nexrad-archive/lib/nexrad/db.py
2025-02-15 14:52:13 -05:00

277 lines
7.3 KiB
Python

import enum
import sqlite3
class DatabaseOrder(enum.Enum):
DEFAULT = 0
ASC = 1
DESC = 2
class DatabaseTable():
__slots__ = '__dirty__', '__dirty_columns__',
def __init__(self):
object.__setattr__(self, '__dirty__', False)
object.__setattr__(self, '__dirty_columns__', dict())
def __reset__(self):
object.__setattr__(self, '__dirty__', False)
object.__setattr__(self, '__dirty_columns__', {k: 0 for k in self.__columns__})
def __setattr__(self, k, v):
object.__setattr__(self, k, v)
values = object.__getattribute__(self, '__dirty_columns__')
if k in values:
object.__setattr__(self, '__dirty__', True)
values[k] += 1
def __format_columns_select__(self):
csel = getattr(self, '__columns_select__')
if csel is None:
return self.__columns__
else:
ret = list()
for c in self.__columns__:
if c in csel:
ret.append(csel[c])
else:
ret.append(c)
return ret
class DatabaseTableCursor():
__slots__ = 'cr', 'table',
def __init__(self, table, cr):
self.cr = cr
self.table = table
def __getattr__(self, name):
return getattr(self.cr, name)
def __map__(self, row):
fn = getattr(self.table, '__from_row__', None)
if fn is not None:
return fn(row)
obj = self.table()
cr = getattr(self.table, '__columns_read__', None)
for name in self.table.__columns__:
try:
v = row[name]
if cr is not None and name in cr:
setattr(obj, name, cr[name](v))
else:
setattr(obj, name, v)
except IndexError:
pass
obj.__reset__()
return obj
def fetchone(self):
row = self.cr.fetchone()
return self.__map__(row) if row is not None else None
def fetchall(self):
return map(self.__map__, self.cr.fetchall())
def each(self):
while True:
obj = self.fetchone()
if obj is None:
break
yield obj
class Database():
__slots__ = 'db',
def __init__(self, db):
self.db = db
def __getattr__(self, name):
return getattr(self.db, name)
@staticmethod
def connect(path: str):
db = sqlite3.connect(path)
db.row_factory = sqlite3.Row
db.enable_load_extension(True)
db.execute("select load_extension('mod_spatialite.so.8')")
db.execute("select InitSpatialMetadata(1)")
return Database(db)
def column_placeholders(self, table, obj) -> list:
ret = list()
for c in table.__columns__:
v = getattr(obj, c)
if v is not None:
ret.append(c)
return ret
def value_placeholders(self, table, obj) -> list:
ci = getattr(table, '__columns_write__', None)
if ci is None:
return [f':{c}' for c in table.__columns__]
else:
ret = list()
for c in table.__columns__:
v = getattr(obj, c, None)
if v is None:
continue
if c in ci:
ret.append(ci[c])
else:
ret.append(f':{c}')
return ret
def row_values(self, table, obj) -> dict:
ret = dict()
vi = getattr(table, '__values_write__', None)
if vi is None:
for c in table.__columns__:
v = getattr(obj, c)
if v is not None:
ret[c] = v
else:
for c in table.__columns__:
v = getattr(obj, c)
if v is not None:
if c in vi:
ret.update(vi[c](v))
else:
ret[c] = v
return ret
def add(self, obj):
fn = getattr(obj, '__insert__', None)
if fn is not None:
return fn(self.db)
table = type(obj)
sql = f"insert into {table.__table__} ("
sql += ", ".join(self.column_placeholders(table, obj))
sql += ') values ('
sql += ", ".join(self.value_placeholders(table, obj))
sql += f") returning {table.__key__}"
values = self.row_values(table, obj)
cr = self.db.execute(sql, values)
setattr(obj, table.__key__, cr.fetchone()[0])
def update(self, obj):
if not obj.__dirty__:
return
dirty = [k for k in obj.__dirty_columns__ if obj.__dirty_columns__[k] > 0]
table = type(obj)
sql = f"update {table.__table__} set "
sql += ", ".join([f"{k} = :{k}" for k in dirty])
sql += f" where {table.__key__} = :{table.__key__}"
values = {
table.__key__: getattr(obj, table.__key__)
}
vi = getattr(table, '__values_write__', None)
for k in dirty:
if vi is not None and k in vi:
values[k] = vi[k](getattr(obj, k))
else:
values[k] = getattr(obj, k)
self.db.execute(sql, values)
def query_sql(self, table, sql, values=list()):
cr = DatabaseTableCursor(table, self.db.cursor())
cr.execute(sql, values)
return cr
def query(self, table, values=dict(), order_by=list()):
selectors = getattr(table, '__columns_select__', None)
if selectors is None:
columns = table.__columns__
else:
columns = [selectors[c] if c in selectors else c for c in table.__columns__]
sql = "select %s from %s" % (
', '.join(columns),
table.__table__
)
if len(values) > 0:
sql += " where "
sql += " and ".join([f"{table.__table__}.{k} = ?" for k in values])
if len(order_by) > 0:
sql += " order by"
first = True
for column, order in order_by:
if first:
first = False
else:
sql += ", "
if order is None or order is DatabaseOrder.DEFAULT:
sql += f" {column}"
elif order is DatabaseOrder.ASC:
sql += f" {column} asc"
elif order is DatabaseOrder.DESC:
sql += f" {column} desc"
return self.query_sql(table, sql, list(values.values()))
def get(self, table, values: dict=dict()):
return self.query(table, values).fetchone()
def _call(self, table, fn: str, column: str, values: dict=dict()) -> int:
sql = f"select {fn}({column}) as ret from {table.__table__}"
if len(values) > 0:
sql += " where "
sql += " and ".join([f"{k} = ?" for k in values])
row = self.db.execute(sql, list(values.values())).fetchone()
return row[0] if row is not None else None
def min(self, table, column: str, values: dict=dict()) -> int:
return self._call(table, 'min', column, values)
def max(self, table, column: str, values: dict=dict()) -> int:
return self._call(table, 'max', column, values)
def count(self, table, values: dict=dict()) -> int:
return self._call(table, 'count', table.__key__, values)