"""
Wrappers for lucene Fields and Documents.
"""
from future_builtins import map, zip
import datetime, calendar
import collections
import lucene
from .queries import Query
[docs]class Field(object):
"""Saved parameters which can generate lucene Fields given values.
:param name: name of field
:param store,index,termvector: field parameters, expressed as bools or strs, with lucene defaults
:param analyzed,omitNorms: additional index boolean settings
:param withPositions,withOffsets: additional termvector boolean settings
:param attrs: additional attributes to set on the field
"""
def __init__(self, name, store=False, index='analyzed', termvector=False, analyzed=False, omitNorms=False, withPositions=False, withOffsets=False, **attrs):
self.name, self.attrs = name, attrs
if isinstance(store, bool):
store = 'yes' if store else 'no'
self.store = lucene.Field.Store.valueOf(store.upper())
if isinstance(index, bool):
self.index = lucene.Field.Index.toIndex(index, analyzed, omitNorms)
else:
self.index = lucene.Field.Index.valueOf(index.upper())
if isinstance(termvector, bool):
self.termvector = lucene.Field.TermVector.toTermVector(termvector, withOffsets, withPositions)
else:
self.termvector = lucene.Field.TermVector.valueOf(termvector.upper())
next(Field.items(self, ' ')) # validate settings
[docs] def items(self, *values):
"Generate lucene Fields suitable for adding to a document."
for value in values:
try:
field = lucene.Field(self.name, value, self.store, self.index, self.termvector)
except lucene.InvalidArgsError:
field = lucene.Field(self.name, value, self.termvector)
for name, value in self.attrs.items():
setattr(field, name, value)
yield field
[docs]class NestedField(Field):
"""Field which indexes every component into its own field.
Original value may be stored for convenience.
:param sep: field separator used on name and values
"""
def __init__(self, name, sep='.', index=True, **kwargs):
Field.__init__(self, name, index=index, **kwargs)
self.sep = sep
self.names = self.split(name)
[docs] def split(self, value):
"Return sequence of words from name or value."
return tuple(value.split(self.sep))
[docs] def join(self, words):
"Return text from separate words."
return self.sep.join(words)
[docs] def getname(self, index):
"Return prefix of field name."
return self.join(self.names[:index])
[docs] def items(self, *values):
"Generate indexed component fields."
if self.store.stored:
for value in values:
yield lucene.Field(self.name, value, self.store, lucene.Field.Index.NO)
for value in values:
value = self.split(value)
for index in range(1, len(value) + 1):
yield lucene.Field(self.getname(index), self.join(value[:index]), lucene.Field.Store.NO, self.index, self.termvector)
[docs] def prefix(self, value):
"Return prefix query of the closest possible prefixed field."
index = len(self.split(value))
return Query.prefix(self.getname(index), value)
[docs] def range(self, start, stop, lower=True, upper=False):
"Return range query of the closest possible prefixed field."
index = max(len(self.split(value)) for value in (start, stop) if value is not None)
return Query.range(self.getname(index), start, stop, lower, upper)
[docs]class NumericField(Field):
"""Field which indexes numbers in a prefix tree.
:param name: name of field
:param step: precision step
"""
def __init__(self, name, step=None, store=False, index=True):
Field.__init__(self, name, store)
self.step = step or lucene.NumericUtils.PRECISION_STEP_DEFAULT
self.index = index
[docs] def items(self, *values):
"Generate lucene NumericFields suitable for adding to a document."
for value in values:
field = lucene.NumericField(self.name, self.step, self.store, self.index)
if isinstance(value, float):
field.doubleValue = value
else:
field.longValue = long(value)
yield field
[docs] def range(self, start, stop, lower=True, upper=False):
"Return lucene NumericRangeQuery."
if isinstance(start, float) or isinstance(stop, float):
start, stop = (value if value is None else lucene.Double(value) for value in (start, stop))
return lucene.NumericRangeQuery.newDoubleRange(self.name, self.step, start, stop, lower, upper)
if start is not None:
start = None if start < lucene.Long.MIN_VALUE else lucene.Long(long(start))
if stop is not None:
stop = None if stop > lucene.Long.MAX_VALUE else lucene.Long(long(stop))
return lucene.NumericRangeQuery.newLongRange(self.name, self.step, start, stop, lower, upper)
[docs] def term(self, value):
"Return range query to match single term."
return self.range(value, value, upper=True)
[docs]class DateTimeField(NumericField):
"""Field which indexes datetimes as a NumericField of timestamps.
Supports datetimes, dates, and any prefix of time tuples.
"""
[docs] def timestamp(self, date):
"Return utc timestamp from date or time tuple."
if isinstance(date, datetime.date):
return calendar.timegm(date.timetuple()) + getattr(date, 'microsecond', 0) * 1e-6
return float(calendar.timegm(tuple(date) + (None, 1, 1, 0, 0, 0)[len(date):]))
[docs] def items(self, *dates):
"Generate lucene NumericFields of timestamps."
return NumericField.items(self, *map(self.timestamp, dates))
[docs] def range(self, start, stop, lower=True, upper=False):
"Return NumericRangeQuery of timestamps."
start, stop = (date and self.timestamp(date) for date in (start, stop))
return NumericField.range(self, start, stop, lower, upper)
[docs] def prefix(self, date):
"Return range query which matches the date prefix."
if isinstance(date, datetime.date):
date = date.timetuple()[:6 if isinstance(date, datetime.datetime) else 3]
if len(date) == 2 and date[1] == 12: # month must be valid
return self.range(date, (date[0]+1, 1))
return self.range(date, tuple(date[:-1]) + (date[-1]+1,))
[docs] def duration(self, date, days=0, **delta):
"""Return date range query within time span of date.
:param date: origin date or tuple
:param days,delta: timedelta parameters
"""
if not isinstance(date, datetime.date):
date = datetime.datetime(*(tuple(date) + (None, 1, 1)[len(date):]))
delta = datetime.timedelta(days, **delta)
return self.range(*sorted([date, date + delta]), upper=True)
[docs] def within(self, days=0, weeks=0, utc=True, **delta):
"""Return date range query within current time and delta.
If the delta is an exact number of days, then dates will be used.
:param days,weeks: number of days to offset from today
:param utc: optionally use utc instead of local time
:param delta: additional timedelta parameters
"""
date = datetime.datetime.utcnow() if utc else datetime.datetime.now()
if not (isinstance(days + weeks, float) or delta):
date = date.date()
return self.duration(date, days, weeks=weeks, **delta)
[docs]class Document(object):
"""Delegated lucene Document.
Provides mapping interface of field names to values, but duplicate field names are allowed.
"""
def __init__(self, doc):
self.doc = doc
[docs] def __len__(self):
return self.doc.getFields().size()
[docs] def __contains__(self, name):
return self.doc[name] is not None
[docs] def __iter__(self):
for field in self.doc.getFields():
yield field.name()
[docs] def items(self):
"Generate name, value pairs for all fields."
for field in self.doc.getFields():
yield field.name(), field.stringValue()
[docs] def __getitem__(self, name):
value = self.doc[name]
if value is None:
raise KeyError(name)
return value
[docs] def get(self, name, default=None):
"Return field value if present, else default."
value = self.doc[name]
return default if value is None else value
[docs] def getlist(self, name):
"Return list of all values for given field."
return list(self.doc.getValues(name))
[docs] def dict(self, *names, **defaults):
"""Return dict representation of document.
:param names: names of multi-valued fields to return as a list
:param defaults: include only given fields, using default values as necessary
"""
for name, value in defaults.items():
defaults[name] = self.get(name, value)
if not defaults:
defaults = dict(self.items())
defaults.update(zip(names, map(self.getlist, names)))
return defaults
[docs]class Hit(Document):
"A Document with an id and score, from a search result."
def __init__(self, doc, id, score):
Document.__init__(self, doc)
self.id, self.score = id, score
[docs] def dict(self, *names, **defaults):
"Return dict representation of document with __id__ and __score__."
result = Document.dict(self, *names, **defaults)
result.update(__id__=self.id, __score__=self.score)
return result
[docs]class Hits(object):
"""Search results: lazily evaluated and memory efficient.
Provides a read-only sequence interface to hit objects.
:param searcher: `IndexSearcher`_ which can retrieve documents
:param ids: ordered doc ids
:param scores: ordered doc scores
:param count: total number of hits
:param maxscore: maximum score
:param fields: optional field selectors
"""
def __init__(self, searcher, ids, scores, count=None, maxscore=None, fields=None):
self.searcher = searcher
self.ids, self.scores = ids, scores
self.count, self.maxscore = count, maxscore
self.fields = lucene.MapFieldSelector(fields) if isinstance(fields, collections.Iterable) else fields
[docs] def __len__(self):
return len(self.ids)
[docs] def __getitem__(self, index):
id, score = self.ids[index], self.scores[index]
if isinstance(index, slice):
return type(self)(self.searcher, id, score, self.count, self.maxscore, self.fields)
return Hit(self.searcher.doc(id, self.fields), id, score)
[docs] def items(self):
"Generate zipped ids and scores."
return zip(self.ids, self.scores)
[docs] def groupby(self, func):
"Return ordered list of `Hits`_ grouped by value of function applied to doc ids."
groups = {}
for id, score in self.items():
value = func(id)
try:
group = groups[value]
except KeyError:
group = groups[value] = type(self)(self.searcher, [], [], fields=self.fields)
group.index, group.value = len(groups), value
group.ids.append(id)
group.scores.append(score)
return sorted(groups.values(), key=lambda group: group.__dict__.pop('index'))