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author | xiubuzhe <xiubuzhe@sina.com> | 2023-10-08 20:59:00 +0800 |
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committer | xiubuzhe <xiubuzhe@sina.com> | 2023-10-08 20:59:00 +0800 |
commit | 1dac2263372df2b85db5d029a45721fa158a5c9d (patch) | |
tree | 0365f9c57df04178a726d7584ca6a6b955a7ce6a /lib/sqlalchemy/dialects/postgresql/hstore.py | |
parent | b494be364bb39e1de128ada7dc576a729d99907e (diff) | |
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Diffstat (limited to 'lib/sqlalchemy/dialects/postgresql/hstore.py')
-rw-r--r-- | lib/sqlalchemy/dialects/postgresql/hstore.py | 455 |
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diff --git a/lib/sqlalchemy/dialects/postgresql/hstore.py b/lib/sqlalchemy/dialects/postgresql/hstore.py new file mode 100644 index 0000000..29800d2 --- /dev/null +++ b/lib/sqlalchemy/dialects/postgresql/hstore.py @@ -0,0 +1,455 @@ +# postgresql/hstore.py +# Copyright (C) 2005-2022 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`. + + 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() + ) |