fields.py

# PATCH to [virtual environment
# path]/lib/python2.7/site-packages/haystack/fields.py encoding: utf-8
from __future__ import (absolute_import, division, print_function,
                        unicode_literals)

import re
from inspect import ismethod

from django.template import loader
from django.utils import datetime_safe, six
from haystack.exceptions import SearchFieldError
from haystack.utils import get_model_ct_tuple
from haystack.utils.geo import Point, ensure_point


class NotProvided:
    pass


# Note that dates in the full ISO 8601 format will be accepted as long as the
# hour/minute/second components are zeroed for compatibility with search
# backends which lack a date time distinct from datetime:
DATE_REGEX = re.compile(
    r'^(?P<year>\d{4})-(?P<month>\d{2})-(?P<day>\d{2})(?:|T00:00:00Z?)$')
DATETIME_REGEX = re.compile(
    r'^(?P<year>\d{4})-(?P<month>\d{2})-(?P<day>\d{2})'
    r'(T|\s+)(?P<hour>\d{2}):(?P<minute>\d{2}):(?P<second>\d{2}).*?$'
)

# All the SearchFields variants.


class SearchField:
    """The base implementation of a search field."""
    field_type = None

    def __init__(self,
                 model_attr=None,
                 use_template=False,
                 template_name=None,
                 document=False,
                 indexed=True,
                 stored=True,
                 faceted=False,
                 default=NotProvided,
                 null=False,
                 index_fieldname=None,
                 facet_class=None,
                 boost=1.0,
                 weight=None):
        # Track what the index thinks this field is called.
        self.instance_name = None
        self.model_attr = model_attr
        self.use_template = use_template
        self.template_name = template_name
        self.document = document
        self.indexed = indexed
        self.stored = stored
        self.faceted = faceted
        self._default = default
        self.null = null
        self.index_fieldname = index_fieldname
        self.boost = weight or boost
        self.is_multivalued = False

        # We supply the facet_class for making it easy to create a faceted
        # field based off of this field.
        self.facet_class = facet_class

        if self.facet_class is None:
            self.facet_class = FacetCharField

        self.set_instance_name(None)

    def set_instance_name(self, instance_name):
        self.instance_name = instance_name

        if self.index_fieldname is None:
            self.index_fieldname = self.instance_name

    def has_default(self):
        """Returns a boolean of whether this field has a default value."""
        return self._default is not NotProvided

    @property
    def default(self):
        """Returns the default value for the field."""
        if callable(self._default):
            return self._default()

        return self._default

    def prepare(self, obj):
        """
        Takes data from the provided object and prepares it for storage in the
        index.
        """
        # Give priority to a template.
        if self.use_template:
            return self.prepare_template(obj)
        if self.model_attr is not None:
            attrs = self.split_model_attr_lookups()
            current_objects = [obj]

            values = self.resolve_attributes_lookup(current_objects, attrs)

            if len(values) == 1:
                return values[0]
            return values

        if self.has_default():
            return self.default
        return None

    def resolve_attributes_lookup(self, current_objects, attributes):
        """
        Recursive method that looks, for one or more objects, for an attribute
        that can be multiple objects (relations) deep.
        """
        values = []

        for current_object in current_objects:
            if not hasattr(current_object, attributes[0]):
                raise SearchFieldError(
                    "The model '%s' does not have a model_attr '%s'." %
                    (repr(current_object), attributes[0]))

            if len(attributes) > 1:
                current_objects_in_attr = self.get_iterable_objects(
                    getattr(current_object, attributes[0]))
                return self.resolve_attributes_lookup(current_objects_in_attr,
                                                      attributes[1:])

            current_object = getattr(current_object, attributes[0])

            if current_object is None:
                if self.has_default():
                    current_object = self._default
                elif self.null:
                    current_object = None
                else:
                    raise SearchFieldError(
                        "The model '%s' combined with model_attr '%s' "
                        "returned None, but doesn't allow a default or null "
                        "value." % (repr(current_object), self.model_attr))

            if callable(current_object):
                values.append(current_object())
            else:
                values.append(current_object)

        return values

    def split_model_attr_lookups(self):
        """Returns list of nested attributes for looking through the
        relation."""
        return self.model_attr.split('__')

    @classmethod
    def get_iterable_objects(cls, current_objects):
        """
        Returns iterable of objects that contain data. For example, resolves
        Django ManyToMany relationship so the attributes of the related models
        can then be accessed.
        """
        if current_objects is None:
            return []

        if hasattr(current_objects, 'all'):
            # i.e, Django ManyToMany relationships
            if ismethod(current_objects.all):
                return current_objects.all()
            return []

        if not hasattr(current_objects, '__iter__'):
            current_objects = [current_objects]

        return current_objects

    def prepare_template(self, obj):
        """
        Flattens an object for indexing.

        This loads a template
        (``search/indexes/{app_label}/{model_name}_{field_name}.txt``) and
        returns the result of rendering that template. ``object`` will be in
        its context.
        """
        if self.instance_name is None and self.template_name is None:
            raise SearchFieldError(
                "This field requires either its instance_name variable to be "
                "populated or an explicit template_name in order to load the "
                "correct template."
            )

        if self.template_name is not None:
            template_names = self.template_name

            if not isinstance(template_names, (list, tuple)):
                template_names = [template_names]
        else:
            app_label, model_name = get_model_ct_tuple(obj)
            template_names = [
                'search/indexes/%s/%s_%s.txt' %
                (app_label, model_name, self.instance_name)
            ]

        t = loader.select_template(template_names)
        return t.render({'object': obj})

    def convert(self, value):
        """
        Handles conversion between the data found and the type of the field.

        Extending classes should override this method and provide correct
        data coercion.
        """
        return value


class CharField(SearchField):
    field_type = 'string'

    def __init__(self, **kwargs):
        if kwargs.get('facet_class') is None:
            kwargs['facet_class'] = FacetCharField

        super().__init__(**kwargs)

    def prepare(self, obj):
        return self.convert(super().prepare(obj))

    def convert(self, value):
        if value is None or value == []:
            return None

        return six.text_type(value)


class LocationField(SearchField):
    field_type = 'location'

    def prepare(self, obj):
        value = super().prepare(obj)

        if value is None or value == []:
            return None

        pnt = ensure_point(value)
        pnt_lng, pnt_lat = pnt.get_coords()
        return "%s,%s" % (pnt_lat, pnt_lng)

    def convert(self, value):
        if value is None or value == []:
            return None

        if hasattr(value, 'geom_type'):
            value = ensure_point(value)
            return value

        if isinstance(value, six.string_types):
            lat, lng = value.split(',')
        elif isinstance(value, (list, tuple)):
            # GeoJSON-alike
            lat, lng = value[1], value[0]
        elif isinstance(value, dict):
            lat = value.get('lat', 0)
            lng = value.get('lon', 0)

        value = Point(float(lng), float(lat))
        return value


class NgramField(CharField):
    field_type = 'ngram'

    def __init__(self, **kwargs):
        if kwargs.get('faceted') is True:
            raise SearchFieldError("%s can not be faceted." %
                                   self.__class__.__name__)

        super().__init__(**kwargs)


class EdgeNgramField(NgramField):
    field_type = 'edge_ngram'


class IntegerField(SearchField):
    field_type = 'integer'

    def __init__(self, **kwargs):
        if kwargs.get('facet_class') is None:
            kwargs['facet_class'] = FacetIntegerField

        super().__init__(**kwargs)

    def prepare(self, obj):
        return self.convert(super().prepare(obj))

    def convert(self, value):
        if value is None or value == []:
            return None
        return int(value)


class FloatField(SearchField):
    field_type = 'float'

    def __init__(self, **kwargs):
        if kwargs.get('facet_class') is None:
            kwargs['facet_class'] = FacetFloatField

        super().__init__(**kwargs)

    def prepare(self, obj):
        return self.convert(super().prepare(obj))

    def convert(self, value):
        if value is None or value == []:
            return None

        return float(value)


class DecimalField(SearchField):
    field_type = 'string'

    def __init__(self, **kwargs):
        if kwargs.get('facet_class') is None:
            kwargs['facet_class'] = FacetDecimalField

        super().__init__(**kwargs)

    def prepare(self, obj):
        return self.convert(super().prepare(obj))

    def convert(self, value):
        if value is None or value == []:
            return None

        return six.text_type(value)


class BooleanField(SearchField):
    field_type = 'boolean'

    def __init__(self, **kwargs):
        if kwargs.get('facet_class') is None:
            kwargs['facet_class'] = FacetBooleanField

        super().__init__(**kwargs)

    def prepare(self, obj):
        return self.convert(super().prepare(obj))

    def convert(self, value):
        if value is None or value == []:
            return None

        return bool(value)


class DateField(SearchField):
    field_type = 'date'

    def __init__(self, **kwargs):
        if kwargs.get('facet_class') is None:
            kwargs['facet_class'] = FacetDateField

        super().__init__(**kwargs)

    def prepare(self, obj):
        return self.convert(super().prepare(obj))

    def convert(self, value):
        if value is None or value == []:
            return None

        if isinstance(value, six.string_types):
            match = DATE_REGEX.search(value)

            if match:
                data = match.groupdict()
                return datetime_safe.date(
                    int(data['year']), int(data['month']), int(data['day']))
            raise SearchFieldError(
                "Date provided to '%s' field doesn't appear to be a valid "
                "date string: '%s'"
                % (self.instance_name, value))

        return value


class DateTimeField(SearchField):
    field_type = 'datetime'

    def __init__(self, **kwargs):
        if kwargs.get('facet_class') is None:
            kwargs['facet_class'] = FacetDateTimeField

        super().__init__(**kwargs)

    def prepare(self, obj):
        return self.convert(super().prepare(obj))

    def convert(self, value):
        if value is None or value == []:
            return None

        if isinstance(value, six.string_types):
            match = DATETIME_REGEX.search(value)

            if match:
                data = match.groupdict()
                return datetime_safe.datetime(int(data['year']),
                                              int(data['month']),
                                              int(data['day']),
                                              int(data['hour']),
                                              int(data['minute']),
                                              int(data['second']))
            raise SearchFieldError(
                "Datetime provided to '%s' field doesn't appear to be a valid "
                "datetime string: '%s'"
                % (self.instance_name, value))

        return value


class MultiValueField(SearchField):
    field_type = 'string'

    def __init__(self, **kwargs):
        if kwargs.get('facet_class') is None:
            kwargs['facet_class'] = FacetMultiValueField

        if kwargs.get('use_template') is True:
            raise SearchFieldError(
                "'%s' fields can not use templates to prepare their data." %
                self.__class__.__name__)

        super().__init__(**kwargs)
        self.is_multivalued = True

    def prepare(self, obj):
        return self.convert(super().prepare(obj))

    def convert(self, value):
        if value is None or value == []:
            return None

        if hasattr(value, '__iter__') and not isinstance(value, six.text_type):
            return value

        return [value]


class FacetField(SearchField):
    """
    ``FacetField`` is slightly different than the other fields because it can
    work in conjunction with other fields as its data source.

    Accepts an optional ``facet_for`` kwarg, which should be the field name
    (not ``index_fieldname``) of the field it should pull data from.
    """
    instance_name = None

    def __init__(self, **kwargs):
        handled_kwargs = self.handle_facet_parameters(kwargs)
        super().__init__(**handled_kwargs)

    def handle_facet_parameters(self, kwargs):
        if kwargs.get('faceted', False):
            raise SearchFieldError(
                "FacetField (%s) does not accept the 'faceted' argument." %
                self.instance_name)

        if not kwargs.get('null', True):
            raise SearchFieldError(
                "FacetField (%s) does not accept False for the 'null' "
                "argument."
                % self.instance_name)

        if not kwargs.get('indexed', True):
            raise SearchFieldError(
                "FacetField (%s) does not accept False for the 'indexed' "
                "argument."
                % self.instance_name)

        if kwargs.get('facet_class'):
            raise SearchFieldError(
                "FacetField (%s) does not accept the 'facet_class' argument." %
                self.instance_name)

        self.facet_for = None
        self.facet_class = None

        # Make sure the field is nullable.
        kwargs['null'] = True

        if 'facet_for' in kwargs:
            self.facet_for = kwargs['facet_for']
            del kwargs['facet_for']

        return kwargs

    def get_facet_for_name(self):
        return self.facet_for or self.instance_name


class FacetCharField(FacetField, CharField):
    pass


class FacetIntegerField(FacetField, IntegerField):
    pass


class FacetFloatField(FacetField, FloatField):
    pass


class FacetDecimalField(FacetField, DecimalField):
    pass


class FacetBooleanField(FacetField, BooleanField):
    pass


class FacetDateField(FacetField, DateField):
    pass


class FacetDateTimeField(FacetField, DateTimeField):
    pass


class FacetMultiValueField(FacetField, MultiValueField):
    pass