def get_backend_object(url_string):
"""
Find the right backend class instance for the given URL, or return None
if the given string looks like a local path rather than a URL.
Raise InvalidBackendURL if the URL is not a valid URL.
"""
if not is_backend_url(url_string):
return None
global _backends, _backend_prefixes
pu = ParsedUrl(url_string)
assert pu.scheme, "should be a backend url according to is_backend_url"
factory = None
for prefix in _backend_prefixes:
if url_string.startswith(prefix + '+'):
factory = _backend_prefixes[prefix]
pu = ParsedUrl(strip_prefix(url_string, prefix))
break
if factory is None:
if pu.scheme not in _backends:
raise UnsupportedBackendScheme(url_string)
else:
factory = _backends[pu.scheme]
try:
return factory(pu)
except ImportError:
raise BackendException(_("Could not initialize backend: %s") % str(sys.exc_info()[1]))
def get_backend(url_string):
"""
Instantiate a backend suitable for the given URL, or return None
if the given string looks like a local path rather than a URL.
Raise InvalidBackendURL if the URL is not a valid URL.
"""
if not is_backend_url(url_string):
return None
pu = ParsedUrl(url_string)
# Implicit local path
assert pu.scheme, "should be a backend url according to is_backend_url"
global _backends, _forced_backend
if _forced_backend:
return _forced_backend(pu)
elif not pu.scheme in _backends:
raise UnsupportedBackendScheme(url_string)
else:
try:
return _backends[pu.scheme](pu)
except ImportError:
raise BackendException(
_("Could not initialize backend: %s") % str(sys.exc_info()[1]))
def get_backend(url_string):
"""
Instantiate a backend suitable for the given URL, or return None
if the given string looks like a local path rather than a URL.
Raise InvalidBackendURL if the URL is not a valid URL.
"""
if not is_backend_url(url_string):
return None
pu = ParsedUrl(url_string)
# Implicit local path
assert pu.scheme, "should be a backend url according to is_backend_url"
global _backends, _forced_backend
if _forced_backend:
return _forced_backend(pu)
elif not pu.scheme in _backends:
raise UnsupportedBackendScheme(url_string)
else:
return _backends[pu.scheme](pu)