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_* = ... and pk* = ..." 174 statements 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 - the last query CAN return other fields which is particularly 179 useful when those other fields are computed in the backend 180 and may thus change upon save but will not have been set by 181 the client code explicitely - this is only really of concern 182 if the saved subclass is to be reused after saving rather 183 than re-instantiated 184 - when subclasses tend to live a while after save_payload() was 185 called and they support computed fields (say, _(some_column) 186 you need to return *all* columns (see cEncounter) 187 188 <_updatable_fields> 189 - a list of fields available for update via object['field'] 190 191 192 A template for new child classes: 193 194 *********** start of template *********** 195 196 #------------------------------------------------------------ 197 from Gnumed.pycommon import gmBusinessDBObject 198 from Gnumed.pycommon import gmPG2 199 200 #============================================================ 201 # short description 202 #------------------------------------------------------------ 203 # use plural form, search-replace get_XXX 204 _SQL_get_XXX = u" "" 205 SELECT *, (xmin AS xmin_XXX) 206 FROM XXX.v_XXX 207 WHERE %s 208 "" " 209 210 class cXxxXxx(gmBusinessDBObject.cBusinessDBObject): 211 " ""Represents ..."" " 212 213 _cmd_fetch_payload = _SQL_get_XXX % u"pk_XXX = %s" 214 _cmds_store_payload = [ 215 u" "" 216 -- typically the underlying table name 217 UPDATE xxx.xxx SET 218 -- typically "table_col = %(view_col)s" 219 xxx = %(xxx)s, 220 xxx = gm.nullify_empty_string(%(xxx)s) 221 WHERE 222 pk = %(pk_XXX)s 223 AND 224 xmin = %(xmin_XXX)s 225 RETURNING 226 xmin as xmin_XXX 227 --, ... 228 --, ... 229 " "" 230 ] 231 # view columns that can be updated: 232 _updatable_fields = [ 233 u'xxx', 234 u'xxx' 235 ] 236 #-------------------------------------------------------- 237 def format(self): 238 return u'%s' % self 239 240 #------------------------------------------------------------ 241 def get_XXX(order_by=None): 242 if order_by is None: 243 order_by = u'true' 244 else: 245 order_by = u'true ORDER BY %s' % order_by 246 247 cmd = _SQL_get_XXX % order_by 248 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': cmd}], get_col_idx = True) 249 return [ cXxxXxx(row = {'data': r, 'idx': idx, 'pk_field': 'xxx'}) for r in rows ] 250 #------------------------------------------------------------ 251 def create_xxx(xxx=None, xxx=None): 252 253 args = { 254 u'xxx': xxx, 255 u'xxx': xxx 256 } 257 cmd = u" "" 258 INSERT INTO xxx.xxx ( 259 xxx, 260 xxx, 261 xxx 262 ) VALUES ( 263 %(xxx)s, 264 %(xxx)s, 265 gm.nullify_empty_string(%(xxx)s) 266 ) 267 RETURNING pk 268 --RETURNING * 269 " "" 270 rows, idx = gmPG2.run_rw_queries(queries = [{'cmd': cmd, 'args': args}], return_data = True, get_col_idx = False) 271 #rows, idx = gmPG2.run_rw_queries(queries = [{'cmd': cmd, 'args': args}], return_data = True, get_col_idx = True) 272 273 return cXxxXxx(aPK_obj = rows[0]['pk']) 274 #return cXxxXxx(row = {'data': r, 'idx': idx, 'pk_field': 'xxx'}) 275 #------------------------------------------------------------ 276 def delete_xxx(xxx=None): 277 args = {'pk': xxx} 278 cmd = u"DELETE FROM xxx.xxx WHERE pk = %(pk)s" 279 gmPG2.run_rw_queries(queries = [{'cmd': cmd, 'args': args}]) 280 return True 281 #------------------------------------------------------------ 282 283 *********** end of template *********** 284 285 """ 286 #--------------------------------------------------------
287 - def __init__(self, aPK_obj=None, row=None):
288 """Init business object. 289 290 Call from child classes: 291 292 super(cChildClass, self).__init__(aPK_obj = aPK_obj, row = row) 293 """ 294 # initialize those "too early" because checking descendants might 295 # fail which will then call __str__ in stack trace logging if --debug 296 # was given which in turn needs those instance variables 297 self.pk_obj = '<uninitialized>' 298 self._idx = {} 299 self._payload = [] # the cache for backend object values (mainly table fields) 300 self._ext_cache = {} # the cache for extended method's results 301 self._is_modified = False 302 303 # check descendants 304 self.__class__._cmd_fetch_payload 305 self.__class__._cmds_store_payload 306 self.__class__._updatable_fields 307 308 if aPK_obj is not None: 309 self.__init_from_pk(aPK_obj=aPK_obj) 310 else: 311 self._init_from_row_data(row=row) 312 313 self._is_modified = False
314 #--------------------------------------------------------
315 - def __init_from_pk(self, aPK_obj=None):
316 """Creates a new clinical item instance by its PK. 317 318 aPK_obj can be: 319 - a simple value 320 * the primary key WHERE condition must be 321 a simple column 322 - a dictionary of values 323 * the primary key where condition must be a 324 subselect consuming the dict and producing 325 the single-value primary key 326 """ 327 self.pk_obj = aPK_obj 328 result = self.refetch_payload() 329 if result is True: 330 self.original_payload = {} 331 for field in self._idx.keys(): 332 self.original_payload[field] = self._payload[self._idx[field]] 333 return True 334 335 if result is False: 336 raise gmExceptions.ConstructorError, "[%s:%s]: error loading instance" % (self.__class__.__name__, self.pk_obj)
337 #--------------------------------------------------------
338 - def _init_from_row_data(self, row=None):
339 """Creates a new clinical item instance given its fields. 340 341 row must be a dict with the fields: 342 - pk_field: the name of the primary key field 343 - idx: a dict mapping field names to position 344 - data: the field values in a list (as returned by 345 cursor.fetchone() in the DB-API) 346 347 row = {'data': row, 'idx': idx, 'pk_field': 'the PK column name'} 348 349 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': cmd, 'args': args}], get_col_idx = True) 350 objects = [ cChildClass(row = {'data': r, 'idx': idx, 'pk_field': 'the PK column name'}) for r in rows ] 351 """ 352 try: 353 self._idx = row['idx'] 354 self._payload = row['data'] 355 self.pk_obj = self._payload[self._idx[row['pk_field']]] 356 except: 357 _log.exception('faulty <row> argument structure: %s' % row) 358 raise gmExceptions.ConstructorError, "[%s:??]: error loading instance from row data" % self.__class__.__name__ 359 360 if len(self._idx.keys()) != len(self._payload): 361 _log.critical('field index vs. payload length mismatch: %s field names vs. %s fields' % (len(self._idx.keys()), len(self._payload))) 362 _log.critical('faulty <row> argument structure: %s' % row) 363 raise gmExceptions.ConstructorError, "[%s:??]: error loading instance from row data" % self.__class__.__name__ 364 365 self.original_payload = {} 366 for field in self._idx.keys(): 367 self.original_payload[field] = self._payload[self._idx[field]]
368 #--------------------------------------------------------
369 - def __del__(self):
370 if self.__dict__.has_key('_is_modified'): 371 if self._is_modified: 372 _log.critical('[%s:%s]: loosing payload changes' % (self.__class__.__name__, self.pk_obj)) 373 _log.debug('original: %s' % self.original_payload) 374 _log.debug('modified: %s' % self._payload)
375 #--------------------------------------------------------
376 - def __str__(self):
377 tmp = [] 378 try: 379 for attr in self._idx.keys(): 380 if self._payload[self._idx[attr]] is None: 381 tmp.append(u'%s: NULL' % attr) 382 else: 383 tmp.append('%s: >>%s<<' % (attr, self._payload[self._idx[attr]])) 384 return '[%s:%s]: %s' % (self.__class__.__name__, self.pk_obj, str(tmp)) 385 except: 386 return 'nascent [%s @ %s], cannot show payload and primary key' %(self.__class__.__name__, id(self))
387 #--------------------------------------------------------
388 - def __getitem__(self, attribute):
389 # use try: except: as it is faster and we want this as fast as possible 390 391 # 1) backend payload cache 392 try: 393 return self._payload[self._idx[attribute]] 394 except KeyError: 395 pass 396 397 # 2) extension method results ... 398 getter = getattr(self, 'get_%s' % attribute, None) 399 if not callable(getter): 400 _log.warning('[%s]: no attribute [%s]' % (self.__class__.__name__, attribute)) 401 _log.warning('[%s]: valid attributes: %s' % (self.__class__.__name__, str(self._idx.keys()))) 402 _log.warning('[%s]: no getter method [get_%s]' % (self.__class__.__name__, attribute)) 403 methods = filter(lambda x: x[0].startswith('get_'), inspect.getmembers(self, inspect.ismethod)) 404 _log.warning('[%s]: valid getter methods: %s' % (self.__class__.__name__, str(methods))) 405 raise KeyError('[%s]: cannot read from key [%s]' % (self.__class__.__name__, attribute)) 406 407 self._ext_cache[attribute] = getter() 408 return self._ext_cache[attribute]
409 #--------------------------------------------------------
410 - def __setitem__(self, attribute, value):
411 412 # 1) backend payload cache 413 if attribute in self.__class__._updatable_fields: 414 try: 415 if self._payload[self._idx[attribute]] != value: 416 self._payload[self._idx[attribute]] = value 417 self._is_modified = True 418 return 419 except KeyError: 420 _log.warning('[%s]: cannot set attribute <%s> despite marked settable' % (self.__class__.__name__, attribute)) 421 _log.warning('[%s]: supposedly settable attributes: %s' % (self.__class__.__name__, str(self.__class__._updatable_fields))) 422 raise KeyError('[%s]: cannot write to key [%s]' % (self.__class__.__name__, attribute)) 423 424 # 2) setters providing extensions 425 if hasattr(self, 'set_%s' % attribute): 426 setter = getattr(self, "set_%s" % attribute) 427 if not callable(setter): 428 raise AttributeError('[%s] setter [set_%s] not callable' % (self.__class__.__name__, attribute)) 429 try: 430 del self._ext_cache[attribute] 431 except KeyError: 432 pass 433 if type(value) is types.TupleType: 434 if setter(*value): 435 self._is_modified = True 436 return 437 raise AttributeError('[%s]: setter [%s] failed for [%s]' % (self.__class__.__name__, setter, value)) 438 if setter(value): 439 self._is_modified = True 440 return 441 442 # 3) don't know what to do with <attribute> 443 _log.error('[%s]: cannot find attribute <%s> or setter method [set_%s]' % (self.__class__.__name__, attribute, attribute)) 444 _log.warning('[%s]: settable attributes: %s' % (self.__class__.__name__, str(self.__class__._updatable_fields))) 445 methods = filter(lambda x: x[0].startswith('set_'), inspect.getmembers(self, inspect.ismethod)) 446 _log.warning('[%s]: valid setter methods: %s' % (self.__class__.__name__, str(methods))) 447 raise AttributeError('[%s]: cannot set [%s]' % (self.__class__.__name__, attribute))
448 #-------------------------------------------------------- 449 # external API 450 #--------------------------------------------------------
451 - def same_payload(self, another_object=None):
452 raise NotImplementedError('comparison between [%s] and [%s] not implemented' % (self, another_object))
453 #--------------------------------------------------------
454 - def is_modified(self):
455 return self._is_modified
456 #--------------------------------------------------------
457 - def get_fields(self):
458 try: 459 return self._idx.keys() 460 except AttributeError: 461 return 'nascent [%s @ %s], cannot return keys' %(self.__class__.__name__, id(self))
462 #--------------------------------------------------------
463 - def get_updatable_fields(self):
464 return self.__class__._updatable_fields
465 #--------------------------------------------------------
466 - def fields_as_dict(self, date_format='%Y %b %d %H:%M', none_string=u'', escape_style=None, bool_strings=None):
467 if bool_strings is None: 468 bools = {True: u'true', False: u'false'} 469 else: 470 bools = {True: bool_strings[0], False: bool_strings[1]} 471 data = {} 472 for field in self._idx.keys(): 473 # FIXME: harden against BYTEA fields 474 #if type(self._payload[self._idx[field]]) == ... 475 # data[field] = _('<%s bytes of binary data>') % len(self._payload[self._idx[field]]) 476 # continue 477 val = self._payload[self._idx[field]] 478 if val is None: 479 data[field] = none_string 480 continue 481 if isinstance(val, bool): 482 data[field] = bools[val] 483 continue 484 485 if isinstance(val, datetime.datetime): 486 data[field] = pydt_strftime(val, format = date_format, encoding = 'utf8') 487 if escape_style in [u'latex', u'tex']: 488 data[field] = tex_escape_string(data[field]) 489 continue 490 491 try: 492 data[field] = unicode(val, encoding = 'utf8', errors = 'replace') 493 except TypeError: 494 try: 495 data[field] = unicode(val) 496 except (UnicodeDecodeError, TypeError): 497 val = '%s' % str(val) 498 data[field] = val.decode('utf8', 'replace') 499 if escape_style in [u'latex', u'tex']: 500 data[field] = tex_escape_string(data[field]) 501 502 return data
503 #--------------------------------------------------------
504 - def get_patient(self):
505 _log.error('[%s:%s]: forgot to override get_patient()' % (self.__class__.__name__, self.pk_obj)) 506 return None
507 #--------------------------------------------------------
508 - def format(self):
509 return u'%s' % self
510 #--------------------------------------------------------
511 - def refetch_payload(self, ignore_changes=False):
512 """Fetch field values from backend. 513 """ 514 if self._is_modified: 515 if ignore_changes: 516 _log.critical('[%s:%s]: loosing payload changes' % (self.__class__.__name__, self.pk_obj)) 517 _log.debug('original: %s' % self.original_payload) 518 _log.debug('modified: %s' % self._payload) 519 else: 520 _log.critical('[%s:%s]: cannot reload, payload changed' % (self.__class__.__name__, self.pk_obj)) 521 return False 522 523 if type(self.pk_obj) == types.DictType: 524 arg = self.pk_obj 525 else: 526 arg = [self.pk_obj] 527 rows, self._idx = gmPG2.run_ro_queries ( 528 queries = [{'cmd': self.__class__._cmd_fetch_payload, 'args': arg}], 529 get_col_idx = True 530 ) 531 if len(rows) == 0: 532 _log.error('[%s:%s]: no such instance' % (self.__class__.__name__, self.pk_obj)) 533 return False 534 self._payload = rows[0] 535 return True
536 #--------------------------------------------------------
537 - def __noop(self):
538 pass
539 #--------------------------------------------------------
540 - def save(self, conn=None):
541 return self.save_payload(conn = conn)
542 #--------------------------------------------------------
543 - def save_payload(self, conn=None):
544 """Store updated values (if any) in database. 545 546 Optionally accepts a pre-existing connection 547 - returns a tuple (<True|False>, <data>) 548 - True: success 549 - False: an error occurred 550 * data is (error, message) 551 * for error meanings see gmPG2.run_rw_queries() 552 """ 553 if not self._is_modified: 554 return (True, None) 555 556 args = {} 557 for field in self._idx.keys(): 558 args[field] = self._payload[self._idx[field]] 559 self.modified_payload = args 560 561 close_conn = self.__noop 562 if conn is None: 563 conn = gmPG2.get_connection(readonly=False) 564 close_conn = conn.close 565 566 queries = [] 567 for query in self.__class__._cmds_store_payload: 568 queries.append({'cmd': query, 'args': args}) 569 rows, idx = gmPG2.run_rw_queries ( 570 link_obj = conn, 571 queries = queries, 572 return_data = True, 573 get_col_idx = True 574 ) 575 576 # this can happen if: 577 # - someone else updated the row so XMIN does not match anymore 578 # - the PK went away (rows were deleted from under us) 579 # - another WHERE condition of the UPDATE did not produce any rows to update 580 # - savepoints are used since subtransactions may relevantly change the xmin/xmax ... 581 if len(rows) == 0: 582 return (False, (u'cannot update row', _('[%s:%s]: row not updated (nothing returned), row in use ?') % (self.__class__.__name__, self.pk_obj))) 583 584 # update cached values from should-be-first-and-only result 585 # row of last query, 586 # update all fields returned such that computed 587 # columns see their new values 588 row = rows[0] 589 for key in idx: 590 try: 591 self._payload[self._idx[key]] = row[idx[key]] 592 except KeyError: 593 conn.rollback() 594 close_conn() 595 _log.error('[%s:%s]: cannot update instance, XMIN refetch key mismatch on [%s]' % (self.__class__.__name__, self.pk_obj, key)) 596 _log.error('payload keys: %s' % str(self._idx)) 597 _log.error('XMIN refetch keys: %s' % str(idx)) 598 _log.error(args) 599 raise 600 601 conn.commit() 602 close_conn() 603 604 self._is_modified = False 605 # update to new "original" payload 606 self.original_payload = {} 607 for field in self._idx.keys(): 608 self.original_payload[field] = self._payload[self._idx[field]] 609 610 return (True, None)
611 612 #============================================================
613 -def jsonclasshintify(obj):
614 # this should eventually be somewhere else 615 """ turn the data into a list of dicts, adding "class hints". 616 all objects get turned into dictionaries which the other end 617 will interpret as "object", via the __jsonclass__ hint, 618 as specified by the JSONRPC protocol standard. 619 """ 620 if isinstance(obj, list): 621 return map(jsonclasshintify, obj) 622 elif isinstance(obj, gmPG2.dbapi.tz.FixedOffsetTimezone): 623 # this will get decoded as "from jsonobjproxy import {clsname}" 624 # at the remote (client) end. 625 res = {'__jsonclass__': ["jsonobjproxy.FixedOffsetTimezone"]} 626 res['name'] = obj._name 627 res['offset'] = jsonclasshintify(obj._offset) 628 return res 629 elif isinstance(obj, datetime.timedelta): 630 # this will get decoded as "from jsonobjproxy import {clsname}" 631 # at the remote (client) end. 632 res = {'__jsonclass__': ["jsonobjproxy.TimeDelta"]} 633 res['days'] = obj.days 634 res['seconds'] = obj.seconds 635 res['microseconds'] = obj.microseconds 636 return res 637 elif isinstance(obj, datetime.time): 638 # this will get decoded as "from jsonobjproxy import {clsname}" 639 # at the remote (client) end. 640 res = {'__jsonclass__': ["jsonobjproxy.Time"]} 641 res['hour'] = obj.hour 642 res['minute'] = obj.minute 643 res['second'] = obj.second 644 res['microsecond'] = obj.microsecond 645 res['tzinfo'] = jsonclasshintify(obj.tzinfo) 646 return res 647 elif isinstance(obj, datetime.datetime): 648 # this will get decoded as "from jsonobjproxy import {clsname}" 649 # at the remote (client) end. 650 res = {'__jsonclass__': ["jsonobjproxy.DateTime"]} 651 res['year'] = obj.year 652 res['month'] = obj.month 653 res['day'] = obj.day 654 res['hour'] = obj.hour 655 res['minute'] = obj.minute 656 res['second'] = obj.second 657 res['microsecond'] = obj.microsecond 658 res['tzinfo'] = jsonclasshintify(obj.tzinfo) 659 return res 660 elif isinstance(obj, cBusinessDBObject): 661 # this will get decoded as "from jsonobjproxy import {clsname}" 662 # at the remote (client) end. 663 res = {'__jsonclass__': ["jsonobjproxy.%s" % obj.__class__.__name__]} 664 for k in obj.get_fields(): 665 t = jsonclasshintify(obj[k]) 666 res[k] = t 667 print "props", res, dir(obj) 668 for attribute in dir(obj): 669 if not attribute.startswith("get_"): 670 continue 671 k = attribute[4:] 672 if res.has_key(k): 673 continue 674 getter = getattr(obj, attribute, None) 675 if callable(getter): 676 res[k] = jsonclasshintify(getter()) 677 return res 678 return obj
679 680 #============================================================ 681 if __name__ == '__main__': 682 683 if len(sys.argv) < 2: 684 sys.exit() 685 686 if sys.argv[1] != u'test': 687 sys.exit() 688 689 #--------------------------------------------------------
690 - class cTestObj(cBusinessDBObject):
691 _cmd_fetch_payload = None 692 _cmds_store_payload = None 693 _updatable_fields = [] 694 #----------------------------------------------------
695 - def get_something(self):
696 pass
697 #----------------------------------------------------
698 - def set_something(self):
699 pass
700 #-------------------------------------------------------- 701 from Gnumed.pycommon import gmI18N 702 gmI18N.activate_locale() 703 gmI18N.install_domain() 704 705 data = { 706 'pk_field': 'bogus_pk', 707 'idx': {'bogus_pk': 0, 'bogus_field': 1, 'bogus_date': 2}, 708 'data': [-1, 'bogus_data', datetime.datetime.now()] 709 } 710 obj = cTestObj(row=data) 711 #print obj['wrong_field'] 712 #print jsonclasshintify(obj) 713 #obj['wrong_field'] = 1 714 print obj.fields_as_dict() 715 716 #============================================================ 717