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Edit File: hstore.py
# postgresql/hstore.py # Copyright (C) 2005-2023 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: https://www.opensource.org/licenses/mit-license.php import re from .array import ARRAY from ... import types as sqltypes from ... import util from ...sql import functions as sqlfunc from ...sql import operators __all__ = ("HSTORE", "hstore") idx_precedence = operators._PRECEDENCE[operators.json_getitem_op] GETITEM = operators.custom_op( "->", precedence=idx_precedence, natural_self_precedent=True, eager_grouping=True, ) HAS_KEY = operators.custom_op( "?", precedence=idx_precedence, natural_self_precedent=True, eager_grouping=True, ) HAS_ALL = operators.custom_op( "?&", precedence=idx_precedence, natural_self_precedent=True, eager_grouping=True, ) HAS_ANY = operators.custom_op( "?|", precedence=idx_precedence, natural_self_precedent=True, eager_grouping=True, ) CONTAINS = operators.custom_op( "@>", precedence=idx_precedence, natural_self_precedent=True, eager_grouping=True, ) CONTAINED_BY = operators.custom_op( "<@", precedence=idx_precedence, natural_self_precedent=True, eager_grouping=True, ) class HSTORE(sqltypes.Indexable, sqltypes.Concatenable, sqltypes.TypeEngine): """Represent the PostgreSQL HSTORE type. The :class:`.HSTORE` type stores dictionaries containing strings, e.g.:: data_table = Table('data_table', metadata, Column('id', Integer, primary_key=True), Column('data', HSTORE) ) with engine.connect() as conn: conn.execute( data_table.insert(), data = {"key1": "value1", "key2": "value2"} ) :class:`.HSTORE` provides for a wide range of operations, including: * Index operations:: data_table.c.data['some key'] == 'some value' * Containment operations:: data_table.c.data.has_key('some key') data_table.c.data.has_all(['one', 'two', 'three']) * Concatenation:: data_table.c.data + {"k1": "v1"} For a full list of special methods see :class:`.HSTORE.comparator_factory`. .. container:: topic **Detecting Changes in HSTORE columns when using the ORM** For usage with the SQLAlchemy ORM, it may be desirable to combine the usage of :class:`.HSTORE` with :class:`.MutableDict` dictionary now part of the :mod:`sqlalchemy.ext.mutable` extension. This extension will allow "in-place" changes to the dictionary, e.g. addition of new keys or replacement/removal of existing keys to/from the current dictionary, to produce events which will be detected by the unit of work:: from sqlalchemy.ext.mutable import MutableDict class MyClass(Base): __tablename__ = 'data_table' id = Column(Integer, primary_key=True) data = Column(MutableDict.as_mutable(HSTORE)) my_object = session.query(MyClass).one() # in-place mutation, requires Mutable extension # in order for the ORM to detect my_object.data['some_key'] = 'some value' session.commit() When the :mod:`sqlalchemy.ext.mutable` extension is not used, the ORM will not be alerted to any changes to the contents of an existing dictionary, unless that dictionary value is re-assigned to the HSTORE-attribute itself, thus generating a change event. .. seealso:: :class:`.hstore` - render the PostgreSQL ``hstore()`` function. """ __visit_name__ = "HSTORE" hashable = False text_type = sqltypes.Text() def __init__(self, text_type=None): """Construct a new :class:`.HSTORE`. :param text_type: the type that should be used for indexed values. Defaults to :class:`_types.Text`. .. versionadded:: 1.1.0 """ if text_type is not None: self.text_type = text_type class Comparator( sqltypes.Indexable.Comparator, sqltypes.Concatenable.Comparator ): """Define comparison operations for :class:`.HSTORE`.""" def has_key(self, other): """Boolean expression. Test for presence of a key. Note that the key may be a SQLA expression. """ return self.operate(HAS_KEY, other, result_type=sqltypes.Boolean) def has_all(self, other): """Boolean expression. Test for presence of all keys in jsonb""" return self.operate(HAS_ALL, other, result_type=sqltypes.Boolean) def has_any(self, other): """Boolean expression. Test for presence of any key in jsonb""" return self.operate(HAS_ANY, other, result_type=sqltypes.Boolean) def contains(self, other, **kwargs): """Boolean expression. Test if keys (or array) are a superset of/contained the keys of the argument jsonb expression. kwargs may be ignored by this operator but are required for API conformance. """ return self.operate(CONTAINS, other, result_type=sqltypes.Boolean) def contained_by(self, other): """Boolean expression. Test if keys are a proper subset of the keys of the argument jsonb expression. """ return self.operate( CONTAINED_BY, other, result_type=sqltypes.Boolean ) def _setup_getitem(self, index): return GETITEM, index, self.type.text_type def defined(self, key): """Boolean expression. Test for presence of a non-NULL value for the key. Note that the key may be a SQLA expression. """ return _HStoreDefinedFunction(self.expr, key) def delete(self, key): """HStore expression. Returns the contents of this hstore with the given key deleted. Note that the key may be a SQLA expression. """ if isinstance(key, dict): key = _serialize_hstore(key) return _HStoreDeleteFunction(self.expr, key) def slice(self, array): """HStore expression. Returns a subset of an hstore defined by array of keys. """ return _HStoreSliceFunction(self.expr, array) def keys(self): """Text array expression. Returns array of keys.""" return _HStoreKeysFunction(self.expr) def vals(self): """Text array expression. Returns array of values.""" return _HStoreValsFunction(self.expr) def array(self): """Text array expression. Returns array of alternating keys and values. """ return _HStoreArrayFunction(self.expr) def matrix(self): """Text array expression. Returns array of [key, value] pairs.""" return _HStoreMatrixFunction(self.expr) comparator_factory = Comparator def bind_processor(self, dialect): if util.py2k: encoding = dialect.encoding def process(value): if isinstance(value, dict): return _serialize_hstore(value).encode(encoding) else: return value else: def process(value): if isinstance(value, dict): return _serialize_hstore(value) else: return value return process def result_processor(self, dialect, coltype): if util.py2k: encoding = dialect.encoding def process(value): if value is not None: return _parse_hstore(value.decode(encoding)) else: return value else: def process(value): if value is not None: return _parse_hstore(value) else: return value return process class hstore(sqlfunc.GenericFunction): """Construct an hstore value within a SQL expression using the PostgreSQL ``hstore()`` function. The :class:`.hstore` function accepts one or two arguments as described in the PostgreSQL documentation. E.g.:: from sqlalchemy.dialects.postgresql import array, hstore select(hstore('key1', 'value1')) select( hstore( array(['key1', 'key2', 'key3']), array(['value1', 'value2', 'value3']) ) ) .. seealso:: :class:`.HSTORE` - the PostgreSQL ``HSTORE`` datatype. """ type = HSTORE name = "hstore" inherit_cache = True class _HStoreDefinedFunction(sqlfunc.GenericFunction): type = sqltypes.Boolean name = "defined" inherit_cache = True class _HStoreDeleteFunction(sqlfunc.GenericFunction): type = HSTORE name = "delete" inherit_cache = True class _HStoreSliceFunction(sqlfunc.GenericFunction): type = HSTORE name = "slice" inherit_cache = True class _HStoreKeysFunction(sqlfunc.GenericFunction): type = ARRAY(sqltypes.Text) name = "akeys" inherit_cache = True class _HStoreValsFunction(sqlfunc.GenericFunction): type = ARRAY(sqltypes.Text) name = "avals" inherit_cache = True class _HStoreArrayFunction(sqlfunc.GenericFunction): type = ARRAY(sqltypes.Text) name = "hstore_to_array" inherit_cache = True class _HStoreMatrixFunction(sqlfunc.GenericFunction): type = ARRAY(sqltypes.Text) name = "hstore_to_matrix" inherit_cache = True # # parsing. note that none of this is used with the psycopg2 backend, # which provides its own native extensions. # # My best guess at the parsing rules of hstore literals, since no formal # grammar is given. This is mostly reverse engineered from PG's input parser # behavior. HSTORE_PAIR_RE = re.compile( r""" ( "(?P<key> (\\ . | [^"])* )" # Quoted key ) [ ]* => [ ]* # Pair operator, optional adjoining whitespace ( (?P<value_null> NULL ) # NULL value | "(?P<value> (\\ . | [^"])* )" # Quoted value ) """, re.VERBOSE, ) HSTORE_DELIMITER_RE = re.compile( r""" [ ]* , [ ]* """, re.VERBOSE, ) def _parse_error(hstore_str, pos): """format an unmarshalling error.""" ctx = 20 hslen = len(hstore_str) parsed_tail = hstore_str[max(pos - ctx - 1, 0) : min(pos, hslen)] residual = hstore_str[min(pos, hslen) : min(pos + ctx + 1, hslen)] if len(parsed_tail) > ctx: parsed_tail = "[...]" + parsed_tail[1:] if len(residual) > ctx: residual = residual[:-1] + "[...]" return "After %r, could not parse residual at position %d: %r" % ( parsed_tail, pos, residual, ) def _parse_hstore(hstore_str): """Parse an hstore from its literal string representation. Attempts to approximate PG's hstore input parsing rules as closely as possible. Although currently this is not strictly necessary, since the current implementation of hstore's output syntax is stricter than what it accepts as input, the documentation makes no guarantees that will always be the case. """ result = {} pos = 0 pair_match = HSTORE_PAIR_RE.match(hstore_str) while pair_match is not None: key = pair_match.group("key").replace(r"\"", '"').replace("\\\\", "\\") if pair_match.group("value_null"): value = None else: value = ( pair_match.group("value") .replace(r"\"", '"') .replace("\\\\", "\\") ) result[key] = value pos += pair_match.end() delim_match = HSTORE_DELIMITER_RE.match(hstore_str[pos:]) if delim_match is not None: pos += delim_match.end() pair_match = HSTORE_PAIR_RE.match(hstore_str[pos:]) if pos != len(hstore_str): raise ValueError(_parse_error(hstore_str, pos)) return result def _serialize_hstore(val): """Serialize a dictionary into an hstore literal. Keys and values must both be strings (except None for values). """ def esc(s, position): if position == "value" and s is None: return "NULL" elif isinstance(s, util.string_types): return '"%s"' % s.replace("\\", "\\\\").replace('"', r"\"") else: raise ValueError( "%r in %s position is not a string." % (s, position) ) return ", ".join( "%s=>%s" % (esc(k, "key"), esc(v, "value")) for k, v in val.items() )