Package Gnumed :: Package pycommon :: Module gmBusinessDBObject
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Source Code for Module Gnumed.pycommon.gmBusinessDBObject

  1  """GNUmed database object business class. 
  2   
  3  Overview 
  4  -------- 
  5  This class wraps a source relation (table, view) which 
  6  represents an entity that makes immediate business sense 
  7  such as a vaccination or a medical document. In many if 
  8  not most cases this source relation is a denormalizing 
  9  view. The data in that view will in most cases, however, 
 10  originate from several normalized tables. One instance 
 11  of this class represents one row of said source relation. 
 12   
 13  Note, however, that this class does not *always* simply 
 14  wrap a single table or view. It can also encompass several 
 15  relations (views, tables, sequences etc) that taken together 
 16  form an object meaningful to *business* logic. 
 17   
 18  Initialization 
 19  -------------- 
 20  There are two ways to initialize an instance with values. 
 21  One way is to pass a "primary key equivalent" object into 
 22  __init__(). Refetch_payload() will then pull the data from 
 23  the backend. Another way would be to fetch the data outside 
 24  the instance and pass it in via the <row> argument. In that 
 25  case the instance will not initially connect to the databse 
 26  which may offer a great boost to performance. 
 27   
 28  Values API 
 29  ---------- 
 30  Field values are cached for later access. They can be accessed 
 31  by a dictionary API, eg: 
 32   
 33          old_value = object['field'] 
 34          object['field'] = new_value 
 35   
 36  The field names correspond to the respective column names 
 37  in the "main" source relation. Accessing non-existant field 
 38  names will raise an error, so does trying to set fields not 
 39  listed in self.__class__._updatable_fields. To actually 
 40  store updated values in the database one must explicitly 
 41  call save_payload(). 
 42   
 43  The class will in many cases be enhanced by accessors to 
 44  related data that is not directly part of the business 
 45  object itself but are closely related, such as codes 
 46  linked to a clinical narrative entry (eg a diagnosis). Such 
 47  accessors in most cases start with get_*. Related setters 
 48  start with set_*. The values can be accessed via the 
 49  object['field'] syntax, too, but they will be cached 
 50  independantly. 
 51   
 52  Concurrency handling 
 53  -------------------- 
 54  GNUmed connections always run transactions in isolation level 
 55  "serializable". This prevents transactions happening at the 
 56  *very same time* to overwrite each other's data. All but one 
 57  of them will abort with a concurrency error (eg if a 
 58  transaction runs a select-for-update later than another one 
 59  it will hang until the first transaction ends. Then it will 
 60  succeed or fail depending on what the first transaction 
 61  did). This is standard transactional behaviour. 
 62   
 63  However, another transaction may have updated our row 
 64  between the time we first fetched the data and the time we 
 65  start the update transaction. This is noticed by getting the 
 66  XMIN system column for the row when initially fetching the 
 67  data and using that value as a where condition value when 
 68  updating the row later. If the row had been updated (xmin 
 69  changed) or deleted (primary key disappeared) in the 
 70  meantime the update will touch zero rows (as no row with 
 71  both PK and XMIN matching is found) even if the query itself 
 72  syntactically succeeds. 
 73   
 74  When detecting a change in a row due to XMIN being different 
 75  one needs to be careful how to represent that to the user. 
 76  The row may simply have changed but it also might have been 
 77  deleted and a completely new and unrelated row which happens 
 78  to have the same primary key might have been created ! This 
 79  row might relate to a totally different context (eg. patient, 
 80  episode, encounter). 
 81   
 82  One can offer all the data to the user: 
 83   
 84  self.original_payload 
 85  - contains the data at the last successful refetch 
 86   
 87  self.modified_payload 
 88  - contains the modified payload just before the last 
 89    failure of save_payload() - IOW what is currently 
 90    in the database 
 91   
 92  self._payload 
 93  - contains the currently active payload which may or 
 94    may not contain changes 
 95   
 96  For discussion on this see the thread starting at: 
 97   
 98          http://archives.postgresql.org/pgsql-general/2004-10/msg01352.php 
 99   
100  and here 
101   
102          http://groups.google.com/group/pgsql.general/browse_thread/thread/e3566ba76173d0bf/6cf3c243a86d9233 
103          (google for "XMIN semantic at peril") 
104   
105  Problem cases with XMIN: 
106   
107  1) not unlikely 
108  - a very old row is read with XMIN 
109  - vacuum comes along and sets XMIN to FrozenTransactionId 
110    - now XMIN changed but the row actually didn't ! 
111  - an update with "... where xmin = old_xmin ..." fails 
112    although there is no need to fail 
113   
114  2) quite unlikely 
115  - a row is read with XMIN 
116  - a long time passes 
117  - the original XMIN gets frozen to FrozenTransactionId 
118  - another writer comes along and changes the row 
119  - incidentally the exact same old row gets the old XMIN *again* 
120    - now XMIN is (again) the same but the data changed ! 
121  - a later update fails to detect the concurrent change !! 
122   
123  TODO: 
124  The solution is to use our own column for optimistic locking 
125  which gets updated by an AFTER UPDATE trigger. 
126  """ 
127  #============================================================ 
128  __version__ = "$Revision: 1.60 $" 
129  __author__ = "K.Hilbert <Karsten.Hilbert@gmx.net>" 
130  __license__ = "GPL" 
131   
132  import sys, copy, types, inspect, logging, datetime 
133   
134   
135  if __name__ == '__main__': 
136          sys.path.insert(0, '../../') 
137  from Gnumed.pycommon import gmExceptions, gmPG2 
138  from Gnumed.pycommon.gmTools import tex_escape_string 
139   
140   
141  _log = logging.getLogger('gm.db') 
142  _log.info(__version__) 
143  #============================================================ 
144 -class cBusinessDBObject(object):
145 """Represents business objects in the database. 146 147 Rules: 148 - instances ARE ASSUMED TO EXIST in the database 149 - PK construction (aPK_obj): DOES verify its existence on instantiation 150 (fetching data fails) 151 - Row construction (row): allowed by using a dict of pairs 152 field name: field value (PERFORMANCE improvement) 153 - does NOT verify FK target existence 154 - does NOT create new entries in the database 155 - does NOT lazy-fetch fields on access 156 157 Class scope SQL commands and variables: 158 159 <_cmd_fetch_payload> 160 - must return exactly one row 161 - where clause argument values are expected 162 in self.pk_obj (taken from __init__(aPK_obj)) 163 - must return xmin of all rows that _cmds_store_payload 164 will be updating, so views must support the xmin columns 165 of their underlying tables 166 167 <_cmds_store_payload> 168 - one or multiple "update ... set ... where xmin_* = ..." statements 169 which actually update the database from the data in self._payload, 170 - the last query must refetch at least the XMIN values needed to detect 171 concurrent updates, their field names had better be the same as 172 in _cmd_fetch_payload, 173 - when subclasses tend to live a while after save_payload() was 174 called and they support computed fields (say, _(some_column) 175 you need to return *all* columns (see cEncounter) 176 177 <_updatable_fields> 178 - a list of fields available for update via object['field'] 179 180 181 A template for new child classes: 182 183 *********** start of template *********** 184 185 #------------------------------------------------------------ 186 from Gnumed.pycommon import gmBusinessDBObject 187 from Gnumed.pycommon import gmPG2 188 189 #============================================================ 190 # short description 191 #------------------------------------------------------------ 192 # use plural form, search-replace get_XXX 193 _SQL_get_XXX = u\""" 194 SELECT *, (xmin AS xmin_XXX) 195 FROM XXX.v_XXX 196 WHERE %s 197 \""" 198 199 class cXxxXxx(gmBusinessDBObject.cBusinessDBObject): 200 \"""Represents ...\""" 201 202 _cmd_fetch_payload = _SQL_get_XXX % u"pk_XXX = %s" 203 _cmds_store_payload = [ 204 u\""" 205 UPDATE xxx.xxx SET -- typically the underlying table name 206 xxx = %(xxx)s, -- typically "table_col = %(view_col)s" 207 xxx = gm.nullify_empty_string(%(xxx)s) 208 WHERE 209 pk = %(pk_XXX)s 210 AND 211 xmin = %(xmin_XXX)s 212 RETURNING 213 pk as pk_XXX, 214 xmin as xmin_XXX 215 \""" 216 ] 217 # view columns that can be updated: 218 _updatable_fields = [ 219 u'xxx', 220 u'xxx' 221 ] 222 #-------------------------------------------------------- 223 def format(self): 224 return u'%s' % self 225 226 #------------------------------------------------------------ 227 def get_XXX(order_by=None): 228 if order_by is None: 229 order_by = u'true' 230 else: 231 order_by = u'true ORDER BY %s' % order_by 232 233 cmd = _SQL_get_XXX % order_by 234 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': cmd}], get_col_idx = True) 235 return [ cXxxXxx(row = {'data': r, 'idx': idx, 'pk_field': 'xxx'}) for r in rows ] 236 #------------------------------------------------------------ 237 def create_xxx(xxx=None, xxx=None): 238 239 args = { 240 u'xxx': xxx, 241 u'xxx': xxx 242 } 243 cmd = u\""" 244 INSERT INTO xxx.xxx ( 245 xxx, 246 xxx, 247 xxx 248 ) VALUES ( 249 %(xxx)s, 250 %(xxx)s, 251 gm.nullify_empty_string(%(xxx)s) 252 ) 253 RETURNING pk 254 \""" 255 rows, idx = gmPG2.run_rw_queries(queries = [{'cmd': cmd, 'args': args}], return_data = True, get_col_idx = False) 256 257 return cXxxXxx(aPK_obj = rows[0]['pk']) 258 #------------------------------------------------------------ 259 def delete_xxx(xxx=None): 260 args = {'pk': xxx} 261 cmd = u"DELETE FROM xxx.xxx WHERE pk = %(pk)s" 262 gmPG2.run_rw_queries(queries = [{'cmd': cmd, 'args': args}]) 263 return True 264 #------------------------------------------------------------ 265 266 *********** end of template *********** 267 268 """ 269 #--------------------------------------------------------
270 - def __init__(self, aPK_obj=None, row=None):
271 """Init business object. 272 273 Call from child classes: 274 275 super(cChildClass, self).__init__(aPK_obj = aPK_obj, row = row) 276 """ 277 # initialize those "too early" because checking descendants might 278 # fail which will then call __str__ in stack trace logging if --debug 279 # was given which in turn needs those instance variables 280 self.pk_obj = '<uninitialized>' 281 self._idx = {} 282 self._payload = [] # the cache for backend object values (mainly table fields) 283 self._ext_cache = {} # the cache for extended method's results 284 self._is_modified = False 285 286 # check descendants 287 self.__class__._cmd_fetch_payload 288 self.__class__._cmds_store_payload 289 self.__class__._updatable_fields 290 291 if aPK_obj is not None: 292 self.__init_from_pk(aPK_obj=aPK_obj) 293 else: 294 self._init_from_row_data(row=row) 295 296 self._is_modified = False
297 #--------------------------------------------------------
298 - def __init_from_pk(self, aPK_obj=None):
299 """Creates a new clinical item instance by its PK. 300 301 aPK_obj can be: 302 - a simple value 303 * the primary key WHERE condition must be 304 a simple column 305 - a dictionary of values 306 * the primary key where condition must be a 307 subselect consuming the dict and producing 308 the single-value primary key 309 """ 310 self.pk_obj = aPK_obj 311 result = self.refetch_payload() 312 if result is True: 313 self.original_payload = {} 314 for field in self._idx.keys(): 315 self.original_payload[field] = self._payload[self._idx[field]] 316 return True 317 318 if result is False: 319 raise gmExceptions.ConstructorError, "[%s:%s]: error loading instance" % (self.__class__.__name__, self.pk_obj)
320 #--------------------------------------------------------
321 - def _init_from_row_data(self, row=None):
322 """Creates a new clinical item instance given its fields. 323 324 row must be a dict with the fields: 325 - pk_field: the name of the primary key field 326 - idx: a dict mapping field names to position 327 - data: the field values in a list (as returned by 328 cursor.fetchone() in the DB-API) 329 330 row = {'data': row, 'idx': idx, 'pk_field': 'the PK column name'} 331 332 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': cmd, 'args': args}], get_col_idx = True) 333 objects = [ cChildClass(row = {'data': r, 'idx': idx, 'pk_field': 'the PK column name'}) for r in rows ] 334 """ 335 try: 336 self._idx = row['idx'] 337 self._payload = row['data'] 338 self.pk_obj = self._payload[self._idx[row['pk_field']]] 339 except: 340 _log.exception('faulty <row> argument structure: %s' % row) 341 raise gmExceptions.ConstructorError, "[%s:??]: error loading instance from row data" % self.__class__.__name__ 342 343 if len(self._idx.keys()) != len(self._payload): 344 _log.critical('field index vs. payload length mismatch: %s field names vs. %s fields' % (len(self._idx.keys()), len(self._payload))) 345 _log.critical('faulty <row> argument structure: %s' % row) 346 raise gmExceptions.ConstructorError, "[%s:??]: error loading instance from row data" % self.__class__.__name__ 347 348 self.original_payload = {} 349 for field in self._idx.keys(): 350 self.original_payload[field] = self._payload[self._idx[field]]
351 #--------------------------------------------------------
352 - def __del__(self):
353 if self.__dict__.has_key('_is_modified'): 354 if self._is_modified: 355 _log.critical('[%s:%s]: loosing payload changes' % (self.__class__.__name__, self.pk_obj)) 356 _log.debug('original: %s' % self.original_payload) 357 _log.debug('modified: %s' % self._payload)
358 #--------------------------------------------------------
359 - def __str__(self):
360 tmp = [] 361 try: 362 for attr in self._idx.keys(): 363 if self._payload[self._idx[attr]] is None: 364 tmp.append(u'%s: NULL' % attr) 365 else: 366 tmp.append('%s: >>%s<<' % (attr, self._payload[self._idx[attr]])) 367 return '[%s:%s]: %s' % (self.__class__.__name__, self.pk_obj, str(tmp)) 368 except: 369 return 'nascent [%s @ %s], cannot show payload and primary key' %(self.__class__.__name__, id(self))
370 #--------------------------------------------------------
371 - def __getitem__(self, attribute):
372 # use try: except: as it is faster and we want this as fast as possible 373 374 # 1) backend payload cache 375 try: 376 return self._payload[self._idx[attribute]] 377 except KeyError: 378 pass 379 380 # 2) extension method results ... 381 getter = getattr(self, 'get_%s' % attribute, None) 382 if not callable(getter): 383 _log.warning('[%s]: no attribute [%s]' % (self.__class__.__name__, attribute)) 384 _log.warning('[%s]: valid attributes: %s' % (self.__class__.__name__, str(self._idx.keys()))) 385 _log.warning('[%s]: no getter method [get_%s]' % (self.__class__.__name__, attribute)) 386 methods = filter(lambda x: x[0].startswith('get_'), inspect.getmembers(self, inspect.ismethod)) 387 _log.warning('[%s]: valid getter methods: %s' % (self.__class__.__name__, str(methods))) 388 raise KeyError('[%s]: cannot read from key [%s]' % (self.__class__.__name__, attribute)) 389 390 self._ext_cache[attribute] = getter() 391 return self._ext_cache[attribute]
392 #--------------------------------------------------------
393 - def __setitem__(self, attribute, value):
394 395 # 1) backend payload cache 396 if attribute in self.__class__._updatable_fields: 397 try: 398 if self._payload[self._idx[attribute]] != value: 399 self._payload[self._idx[attribute]] = value 400 self._is_modified = True 401 return 402 except KeyError: 403 _log.warning('[%s]: cannot set attribute <%s> despite marked settable' % (self.__class__.__name__, attribute)) 404 _log.warning('[%s]: supposedly settable attributes: %s' % (self.__class__.__name__, str(self.__class__._updatable_fields))) 405 raise KeyError('[%s]: cannot write to key [%s]' % (self.__class__.__name__, attribute)) 406 407 # 2) setters providing extensions 408 if hasattr(self, 'set_%s' % attribute): 409 setter = getattr(self, "set_%s" % attribute) 410 if not callable(setter): 411 raise AttributeError('[%s] setter [set_%s] not callable' % (self.__class__.__name__, attribute)) 412 try: 413 del self._ext_cache[attribute] 414 except KeyError: 415 pass 416 if type(value) is types.TupleType: 417 if setter(*value): 418 self._is_modified = True 419 return 420 raise AttributeError('[%s]: setter [%s] failed for [%s]' % (self.__class__.__name__, setter, value)) 421 if setter(value): 422 self._is_modified = True 423 return 424 425 # 3) don't know what to do with <attribute> 426 _log.error('[%s]: cannot find attribute <%s> or setter method [set_%s]' % (self.__class__.__name__, attribute, attribute)) 427 _log.warning('[%s]: settable attributes: %s' % (self.__class__.__name__, str(self.__class__._updatable_fields))) 428 methods = filter(lambda x: x[0].startswith('set_'), inspect.getmembers(self, inspect.ismethod)) 429 _log.warning('[%s]: valid setter methods: %s' % (self.__class__.__name__, str(methods))) 430 raise AttributeError('[%s]: cannot set [%s]' % (self.__class__.__name__, attribute))
431 #-------------------------------------------------------- 432 # external API 433 #--------------------------------------------------------
434 - def same_payload(self, another_object=None):
435 raise NotImplementedError('comparison between [%s] and [%s] not implemented' % (self, another_object))
436 #--------------------------------------------------------
437 - def is_modified(self):
438 return self._is_modified
439 #--------------------------------------------------------
440 - def get_fields(self):
441 try: 442 return self._idx.keys() 443 except AttributeError: 444 return 'nascent [%s @ %s], cannot return keys' %(self.__class__.__name__, id(self))
445 #--------------------------------------------------------
446 - def get_updatable_fields(self):
447 return self.__class__._updatable_fields
448 #--------------------------------------------------------
449 - def fields_as_dict(self, date_format='%c', none_string=u'', escape_style=None, bool_strings=None):
450 if bool_strings is None: 451 bools = {True: u'true', False: u'false'} 452 else: 453 bools = {True: bool_strings[0], False: bool_strings[1]} 454 data = {} 455 for field in self._idx.keys(): 456 # FIXME: harden against BYTEA fields 457 #if type(self._payload[self._idx[field]]) == ... 458 # data[field] = _('<%s bytes of binary data>') % len(self._payload[self._idx[field]]) 459 # continue 460 val = self._payload[self._idx[field]] 461 if val is None: 462 data[field] = none_string 463 continue 464 if isinstance(val, bool): 465 data[field] = bools[val] 466 continue 467 if isinstance(val, datetime.datetime): 468 try: 469 data[field] = val.strftime(date_format).decode('utf8', 'replace') 470 except ValueError: 471 data[field] = val.isoformat() 472 if escape_style in [u'latex', u'tex']: 473 data[field] = tex_escape_string(data[field]) 474 continue 475 try: 476 data[field] = unicode(val, encoding = 'utf8', errors = 'replace') 477 except TypeError: 478 try: 479 data[field] = unicode(val) 480 except (UnicodeDecodeError, TypeError): 481 val = '%s' % str(val) 482 data[field] = val.decode('utf8', 'replace') 483 if escape_style in [u'latex', u'tex']: 484 data[field] = tex_escape_string(data[field]) 485 486 return data
487 #--------------------------------------------------------
488 - def get_patient(self):
489 _log.error('[%s:%s]: forgot to override get_patient()' % (self.__class__.__name__, self.pk_obj)) 490 return None
491 #--------------------------------------------------------
492 - def format(self):
493 return u'%s' % self
494 #--------------------------------------------------------
495 - def refetch_payload(self, ignore_changes=False):
496 """Fetch field values from backend. 497 """ 498 if self._is_modified: 499 if ignore_changes: 500 _log.critical('[%s:%s]: loosing payload changes' % (self.__class__.__name__, self.pk_obj)) 501 _log.debug('original: %s' % self.original_payload) 502 _log.debug('modified: %s' % self._payload) 503 else: 504 _log.critical('[%s:%s]: cannot reload, payload changed' % (self.__class__.__name__, self.pk_obj)) 505 return False 506 507 if type(self.pk_obj) == types.DictType: 508 arg = self.pk_obj 509 else: 510 arg = [self.pk_obj] 511 rows, self._idx = gmPG2.run_ro_queries ( 512 queries = [{'cmd': self.__class__._cmd_fetch_payload, 'args': arg}], 513 get_col_idx = True 514 ) 515 if len(rows) == 0: 516 _log.error('[%s:%s]: no such instance' % (self.__class__.__name__, self.pk_obj)) 517 return False 518 self._payload = rows[0] 519 return True
520 #--------------------------------------------------------
521 - def __noop(self):
522 pass
523 #--------------------------------------------------------
524 - def save(self, conn=None):
525 return self.save_payload(conn = conn)
526 #--------------------------------------------------------
527 - def save_payload(self, conn=None):
528 """Store updated values (if any) in database. 529 530 Optionally accepts a pre-existing connection 531 - returns a tuple (<True|False>, <data>) 532 - True: success 533 - False: an error occurred 534 * data is (error, message) 535 * for error meanings see gmPG2.run_rw_queries() 536 """ 537 if not self._is_modified: 538 return (True, None) 539 540 args = {} 541 for field in self._idx.keys(): 542 args[field] = self._payload[self._idx[field]] 543 self.modified_payload = args 544 545 close_conn = self.__noop 546 if conn is None: 547 conn = gmPG2.get_connection(readonly=False) 548 close_conn = conn.close 549 550 # query succeeded but failed to find the row to lock 551 # because another transaction committed an UPDATE or 552 # DELETE *before* we attempted to lock it ... 553 # FIXME: this can fail if savepoints are used since subtransactions change the xmin/xmax ... 554 555 queries = [] 556 for query in self.__class__._cmds_store_payload: 557 queries.append({'cmd': query, 'args': args}) 558 rows, idx = gmPG2.run_rw_queries ( 559 link_obj = conn, 560 queries = queries, 561 return_data = True, 562 get_col_idx = True 563 ) 564 565 # this can happen if: 566 # - someone else updated the row so XMIN does not match anymore 567 # - the PK went away (rows was deleted from under us) 568 # - another WHERE condition of the UPDATE did not produce any rows to update 569 if len(rows) == 0: 570 return (False, (u'cannot update row', _('[%s:%s]: row not updated (nothing returned), row in use ?') % (self.__class__.__name__, self.pk_obj))) 571 572 # update cached XMIN values (should be in first-and-only result row of last query) 573 row = rows[0] 574 for key in idx: 575 try: 576 self._payload[self._idx[key]] = row[idx[key]] 577 except KeyError: 578 conn.rollback() 579 close_conn() 580 _log.error('[%s:%s]: cannot update instance, XMIN refetch key mismatch on [%s]' % (self.__class__.__name__, self.pk_obj, key)) 581 _log.error('payload keys: %s' % str(self._idx)) 582 _log.error('XMIN refetch keys: %s' % str(idx)) 583 _log.error(args) 584 raise 585 586 conn.commit() 587 close_conn() 588 589 self._is_modified = False 590 # update to new "original" payload 591 self.original_payload = {} 592 for field in self._idx.keys(): 593 self.original_payload[field] = self._payload[self._idx[field]] 594 595 return (True, None)
596 597 #============================================================
598 -def jsonclasshintify(obj):
599 # this should eventually be somewhere else 600 """ turn the data into a list of dicts, adding "class hints". 601 all objects get turned into dictionaries which the other end 602 will interpret as "object", via the __jsonclass__ hint, 603 as specified by the JSONRPC protocol standard. 604 """ 605 if isinstance(obj, list): 606 return map(jsonclasshintify, obj) 607 elif isinstance(obj, gmPG2.dbapi.tz.FixedOffsetTimezone): 608 # this will get decoded as "from jsonobjproxy import {clsname}" 609 # at the remote (client) end. 610 res = {'__jsonclass__': ["jsonobjproxy.FixedOffsetTimezone"]} 611 res['name'] = obj._name 612 res['offset'] = jsonclasshintify(obj._offset) 613 return res 614 elif isinstance(obj, datetime.timedelta): 615 # this will get decoded as "from jsonobjproxy import {clsname}" 616 # at the remote (client) end. 617 res = {'__jsonclass__': ["jsonobjproxy.TimeDelta"]} 618 res['days'] = obj.days 619 res['seconds'] = obj.seconds 620 res['microseconds'] = obj.microseconds 621 return res 622 elif isinstance(obj, datetime.time): 623 # this will get decoded as "from jsonobjproxy import {clsname}" 624 # at the remote (client) end. 625 res = {'__jsonclass__': ["jsonobjproxy.Time"]} 626 res['hour'] = obj.hour 627 res['minute'] = obj.minute 628 res['second'] = obj.second 629 res['microsecond'] = obj.microsecond 630 res['tzinfo'] = jsonclasshintify(obj.tzinfo) 631 return res 632 elif isinstance(obj, datetime.datetime): 633 # this will get decoded as "from jsonobjproxy import {clsname}" 634 # at the remote (client) end. 635 res = {'__jsonclass__': ["jsonobjproxy.DateTime"]} 636 res['year'] = obj.year 637 res['month'] = obj.month 638 res['day'] = obj.day 639 res['hour'] = obj.hour 640 res['minute'] = obj.minute 641 res['second'] = obj.second 642 res['microsecond'] = obj.microsecond 643 res['tzinfo'] = jsonclasshintify(obj.tzinfo) 644 return res 645 elif isinstance(obj, cBusinessDBObject): 646 # this will get decoded as "from jsonobjproxy import {clsname}" 647 # at the remote (client) end. 648 res = {'__jsonclass__': ["jsonobjproxy.%s" % obj.__class__.__name__]} 649 for k in obj.get_fields(): 650 t = jsonclasshintify(obj[k]) 651 res[k] = t 652 print "props", res, dir(obj) 653 for attribute in dir(obj): 654 if not attribute.startswith("get_"): 655 continue 656 k = attribute[4:] 657 if res.has_key(k): 658 continue 659 getter = getattr(obj, attribute, None) 660 if callable(getter): 661 res[k] = jsonclasshintify(getter()) 662 return res 663 return obj
664 665 #============================================================ 666 if __name__ == '__main__': 667 668 if len(sys.argv) < 2: 669 sys.exit() 670 671 if sys.argv[1] != u'test': 672 sys.exit() 673 674 #--------------------------------------------------------
675 - class cTestObj(cBusinessDBObject):
676 _cmd_fetch_payload = None 677 _cmds_store_payload = None 678 _updatable_fields = [] 679 #----------------------------------------------------
680 - def get_something(self):
681 pass
682 #----------------------------------------------------
683 - def set_something(self):
684 pass
685 #-------------------------------------------------------- 686 from Gnumed.pycommon import gmI18N 687 gmI18N.activate_locale() 688 gmI18N.install_domain() 689 690 data = { 691 'pk_field': 'bogus_pk', 692 'idx': {'bogus_pk': 0, 'bogus_field': 1, 'bogus_date': 2}, 693 'data': [-1, 'bogus_data', datetime.datetime.now()] 694 } 695 obj = cTestObj(row=data) 696 #print obj['wrong_field'] 697 #print jsonclasshintify(obj) 698 #obj['wrong_field'] = 1 699 print obj.fields_as_dict() 700 701 #============================================================ 702