Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tree: 2c2bdc6254
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 810 lines (633 sloc) 31.192 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809
import datetime
from dateutil.parser import parse
from decimal import Decimal
import re
from django.core.exceptions import ObjectDoesNotExist, MultipleObjectsReturned
from django.utils import datetime_safe, importlib
from tastypie.bundle import Bundle
from tastypie.exceptions import ApiFieldError, NotFound, BadRequest
from tastypie.utils import dict_strip_unicode_keys

class NOT_PROVIDED:
    pass


DATE_REGEX = re.compile('^(?P<year>\d{4})-(?P<month>\d{2})-(?P<day>\d{2}).*?$')
DATETIME_REGEX = re.compile('^(?P<year>\d{4})-(?P<month>\d{2})-(?P<day>\d{2})(T|\s+)(?P<hour>\d{2}):(?P<minute>\d{2}):(?P<second>\d{2}).*?$')


# All the ApiField variants.

class ApiField(object):
    """The base implementation of a field used by the resources."""
    dehydrated_type = 'string'
    help_text = ''
    
    def __init__(self, attribute=None, default=NOT_PROVIDED, null=False, blank=False, readonly=False, unique=False, help_text=None):
        """
Sets up the field. This is generally called when the containing
``Resource`` is initialized.
Optionally accepts an ``attribute``, which should be a string of
either an instance attribute or callable off the object during the
``dehydrate`` or push data onto an object during the ``hydrate``.
Defaults to ``None``, meaning data will be manually accessed.
Optionally accepts a ``default``, which provides default data when the
object being ``dehydrated``/``hydrated`` has no data on the field.
Defaults to ``NOT_PROVIDED``.
Optionally accepts a ``null``, which indicated whether or not a
``None`` is allowable data on the field. Defaults to ``False``.
Optionally accepts a ``blank``, which indicated whether or not
data may be omitted on the field. Defaults to ``False``.
Optionally accepts a ``readonly``, which indicates whether the field
is used during the ``hydrate`` or not. Defaults to ``False``.
Optionally accepts a ``unique``, which indicates if the field is a
unique identifier for the object.
Optionally accepts ``help_text``, which lets you provide a
human-readable description of the field exposed at the schema level.
Defaults to the per-Field definition.
"""
        # Track what the index thinks this field is called.
        self.instance_name = None
        self._resource = None
        self.attribute = attribute
        self._default = default
        self.null = null
        self.blank = blank
        self.readonly = readonly
        self.value = None
        self.unique = unique
        
        if help_text:
            self.help_text = help_text
    
    def contribute_to_class(self, cls, name):
        # Do the least we can here so that we don't hate ourselves in the
        # morning.
        self.instance_name = name
        self._resource = cls
    
    def has_default(self):
        """Returns a boolean of whether this field has a default value."""
        return self._default is not NOT_PROVIDED
    
    @property
    def default(self):
        """Returns the default value for the field."""
        if callable(self._default):
            return self._default()
        
        return self._default
    
    def dehydrate(self, bundle):
        """
Takes data from the provided object and prepares it for the
resource.
"""
        if self.attribute is not None:
            # Check for `__` in the field for looking through the relation.
            attrs = self.attribute.split('__')
            current_object = bundle.obj
            
            for attr in attrs:
                previous_object = current_object
                current_object = getattr(current_object, attr, None)
                
                if current_object is None:
                    if self.has_default():
                        current_object = self._default
                        # Fall out of the loop, given any further attempts at
                        # accesses will fail miserably.
                        break
                    elif self.null:
                        current_object = None
                        # Fall out of the loop, given any further attempts at
                        # accesses will fail miserably.
                        break
                    else:
                        raise ApiFieldError("The object '%r' has an empty attribute '%s' and doesn't allow a default or null value." % (previous_object, attr))
            
            if callable(current_object):
                current_object = current_object()
            
            return self.convert(current_object)
        
        if self.has_default():
            return self.convert(self.default)
        else:
            return None
    
    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
    
    def hydrate(self, bundle):
        """
Takes data stored in the bundle for the field and returns it. Used for
taking simple data and building a instance object.
"""
        if self.readonly:
            return None
        
        if not bundle.data.has_key(self.instance_name):
            if self.blank:
                return None
            elif self.attribute and getattr(bundle.obj, self.attribute, None):
                return getattr(bundle.obj, self.attribute)
            elif self.instance_name and hasattr(bundle.obj, self.instance_name):
                return getattr(bundle.obj, self.instance_name)
            elif self.has_default():
                if callable(self._default):
                    return self._default()
                
                return self._default
            elif self.null:
                return None
            else:
                raise ApiFieldError("The '%s' field has no data and doesn't allow a default or null value." % self.instance_name)
        
        return bundle.data[self.instance_name]


class CharField(ApiField):
    """
A text field of arbitrary length.
Covers both ``models.CharField`` and ``models.TextField``.
"""
    dehydrated_type = 'string'
    help_text = 'Unicode string data. Ex: "Hello World"'
    
    def convert(self, value):
        if value is None:
            return None
        
        return unicode(value)


class FileField(ApiField):
    """
A file-related field.
Covers both ``models.FileField`` and ``models.ImageField``.
"""
    dehydrated_type = 'string'
    help_text = 'A file URL as a string. Ex: "http://media.example.com/media/photos/my_photo.jpg"'
    
    def convert(self, value):
        if value is None:
            return None
        
        try:
            # Try to return the URL if it's a ``File``, falling back to the string
            # itself if it's been overridden or is a default.
            return getattr(value, 'url', value)
        except ValueError:
            return None


class IntegerField(ApiField):
    """
An integer field.
Covers ``models.IntegerField``, ``models.PositiveIntegerField``,
``models.PositiveSmallIntegerField`` and ``models.SmallIntegerField``.
"""
    dehydrated_type = 'integer'
    help_text = 'Integer data. Ex: 2673'
    
    def convert(self, value):
        if value is None:
            return None
        
        return int(value)


class FloatField(ApiField):
    """
A floating point field.
"""
    dehydrated_type = 'float'
    help_text = 'Floating point numeric data. Ex: 26.73'
    
    def convert(self, value):
        if value is None:
            return None
        
        return float(value)


class DecimalField(ApiField):
    """
A decimal field.
"""
    dehydrated_type = 'decimal'
    help_text = 'Fixed precision numeric data. Ex: 26.73'
    
    def convert(self, value):
        if value is None:
            return None
        
        return Decimal(value)


class BooleanField(ApiField):
    """
A boolean field.
Covers both ``models.BooleanField`` and ``models.NullBooleanField``.
"""
    dehydrated_type = 'boolean'
    help_text = 'Boolean data. Ex: True'
    
    def convert(self, value):
        if value is None:
            return None
        
        return bool(value)


class ListField(ApiField):
    """
A list field.
"""
    dehydrated_type = 'list'
    help_text = "A list of data. Ex: ['abc', 26.73, 8]"
    
    def convert(self, value):
        if value is None:
            return None
        
        return list(value)


class DictField(ApiField):
    """
A dictionary field.
"""
    dehydrated_type = 'dict'
    help_text = "A dictionary of data. Ex: {'price': 26.73, 'name': 'Daniel'}"
    
    def convert(self, value):
        if value is None:
            return None
        
        return dict(value)


class DateField(ApiField):
    """
A date field.
"""
    dehydrated_type = 'date'
    help_text = 'A date as a string. Ex: "2010-11-10"'
    
    def convert(self, value):
        if value is None:
            return None
        
        if isinstance(value, basestring):
            match = DATE_REGEX.search(value)
            
            if match:
                data = match.groupdict()
                return datetime_safe.date(int(data['year']), int(data['month']), int(data['day']))
            else:
                raise ApiFieldError("Date provided to '%s' field doesn't appear to be a valid date string: '%s'" % (self.instance_name, value))
        
        return value
    
    def hydrate(self, bundle):
        value = super(DateField, self).hydrate(bundle)
        
        if value and not hasattr(value, 'year'):
            try:
                # Try to rip a date/datetime out of it.
                value = parse(value)
                
                if hasattr(value, 'hour'):
                    value = value.date()
            except ValueError:
                pass
        
        return value


class DateTimeField(ApiField):
    """
A datetime field.
"""
    dehydrated_type = 'datetime'
    help_text = 'A date & time as a string. Ex: "2010-11-10T03:07:43"'
    
    def convert(self, value):
        if value is None:
            return None
        
        if isinstance(value, basestring):
            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']))
            else:
                raise ApiFieldError("Datetime provided to '%s' field doesn't appear to be a valid datetime string: '%s'" % (self.instance_name, value))
        
        return value
    
    def hydrate(self, bundle):
        value = super(DateTimeField, self).hydrate(bundle)
        
        if value and not hasattr(value, 'year'):
            try:
                # Try to rip a date/datetime out of it.
                value = parse(value)
            except ValueError:
                pass
        
        return value


class RelatedField(ApiField):
    """
Provides access to data that is related within the database.
The ``RelatedField`` base class is not intended for direct use but provides
functionality that ``ToOneField`` and ``ToManyField`` build upon.
The contents of this field actually point to another ``Resource``,
rather than the related object. This allows the field to represent its data
in different ways.
The abstractions based around this are "leaky" in that, unlike the other
fields provided by ``tastypie``, these fields don't handle arbitrary objects
very well. The subclasses use Django's ORM layer to make things go, though
there is no ORM-specific code at this level.
"""
    dehydrated_type = 'related'
    is_related = True
    self_referential = False
    help_text = 'A related resource. Can be either a URI or set of nested resource data.'
    
    def __init__(self, to, attribute, related_name=None, default=NOT_PROVIDED, null=False, blank=False, readonly=False, full=False, unique=False, help_text=None, contenttype_field=None):
        """
Builds the field and prepares it to access to related data.
The ``to`` argument should point to a ``Resource`` class, NOT
to a ``Model`` or be a dictionary matching ``Model`` classes to ``Resource`` classes. Required.
The ``attribute`` argument should specify what field/callable points to
the related data on the instance object. Required.
Optionally accepts a ``related_name`` argument. Currently unused, as
unlike Django's ORM layer, reverse relations between ``Resource``
classes are not automatically created. Defaults to ``None``.
Optionally accepts a ``null``, which indicated whether or not a
``None`` is allowable data on the field. Defaults to ``False``.
Optionally accepts a ``blank``, which indicated whether or not
data may be omitted on the field. Defaults to ``False``.
Optionally accepts a ``readonly``, which indicates whether the field
is used during the ``hydrate`` or not. Defaults to ``False``.
Optionally accepts a ``full``, which indicates how the related
``Resource`` will appear post-``dehydrate``. If ``False``, the
related ``Resource`` will appear as a URL to the endpoint of that
resource. If ``True``, the result of the sub-resource's
``dehydrate`` will be included in full.
Optionally accepts a ``unique``, which indicates if the field is a
unique identifier for the object.
Optionally accepts ``help_text``, which lets you provide a
human-readable description of the field exposed at the schema level.
Defaults to the per-Field definition.
Optionally accepts ``contenttype_field`` which is the
field which points to the appropriate contenttype for the relation.
Dictionary must be provided for ``to`` to provide ``Resource`` mappings
for possible content types or a ``ValueError`` will be raised.
"""
        self.instance_name = None
        self._resource = None
        self.to = to
        self.attribute = attribute
        self.related_name = related_name
        self._default = default
        self.null = null
        self.blank = blank
        self.readonly = readonly
        self.full = full
        self.api_name = None
        self.resource_name = None
        self.unique = unique
        self._to_class = None
        self.contenttype_field = contenttype_field
        
        if self.contenttype_field and not isinstance(self.to, dict):
            raise ValueError(
                "to argument must be a dictionary " +
                "when used with contenttype_field")

        if self.contenttype_field and not issubclass(type(self.contenttype_field), ToOneField):
            raise ValueError(
                "contenttype_field must be a ToOneField which provides access"+
                " to the Resource's content_type ForeignKey")
            from tastypie.resources import ContentTypeResource
            if not issubclass(type(self.contentype_field.to), ContentTypeResource):
                raise ValueError("contenttype_field.to must be a ContentTypeResource or subclass")
        if self.to == 'self':
            self.self_referential = True
            self._to_class = self.__class__
        
        if help_text:
            self.help_text = help_text
    
    def contribute_to_class(self, cls, name):
        super(RelatedField, self).contribute_to_class(cls, name)
        
        # Check if we're self-referential and hook it up.
        # We can't do this quite like Django because there's no ``AppCache``
        # here (which I think we should avoid as long as possible).
        if self.self_referential or self.to == 'self':
            self._to_class = cls
    
    def get_related_resource(self, related_instance):
        """
Instaniates the related resource.
"""
        related_resource = self.to_class()
        
        if isinstance(self.to, dict):
            # we're using a dict for self.to. we also finally know the
            # actual type of the related object
            self._to_class = self.to[type(related_instance)]
            # TODO make so if key is not in dictionary we check if we have default or set to null
            related_resource = self.to_class()
                
        
        # Fix the ``api_name`` if it's not present.
        if related_resource._meta.api_name is None:
            if self._resource and not self._resource._meta.api_name is None:
                related_resource._meta.api_name = self._resource._meta.api_name
        
        # Try to be efficient about DB queries.
        related_resource.instance = related_instance
        return related_resource
    
    @property
    def to_class(self):
        # We need to be lazy here, because when the metaclass constructs the
        # Resources, other classes may not exist yet.
        # That said, memoize this so we never have to relookup/reimport.
        if self._to_class:
            return self._to_class
        
        if not isinstance(self.to, basestring):
            if isinstance(self.to, dict):
                # we're expected to return a functioning resource class
                # import is here because at top it creates a circular import to
                # resources
                from tastypie.resources import ModelResource
                self._to_class = ModelResource
            else:
                self._to_class = self.to
            return self._to_class
        
        # It's a string. Let's figure it out.
        if '.' in self.to:
            # Try to import.
            module_bits = self.to.split('.')
            module_path, class_name = '.'.join(module_bits[:-1]), module_bits[-1]
            module = importlib.import_module(module_path)
        else:
            # We've got a bare class name here, which won't work (No AppCache
            # to rely on). Try to throw a useful error.
            raise ImportError("Tastypie requires a Python-style path (<module.module.Class>) to lazy load related resources. Only given '%s'." % self.to)
        
        self._to_class = getattr(module, class_name, None)
        
        if self._to_class is None:
            raise ImportError("Module '%s' does not appear to have a class called '%s'." % (module_path, class_name))
        
        return self._to_class
    
    def dehydrate_related(self, bundle, related_resource):
        """
Based on the ``full_resource``, returns either the endpoint or the data
from ``full_dehydrate`` for the related resource.
"""
        if not self.full:
            # Be a good netizen.
            return related_resource.get_resource_uri(bundle)
        else:
            # ZOMG extra data and big payloads.
            bundle = related_resource.build_bundle(obj=related_resource.instance, request=bundle.request)
            return related_resource.full_dehydrate(bundle)
    
    def build_related_resource(self, value, request=None, resource_type=None):
        """
Used to ``hydrate`` the data provided. If just a URL is provided,
the related resource is attempted to be loaded. If a
dictionary-like structure is provided, a fresh resource is
created.
"""
        
        if resource_type:
            self._to_class = resource_type
            
        self.fk_resource = self.to_class()
    
        if isinstance(value, basestring):
            # We got a URI. Load the object and assign it.
            try:
                obj = self.fk_resource.get_via_uri(value)
                # at this point even though our obj is the right type,
                # fk_resource may be the wrong type. set it to the right type
                if isinstance(self.to, dict):
                    self.fk_resource = self.get_related_resource(obj)
                bundle = self.fk_resource.build_bundle(obj=obj, request=request)
                return self.fk_resource.full_dehydrate(bundle)
            except ObjectDoesNotExist:
                raise ApiFieldError("Could not find the provided object via resource URI '%s'." % value)
        elif hasattr(value, 'items'):
            # Make sure they included the contenttype_field which is required
            # if the api is used in this way.
            if not resource_type and isinstance(self.to, dict):
                if self.contenttype_field:
                    raise BadRequest("You must set the %s field when setting a GenericForeignKey in this way" % (self.contenttype_field.instance_name))
            # Try to hydrate the data provided.
            value = dict_strip_unicode_keys(value)
                
            self.fk_bundle = self.fk_resource.build_bundle(data=value, request=request)
            
            # We need to check to see if updates are allowed on the FK
            # resource. If not, we'll just return a populated bundle instead
            # of mistakenly updating something that should be read-only.
            if not self.fk_resource.can_update():
                return self.fk_resource.full_hydrate(self.fk_bundle)
            
            try:
                return self.fk_resource.obj_update(self.fk_bundle, **value)
            except NotFound:
                try:
                    # Attempt lookup by primary key
                    lookup_kwargs = dict((k, v) for k, v in value.iteritems() if getattr(self.fk_resource, k).unique)
                    
                    if not lookup_kwargs:
                        raise NotFound()
                    
                    return self.fk_resource.obj_update(self.fk_bundle, **lookup_kwargs)
                except NotFound:
                    return self.fk_resource.full_hydrate(self.fk_bundle)
            except MultipleObjectsReturned:
                return self.fk_resource.full_hydrate(self.fk_bundle)
        elif hasattr(value, 'pk'):
            bundle = self.fk_resource.build_bundle(obj=value, request=request)
            return self.fk_resource.full_dehydrate(bundle)
        else:
            raise ApiFieldError("The '%s' field has was given data that was not a URI and not a dictionary-alike: %s." % (self.instance_name, value))


class ToOneField(RelatedField):
    """
Provides access to related data via foreign key.
This subclass requires Django's ORM layer to work properly.
"""
    help_text = 'A single related resource. Can be either a URI or set of nested resource data.'
    
    def __init__(self, to, attribute, related_name=None, default=NOT_PROVIDED, null=False, blank=False, readonly=False, full=False, unique=False, help_text=None, contenttype_field=None):
        if isinstance(to, dict):
            if contenttype_field:
                help_text = 'A single related resource. Can be either a URI or set of nested resource data. If nested resource data is provided, the resource\'s %s must be set.' % contenttype_field.instance_name
        super(ToOneField, self).__init__(to, attribute, related_name=related_name, default=default, null=null, blank=blank, readonly=readonly, full=full, unique=unique, help_text=help_text, contenttype_field=contenttype_field)
        self.fk_resource = None
    
    def dehydrate(self, bundle):
        try:
            foreign_obj = getattr(bundle.obj, self.attribute)
        except ObjectDoesNotExist:
            foreign_obj = None
        
        if not foreign_obj:
            if not self.null:
                raise ApiFieldError("The model '%r' has an empty attribute '%s' and doesn't allow a null value." % (bundle.obj, self.attribute))
            
            return None
        
        self.fk_resource = self.get_related_resource(foreign_obj)
        fk_bundle = Bundle(obj=foreign_obj, request=bundle.request)
        return self.dehydrate_related(fk_bundle, self.fk_resource)
    
    def hydrate(self, bundle):
        value = super(ToOneField, self).hydrate(bundle)
        
        if value is None:
            return value
        
        resource_type = None
        # see if we have a contenttype_field
        if self.contenttype_field:
            # find out the class of model we're looking at from this field
            related_content_type = self.contenttype_field.hydrate(bundle)
            if related_content_type:
                resource_type = self.to[related_content_type.obj.model_class()]
            else:
                # check to see if the obj knows its content type
                try:
                    if hasattr(bundle.obj, self.contenttype_field.attribute):
                        resource_type = getattr(bundle.obj, self.contenttype_field.attribute)
                        if resource_type:
                            resource_type = self.to[resource_type.model_class()]
                except ObjectDoesNotExist:
                    resource_type = None
        if 'content_type' in bundle.data and not 'content_object' in bundle.data:
            raise BadRequest("You must supply a content_object when setting content_type")
        
        return self.build_related_resource(value, request=bundle.request,
                                           resource_type=resource_type)

class ForeignKey(ToOneField):
    """
A convenience subclass for those who prefer to mirror ``django.db.models``.
"""
    pass


class OneToOneField(ToOneField):
    """
A convenience subclass for those who prefer to mirror ``django.db.models``.
"""
    pass

class ContentTypeField(ToOneField):
    """
A convenience subclass to easily create a ContentTypeField for a
``ContentType`` ForeignKey. Assumes ``django.contrib.contentypes`` is an
installed app. Ensure you register ``ContentTypeResource`` with your
``Api`` or include ContentTypeResource URLs in another manner.
"""
    def __init__(self, to=None, attribute="content_type", related_name=None, default=NOT_PROVIDED, null=False, blank=True, readonly=False, full=False, unique=False, help_text=None, contenttype_field=None):
        from tastypie.resources import ContentTypeResource
        if not to:
            to = ContentTypeResource
        super(ToOneField, self).__init__(to, attribute, related_name=related_name, default=default, null=null, blank=blank, readonly=readonly, full=full, unique=unique, help_text=help_text, contenttype_field=contenttype_field)
        self.fk_resource = None
        
class ToManyField(RelatedField):
    """
Provides access to related data via a join table.
This subclass requires Django's ORM layer to work properly.
Note that the ``hydrate`` portions of this field are quite different than
any other field. ``hydrate_m2m`` actually handles the data and relations.
This is due to the way Django implements M2M relationships.
Can be used to represent a ``GenericRelation``
(reverse of ``GenericForeignKey``). Simply set ``to`` to the resource
which represents the other end of the relation.
"""
    is_m2m = True
    help_text = 'Many related resources. Can be either a list of URIs or list of individually nested resource data.'
    
    def __init__(self, to, attribute, related_name=None, default=NOT_PROVIDED, null=False, blank=False, readonly=False, full=False, unique=False, help_text=None):
        super(ToManyField, self).__init__(to, attribute, related_name=related_name, default=default, null=null, blank=blank, readonly=readonly, full=full, unique=unique, help_text=help_text)
        self.m2m_bundles = []
    
    def dehydrate(self, bundle):
        if not bundle.obj or not bundle.obj.pk:
            if not self.null:
                raise ApiFieldError("The model '%r' does not have a primary key and can not be used in a ToMany context." % bundle.obj)
            
            return []
        
        if isinstance(self.attribute, basestring):
            the_m2ms = getattr(bundle.obj, self.attribute)
        elif callable(self.attribute):
            the_m2ms = self.attribute(bundle)
        
        if not the_m2ms:
            if not self.null:
                raise ApiFieldError("The model '%r' has an empty attribute '%s' and doesn't allow a null value." % (bundle.obj, self.attribute))
            
            return []
        
        self.m2m_resources = []
        m2m_dehydrated = []
        
        # TODO: Also model-specific and leaky. Relies on there being a
        # ``Manager`` there.
        for m2m in the_m2ms.all():
            m2m_resource = self.get_related_resource(m2m)
            m2m_bundle = Bundle(obj=m2m, request=bundle.request)
            self.m2m_resources.append(m2m_resource)
            m2m_dehydrated.append(self.dehydrate_related(m2m_bundle, m2m_resource))
        
        return m2m_dehydrated
    
    def hydrate(self, bundle):
        pass
    
    def hydrate_m2m(self, bundle):
        if self.readonly:
            return None
        
        if bundle.data.get(self.instance_name) is None:
            if self.blank:
                return []
            elif self.null:
                return []
            else:
                raise ApiFieldError("The '%s' field has no data and doesn't allow a null value." % self.instance_name)
        
        m2m_hydrated = []
        
        for value in bundle.data.get(self.instance_name):
            if value is None:
                continue
            
            m2m_hydrated.append(self.build_related_resource(value, request=bundle.request))
        
        return m2m_hydrated


class ManyToManyField(ToManyField):
    """
A convenience subclass for those who prefer to mirror ``django.db.models``.
"""
    pass


class OneToManyField(ToManyField):
    """
A convenience subclass for those who prefer to mirror ``django.db.models``.
"""
    pass


class TimeField(ApiField):
    dehydrated_type = 'time'
    help_text = 'A time as string. Ex: "20:05:23"'

    def dehydrate(self, obj):
        return self.convert(super(TimeField, self).dehydrate(obj))

    def convert(self, value):
        if isinstance(value, basestring):
            return self.to_time(value)
        return value

    def to_time(self, s):
        try:
            dt = parse(s)
        except ValueError, e:
            raise ApiFieldError(str(e))
        else:
            return datetime.time(dt.hour, dt.minute, dt.second)

    def hydrate(self, bundle):
        value = super(TimeField, self).hydrate(bundle)
        
        if value and not isinstance(value, datetime.time):
            value = self.to_time(value)
        
        return value
Something went wrong with that request. Please try again.