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import logging
import psycopg2
import psycopg2.extras
import psycopg2.extensions as ext
import sqlparse
from .packages import pgspecial
from .encodingutils import unicode2utf8, PY2
_logger = logging.getLogger(__name__)
# Cast all database input to unicode automatically.
# See http://initd.org/psycopg/docs/usage.html#unicode-handling for more info.
ext.register_type(ext.UNICODE)
ext.register_type(ext.UNICODEARRAY)
ext.register_type(ext.new_type((705,), "UNKNOWN", ext.UNICODE))
# Cast bytea fields to text. By default, this will render as hex strings with
# Postgres 9+ and as escaped binary in earlier versions.
ext.register_type(ext.new_type((17,), 'BYTEA_TEXT', psycopg2.STRING))
# When running a query, make pressing CTRL+C raise a KeyboardInterrupt
# See http://initd.org/psycopg/articles/2014/07/20/cancelling-postgresql-statements-python/
ext.set_wait_callback(psycopg2.extras.wait_select)
def register_json_typecasters(conn, loads_fn):
"""Set the function for converting JSON data for a connection.
Use the supplied function to decode JSON data returned from the database
via the given connection. The function should accept a single argument of
the data as a string encoded in the database's character encoding.
psycopg2's default handler for JSON data is json.loads.
http://initd.org/psycopg/docs/extras.html#json-adaptation
This function attempts to register the typecaster for both JSON and JSONB
types.
Returns a set that is a subset of {'json', 'jsonb'} indicating which types
(if any) were successfully registered.
"""
available = set()
for name in ['json', 'jsonb']:
try:
psycopg2.extras.register_json(conn, loads=loads_fn, name=name)
available.add(name)
except psycopg2.ProgrammingError:
pass
return available
def register_hstore_typecaster(conn):
"""
Instead of using register_hstore() which converts hstore into a python
dict, we query the 'oid' of hstore which will be different for each
database and register a type caster that converts it to unicode.
http://initd.org/psycopg/docs/extras.html#psycopg2.extras.register_hstore
"""
with conn.cursor() as cur:
try:
cur.execute("SELECT 'hstore'::regtype::oid")
oid = cur.fetchone()[0]
ext.register_type(ext.new_type((oid,), "HSTORE", ext.UNICODE))
except Exception:
pass
class PGExecute(object):
# The boolean argument to the current_schemas function indicates whether
# implicit schemas, e.g. pg_catalog
search_path_query = '''
SELECT * FROM unnest(current_schemas(true))'''
schemata_query = '''
SELECT nspname
FROM pg_catalog.pg_namespace
ORDER BY 1 '''
tables_query = '''
SELECT n.nspname schema_name,
c.relname table_name
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n
ON n.oid = c.relnamespace
WHERE c.relkind = ANY(%s)
ORDER BY 1,2;'''
columns_query = '''
SELECT nsp.nspname schema_name,
cls.relname table_name,
att.attname column_name
FROM pg_catalog.pg_attribute att
INNER JOIN pg_catalog.pg_class cls
ON att.attrelid = cls.oid
INNER JOIN pg_catalog.pg_namespace nsp
ON cls.relnamespace = nsp.oid
WHERE cls.relkind = ANY(%s)
AND NOT att.attisdropped
AND att.attnum > 0
ORDER BY 1, 2, 3'''
functions_query = '''
SELECT DISTINCT --multiple dispatch means possible duplicates
n.nspname schema_name,
p.proname func_name
FROM pg_catalog.pg_proc p
INNER JOIN pg_catalog.pg_namespace n
ON n.oid = p.pronamespace
WHERE n.nspname NOT IN ('pg_catalog', 'information_schema')
ORDER BY 1, 2'''
databases_query = """SELECT d.datname as "Name",
pg_catalog.pg_get_userbyid(d.datdba) as "Owner",
pg_catalog.pg_encoding_to_char(d.encoding) as "Encoding",
d.datcollate as "Collate",
d.datctype as "Ctype",
pg_catalog.array_to_string(d.datacl, E'\n') AS "Access privileges"
FROM pg_catalog.pg_database d
ORDER BY 1;"""
datatypes_query = '''
SELECT n.nspname schema_name,
t.typname type_name
FROM pg_catalog.pg_type t
INNER JOIN pg_catalog.pg_namespace n
ON n.oid = t.typnamespace
WHERE ( t.typrelid = 0 -- non-composite types
OR ( -- composite type, but not a table
SELECT c.relkind = 'c'
FROM pg_catalog.pg_class c
WHERE c.oid = t.typrelid
)
)
AND NOT EXISTS( -- ignore array types
SELECT 1
FROM pg_catalog.pg_type el
WHERE el.oid = t.typelem AND el.typarray = t.oid
)
AND n.nspname <> 'pg_catalog'
AND n.nspname <> 'information_schema'
ORDER BY 1, 2;'''
def __init__(self, database, user, password, host, port):
self.dbname = database
self.user = user
self.password = password
self.host = host
self.port = port
self.connect()
def connect(self, database=None, user=None, password=None, host=None,
port=None):
db = unicode2utf8(database or self.dbname)
user = unicode2utf8(user or self.user)
password = unicode2utf8(password or self.password)
host = unicode2utf8(host or self.host)
port = unicode2utf8(port or self.port)
conn = psycopg2.connect(database=db, user=user, password=password,
host=host, port=port)
if hasattr(self, 'conn'):
self.conn.close()
self.conn = conn
self.conn.autocommit = True
register_json_typecasters(self.conn, self._json_typecaster)
register_hstore_typecaster(self.conn)
def _json_typecaster(self, json_data):
"""Interpret incoming JSON data as a string.
The raw data is decoded using the connection's encoding, which defaults
to the database's encoding.
See http://initd.org/psycopg/docs/connection.html#connection.encoding
"""
if PY2:
return json_data.decode(self.conn.encoding)
else:
return json_data
def run(self, statement):
"""Execute the sql in the database and return the results. The results
are a list of tuples. Each tuple has 4 values (title, rows, headers, status).
"""
# Remove spaces and EOL
statement = statement.strip()
if not statement: # Empty string
yield (None, None, None, None)
# Split the sql into separate queries and run each one.
for sql in sqlparse.split(statement):
# Remove spaces, eol and semi-colons.
sql = sql.rstrip(';')
# Check if the command is a \c or 'use'. This is a special
# exception that cannot be offloaded to `pgspecial` lib. Because we
# have to change the database connection that we're connected to.
command = sql.split()[0]
if command == '\c' or command == '\connect' or command.lower() == 'use':
_logger.debug('Database change command detected.')
try:
dbname = sql.split()[1]
except:
_logger.debug('Database name missing.')
raise RuntimeError('Database name missing.')
self.connect(database=dbname)
self.dbname = dbname
_logger.debug('Successfully switched to DB: %r', dbname)
yield (None, None, None, 'You are now connected to database "%s" as '
'user "%s"' % (self.dbname, self.user))
else:
try: # Special command
_logger.debug('Trying a pgspecial command. sql: %r', sql)
cur = self.conn.cursor()
for result in pgspecial.execute(cur, sql):
yield result
except KeyError: # Regular SQL
yield self.execute_normal_sql(sql)
def execute_normal_sql(self, split_sql):
_logger.debug('Regular sql statement. sql: %r', split_sql)
cur = self.conn.cursor()
cur.execute(split_sql)
try:
title = self.conn.notices.pop()
except IndexError:
title = None
# cur.description will be None for operations that do not return
# rows.
if cur.description:
headers = [x[0] for x in cur.description]
return (title, cur, headers, cur.statusmessage)
else:
_logger.debug('No rows in result.')
return (title, None, None, cur.statusmessage)
def search_path(self):
"""Returns the current search path as a list of schema names"""
with self.conn.cursor() as cur:
_logger.debug('Search path query. sql: %r', self.search_path_query)
cur.execute(self.search_path_query)
return [x[0] for x in cur.fetchall()]
def schemata(self):
"""Returns a list of schema names in the database"""
with self.conn.cursor() as cur:
_logger.debug('Schemata Query. sql: %r', self.schemata_query)
cur.execute(self.schemata_query)
return [x[0] for x in cur.fetchall()]
def _relations(self, kinds=('r', 'v', 'm')):
"""Get table or view name metadata
:param kinds: list of postgres relkind filters:
'r' - table
'v' - view
'm' - materialized view
:return: (schema_name, rel_name) tuples
"""
with self.conn.cursor() as cur:
sql = cur.mogrify(self.tables_query, [kinds])
_logger.debug('Tables Query. sql: %r', sql)
cur.execute(sql)
for row in cur:
yield row
def tables(self):
"""Yields (schema_name, table_name) tuples"""
for row in self._relations(kinds=['r']):
yield row
def views(self):
"""Yields (schema_name, view_name) tuples.
Includes both views and and materialized views
"""
for row in self._relations(kinds=['v', 'm']):
yield row
def _columns(self, kinds=('r', 'v', 'm')):
"""Get column metadata for tables and views
:param kinds: kinds: list of postgres relkind filters:
'r' - table
'v' - view
'm' - materialized view
:return: list of (schema_name, relation_name, column_name) tuples
"""
with self.conn.cursor() as cur:
sql = cur.mogrify(self.columns_query, [kinds])
_logger.debug('Columns Query. sql: %r', sql)
cur.execute(sql)
for row in cur:
yield row
def table_columns(self):
for row in self._columns(kinds=['r']):
yield row
def view_columns(self):
for row in self._columns(kinds=['v', 'm']):
yield row
def databases(self):
with self.conn.cursor() as cur:
_logger.debug('Databases Query. sql: %r', self.databases_query)
cur.execute(self.databases_query)
return [x[0] for x in cur.fetchall()]
def functions(self):
"""Yields tuples of (schema_name, function_name)"""
with self.conn.cursor() as cur:
_logger.debug('Functions Query. sql: %r', self.functions_query)
cur.execute(self.functions_query)
for row in cur:
yield row
def datatypes(self):
"""Yields tuples of (schema_name, type_name)"""
with self.conn.cursor() as cur:
_logger.debug('Datatypes Query. sql: %r', self.datatypes_query)
cur.execute(self.datatypes_query)
for row in cur:
yield row
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