def get_by_regexp (entity, method):
''' returns a specific field of the given entity '''
meth = Autoload.get_by_regexp ("format", entity)
if meth and meth.data.has_key (method):
return meth.data [method]
return None
def bibopen (entity, how = None):
''' Generic function to open a bibliographic database '''
def simple_try (url, how):
# url is Fields.URL instance, only to be passed to opener
base = None
if how == None:
listedmethods = Autoload.available ("format")
for method in listedmethods:
opener = get_by_name (method, 'open')
if opener:
base = opener (url, 1)
if base is not None:
return base
return None
opener = get_by_name (how, 'open')
if opener:
base = opener (url, 0)
else:
raise Exceptions.FormatError (_(u"method “%s” provides no opener") % how)
return base
# Consider the reference as an URL: url is an Fields.URL instance
url = Fields.URL (entity)
if url.url [0] == 'file' and not os.path.exists (url.url [2]):
raise Exceptions.FileError (_(u"File “%s” does not exist") % url.get_url ())
# eventually load a new module
if how is None:
handler = Autoload.get_by_regexp ("format", url.get_url ())
if handler:
how = handler.name
base = simple_try (url, how)
if base is None:
raise Exceptions.FormatError (_(u"don’t know how to open “%s”") % entity)
return base
