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|
import re
import cgi
import sys
import urllib
from sqlalchemy import exceptions
"""Provide the URL object as well as the make_url parsing function."""
class URL(object):
"""Represent the components of a URL used to connect to a database.
This object is suitable to be passed directly to a ``create_engine()``
call. The fields of the URL are parsed from a string by the
``module-level make_url()`` function. the string format of the URL is
an RFC-1738-style string.
Attributes on URL include:
drivername
The name of the database backend. this name will correspond to a module in sqlalchemy/databases
username
The user name for the connection.
password
database password.
host
The name of the host.
port
The port number.
database
The database.
query
A dictionary containing key/value pairs representing the URL's query string.
"""
def __init__(self, drivername, username=None, password=None, host=None, port=None, database=None, query=None):
self.drivername = drivername
self.username = username
self.password = password
self.host = host
if port is not None:
self.port = int(port)
else:
self.port = None
self.database= database
self.query = query or {}
def __str__(self):
s = self.drivername + "://"
if self.username is not None:
s += self.username
if self.password is not None:
s += ':' + urllib.quote_plus(self.password)
s += "@"
if self.host is not None:
s += self.host
if self.port is not None:
s += ':' + str(self.port)
if self.database is not None:
s += '/' + self.database
if len(self.query):
keys = self.query.keys()
keys.sort()
s += '?' + "&".join(["%s=%s" % (k, self.query[k]) for k in keys])
return s
def get_dialect(self):
"""Return the SQLAlchemy database dialect class corresponding to this URL's driver name."""
dialect=None
if self.drivername == 'ansi':
import sqlalchemy.ansisql
return sqlalchemy.ansisql.dialect
try:
module=getattr(__import__('sqlalchemy.databases.%s' % self.drivername).databases, self.drivername)
dialect=module.dialect
except ImportError:
if sys.exc_info()[2].tb_next is None:
import pkg_resources
for res in pkg_resources.iter_entry_points('sqlalchemy.databases'):
if res.name==self.drivername:
dialect=res.load()
else:
raise
if dialect is not None:
return dialect
raise ImportError('unknown database %r' % self.drivername)
def translate_connect_args(self, names):
"""Translate this URL's attributes into a dictionary of connection arguments.
Given a list of argument names corresponding to the URL
attributes (`host`, `database`, `username`, `password`,
`port`), will assemble the attribute values of this URL into
the dictionary using the given names.
"""
a = {}
attribute_names = ['host', 'database', 'username', 'password', 'port']
for n in names:
sname = attribute_names.pop(0)
if n is None:
continue
if getattr(self, sname, None):
a[n] = getattr(self, sname)
return a
def make_url(name_or_url):
"""Given a string or unicode instance, produce a new URL instance.
The given string is parsed according to the rfc1738 spec. If an
existing URL object is passed, just returns the object.
"""
if isinstance(name_or_url, basestring):
return _parse_rfc1738_args(name_or_url)
else:
return name_or_url
def _parse_rfc1738_args(name):
pattern = re.compile(r'''
(\w+)://
(?:
([^:/]*)
(?::([^/]*))?
@)?
(?:
([^/:]*)
(?::([^/]*))?
)?
(?:/(.*))?
'''
, re.X)
m = pattern.match(name)
if m is not None:
(name, username, password, host, port, database) = m.group(1, 2, 3, 4, 5, 6)
if database is not None:
tokens = database.split(r"?", 2)
database = tokens[0]
query = (len(tokens) > 1 and dict( cgi.parse_qsl(tokens[1]) ) or None)
if query is not None:
query = dict([(k.encode('ascii'), query[k]) for k in query])
else:
query = None
opts = {'username':username,'password':password,'host':host,'port':port,'database':database, 'query':query}
if opts['password'] is not None:
opts['password'] = urllib.unquote_plus(opts['password'])
return URL(name, **opts)
else:
raise exceptions.ArgumentError("Could not parse rfc1738 URL from string '%s'" % name)
def _parse_keyvalue_args(name):
m = re.match( r'(\w+)://(.*)', name)
if m is not None:
(name, args) = m.group(1, 2)
opts = dict( cgi.parse_qsl( args ) )
return URL(name, *opts)
else:
return None
|
