osm_common/dbbase.py

   1 import yaml
   2 from http import HTTPStatus
   3 from copy import deepcopy
   4
   5 __author__ = "Alfonso Tierno <alfonso.tiernosepulveda@telefonica.com>"
   6
   7
   8 class DbException(Exception):
   9
  10     def __init__(self, message, http_code=HTTPStatus.NOT_FOUND):
  11         # TODO change to http.HTTPStatus instead of int that allows .value and .name
  12         self.http_code = http_code
  13         Exception.__init__(self, "database exception " + message)
  14
  15
  16 class DbBase(object):
  17
  18     def __init__(self):
  19         pass
  20
  21     def db_connect(self, config):
  22         pass
  23
  24     def db_disconnect(self):
  25         pass
  26
  27     def get_list(self, table, filter={}):
  28         raise DbException("Method 'get_list' not implemented")
  29
  30     def get_one(self, table, filter={}, fail_on_empty=True, fail_on_more=True):
  31         raise DbException("Method 'get_one' not implemented")
  32
  33     def create(self, table, indata):
  34         raise DbException("Method 'create' not implemented")
  35
  36     def del_list(self, table, filter={}):
  37         raise DbException("Method 'del_list' not implemented")
  38
  39     def del_one(self, table, filter={}, fail_on_empty=True):
  40         raise DbException("Method 'del_one' not implemented")
  41
  42
  43 def deep_update(dict_to_change, dict_reference, key_list=None):
  44     """
  45     Modifies one dictionary with the information of the other following https://tools.ietf.org/html/rfc7396
  46     Basically is a recursive python 'dict_to_change.update(dict_reference)', but a value of None is used to delete.
  47     It implements an extra feature that allows modifying an array. RFC7396 only allows replacing the entire array.
  48     For that, dict_reference should contains a dict with keys starting by "$" with the following meaning:
  49         $[index]    <index> is an integer for targeting a concrete index from dict_to_change array. If the value is None
  50                     the element of the array is deleted, otherwise it is edited.
  51         $+[index]   The value is inserted at this <index>. A value of None has not sense and an exception is raised.
  52         $+          The value is appended at the end. A value of None has not sense and an exception is raised.
  53         $val        It looks for all the items in the array dict_to_change equal to <val>. <val> is evaluated as yaml,
  54                     that is, numbers are taken as type int, true/false as boolean, etc. Use quotes to force string.
  55                     Nothing happens if no match is found. If the value is None the matched elements are deleted.
  56         $key: val   In case a dictionary is passed in yaml format, if looks for all items in the array dict_to_change
  57                     that are dictionaries and contains this <key> equal to <val>. Several keys can be used by yaml
  58                     format '{key: val, key: val, ...}'; and all of them mast match. Nothing happens if no match is
  59                     found. If value is None the matched items are deleted, otherwise they are edited.
  60         $+val       If no match if found (see '$val'), the value is appended to the array. If any match is found nothing
  61                     is changed. A value of None has not sense.
  62         $+key: val  If no match if found (see '$key: val'), the value is appended to the array. If any match is found
  63                     nothing is changed. A value of None has not sense.
  64     If there are several editions, insertions and deletions; editions and deletions are done first in reverse index
  65         order; then insertions also in reverse index order; and finally appends in any order. So indexes used at
  66         insertions must take into account the deleted items.
  67     :param dict_to_change:  Target dictionary to be changed.
  68     :param dict_reference: Dictionary that contains changes to be applied.
  69     :param key_list: This is used internally for recursive calls. Do not fill this parameter.
  70     :return: none or raises and exception only at array modification when there is a bad format or conflict.
  71     """
  72     def _deep_update_array(array_to_change, _dict_reference, _key_list):
  73         to_append = {}
  74         to_insert_at_index = {}
  75         values_to_edit_delete = {}
  76         indexes_to_edit_delete = []
  77         array_edition = None
  78         _key_list.append("")
  79         for k in _dict_reference:
  80             _key_list[-1] = str(k)
  81             if not isinstance(k, str) or not k.startswith("$"):
  82                 if array_edition is True:
  83                     raise DbException("Found array edition (keys starting with '$') and pure dictionary edition in the"
  84                                       " same dict at '{}'".format(":".join(_key_list[:-1])))
  85                 array_edition = False
  86                 continue
  87             else:
  88                 if array_edition is False:
  89                     raise DbException("Found array edition (keys starting with '$') and pure dictionary edition in the"
  90                                       " same dict at '{}'".format(":".join(_key_list[:-1])))
  91                 array_edition = True
  92             insert = False
  93             indexes = []  # indexes to edit or insert
  94             kitem = k[1:]
  95             if kitem.startswith('+'):
  96                 insert = True
  97                 kitem = kitem[1:]
  98                 if _dict_reference[k] is None:
  99                     raise DbException("A value of None has not sense for insertions at '{}'".format(
 100                         ":".join(_key_list)))
 101
 102             if kitem.startswith('[') and kitem.endswith(']'):
 103                 try:
 104                     index = int(kitem[1:-1])
 105                     if index < 0:
 106                         index += len(array_to_change)
 107                     if index < 0:
 108                         index = 0  # skip outside index edition
 109                     indexes.append(index)
 110                 except Exception:
 111                     raise DbException("Wrong format at '{}'. Expecting integer index inside quotes".format(
 112                         ":".join(_key_list)))
 113             elif kitem:
 114                 # match_found_skip = False
 115                 try:
 116                     filter_in = yaml.safe_load(kitem)
 117                 except Exception:
 118                     raise DbException("Wrong format at '{}'. Expecting '$<yaml-format>'".format(":".join(_key_list)))
 119                 if isinstance(filter_in, dict):
 120                     for index, item in enumerate(array_to_change):
 121                         for filter_k, filter_v in filter_in.items():
 122                             if not isinstance(item, dict) or filter_k not in item or item[filter_k] != filter_v:
 123                                 break
 124                         else:  # match found
 125                             if insert:
 126                                 # match_found_skip = True
 127                                 insert = False
 128                                 break
 129                             else:
 130                                 indexes.append(index)
 131                 else:
 132                     index = 0
 133                     try:
 134                         while True:  # if not match a ValueError exception will be raise
 135                             index = array_to_change.index(filter_in, index)
 136                             if insert:
 137                                 # match_found_skip = True
 138                                 insert = False
 139                                 break
 140                             indexes.append(index)
 141                             index += 1
 142                     except ValueError:
 143                         pass
 144
 145                 # if match_found_skip:
 146                 #     continue
 147             elif not insert:
 148                 raise DbException("Wrong format at '{}'. Expecting '$+', '$[<index]' or '$[<filter>]'".format(
 149                     ":".join(_key_list)))
 150             for index in indexes:
 151                 if insert:
 152                     if index in to_insert_at_index and to_insert_at_index[index] != _dict_reference[k]:
 153                         # Several different insertions on the same item of the array
 154                         raise DbException("Conflict at '{}'. Several insertions on same array index {}".format(
 155                             ":".join(_key_list), index))
 156                     to_insert_at_index[index] = _dict_reference[k]
 157                 else:
 158                     if index in indexes_to_edit_delete and values_to_edit_delete[index] != _dict_reference[k]:
 159                         # Several different editions on the same item of the array
 160                         raise DbException("Conflict at '{}'. Several editions on array index {}".format(
 161                             ":".join(_key_list), index))
 162                     indexes_to_edit_delete.append(index)
 163                     values_to_edit_delete[index] = _dict_reference[k]
 164             if not indexes:
 165                 if insert:
 166                     to_append[k] = _dict_reference[k]
 167                 # elif _dict_reference[k] is not None:
 168                 #     raise DbException("Not found any match to edit in the array, or wrong format at '{}'".format(
 169                 #         ":".join(_key_list)))
 170
 171         # edition/deletion is done before insertion
 172         indexes_to_edit_delete.sort(reverse=True)
 173         for index in indexes_to_edit_delete:
 174             _key_list[-1] = str(index)
 175             try:
 176                 if values_to_edit_delete[index] is None:  # None->Anything
 177                     try:
 178                         del (array_to_change[index])
 179                     except IndexError:
 180                         pass  # it is not consider an error if this index does not exist
 181                 elif not isinstance(values_to_edit_delete[index], dict):  # NotDict->Anything
 182                     array_to_change[index] = deepcopy(values_to_edit_delete[index])
 183                 elif isinstance(array_to_change[index], dict):  # Dict->Dict
 184                     deep_update(array_to_change[index], values_to_edit_delete[index], _key_list)
 185                 else:  # Dict->NotDict
 186                     if isinstance(array_to_change[index], list):  # Dict->List. Check extra array edition
 187                         if _deep_update_array(array_to_change[index], values_to_edit_delete[index], _key_list):
 188                             continue
 189                     array_to_change[index] = deepcopy(values_to_edit_delete[index])
 190                     # calling deep_update to delete the None values
 191                     deep_update(array_to_change[index], values_to_edit_delete[index], _key_list)
 192             except IndexError:
 193                 raise DbException("Array edition index out of range at '{}'".format(":".join(_key_list)))
 194
 195         # insertion with indexes
 196         to_insert_indexes = list(to_insert_at_index.keys())
 197         to_insert_indexes.sort(reverse=True)
 198         for index in to_insert_indexes:
 199             array_to_change.insert(index, to_insert_at_index[index])
 200
 201         # append
 202         for k, insert_value in to_append.items():
 203             _key_list[-1] = str(k)
 204             insert_value_copy = deepcopy(insert_value)
 205             if isinstance(insert_value_copy, dict):
 206                 # calling deep_update to delete the None values
 207                 deep_update(insert_value_copy, insert_value, _key_list)
 208             array_to_change.append(insert_value_copy)
 209
 210         _key_list.pop()
 211         if array_edition:
 212             return True
 213         return False
 214
 215     if key_list is None:
 216         key_list = []
 217     key_list.append("")
 218     for k in dict_reference:
 219         key_list[-1] = str(k)
 220         if dict_reference[k] is None:   # None->Anything
 221             if k in dict_to_change:
 222                 del dict_to_change[k]
 223         elif not isinstance(dict_reference[k], dict):  # NotDict->Anything
 224             dict_to_change[k] = deepcopy(dict_reference[k])
 225         elif k not in dict_to_change:  # Dict->Empty
 226             dict_to_change[k] = deepcopy(dict_reference[k])
 227             # calling deep_update to delete the None values
 228             deep_update(dict_to_change[k], dict_reference[k], key_list)
 229         elif isinstance(dict_to_change[k], dict):  # Dict->Dict
 230             deep_update(dict_to_change[k], dict_reference[k], key_list)
 231         else:       # Dict->NotDict
 232             if isinstance(dict_to_change[k], list):  # Dict->List. Check extra array edition
 233                 if _deep_update_array(dict_to_change[k], dict_reference[k], key_list):
 234                     continue
 235             dict_to_change[k] = deepcopy(dict_reference[k])
 236             # calling deep_update to delete the None values
 237             deep_update(dict_to_change[k], dict_reference[k], key_list)
 238     key_list.pop()