_LOOKUP_RESULTS = 10
# 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 = {}
for cls in [
tables.Ability,
tables.Item,
tables.Move,
tables.Pokemon,
tables.Type,
]:
indexed_tables[cls.__tablename__] = cls
def open_index(directory=None, session=None, recreate=False):
"""Opens the whoosh index stored in the named directory and returns (index,
speller). 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`
If the index needs to be created, this database session will be used.
Defaults to an attempt to connect to the default SQLite database
installed by `pokedex setup`.
`recreate`
If set to True, the whoosh index will be created even if it already
exists.
"""
# Defaults
if not directory:
directory = pkg_resources.resource_filename('pokedex',
'data/whoosh-index')
if not session:
session = connect()
# Attempt to open or create the index
directory_exists = os.path.exists(directory)
if directory_exists and not recreate:
# Already exists; should be an index!
try:
index = whoosh.index.open_dir(directory, indexname='MAIN')
spell_store = whoosh.filedb.filestore.FileStorage(directory)
speller = whoosh.spelling.SpellChecker(spell_store)
return index, speller
except whoosh.index.EmptyIndexError as e:
# Apparently not a real index. Fall out of the if and create it
pass
# Delete and start over if we're going to bail anyway.
if directory_exists and recreate:
# Be safe and only delete if it looks like a whoosh index, i.e.,
# everything starts with _
if all(f[0] == '_' for f in os.listdir(directory)):
shutil.rmtree(directory)
directory_exists = False
if not directory_exists:
os.mkdir(directory)
### Create index
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,
iso3166=whoosh.fields.STORED,
display_name=whoosh.fields.STORED, # non-lowercased name
forme_name=whoosh.fields.ID,
)
index = whoosh.index.create_in(directory, schema=schema, indexname='MAIN')
writer = index.writer()
# Index every name in all our tables of interest
# speller_entries becomes a list of (word, score) tuples; the score is 2
# for English names, 1.5 for Roomaji, and 1 for everything else. I think
# this biases the results in the direction most people expect, especially
# when e.g. German names are very similar to English names
speller_entries = []
for cls in indexed_tables.values():
q = session.query(cls)
for row in q.yield_per(5):
# XXX need to give forme_name a dummy value because I can't search
# for explicitly empty fields. boo.
row_key = dict(table=unicode(cls.__tablename__),
row_id=unicode(row.id),
forme_name=u'XXX')
def add(name, language, iso3166, score):
writer.add_document(name=name.lower(), display_name=name,
language=language,
iso3166=iso3166,
**row_key)
speller_entries.append((name.lower(), score))
# If this is a form, mark it as such
if getattr(row, 'forme_base_pokemon_id', None):
row_key['forme_name'] = row.forme_name
name = row.name
add(name, None, u'us', 1)
# Pokemon also get other languages
for foreign_name in getattr(row, 'foreign_names', []):
moonspeak = foreign_name.name
if 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.iso3166,
3)
# Add Roomaji too
if foreign_name.language.name == 'Japanese':
roomaji = romanize(foreign_name.name)
add(roomaji, u'Roomaji', u'jp', 8)
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
speller = whoosh.spelling.SpellChecker(index.storage)
speller.add_scored_words(speller_entries)
return index, speller
class LanguageWeighting(whoosh.scoring.Weighting):
"""A scoring class that forces otherwise-equal English results to come
before foreign results.
"""
def score(self, searcher, fieldnum, text, docnum, weight, QTF=1):
doc = searcher.stored_fields(docnum)
if doc['language'] == None:
# English (well, "default"); leave it at 1
return weight
elif doc['language'] == u'Roomaji':
# Give Roomaji a bit of a boost, as it's most likely to be searched
return weight * 0.95
else:
# Everything else can drop down the totem pole
return weight * 0.9
rx_is_number = re.compile('^\d+$')
LookupResult = namedtuple('LookupResult',
['object', 'name', 'language', 'iso3166', 'exact'])
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def _parse_table_name(name):
"""Takes a singular table name, table name, or table object and returns the
table name.
Returns None for a bogus name.
"""
if hasattr(name, '__tablename__'):
return getattr(name, '__tablename__')
elif name in indexed_tables:
return name
elif name + 's' in indexed_tables:
return name + 's'
else:
# Bogus. Be nice and return dummy
return None
def _whoosh_records_to_results(records, session, 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 = indexed_tables[record['table']]
obj = session.query(cls).get(record['row_id'])
results.append(LookupResult(object=obj,
name=record['display_name'],
language=record['language'],
iso3166=record['iso3166'],
exact=exact))
return results
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def lookup(input, valid_types=[], session=None, indices=None, exact_only=False):
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"""Attempts to find some sort of object, given a database session and name.
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Returns a list of named (object, name, language, iso3166, exact) tuples.
`object` is a database object, `name` is the name under which the object
was found, `language` and `iso3166` are the name and country code of the
language in which the name was found, and `exact` is True iff this was an
exact match.
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This function currently ONLY does fuzzy matching if there are no exact
matches.
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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". If `valid_types` are provided, any type prefix
will be ignored.
- Alternate formes can be specified merely like "wash rotom".
`input`
Name of the thing to look for.
`valid_types`
A list of table objects or names, e.g., `['pokemon', 'moves']`. If
this is provided, only results in one of the given tables will be
returned.
`session`
A database session to use for retrieving objects. As with get_index,
if this is not provided, a connection to the default database will be
attempted.
`indices`
Tuple of index, speller as returned from `open_index()`. Defaults to
a call to `open_index()`.
`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.
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"""
if not session:
session = connect()
if indices:
index, speller = indices
else:
index, speller = open_index()
name = unicode(input).strip().lower()
exact = True
form = None
# Remove any type prefix (pokemon:133) before constructing a query
if ':' in name:
prefix_chunk, name = name.split(':', 1)
name = name.strip()
if not valid_types:
# Only use types from the query string if none were explicitly
# provided
prefixes = prefix_chunk.split(',')
valid_types = [_.strip() for _ in prefixes]
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# Random lookup
if name == 'random':
return random_lookup(indices=(index, speller),
session=session,
valid_types=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
if '*' in name or '?' in name:
exact_only = True
query = whoosh.query.Wildcard(u'name', name)
elif rx_is_number.match(name):
# Don't spell-check numbers!
exact_only = True
query = whoosh.query.Term(u'row_id', name)
else:
# Not an integer
query = whoosh.query.Term(u'name', name) \
& whoosh.query.Term(u'forme_name', u'XXX')
# If there's a space in the input, this might be a form
if ' ' in name:
form, formless_name = name.split(' ', 1)
form_query = whoosh.query.Term(u'name', formless_name) \
& whoosh.query.Term(u'forme_name', form)
query = query | form_query
### Filter by type of object
type_terms = []
for valid_type in valid_types:
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table_name = _parse_table_name(valid_type)
if table_name:
# Quietly ignore bogus valid_types; more likely to DTRT
type_terms.append(whoosh.query.Term(u'table', table_name))
if type_terms:
query = query & whoosh.query.Or(type_terms)
### Actual searching
searcher = index.searcher()
searcher.weighting = LanguageWeighting() # XXX kosher? docs say search()
# takes a weighting kw but it
# certainly does not
results = searcher.search(query, limit=INTERMEDIATE_LOOKUP_RESULTS)
# Look for some fuzzy matches if necessary
if not exact_only and not results:
exact = False
results = []
for suggestion in speller.suggest(name, INTERMEDIATE_LOOKUP_RESULTS):
query = whoosh.query.Term('name', suggestion)
results.extend(searcher.search(query))
### Convert results to db objects
objects = _whoosh_records_to_results(results, session, exact=exact)
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# Only return up to 10 matches; beyond that, something is wrong.
# We strip out duplicate entries above, so it's remotely possible that we
# should have more than 10 here and lost a few. The speller returns 25 to
# give us some padding, and should avoid that problem. Not a big deal if
# we lose the 25th-most-likely match anyway.
return objects[:MAX_LOOKUP_RESULTS]
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def random_lookup(valid_types=[], session=None, indices=None):
"""Takes similar arguments as `lookup()`, but returns a random lookup
result from one of the provided `valid_types`.
"""
tables = []
for valid_type in valid_types:
table_name = _parse_table_name(valid_type)
if table_name:
tables.append(indexed_tables[table_name])
if not tables:
# 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 isntead
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tables = indexed_tables.values()
# 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
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total = 0
partitions = []
for table in tables:
count = session.query(table).count()
total += count
partitions.append((table, count))
n = random.randint(1, total)
while n > partitions[0][1]:
n -= partitions[0][1]
partitions.pop(0)
return lookup(unicode(n), valid_types=[ partitions[0][0] ],
indices=indices, session=session)
def prefix_lookup(prefix, session=None, indices=None):
"""Returns terms starting with the given exact prefix.
No special magic is currently done with the name; type prefixes are not
recognized.
`session` and `indices` are treated as with `lookup()`.
"""
if not session:
session = connect()
if indices:
index, speller = indices
else:
index, speller = open_index()
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query = whoosh.query.Prefix(u'name', prefix.lower())
searcher = index.searcher()
searcher.weighting = LanguageWeighting()
results = searcher.search(query) # XXX , limit=MAX_LOOKUP_RESULTS)
return _whoosh_records_to_results(results, session)