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# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org)
# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
from __future__ import with_statement
import os
import sys
import re
import pkg_resources
from paste.deploy.compat import ConfigParser, unquote, iteritems, dictkeys
from paste.deploy.util import fix_call, lookup_object
__all__ = ['loadapp', 'loadserver', 'loadfilter', 'appconfig']
############################################################
## Utility functions
############################################################
def import_string(s):
ep = pkg_resources.EntryPoint.parse("x=" + s)
if hasattr(ep, 'resolve'):
# this is available on setuptools >= 10.2
return ep.resolve()
else:
# this causes a DeprecationWarning on setuptools >= 11.3
return ep.load(False)
def _aslist(obj):
"""
Turn object into a list; lists and tuples are left as-is, None
becomes [], and everything else turns into a one-element list.
"""
if obj is None:
return []
elif isinstance(obj, (list, tuple)):
return obj
else:
return [obj]
def _flatten(lst):
"""
Flatten a nested list.
"""
if not isinstance(lst, (list, tuple)):
return [lst]
result = []
for item in lst:
result.extend(_flatten(item))
return result
class NicerConfigParser(ConfigParser):
def __init__(self, filename, *args, **kw):
ConfigParser.__init__(self, *args, **kw)
self.filename = filename
if hasattr(self, '_interpolation'):
self._interpolation = self.InterpolateWrapper(self._interpolation)
read_file = getattr(ConfigParser, 'read_file', ConfigParser.readfp)
def defaults(self):
"""Return the defaults, with their values interpolated (with the
defaults dict itself)
Mainly to support defaults using values such as %(here)s
"""
defaults = ConfigParser.defaults(self).copy()
for key, val in iteritems(defaults):
defaults[key] = self.get('DEFAULT', key) or val
return defaults
def _interpolate(self, section, option, rawval, vars):
# Python < 3.2
try:
return ConfigParser._interpolate(
self, section, option, rawval, vars)
except Exception:
e = sys.exc_info()[1]
args = list(e.args)
args[0] = 'Error in file %s: %s' % (self.filename, e)
e.args = tuple(args)
e.message = args[0]
raise
class InterpolateWrapper(object):
# Python >= 3.2
def __init__(self, original):
self._original = original
def __getattr__(self, name):
return getattr(self._original, name)
def before_get(self, parser, section, option, value, defaults):
try:
return self._original.before_get(parser, section, option,
value, defaults)
except Exception:
e = sys.exc_info()[1]
args = list(e.args)
args[0] = 'Error in file %s: %s' % (parser.filename, e)
e.args = tuple(args)
e.message = args[0]
raise
############################################################
## Object types
############################################################
class _ObjectType(object):
name = None
egg_protocols = None
config_prefixes = None
def __init__(self):
# Normalize these variables:
self.egg_protocols = [_aslist(p) for p in _aslist(self.egg_protocols)]
self.config_prefixes = [_aslist(p) for p in _aslist(self.config_prefixes)]
def __repr__(self):
return '<%s protocols=%r prefixes=%r>' % (
self.name, self.egg_protocols, self.config_prefixes)
def invoke(self, context):
assert context.protocol in _flatten(self.egg_protocols)
return fix_call(context.object,
context.global_conf, **context.local_conf)
class _App(_ObjectType):
name = 'application'
egg_protocols = ['paste.app_factory', 'paste.composite_factory',
'paste.composit_factory']
config_prefixes = [['app', 'application'], ['composite', 'composit'],
'pipeline', 'filter-app']
def invoke(self, context):
if context.protocol in ('paste.composit_factory',
'paste.composite_factory'):
return fix_call(context.object,
context.loader, context.global_conf,
**context.local_conf)
elif context.protocol == 'paste.app_factory':
return fix_call(context.object, context.global_conf, **context.local_conf)
else:
assert 0, "Protocol %r unknown" % context.protocol
APP = _App()
class _Filter(_ObjectType):
name = 'filter'
egg_protocols = [['paste.filter_factory', 'paste.filter_app_factory']]
config_prefixes = ['filter']
def invoke(self, context):
if context.protocol == 'paste.filter_factory':
return fix_call(context.object,
context.global_conf, **context.local_conf)
elif context.protocol == 'paste.filter_app_factory':
def filter_wrapper(wsgi_app):
# This should be an object, so it has a nicer __repr__
return fix_call(context.object,
wsgi_app, context.global_conf,
**context.local_conf)
return filter_wrapper
else:
assert 0, "Protocol %r unknown" % context.protocol
FILTER = _Filter()
class _Server(_ObjectType):
name = 'server'
egg_protocols = [['paste.server_factory', 'paste.server_runner']]
config_prefixes = ['server']
def invoke(self, context):
if context.protocol == 'paste.server_factory':
return fix_call(context.object,
context.global_conf, **context.local_conf)
elif context.protocol == 'paste.server_runner':
def server_wrapper(wsgi_app):
# This should be an object, so it has a nicer __repr__
return fix_call(context.object,
wsgi_app, context.global_conf,
**context.local_conf)
return server_wrapper
else:
assert 0, "Protocol %r unknown" % context.protocol
SERVER = _Server()
# Virtual type: (@@: There's clearly something crufty here;
# this probably could be more elegant)
class _PipeLine(_ObjectType):
name = 'pipeline'
def invoke(self, context):
app = context.app_context.create()
filters = [c.create() for c in context.filter_contexts]
filters.reverse()
for filter in filters:
app = filter(app)
return app
PIPELINE = _PipeLine()
class _FilterApp(_ObjectType):
name = 'filter_app'
def invoke(self, context):
next_app = context.next_context.create()
filter = context.filter_context.create()
return filter(next_app)
FILTER_APP = _FilterApp()
class _FilterWith(_App):
name = 'filtered_with'
def invoke(self, context):
filter = context.filter_context.create()
filtered = context.next_context.create()
if context.next_context.object_type is APP:
return filter(filtered)
else:
# filtering a filter
def composed(app):
return filter(filtered(app))
return composed
FILTER_WITH = _FilterWith()
############################################################
## Loaders
############################################################
def loadapp(uri, name=None, **kw):
return loadobj(APP, uri, name=name, **kw)
def loadfilter(uri, name=None, **kw):
return loadobj(FILTER, uri, name=name, **kw)
def loadserver(uri, name=None, **kw):
return loadobj(SERVER, uri, name=name, **kw)
def appconfig(uri, name=None, relative_to=None, global_conf=None):
context = loadcontext(APP, uri, name=name,
relative_to=relative_to,
global_conf=global_conf)
return context.config()
_loaders = {}
def loadobj(object_type, uri, name=None, relative_to=None,
global_conf=None):
context = loadcontext(
object_type, uri, name=name, relative_to=relative_to,
global_conf=global_conf)
return context.create()
def loadcontext(object_type, uri, name=None, relative_to=None,
global_conf=None):
if '#' in uri:
if name is None:
uri, name = uri.split('#', 1)
else:
# @@: Ignore fragment or error?
uri = uri.split('#', 1)[0]
if name is None:
name = 'main'
if ':' not in uri:
raise LookupError("URI has no scheme: %r" % uri)
scheme, path = uri.split(':', 1)
scheme = scheme.lower()
if scheme not in _loaders:
raise LookupError(
"URI scheme not known: %r (from %s)"
% (scheme, ', '.join(_loaders.keys())))
return _loaders[scheme](
object_type,
uri, path, name=name, relative_to=relative_to,
global_conf=global_conf)
def _loadconfig(object_type, uri, path, name, relative_to,
global_conf):
isabs = os.path.isabs(path)
# De-Windowsify the paths:
path = path.replace('\\', '/')
if not isabs:
if not relative_to:
raise ValueError(
"Cannot resolve relative uri %r; no relative_to keyword "
"argument given" % uri)
relative_to = relative_to.replace('\\', '/')
if relative_to.endswith('/'):
path = relative_to + path
else:
path = relative_to + '/' + path
if path.startswith('///'):
path = path[2:]
path = unquote(path)
loader = ConfigLoader(path)
if global_conf:
loader.update_defaults(global_conf, overwrite=False)
return loader.get_context(object_type, name, global_conf)
_loaders['config'] = _loadconfig
def _loadegg(object_type, uri, spec, name, relative_to,
global_conf):
loader = EggLoader(spec)
return loader.get_context(object_type, name, global_conf)
_loaders['egg'] = _loadegg
def _loadfunc(object_type, uri, spec, name, relative_to,
global_conf):
loader = FuncLoader(spec)
return loader.get_context(object_type, name, global_conf)
_loaders['call'] = _loadfunc
############################################################
## Loaders
############################################################
class _Loader(object):
def get_app(self, name=None, global_conf=None):
return self.app_context(
name=name, global_conf=global_conf).create()
def get_filter(self, name=None, global_conf=None):
return self.filter_context(
name=name, global_conf=global_conf).create()
def get_server(self, name=None, global_conf=None):
return self.server_context(
name=name, global_conf=global_conf).create()
def app_context(self, name=None, global_conf=None):
return self.get_context(
APP, name=name, global_conf=global_conf)
def filter_context(self, name=None, global_conf=None):
return self.get_context(
FILTER, name=name, global_conf=global_conf)
def server_context(self, name=None, global_conf=None):
return self.get_context(
SERVER, name=name, global_conf=global_conf)
_absolute_re = re.compile(r'^[a-zA-Z]+:')
def absolute_name(self, name):
"""
Returns true if the name includes a scheme
"""
if name is None:
return False
return self._absolute_re.search(name)
class ConfigLoader(_Loader):
def __init__(self, filename):
self.filename = filename = filename.strip()
defaults = {
'here': os.path.dirname(os.path.abspath(filename)),
'__file__': os.path.abspath(filename)
}
self.parser = NicerConfigParser(filename, defaults=defaults)
self.parser.optionxform = str # Don't lower-case keys
with open(filename) as f:
self.parser.read_file(f)
def update_defaults(self, new_defaults, overwrite=True):
for key, value in iteritems(new_defaults):
if not overwrite and key in self.parser._defaults:
continue
self.parser._defaults[key] = value
def get_context(self, object_type, name=None, global_conf=None):
if self.absolute_name(name):
return loadcontext(object_type, name,
relative_to=os.path.dirname(self.filename),
global_conf=global_conf)
section = self.find_config_section(
object_type, name=name)
defaults = self.parser.defaults()
_global_conf = defaults.copy()
if global_conf is not None:
_global_conf.update(global_conf)
global_conf = _global_conf
local_conf = {}
global_additions = {}
get_from_globals = {}
for option in self.parser.options(section):
if option.startswith('set '):
name = option[4:].strip()
global_additions[name] = global_conf[name] = (
self.parser.get(section, option))
elif option.startswith('get '):
name = option[4:].strip()
get_from_globals[name] = self.parser.get(section, option)
else:
if option in defaults:
# @@: It's a global option (?), so skip it
continue
local_conf[option] = self.parser.get(section, option)
for local_var, glob_var in get_from_globals.items():
local_conf[local_var] = global_conf[glob_var]
if object_type in (APP, FILTER) and 'filter-with' in local_conf:
filter_with = local_conf.pop('filter-with')
else:
filter_with = None
if 'require' in local_conf:
for spec in local_conf['require'].split():
pkg_resources.require(spec)
del local_conf['require']
if section.startswith('filter-app:'):
context = self._filter_app_context(
object_type, section, name=name,
global_conf=global_conf, local_conf=local_conf,
global_additions=global_additions)
elif section.startswith('pipeline:'):
context = self._pipeline_app_context(
object_type, section, name=name,
global_conf=global_conf, local_conf=local_conf,
global_additions=global_additions)
elif 'use' in local_conf:
context = self._context_from_use(
object_type, local_conf, global_conf, global_additions,
section)
else:
context = self._context_from_explicit(
object_type, local_conf, global_conf, global_additions,
section)
if filter_with is not None:
filter_with_context = LoaderContext(
obj=None,
object_type=FILTER_WITH,
protocol=None,
global_conf=global_conf, local_conf=local_conf,
loader=self)
filter_with_context.filter_context = self.filter_context(
name=filter_with, global_conf=global_conf)
filter_with_context.next_context = context
return filter_with_context
return context
def _context_from_use(self, object_type, local_conf, global_conf,
global_additions, section):
use = local_conf.pop('use')
context = self.get_context(
object_type, name=use, global_conf=global_conf)
context.global_conf.update(global_additions)
context.local_conf.update(local_conf)
if '__file__' in global_conf:
# use sections shouldn't overwrite the original __file__
context.global_conf['__file__'] = global_conf['__file__']
# @@: Should loader be overwritten?
context.loader = self
if context.protocol is None:
# Determine protocol from section type
section_protocol = section.split(':', 1)[0]
if section_protocol in ('application', 'app'):
context.protocol = 'paste.app_factory'
elif section_protocol in ('composit', 'composite'):
context.protocol = 'paste.composit_factory'
else:
# This will work with 'server' and 'filter', otherwise it
# could fail but there is an error message already for
# bad protocols
context.protocol = 'paste.%s_factory' % section_protocol
return context
def _context_from_explicit(self, object_type, local_conf, global_conf,
global_addition, section):
possible = []
for protocol_options in object_type.egg_protocols:
for protocol in protocol_options:
if protocol in local_conf:
possible.append((protocol, local_conf[protocol]))
break
if len(possible) > 1:
raise LookupError(
"Multiple protocols given in section %r: %s"
% (section, possible))
if not possible:
raise LookupError(
"No loader given in section %r" % section)
found_protocol, found_expr = possible[0]
del local_conf[found_protocol]
value = import_string(found_expr)
context = LoaderContext(
value, object_type, found_protocol,
global_conf, local_conf, self)
return context
def _filter_app_context(self, object_type, section, name,
global_conf, local_conf, global_additions):
if 'next' not in local_conf:
raise LookupError(
"The [%s] section in %s is missing a 'next' setting"
% (section, self.filename))
next_name = local_conf.pop('next')
context = LoaderContext(None, FILTER_APP, None, global_conf,
local_conf, self)
context.next_context = self.get_context(
APP, next_name, global_conf)
if 'use' in local_conf:
context.filter_context = self._context_from_use(
FILTER, local_conf, global_conf, global_additions,
section)
else:
context.filter_context = self._context_from_explicit(
FILTER, local_conf, global_conf, global_additions,
section)
return context
def _pipeline_app_context(self, object_type, section, name,
global_conf, local_conf, global_additions):
if 'pipeline' not in local_conf:
raise LookupError(
"The [%s] section in %s is missing a 'pipeline' setting"
% (section, self.filename))
pipeline = local_conf.pop('pipeline').split()
if local_conf:
raise LookupError(
"The [%s] pipeline section in %s has extra "
"(disallowed) settings: %s"
% (section, self.filename, ', '.join(local_conf.keys())))
context = LoaderContext(None, PIPELINE, None, global_conf,
local_conf, self)
context.app_context = self.get_context(
APP, pipeline[-1], global_conf)
context.filter_contexts = [
self.get_context(FILTER, name, global_conf)
for name in pipeline[:-1]]
return context
def find_config_section(self, object_type, name=None):
"""
Return the section name with the given name prefix (following the
same pattern as ``protocol_desc`` in ``config``. It must have the
given name, or for ``'main'`` an empty name is allowed. The
prefix must be followed by a ``:``.
Case is *not* ignored.
"""
possible = []
for name_options in object_type.config_prefixes:
for name_prefix in name_options:
found = self._find_sections(
self.parser.sections(), name_prefix, name)
if found:
possible.extend(found)
break
if not possible:
raise LookupError(
"No section %r (prefixed by %s) found in config %s"
% (name,
' or '.join(map(repr, _flatten(object_type.config_prefixes))),
self.filename))
if len(possible) > 1:
raise LookupError(
"Ambiguous section names %r for section %r (prefixed by %s) "
"found in config %s"
% (possible, name,
' or '.join(map(repr, _flatten(object_type.config_prefixes))),
self.filename))
return possible[0]
def _find_sections(self, sections, name_prefix, name):
found = []
if name is None:
if name_prefix in sections:
found.append(name_prefix)
name = 'main'
for section in sections:
if section.startswith(name_prefix + ':'):
if section[len(name_prefix) + 1:].strip() == name:
found.append(section)
return found
class EggLoader(_Loader):
def __init__(self, spec):
self.spec = spec
def get_context(self, object_type, name=None, global_conf=None):
if self.absolute_name(name):
return loadcontext(object_type, name,
global_conf=global_conf)
entry_point, protocol, ep_name = self.find_egg_entry_point(
object_type, name=name)
return LoaderContext(
entry_point,
object_type,
protocol,
global_conf or {}, {},
self,
distribution=pkg_resources.get_distribution(self.spec),
entry_point_name=ep_name)
def find_egg_entry_point(self, object_type, name=None):
"""
Returns the (entry_point, protocol) for the with the given
``name``.
"""
if name is None:
name = 'main'
possible = []
for protocol_options in object_type.egg_protocols:
for protocol in protocol_options:
pkg_resources.require(self.spec)
entry = pkg_resources.get_entry_info(
self.spec,
protocol,
name)
if entry is not None:
possible.append((entry.load(), protocol, entry.name))
break
if not possible:
# Better exception
dist = pkg_resources.get_distribution(self.spec)
raise LookupError(
"Entry point %r not found in egg %r (dir: %s; protocols: %s; "
"entry_points: %s)"
% (name, self.spec,
dist.location,
', '.join(_flatten(object_type.egg_protocols)),
', '.join(_flatten([
dictkeys(pkg_resources.get_entry_info(self.spec, prot, name) or {})
for prot in protocol_options] or '(no entry points)'))))
if len(possible) > 1:
raise LookupError(
"Ambiguous entry points for %r in egg %r (protocols: %s)"
% (name, self.spec, ', '.join(_flatten(protocol_options))))
return possible[0]
class FuncLoader(_Loader):
""" Loader that supports specifying functions inside modules, without
using eggs at all. Configuration should be in the format:
use = call:my.module.path:function_name
Dot notation is supported in both the module and function name, e.g.:
use = call:my.module.path:object.method
"""
def __init__(self, spec):
self.spec = spec
if not ':' in spec:
raise LookupError("Configuration not in format module:function")
def get_context(self, object_type, name=None, global_conf=None):
obj = lookup_object(self.spec)
return LoaderContext(
obj,
object_type,
None, # determine protocol from section type
global_conf or {},
{},
self,
)
class LoaderContext(object):
def __init__(self, obj, object_type, protocol,
global_conf, local_conf, loader,
distribution=None, entry_point_name=None):
self.object = obj
self.object_type = object_type
self.protocol = protocol
#assert protocol in _flatten(object_type.egg_protocols), (
# "Bad protocol %r; should be one of %s"
# % (protocol, ', '.join(map(repr, _flatten(object_type.egg_protocols)))))
self.global_conf = global_conf
self.local_conf = local_conf
self.loader = loader
self.distribution = distribution
self.entry_point_name = entry_point_name
def create(self):
return self.object_type.invoke(self)
def config(self):
conf = AttrDict(self.global_conf)
conf.update(self.local_conf)
conf.local_conf = self.local_conf
conf.global_conf = self.global_conf
conf.context = self
return conf
class AttrDict(dict):
"""
A dictionary that can be assigned to.
"""
pass
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