Source code for engine.documents

"""
Wrappers for lucene Fields and Documents.
"""

from future_builtins import map, zip
import warnings
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 attrs: additional attributes to set on the field """ def __init__(self, name, store=False, index='analyzed', termvector=False, **attrs): self.name = name self.attrs = attrs if isinstance(store, bool): store = 'yes' if store else 'no' if isinstance(index, bool): index = 'not_analyzed' if index else 'no' if isinstance(termvector, bool): termvector = 'yes' if termvector else 'no' for name, value in zip(['Store', 'Index', 'TermVector'], [store, index, termvector]): setattr(self, name.lower(), getattr(getattr(lucene.Field, name), value.upper()))
[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 FormatField(Field): """Field which uses string formatting on its values. :param format: format string """ def __init__(self, name, format='{0}', **kwargs): Field.__init__(self, name, **kwargs) self.format = format.format
[docs] def items(self, *values): "Generate fields with formatted values." return Field.items(self, *map(self.format, values))
class PrefixField(Field): """Field which indexes every prefix of a value into a separate component field. The customizable component field names are expressed as slices. Original value may be stored for convenience. :param start,stop,step: optional slice parameters of the prefix depths (not indices) """ def __init__(self, name, start=1, stop=None, step=1, index=True, **kwargs): warnings.warn('PrefixFields have been deprecated; customize NestedField instead.', DeprecationWarning) Field.__init__(self, name, index=index, **kwargs) self.depths = slice(start, stop, step) def split(self, text): "Return immutable sequence of words from name or value." return text def join(self, words): "Return text from separate words." return words def getname(self, depth): "Return prefix field name for given depth." return '{0}[:{1:d}]'.format(self.name, depth) def indices(self, depth): "Return range of valid depth indices." return xrange(*self.depths.indices(depth + self.depths.step)) def items(self, *values): """Generate indexed component fields. Optimized to handle duplicate values. """ if self.store != lucene.Field.Store.NO: for value in values: yield lucene.Field(self.name, value, self.store, lucene.Field.Index.NO) values = list(map(self.split, values)) for depth in self.indices(max(map(len, values))): name = self.getname(depth) for value in sorted(set(value[:depth] for value in values if len(value) > (depth-self.depths.step))): yield lucene.Field(name, self.join(value), lucene.Field.Store.NO, self.index, self.termvector) def prefix(self, value): "Return prefix query of the closest possible prefixed field." depths = self.indices(len(self.split(value))) depth = depths[-1] if depths else self.depths.start return Query.prefix(self.getname(depth), value) def range(self, start, stop, lower=True, upper=False): "Return range query of the closest possible prefixed field." depths = self.indices(max(len(self.split(value)) for value in (start, stop) if value is not None)) depth = depths[-1] if depths else self.depths.start return Query.range(self.getname(depth), start, stop, lower, upper)
[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): if sep not in name and ':' in name: warnings.warn("Default separator has changed from ':' to '.'", DeprecationWarning) sep = ':' 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 != lucene.Field.Store.NO: 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]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 = tuple(date) + (None, 1, 1)[len(date):] date = (datetime.datetime if len(date) > 3 else datetime.date)(*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 fields(self): "Generate lucene Fields." return map(lucene.Field.cast_, self.doc.getFields())
[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.fields(): yield field.name()
[docs] def items(self): "Generate name, value pairs for all fields." for field in self.fields(): 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: `Searcher`_ 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)