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  __author__ = "K.Hilbert <Karsten.Hilbert@gmx.net>" 
129  __license__ = "GPL v2 or later" 
130   
131   
132  import sys 
133  import types 
134  import inspect 
135  import logging 
136  import datetime 
137   
138   
139  if __name__ == '__main__': 
140          sys.path.insert(0, '../../') 
141  from Gnumed.pycommon import gmExceptions 
142  from Gnumed.pycommon import gmPG2 
143  from Gnumed.pycommon.gmDateTime import pydt_strftime 
144  from Gnumed.pycommon.gmTools import tex_escape_string 
145   
146   
147  _log = logging.getLogger('gm.db') 
148  #============================================================ 
149 -class cBusinessDBObject(object):
150 """Represents business objects in the database. 151 152 Rules: 153 - instances ARE ASSUMED TO EXIST in the database 154 - PK construction (aPK_obj): DOES verify its existence on instantiation 155 (fetching data fails) 156 - Row construction (row): allowed by using a dict of pairs 157 field name: field value (PERFORMANCE improvement) 158 - does NOT verify FK target existence 159 - does NOT create new entries in the database 160 - does NOT lazy-fetch fields on access 161 162 Class scope SQL commands and variables: 163 164 <_cmd_fetch_payload> 165 - must return exactly one row 166 - where clause argument values are expected 167 in self.pk_obj (taken from __init__(aPK_obj)) 168 - must return xmin of all rows that _cmds_store_payload 169 will be updating, so views must support the xmin columns 170 of their underlying tables 171 172 <_cmds_store_payload> 173 - one or multiple "update ... set ... where xmin_* = ..." statements 174 which actually update the database from the data in self._payload, 175 - the last query must refetch at least the XMIN values needed to detect 176 concurrent updates, their field names had better be the same as 177 in _cmd_fetch_payload, 178 - when subclasses tend to live a while after save_payload() was 179 called and they support computed fields (say, _(some_column) 180 you need to return *all* columns (see cEncounter) 181 182 <_updatable_fields> 183 - a list of fields available for update via object['field'] 184 185 186 A template for new child classes: 187 188 *********** start of template *********** 189 190 #------------------------------------------------------------ 191 from Gnumed.pycommon import gmBusinessDBObject 192 from Gnumed.pycommon import gmPG2 193 194 #============================================================ 195 # short description 196 #------------------------------------------------------------ 197 # use plural form, search-replace get_XXX 198 _SQL_get_XXX = u\""" 199 SELECT *, (xmin AS xmin_XXX) 200 FROM XXX.v_XXX 201 WHERE %s 202 \""" 203 204 class cXxxXxx(gmBusinessDBObject.cBusinessDBObject): 205 \"""Represents ...\""" 206 207 _cmd_fetch_payload = _SQL_get_XXX % u"pk_XXX = %s" 208 _cmds_store_payload = [ 209 u\""" 210 -- typically the underlying table name 211 UPDATE xxx.xxx SET 212 -- typically "table_col = %(view_col)s" 213 xxx = %(xxx)s, 214 xxx = gm.nullify_empty_string(%(xxx)s) 215 WHERE 216 pk = %(pk_XXX)s 217 AND 218 xmin = %(xmin_XXX)s 219 RETURNING 220 pk as pk_XXX, 221 xmin as xmin_XXX 222 \""" 223 ] 224 # view columns that can be updated: 225 _updatable_fields = [ 226 u'xxx', 227 u'xxx' 228 ] 229 #-------------------------------------------------------- 230 def format(self): 231 return u'%s' % self 232 233 #------------------------------------------------------------ 234 def get_XXX(order_by=None): 235 if order_by is None: 236 order_by = u'true' 237 else: 238 order_by = u'true ORDER BY %s' % order_by 239 240 cmd = _SQL_get_XXX % order_by 241 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': cmd}], get_col_idx = True) 242 return [ cXxxXxx(row = {'data': r, 'idx': idx, 'pk_field': 'xxx'}) for r in rows ] 243 #------------------------------------------------------------ 244 def create_xxx(xxx=None, xxx=None): 245 246 args = { 247 u'xxx': xxx, 248 u'xxx': xxx 249 } 250 cmd = u\""" 251 INSERT INTO xxx.xxx ( 252 xxx, 253 xxx, 254 xxx 255 ) VALUES ( 256 %(xxx)s, 257 %(xxx)s, 258 gm.nullify_empty_string(%(xxx)s) 259 ) 260 RETURNING pk 261 \""" 262 rows, idx = gmPG2.run_rw_queries(queries = [{'cmd': cmd, 'args': args}], return_data = True, get_col_idx = False) 263 264 return cXxxXxx(aPK_obj = rows[0]['pk']) 265 #------------------------------------------------------------ 266 def delete_xxx(xxx=None): 267 args = {'pk': xxx} 268 cmd = u"DELETE FROM xxx.xxx WHERE pk = %(pk)s" 269 gmPG2.run_rw_queries(queries = [{'cmd': cmd, 'args': args}]) 270 return True 271 #------------------------------------------------------------ 272 273 *********** end of template *********** 274 275 """ 276 #--------------------------------------------------------
277 - def __init__(self, aPK_obj=None, row=None):
278 """Init business object. 279 280 Call from child classes: 281 282 super(cChildClass, self).__init__(aPK_obj = aPK_obj, row = row) 283 """ 284 # initialize those "too early" because checking descendants might 285 # fail which will then call __str__ in stack trace logging if --debug 286 # was given which in turn needs those instance variables 287 self.pk_obj = '<uninitialized>' 288 self._idx = {} 289 self._payload = [] # the cache for backend object values (mainly table fields) 290 self._ext_cache = {} # the cache for extended method's results 291 self._is_modified = False 292 293 # check descendants 294 self.__class__._cmd_fetch_payload 295 self.__class__._cmds_store_payload 296 self.__class__._updatable_fields 297 298 if aPK_obj is not None: 299 self.__init_from_pk(aPK_obj=aPK_obj) 300 else: 301 self._init_from_row_data(row=row) 302 303 self._is_modified = False
304 #--------------------------------------------------------
305 - def __init_from_pk(self, aPK_obj=None):
306 """Creates a new clinical item instance by its PK. 307 308 aPK_obj can be: 309 - a simple value 310 * the primary key WHERE condition must be 311 a simple column 312 - a dictionary of values 313 * the primary key where condition must be a 314 subselect consuming the dict and producing 315 the single-value primary key 316 """ 317 self.pk_obj = aPK_obj 318 result = self.refetch_payload() 319 if result is True: 320 self.original_payload = {} 321 for field in self._idx.keys(): 322 self.original_payload[field] = self._payload[self._idx[field]] 323 return True 324 325 if result is False: 326 raise gmExceptions.ConstructorError, "[%s:%s]: error loading instance" % (self.__class__.__name__, self.pk_obj)
327 #--------------------------------------------------------
328 - def _init_from_row_data(self, row=None):
329 """Creates a new clinical item instance given its fields. 330 331 row must be a dict with the fields: 332 - pk_field: the name of the primary key field 333 - idx: a dict mapping field names to position 334 - data: the field values in a list (as returned by 335 cursor.fetchone() in the DB-API) 336 337 row = {'data': row, 'idx': idx, 'pk_field': 'the PK column name'} 338 339 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': cmd, 'args': args}], get_col_idx = True) 340 objects = [ cChildClass(row = {'data': r, 'idx': idx, 'pk_field': 'the PK column name'}) for r in rows ] 341 """ 342 try: 343 self._idx = row['idx'] 344 self._payload = row['data'] 345 self.pk_obj = self._payload[self._idx[row['pk_field']]] 346 except: 347 _log.exception('faulty <row> argument structure: %s' % row) 348 raise gmExceptions.ConstructorError, "[%s:??]: error loading instance from row data" % self.__class__.__name__ 349 350 if len(self._idx.keys()) != len(self._payload): 351 _log.critical('field index vs. payload length mismatch: %s field names vs. %s fields' % (len(self._idx.keys()), len(self._payload))) 352 _log.critical('faulty <row> argument structure: %s' % row) 353 raise gmExceptions.ConstructorError, "[%s:??]: error loading instance from row data" % self.__class__.__name__ 354 355 self.original_payload = {} 356 for field in self._idx.keys(): 357 self.original_payload[field] = self._payload[self._idx[field]]
358 #--------------------------------------------------------
359 - def __del__(self):
360 if self.__dict__.has_key('_is_modified'): 361 if self._is_modified: 362 _log.critical('[%s:%s]: loosing payload changes' % (self.__class__.__name__, self.pk_obj)) 363 _log.debug('original: %s' % self.original_payload) 364 _log.debug('modified: %s' % self._payload)
365 #--------------------------------------------------------
366 - def __str__(self):
367 tmp = [] 368 try: 369 for attr in self._idx.keys(): 370 if self._payload[self._idx[attr]] is None: 371 tmp.append(u'%s: NULL' % attr) 372 else: 373 tmp.append('%s: >>%s<<' % (attr, self._payload[self._idx[attr]])) 374 return '[%s:%s]: %s' % (self.__class__.__name__, self.pk_obj, str(tmp)) 375 except: 376 return 'nascent [%s @ %s], cannot show payload and primary key' %(self.__class__.__name__, id(self))
377 #--------------------------------------------------------
378 - def __getitem__(self, attribute):
379 # use try: except: as it is faster and we want this as fast as possible 380 381 # 1) backend payload cache 382 try: 383 return self._payload[self._idx[attribute]] 384 except KeyError: 385 pass 386 387 # 2) extension method results ... 388 getter = getattr(self, 'get_%s' % attribute, None) 389 if not callable(getter): 390 _log.warning('[%s]: no attribute [%s]' % (self.__class__.__name__, attribute)) 391 _log.warning('[%s]: valid attributes: %s' % (self.__class__.__name__, str(self._idx.keys()))) 392 _log.warning('[%s]: no getter method [get_%s]' % (self.__class__.__name__, attribute)) 393 methods = filter(lambda x: x[0].startswith('get_'), inspect.getmembers(self, inspect.ismethod)) 394 _log.warning('[%s]: valid getter methods: %s' % (self.__class__.__name__, str(methods))) 395 raise KeyError('[%s]: cannot read from key [%s]' % (self.__class__.__name__, attribute)) 396 397 self._ext_cache[attribute] = getter() 398 return self._ext_cache[attribute]
399 #--------------------------------------------------------
400 - def __setitem__(self, attribute, value):
401 402 # 1) backend payload cache 403 if attribute in self.__class__._updatable_fields: 404 try: 405 if self._payload[self._idx[attribute]] != value: 406 self._payload[self._idx[attribute]] = value 407 self._is_modified = True 408 return 409 except KeyError: 410 _log.warning('[%s]: cannot set attribute <%s> despite marked settable' % (self.__class__.__name__, attribute)) 411 _log.warning('[%s]: supposedly settable attributes: %s' % (self.__class__.__name__, str(self.__class__._updatable_fields))) 412 raise KeyError('[%s]: cannot write to key [%s]' % (self.__class__.__name__, attribute)) 413 414 # 2) setters providing extensions 415 if hasattr(self, 'set_%s' % attribute): 416 setter = getattr(self, "set_%s" % attribute) 417 if not callable(setter): 418 raise AttributeError('[%s] setter [set_%s] not callable' % (self.__class__.__name__, attribute)) 419 try: 420 del self._ext_cache[attribute] 421 except KeyError: 422 pass 423 if type(value) is types.TupleType: 424 if setter(*value): 425 self._is_modified = True 426 return 427 raise AttributeError('[%s]: setter [%s] failed for [%s]' % (self.__class__.__name__, setter, value)) 428 if setter(value): 429 self._is_modified = True 430 return 431 432 # 3) don't know what to do with <attribute> 433 _log.error('[%s]: cannot find attribute <%s> or setter method [set_%s]' % (self.__class__.__name__, attribute, attribute)) 434 _log.warning('[%s]: settable attributes: %s' % (self.__class__.__name__, str(self.__class__._updatable_fields))) 435 methods = filter(lambda x: x[0].startswith('set_'), inspect.getmembers(self, inspect.ismethod)) 436 _log.warning('[%s]: valid setter methods: %s' % (self.__class__.__name__, str(methods))) 437 raise AttributeError('[%s]: cannot set [%s]' % (self.__class__.__name__, attribute))
438 #-------------------------------------------------------- 439 # external API 440 #--------------------------------------------------------
441 - def same_payload(self, another_object=None):
442 raise NotImplementedError('comparison between [%s] and [%s] not implemented' % (self, another_object))
443 #--------------------------------------------------------
444 - def is_modified(self):
445 return self._is_modified
446 #--------------------------------------------------------
447 - def get_fields(self):
448 try: 449 return self._idx.keys() 450 except AttributeError: 451 return 'nascent [%s @ %s], cannot return keys' %(self.__class__.__name__, id(self))
452 #--------------------------------------------------------
453 - def get_updatable_fields(self):
454 return self.__class__._updatable_fields
455 #--------------------------------------------------------
456 - def fields_as_dict(self, date_format='%c', none_string=u'', escape_style=None, bool_strings=None):
457 if bool_strings is None: 458 bools = {True: u'true', False: u'false'} 459 else: 460 bools = {True: bool_strings[0], False: bool_strings[1]} 461 data = {} 462 for field in self._idx.keys(): 463 # FIXME: harden against BYTEA fields 464 #if type(self._payload[self._idx[field]]) == ... 465 # data[field] = _('<%s bytes of binary data>') % len(self._payload[self._idx[field]]) 466 # continue 467 val = self._payload[self._idx[field]] 468 if val is None: 469 data[field] = none_string 470 continue 471 if isinstance(val, bool): 472 data[field] = bools[val] 473 continue 474 475 if isinstance(val, datetime.datetime): 476 data[field] = pydt_strftime(val, format = date_format, encoding = 'utf8') 477 if escape_style in [u'latex', u'tex']: 478 data[field] = tex_escape_string(data[field]) 479 continue 480 481 try: 482 data[field] = unicode(val, encoding = 'utf8', errors = 'replace') 483 except TypeError: 484 try: 485 data[field] = unicode(val) 486 except (UnicodeDecodeError, TypeError): 487 val = '%s' % str(val) 488 data[field] = val.decode('utf8', 'replace') 489 if escape_style in [u'latex', u'tex']: 490 data[field] = tex_escape_string(data[field]) 491 492 return data
493 #--------------------------------------------------------
494 - def get_patient(self):
495 _log.error('[%s:%s]: forgot to override get_patient()' % (self.__class__.__name__, self.pk_obj)) 496 return None
497 #--------------------------------------------------------
498 - def format(self):
499 return u'%s' % self
500 #--------------------------------------------------------
501 - def refetch_payload(self, ignore_changes=False):
502 """Fetch field values from backend. 503 """ 504 if self._is_modified: 505 if ignore_changes: 506 _log.critical('[%s:%s]: loosing payload changes' % (self.__class__.__name__, self.pk_obj)) 507 _log.debug('original: %s' % self.original_payload) 508 _log.debug('modified: %s' % self._payload) 509 else: 510 _log.critical('[%s:%s]: cannot reload, payload changed' % (self.__class__.__name__, self.pk_obj)) 511 return False 512 513 if type(self.pk_obj) == types.DictType: 514 arg = self.pk_obj 515 else: 516 arg = [self.pk_obj] 517 rows, self._idx = gmPG2.run_ro_queries ( 518 queries = [{'cmd': self.__class__._cmd_fetch_payload, 'args': arg}], 519 get_col_idx = True 520 ) 521 if len(rows) == 0: 522 _log.error('[%s:%s]: no such instance' % (self.__class__.__name__, self.pk_obj)) 523 return False 524 self._payload = rows[0] 525 return True
526 #--------------------------------------------------------
527 - def __noop(self):
528 pass
529 #--------------------------------------------------------
530 - def save(self, conn=None):
531 return self.save_payload(conn = conn)
532 #--------------------------------------------------------
533 - def save_payload(self, conn=None):
534 """Store updated values (if any) in database. 535 536 Optionally accepts a pre-existing connection 537 - returns a tuple (<True|False>, <data>) 538 - True: success 539 - False: an error occurred 540 * data is (error, message) 541 * for error meanings see gmPG2.run_rw_queries() 542 """ 543 if not self._is_modified: 544 return (True, None) 545 546 args = {} 547 for field in self._idx.keys(): 548 args[field] = self._payload[self._idx[field]] 549 self.modified_payload = args 550 551 close_conn = self.__noop 552 if conn is None: 553 conn = gmPG2.get_connection(readonly=False) 554 close_conn = conn.close 555 556 # query succeeded but failed to find the row to lock 557 # because another transaction committed an UPDATE or 558 # DELETE *before* we attempted to lock it ... 559 # FIXME: this can fail if savepoints are used since subtransactions change the xmin/xmax ... 560 561 queries = [] 562 for query in self.__class__._cmds_store_payload: 563 queries.append({'cmd': query, 'args': args}) 564 rows, idx = gmPG2.run_rw_queries ( 565 link_obj = conn, 566 queries = queries, 567 return_data = True, 568 get_col_idx = True 569 ) 570 571 # this can happen if: 572 # - someone else updated the row so XMIN does not match anymore 573 # - the PK went away (rows was deleted from under us) 574 # - another WHERE condition of the UPDATE did not produce any rows to update 575 if len(rows) == 0: 576 return (False, (u'cannot update row', _('[%s:%s]: row not updated (nothing returned), row in use ?') % (self.__class__.__name__, self.pk_obj))) 577 578 # update cached XMIN values (should be in first-and-only result row of last query) 579 row = rows[0] 580 for key in idx: 581 try: 582 self._payload[self._idx[key]] = row[idx[key]] 583 except KeyError: 584 conn.rollback() 585 close_conn() 586 _log.error('[%s:%s]: cannot update instance, XMIN refetch key mismatch on [%s]' % (self.__class__.__name__, self.pk_obj, key)) 587 _log.error('payload keys: %s' % str(self._idx)) 588 _log.error('XMIN refetch keys: %s' % str(idx)) 589 _log.error(args) 590 raise 591 592 conn.commit() 593 close_conn() 594 595 self._is_modified = False 596 # update to new "original" payload 597 self.original_payload = {} 598 for field in self._idx.keys(): 599 self.original_payload[field] = self._payload[self._idx[field]] 600 601 return (True, None)
602 603 #============================================================
604 -def jsonclasshintify(obj):
605 # this should eventually be somewhere else 606 """ turn the data into a list of dicts, adding "class hints". 607 all objects get turned into dictionaries which the other end 608 will interpret as "object", via the __jsonclass__ hint, 609 as specified by the JSONRPC protocol standard. 610 """ 611 if isinstance(obj, list): 612 return map(jsonclasshintify, obj) 613 elif isinstance(obj, gmPG2.dbapi.tz.FixedOffsetTimezone): 614 # this will get decoded as "from jsonobjproxy import {clsname}" 615 # at the remote (client) end. 616 res = {'__jsonclass__': ["jsonobjproxy.FixedOffsetTimezone"]} 617 res['name'] = obj._name 618 res['offset'] = jsonclasshintify(obj._offset) 619 return res 620 elif isinstance(obj, datetime.timedelta): 621 # this will get decoded as "from jsonobjproxy import {clsname}" 622 # at the remote (client) end. 623 res = {'__jsonclass__': ["jsonobjproxy.TimeDelta"]} 624 res['days'] = obj.days 625 res['seconds'] = obj.seconds 626 res['microseconds'] = obj.microseconds 627 return res 628 elif isinstance(obj, datetime.time): 629 # this will get decoded as "from jsonobjproxy import {clsname}" 630 # at the remote (client) end. 631 res = {'__jsonclass__': ["jsonobjproxy.Time"]} 632 res['hour'] = obj.hour 633 res['minute'] = obj.minute 634 res['second'] = obj.second 635 res['microsecond'] = obj.microsecond 636 res['tzinfo'] = jsonclasshintify(obj.tzinfo) 637 return res 638 elif isinstance(obj, datetime.datetime): 639 # this will get decoded as "from jsonobjproxy import {clsname}" 640 # at the remote (client) end. 641 res = {'__jsonclass__': ["jsonobjproxy.DateTime"]} 642 res['year'] = obj.year 643 res['month'] = obj.month 644 res['day'] = obj.day 645 res['hour'] = obj.hour 646 res['minute'] = obj.minute 647 res['second'] = obj.second 648 res['microsecond'] = obj.microsecond 649 res['tzinfo'] = jsonclasshintify(obj.tzinfo) 650 return res 651 elif isinstance(obj, cBusinessDBObject): 652 # this will get decoded as "from jsonobjproxy import {clsname}" 653 # at the remote (client) end. 654 res = {'__jsonclass__': ["jsonobjproxy.%s" % obj.__class__.__name__]} 655 for k in obj.get_fields(): 656 t = jsonclasshintify(obj[k]) 657 res[k] = t 658 print "props", res, dir(obj) 659 for attribute in dir(obj): 660 if not attribute.startswith("get_"): 661 continue 662 k = attribute[4:] 663 if res.has_key(k): 664 continue 665 getter = getattr(obj, attribute, None) 666 if callable(getter): 667 res[k] = jsonclasshintify(getter()) 668 return res 669 return obj
670 671 #============================================================ 672 if __name__ == '__main__': 673 674 if len(sys.argv) < 2: 675 sys.exit() 676 677 if sys.argv[1] != u'test': 678 sys.exit() 679 680 #--------------------------------------------------------
681 - class cTestObj(cBusinessDBObject):
682 _cmd_fetch_payload = None 683 _cmds_store_payload = None 684 _updatable_fields = [] 685 #----------------------------------------------------
686 - def get_something(self):
687 pass
688 #----------------------------------------------------
689 - def set_something(self):
690 pass
691 #-------------------------------------------------------- 692 from Gnumed.pycommon import gmI18N 693 gmI18N.activate_locale() 694 gmI18N.install_domain() 695 696 data = { 697 'pk_field': 'bogus_pk', 698 'idx': {'bogus_pk': 0, 'bogus_field': 1, 'bogus_date': 2}, 699 'data': [-1, 'bogus_data', datetime.datetime.now()] 700 } 701 obj = cTestObj(row=data) 702 #print obj['wrong_field'] 703 #print jsonclasshintify(obj) 704 #obj['wrong_field'] = 1 705 print obj.fields_as_dict() 706 707 #============================================================ 708