djangoappengine / db / compiler.py

  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
from .db_settings import get_model_indexes
from .utils import commit_locked
from .expressions import ExpressionEvaluator
from ..fields import GAEKeyField
from ..models import GAEKey, GAEAncestorKey

import datetime
import sys

from django.db.models.sql import aggregates as sqlaggregates
from django.db.models.sql.constants import LOOKUP_SEP, MULTI, SINGLE
from django.db.models.sql.where import AND, OR
from django.db.utils import DatabaseError, IntegrityError
from django.utils.tree import Node

from functools import wraps

from google.appengine.api.datastore import Entity, Query, MultiQuery, \
    Put, Get, Delete, Key
from google.appengine.api.datastore_errors import Error as GAEError
from google.appengine.api.datastore_types import Text, Category, Email, Link, \
    PhoneNumber, PostalAddress, Text, Blob, ByteString, GeoPt, IM, Key, \
    Rating, BlobKey

from djangotoolbox.db.basecompiler import NonrelQuery, NonrelCompiler, \
    NonrelInsertCompiler, NonrelUpdateCompiler, NonrelDeleteCompiler

import cPickle as pickle

import decimal

# Valid query types (a dictionary is used for speedy lookups).
OPERATORS_MAP = {
    'exact': '=',
    'gt': '>',
    'gte': '>=',
    'lt': '<',
    'lte': '<=',

    # The following operators are supported with special code below:
    'isnull': None,
    'in': None,
    'startswith': None,
    'range': None,
    'year': None,
}

NEGATION_MAP = {
    'gt': '<=',
    'gte': '<',
    'lt': '>=',
    'lte': '>',
    # TODO: support these filters
    #'exact': '!=', # this might actually become individual '<' and '>' queries
}

NOT_PROVIDED = object()

def safe_call(func):
    @wraps(func)
    def _func(*args, **kwargs):
        try:
            return func(*args, **kwargs)
        except GAEError, e:
            raise DatabaseError, DatabaseError(str(e)), sys.exc_info()[2]
    return _func

class GAEQuery(NonrelQuery):
    # ----------------------------------------------
    # Public API
    # ----------------------------------------------
    def __init__(self, compiler, fields):
        super(GAEQuery, self).__init__(compiler, fields)
        self.inequality_field = None
        self.pk_filters = None
        self.excluded_pks = ()
        self.has_negated_exact_filter = False
        self.ancestor_key = None
        self.ordering = ()
        self.gae_ordering = []
        pks_only = False
        if len(fields) == 1 and fields[0].primary_key:
            pks_only = True
        self.db_table = self.query.get_meta().db_table
        self.pks_only = pks_only
        start_cursor = getattr(self.query, '_gae_start_cursor', None)
        end_cursor = getattr(self.query, '_gae_end_cursor', None)
        self.gae_query = [Query(self.db_table, keys_only=self.pks_only,
                                cursor=start_cursor, end_cursor=end_cursor)]

    # This is needed for debugging
    def __repr__(self):
        return '<GAEQuery: %r ORDER %r>' % (self.gae_query, self.ordering)

    @safe_call
    def fetch(self, low_mark, high_mark):
        query = self._build_query()
        executed = False
        if self.excluded_pks and high_mark is not None:
            high_mark += len(self.excluded_pks)
        if self.pk_filters is not None:
            results = self.get_matching_pk(low_mark, high_mark)
        else:
            if high_mark is None:
                kw = {}
                if low_mark:
                    kw['offset'] = low_mark
                results = query.Run(**kw)
                executed = True
            elif high_mark > low_mark:
                results = query.Get(high_mark - low_mark, low_mark)
                executed = True
            else:
                results = ()

        for entity in results:
            if isinstance(entity, Key):
                key = entity
            else:
                key = entity.key()
            if key in self.excluded_pks:
                continue
            yield self._make_entity(entity)

        if executed and not isinstance(query, MultiQuery):
            try:
                self.query._gae_cursor = query.GetCompiledCursor()
            except:
                pass

    @safe_call
    def count(self, limit=NOT_PROVIDED):
        if self.pk_filters is not None:
            return len(self.get_matching_pk(0, limit))
        if self.excluded_pks:
            return len(list(self.fetch(0, 2000)))
        # The datastore's Count() method has a 'limit' kwarg, which has
        # a default value (obviously).  This value can be overridden to anything
        # you like, and importantly can be overridden to unlimited by passing
        # a value of None.  Hence *this* method has a default value of
        # NOT_PROVIDED, rather than a default value of None
        kw = {}
        if limit is not NOT_PROVIDED:
            kw['limit'] = limit
        return self._build_query().Count(**kw)

    @safe_call
    def delete(self):
        if self.pk_filters is not None:
            keys = [key for key in self.pk_filters if key is not None]
        else:
            keys = self.fetch()
        if keys:
            Delete(keys)

    @safe_call
    def order_by(self, ordering):
        self.ordering = ordering
        for order in self.ordering:
            if order.startswith('-'):
                order, direction = order[1:], Query.DESCENDING
            else:
                direction = Query.ASCENDING
            if order == self.query.get_meta().pk.column:
                order = '__key__'
            self.gae_ordering.append((order, direction))

    # This function is used by the default add_filters() implementation
    @safe_call
    def add_filter(self, column, lookup_type, negated, db_type, value):
        if value in ([], ()):
            self.pk_filters = []
            return

        # Emulated/converted lookups
        if column == self.query.get_meta().pk.column:
            column = '__key__'
            db_table = self.query.get_meta().db_table
            
            if lookup_type == 'exact' and isinstance(value, GAEAncestorKey):
                if negated:
                    raise DatabaseError("You can't negate an ancestor operation.")
                if self.ancestor_key is not None:
                    raise DatabaseError("You can't use more than one ancestor operation.")
                self.ancestor_key = value.key()
                return
            if lookup_type in ('exact', 'in'):
                # Optimization: batch-get by key
                if self.pk_filters is not None:
                    raise DatabaseError("You can't apply multiple AND filters "
                                        "on the primary key. "
                                        "Did you mean __in=[...]?")
                if not isinstance(value, (tuple, list)):
                    value = [value]
                pks = [create_key(db_table, pk) for pk in value if pk]
                if negated:
                    self.excluded_pks = pks
                else:
                    self.pk_filters = pks
                return
            else:
                # XXX: set db_type to 'gae_key' in order to allow
                # convert_value_for_db to recognize the value to be a Key and
                # not a str. Otherwise the key would be converted back to a
                # unicode (see convert_value_for_db)
                db_type = 'gae_key'
                key_type_error = 'Lookup values on primary keys have to be' \
                                 'a string or an integer.'
                if lookup_type == 'range':
                    if isinstance(value, (list, tuple)) and not (
                            isinstance(value[0], (basestring, int, long)) and
                            isinstance(value[1], (basestring, int, long))):
                        raise DatabaseError(key_type_error)
                elif not isinstance(value, (basestring, int, long)):
                    raise DatabaseError(key_type_error)
                # for lookup type range we have to deal with a list
                if lookup_type == 'range':
                    value[0] = create_key(db_table, value[0])
                    value[1] = create_key(db_table, value[1])
                else:
                    value = create_key(db_table, value)
        if lookup_type not in OPERATORS_MAP:
            raise DatabaseError("Lookup type %r isn't supported" % lookup_type)

        # We check for negation after lookup_type isnull because it
        # simplifies the code. All following lookup_type checks assume
        # that they're not negated.
        if lookup_type == 'isnull':
            if (negated and value) or not value:
                # TODO/XXX: is everything greater than None?
                op = '>'
            else:
                op = '='
            value = None
        elif negated and lookup_type == 'exact':
            if self.has_negated_exact_filter:
                raise DatabaseError("You can't exclude more than one __exact "
                                    "filter")
            self.has_negated_exact_filter = True
            self._combine_filters(column, db_type,
                                  (('<', value), ('>', value)))
            return
        elif negated:
            try:
                op = NEGATION_MAP[lookup_type]
            except KeyError:
                raise DatabaseError("Lookup type %r can't be negated" % lookup_type)
            if self.inequality_field and column != self.inequality_field:
                raise DatabaseError("Can't have inequality filters on multiple "
                    "columns (here: %r and %r)" % (self.inequality_field, column))
            self.inequality_field = column
        elif lookup_type == 'in':
            # Create sub-query combinations, one for each value
            if len(self.gae_query) * len(value) > 30:
                raise DatabaseError("You can't query against more than "
                                    "30 __in filter value combinations")
            op_values = [('=', v) for v in value]
            self._combine_filters(column, db_type, op_values)
            return
        elif lookup_type == 'startswith':
            self._add_filter(column, '>=', db_type, value)
            if isinstance(value, str):
                value = value.decode('utf8')
            if isinstance(value, Key):
                value = list(value.to_path())
                if isinstance(value[-1], str):
                    value[-1] = value[-1].decode('utf8')
                value[-1] += u'\ufffd'
                value = Key.from_path(*value)
            else:
                value += u'\ufffd'
            self._add_filter(column, '<=', db_type, value)
            return
        elif lookup_type in ('range', 'year'):
            self._add_filter(column, '>=', db_type, value[0])
            op = '<=' if lookup_type == 'range' else '<'
            self._add_filter(column, op, db_type, value[1])
            return
        else:
            op = OPERATORS_MAP[lookup_type]

        self._add_filter(column, op, db_type, value)

    # ----------------------------------------------
    # Internal API
    # ----------------------------------------------
    def _add_filter(self, column, op, db_type, value):
        for query in self.gae_query:
            key = '%s %s' % (column, op)
            value = self.convert_value_for_db(db_type, value)
            if isinstance(value, Text):
                raise DatabaseError('TextField is not indexed, by default, '
                                    "so you can't filter on it. Please add "
                                    'an index definition for the column %s '
                                    'on the model %s.%s as described here:\n'
                                    'http://www.allbuttonspressed.com/blog/django/2010/07/Managing-per-field-indexes-on-App-Engine'
                                    % (column, self.query.model.__module__, self.query.model.__name__))
            if key in query:
                existing_value = query[key]
                if isinstance(existing_value, list):
                    existing_value.append(value)
                else:
                    query[key] = [existing_value, value]
            else:
                query[key] = value

    def _combine_filters(self, column, db_type, op_values):
        gae_query = self.gae_query
        combined = []
        for query in gae_query:
            for op, value in op_values:
                self.gae_query = [Query(self.db_table,
                                        keys_only=self.pks_only)]
                self.gae_query[0].update(query)
                self._add_filter(column, op, db_type, value)
                combined.append(self.gae_query[0])
        self.gae_query = combined

    def _make_entity(self, entity):
        if isinstance(entity, Key):
            key = entity
            entity = {}
        else:
            key = entity.key()

        entity[self.query.get_meta().pk.column] = key
        return entity

    @safe_call
    def _build_query(self):
        for query in self.gae_query:
            query.Order(*self.gae_ordering)
            if self.ancestor_key:
                query.Ancestor(self.ancestor_key)
        if len(self.gae_query) > 1:
            return MultiQuery(self.gae_query, self.gae_ordering)
        return self.gae_query[0]

    def get_matching_pk(self, low_mark=0, high_mark=None):
        if not self.pk_filters:
            return []

        results = [result for result in Get(self.pk_filters)
                   if result is not None and
                       self.matches_filters(result)]
        if self.ordering:
            results.sort(cmp=self.order_pk_filtered)
        if high_mark is not None and high_mark < len(results) - 1:
            results = results[:high_mark]
        if low_mark:
            results = results[low_mark:]
        return results

    def order_pk_filtered(self, lhs, rhs):
        left = dict(lhs)
        left[self.query.get_meta().pk.column] = lhs.key().to_path()
        right = dict(rhs)
        right[self.query.get_meta().pk.column] = rhs.key().to_path()
        return self._order_in_memory(left, right)

    def matches_filters(self, entity):
        item = dict(entity)
        pk = self.query.get_meta().pk
        value = self.convert_value_from_db(pk.db_type(connection=self.connection),
            entity.key())
        item[pk.column] = value
        result = self._matches_filters(item, self.query.where)
        return result

class SQLCompiler(NonrelCompiler):
    """
    A simple App Engine query: no joins, no distinct, etc.
    """
    query_class = GAEQuery

    def convert_value_from_db(self, db_type, value):
        if isinstance(value, (list, tuple, set)) and \
                db_type.startswith(('ListField:', 'SetField:')):
            db_sub_type = db_type.split(':', 1)[1]
            value = [self.convert_value_from_db(db_sub_type, subvalue)
                     for subvalue in value]

        if db_type.startswith('SetField:') and value is not None:
            value = set(value)

        if db_type.startswith('DictField:') and value is not None:
            value = pickle.loads(value)
            if ':' in db_type:
                db_sub_type = db_type.split(':', 1)[1]
                value = dict((key, self.convert_value_from_db(db_sub_type, value[key]))
                             for key in value)

        # the following GAE database types are all unicode subclasses, cast them
        # to unicode so they appear like pure unicode instances for django
        if isinstance(value, basestring) and value and db_type.startswith('decimal'):
            value = decimal.Decimal(value)
        elif isinstance(value, (Category, Email, Link, PhoneNumber, PostalAddress,
                Text, unicode)):
            value = unicode(value)
        elif isinstance(value, Blob):
            value = str(value)
        elif isinstance(value, str):
            # always retrieve strings as unicode (it is possible that old datasets
            # contain non unicode strings, nevertheless work with unicode ones)
            value = value.decode('utf-8')
        elif isinstance(value, Key):
            if db_type == 'gae_key':
                value = GAEKey(real_key=value)
            else:
                assert value.parent() is None, "Use GAEKeyField to enable parent keys!"
                if db_type == 'integer':
                    if value.id() is None:
                        raise DatabaseError('Wrong type for Key. Expected integer, found'
                            'None')
                    else:
                        value = value.id()
                elif db_type == 'text':
                    if value.name() is None:
                        raise DatabaseError('Wrong type for Key. Expected string, found'
                            'None')
                    else:
                        value = value.name()
                else:
                    raise DatabaseError("%s fields cannot be keys on GAE" % db_type)
        elif db_type == 'date' and isinstance(value, datetime.datetime):
            value = value.date()
        elif db_type == 'time' and isinstance(value, datetime.datetime):
            value = value.time()
        return value

    def convert_value_for_db(self, db_type, value):
        if isinstance(value, unicode):
            value = unicode(value)
        elif isinstance(value, str):
            value = str(value)
        elif isinstance(value, (list, tuple, set)) and \
                db_type.startswith(('ListField:', 'SetField:')):
            db_sub_type = db_type.split(':', 1)[1]
            value = [self.convert_value_for_db(db_sub_type, subvalue)
                     for subvalue in value]
        elif isinstance(value, decimal.Decimal) and db_type.startswith("decimal:"):
            value = self.connection.ops.value_to_db_decimal(value, *eval(db_type[8:]))
        elif isinstance(value, dict) and db_type.startswith('DictField:'):
            if ':' in db_type:
                db_sub_type = db_type.split(':', 1)[1]
                value = dict([(key, self.convert_value_for_db(db_sub_type, value[key]))
                              for key in value])
            value = Blob(pickle.dumps(value))

        if db_type == 'gae_key':
            return value
        elif db_type == 'longtext':
            # long text fields cannot be indexed on GAE so use GAE's database
            # type Text
            if value is not None:
                value = Text(value.decode('utf-8') if isinstance(value, str) else value)
        elif db_type == 'text':
            value = value.decode('utf-8') if isinstance(value, str) else value
        elif db_type == 'blob':
            if value is not None:
                value = Blob(value)
        elif type(value) is str:
            # always store unicode strings
            value = value.decode('utf-8')
        elif db_type == 'date' or db_type == 'time' or db_type == 'datetime':
            # here we have to check the db_type because GAE always stores datetimes
            value = to_datetime(value)
        return value

class SQLInsertCompiler(NonrelInsertCompiler, SQLCompiler):
    @safe_call
    def insert(self, data, return_id=False):
        gae_data = {}
        opts = self.query.get_meta()
        unindexed_fields = get_model_indexes(self.query.model)['unindexed']
        unindexed_cols = [opts.get_field(name).column
                          for name in unindexed_fields]
        kwds = {'unindexed_properties': unindexed_cols}
        for column, value in data.items():
            if column == opts.pk.column:
                if isinstance(value, GAEKey):
                    if value.parent_key:
                        kwds['parent'] = value.parent_key.real_key
                    if isinstance(value.id_or_name, basestring):
                        kwds['name'] = value.id_or_name
                    elif value.id_or_name is not None:
                        kwds['id'] = value.id_or_name
                elif isinstance(value, basestring):
                    kwds['name'] = value
                else:
                    kwds['id'] = value
            elif isinstance(value, (tuple, list)) and not len(value):
                # gae does not store empty lists (and even does not allow passing empty
                # lists to Entity.update) so skip them
                continue
            else:
                gae_data[column] = value

        entity = Entity(opts.db_table, **kwds)
        entity.update(gae_data)
        key = Put(entity)
        
        if not isinstance(opts.pk, GAEKeyField):
            if key.id() is not None:
                key = key.id()
            else:
                key = key.name()
        
        return key

class SQLUpdateCompiler(NonrelUpdateCompiler, SQLCompiler):
    def execute_sql(self, result_type=MULTI):
        # modify query to fetch pks only and then execute the query
        # to get all pks
        pk = self.query.model._meta.pk.name
        self.query.add_immediate_loading([pk])
        pks = [row for row in self.results_iter()]
        self.update_entities(pks)
        return len(pks)

    def update_entities(self, pks):
        for pk in pks:
            self.update_entity(pk[0])

    @commit_locked
    def update_entity(self, pk):
        gae_query = self.build_query()
        key = create_key(self.query.get_meta().db_table, pk)
        entity = Get(key)
        if not gae_query.matches_filters(entity):
            return

        qn = self.quote_name_unless_alias
        update_dict = {}
        for field, o, value in self.query.values:
            if hasattr(value, 'prepare_database_save'):
                value = value.prepare_database_save(field)
            else:
                value = field.get_db_prep_save(value, connection=self.connection)

            if hasattr(value, "evaluate"):
                assert not value.negated
                assert not value.subtree_parents
                value = ExpressionEvaluator(value, self.query, entity,
                                                allow_joins=False)

            if hasattr(value, 'as_sql'):
                # evaluate expression and return the new value
                val = value.as_sql(qn, self.connection)
                update_dict[field] = val
            else:
                update_dict[field] = value

        for field, value in update_dict.iteritems():
            db_type = field.db_type(connection=self.connection)
            entity[qn(field.column)] = self.convert_value_for_db(db_type, value)

        key = Put(entity)

class SQLDeleteCompiler(NonrelDeleteCompiler, SQLCompiler):
    pass

def to_datetime(value):
    """Convert a time or date to a datetime for datastore storage.

    Args:
    value: A datetime.time, datetime.date or string object.

    Returns:
    A datetime object with date set to 1970-01-01 if value is a datetime.time
    A datetime object with date set to value.year - value.month - value.day and
    time set to 0:00 if value is a datetime.date
    """

    if value is None:
        return value
    elif isinstance(value, datetime.datetime):
        return value
    elif isinstance(value, datetime.date):
        return datetime.datetime(value.year, value.month, value.day)
    elif isinstance(value, datetime.time):
        return datetime.datetime(1970, 1, 1, value.hour, value.minute,
            value.second, value.microsecond)

def create_key(db_table, value):
    if isinstance(value, GAEKey):
        parent = None
        if value.parent_key is not None:
            parent = value.parent.real_key
        return Key.from_path(db_table, value.id_or_name, parent=parent)
    if isinstance(value, (int, long)) and value < 1:
        return None
    return Key.from_path(db_table, value)
Tip: Filter by directory path e.g. /media app.js to search for public/media/app.js.
Tip: Use camelCasing e.g. ProjME to search for ProjectModifiedEvent.java.
Tip: Filter by extension type e.g. /repo .js to search for all .js files in the /repo directory.
Tip: Separate your search with spaces e.g. /ssh pom.xml to search for src/ssh/pom.xml.
Tip: Use ↑ and ↓ arrow keys to navigate and return to view the file.
Tip: You can also navigate files with Ctrl+j (next) and Ctrl+k (previous) and view the file with Ctrl+o.
Tip: You can also navigate files with Alt+j (next) and Alt+k (previous) and view the file with Alt+o.