Source code for sqlalchemy_utils.functions.render

import inspect
import io

import sqlalchemy as sa

from .mock import create_mock_engine
from .orm import _get_query_compile_state

[docs]def render_expression(expression, bind, stream=None): """Generate a SQL expression from the passed python expression. Only the global variable, `engine`, is available for use in the expression. Additional local variables may be passed in the context parameter. Note this function is meant for convenience and protected usage. Do NOT blindly pass user input to this function as it uses exec. :param bind: A SQLAlchemy engine or bind URL. :param stream: Render all DDL operations to the stream. """ # Create a stream if not present. if stream is None: stream = io.StringIO() engine = create_mock_engine(bind, stream) # Navigate the stack and find the calling frame that allows the # expression to execuate. for frame in inspect.stack()[1:]: try: frame = frame[0] local = dict(frame.f_locals) local['engine'] = engine exec(expression, frame.f_globals, local) break except Exception: pass else: raise ValueError('Not a valid python expression', engine) return stream
[docs]def render_statement(statement, bind=None): """ Generate an SQL expression string with bound parameters rendered inline for the given SQLAlchemy statement. :param statement: SQLAlchemy Query object. :param bind: Optional SQLAlchemy bind, if None uses the bind of the given query object. """ if isinstance(statement, sa.orm.query.Query): if bind is None: bind = statement.session.get_bind( _get_query_compile_state(statement)._mapper_zero() ) statement = statement.statement elif bind is None: bind = statement.bind stream = io.StringIO() engine = create_mock_engine(bind.engine, stream=stream) engine.execute(statement) return stream.getvalue()