+from collections import OrderedDict
+from moz_sql_parser import parse
+import re
import tables
+_connector_type = 'pytables'
+
def inspect(path):
"Open file and return tables info"
h5tables = {}
'name': table._v_pathname,
'columns': colnames,
'primary_keys': [],
- 'count': table.nrows,
+ 'count': int(table.nrows),
'label_column': None,
'hidden': False,
'fts_table': None,
}
h5file.close()
- return h5tables, views
+ return h5tables, views, _connector_type
+
+def _parse_sql(sql, params):
+ # Table name
+ sql = re.sub('(?i)from \[(.*)]', 'from "\g<1>"', sql)
+ # Params
+ for param in params:
+ sql = sql.replace(":" + param, param)
+
+ try:
+ parsed = parse(sql)
+ except:
+ # Propably it's a PyTables expression
+ for token in ['group by', 'order by', 'limit']:
+ res = re.search('(?i)where (.*)' + token, sql)
+ if res:
+ modified_sql = re.sub('(?i)where (.*)(' + token + ')', '\g<2>', sql)
+ parsed = parse(modified_sql)
+ parsed['where'] = res.group(1)
+ break
+
+ # Always a list of fields
+ if type(parsed['select']) is not list:
+ parsed['select'] = [parsed['select']]
+
+ return parsed
+
+_operators = {
+ 'eq': '==',
+ 'neq': '!=',
+ 'gt': '>',
+ 'gte': '>=',
+ 'lt': '<',
+ 'lte': '<=',
+ 'and': '&',
+ 'or': '|',
+}
+
+class Connection:
+ def __init__(self, path):
+ self.path = path
+ self.h5file = tables.open_file(path)
+
+ def execute(self, sql, params=None, truncate=False):
+ if params is None:
+ params = {}
+ rows = []
+ truncated = False
+ description = []
+
+ parsed_sql = _parse_sql(sql, params)
+ table = self.h5file.get_node(parsed_sql['from'])
+ table_rows = []
+ fields = parsed_sql['select']
+
+ query = ''
+ start = 0
+ end = table.nrows
+
+ # Use 'where' statement or get all the rows
+ def _cast_param(field, pname):
+ # Cast value to the column type
+ coltype = table.coltypes[field]
+ fcast = None
+ if coltype == 'string':
+ fcast = str
+ elif coltype.startswith('int'):
+ fcast = int
+ elif coltype.startswith('float'):
+ fcast = float
+ if fcast:
+ params[pname] = fcast(params[pname])
+
+ def _translate_where(where):
+ # Translate SQL to PyTables expression
+ expr = ''
+ operator = list(where)[0]
+
+ if operator in ['and', 'or']:
+ subexpr = ["({})".format(_translate_where(q)) for q in where[operator]]
+ expr = " {} ".format(_operators[operator]).join(subexpr)
+ elif where == {'eq': ['rowid', 'p0']}:
+ nonlocal start, end
+ start = int(params['p0'])
+ end = start + 1
+ else:
+ left, right = where[operator]
+ if left in params:
+ _cast_param(right, left)
+ elif right in params:
+ _cast_param(left, right)
+
+ expr = "{left} {operator} {right}".format(left=left, operator=_operators.get(operator, operator), right=right)
+
+ return expr
+
+ if 'where' in parsed_sql:
+ if type(parsed_sql['where']) is dict:
+ query = _translate_where(parsed_sql['where'])
+ else:
+ query = parsed_sql['where']
+
+ # Limit number of rows
+ if 'limit' in parsed_sql:
+ max_rows = int(parsed_sql['limit'])
+ if end - start > max_rows:
+ end = start + max_rows
+
+ # Execute query
+ if query:
+ table_rows = table.where(query, params, start, end)
+ else:
+ table_rows = table.iterrows(start, end)
+
+ # Prepare rows
+ if len(fields) == 1 and type(fields[0]['value']) is dict and \
+ fields[0]['value'].get('count') == '*':
+ rows.append(Row({'count(*)': int(table.nrows)}))
+ else:
+ for table_row in table_rows:
+ row = Row()
+ for field in fields:
+ if field['value'] == 'rowid':
+ row['rowid'] = int(table_row.nrow)
+ elif field['value'] == '*':
+ for col in table.colnames:
+ value = table_row[col]
+ if type(value) is bytes:
+ value = value.decode('utf-8')
+ row[col] = value
+ else:
+ row[field['value']] = table_row[field['value']]
+ rows.append(row)
+
+ # Prepare query description
+ for field in [f['value'] for f in fields]:
+ if field == '*':
+ for col in table.colnames:
+ description.append((col,))
+ else:
+ description.append((field,))
+
+ # Return the rows
+ if truncate:
+ return rows, truncated, tuple(description)
+ else:
+ return rows
+
+class Row(OrderedDict):
+ def __getitem__(self, label):
+ if type(label) is int:
+ return super(OrderedDict, self).__getitem__(list(self.keys())[label])
+ else:
+ return super(OrderedDict, self).__getitem__(label)
+
+ def __iter__(self):
+ return self.values().__iter__()
projects / datasette-pytables.git / blobdiff