<s> import logging <EOL> logger = logging . getLogger ( __name__ ) <EOL> class HookRegistryError ( Exception ) : <EOL> pass <EOL> class HookRegistry ( object ) : <EOL> _REGISTRY = { } <EOL> @ classmethod <EOL> def register_hook ( cls , name , hook_class ) : <EOL> if not name : <EOL> raise HookRegistryError ( <EOL> "<STR_LIT>" % hook_class ) <EOL> elif name not in cls . _REGISTRY : <EOL> logger . debug ( u'<STR_LIT>' , name ) <EOL> cls . _REGISTRY [ name ] = hook_class <EOL> else : <EOL> if cls . _REGISTRY [ name ] != hook_class : <EOL> raise HookRegistryError ( <EOL> "<STR_LIT>" ) <EOL> def create ( self , name , ** kwargs ) : <EOL> if name not in self . _REGISTRY : <EOL> raise HookRegistryError ( <EOL> "<STR_LIT>" <EOL> % ( name , '<STR_LIT:U+002CU+0020>' . join ( self . _REGISTRY . keys ( ) ) ) ) <EOL> return self . _REGISTRY [ name ] ( ** kwargs ) <EOL> def register_hook ( hook_class ) : <EOL> HookRegistry . register_hook ( hook_class . name , hook_class ) <EOL> return hook_class <EOL> class MPDHook ( object ) : <EOL> """<STR_LIT>""" <EOL> name = '<STR_LIT>' <EOL> def __init__ ( self , ** kwargs ) : <EOL> super ( MPDHook , self ) . __init__ ( ** kwargs ) <EOL> self . previous_keys = { } <EOL> def fetch ( self , client ) : <EOL> return None <EOL> def extract_key ( self , data , key = '<STR_LIT>' ) : <EOL> """<STR_LIT>""" <EOL> return data <EOL> def handle ( self , client , subhooks = ( ) ) : <EOL> """<STR_LIT>""" <EOL> new_data = self . fetch ( client ) <EOL> updated = { } <EOL> if not subhooks : <EOL> subhooks = [ self . name ] <EOL> for subhook in subhooks : <EOL> new_key = self . extract_key ( new_data , subhook ) <EOL> if new_key != self . previous_keys . get ( subhook ) : <EOL> updated [ subhook ] = new_key <EOL> if updated : <EOL> logger . debug ( u"<STR_LIT>" , <EOL> self . name , self . previous_keys , updated ) <EOL> self . previous_keys . update ( updated ) <EOL> return ( True , new_data ) <EOL> return ( False , None ) <EOL> @ register_hook <EOL> class StatusHook ( MPDHook ) : <EOL> """<STR_LIT>""" <EOL> name = '<STR_LIT:status>' <EOL> def fetch ( self , client ) : <EOL> return client . status <EOL> @ register_hook <EOL> class StateHook ( MPDHook ) : <EOL> name = '<STR_LIT:state>' <EOL> def fetch ( self , client ) : <EOL> return client . state <EOL> @ register_hook <EOL> class ElapsedAndTotalHook ( MPDHook ) : <EOL> name = '<STR_LIT>' <EOL> def fetch ( self , client ) : <EOL> return client . elapsed_and_total <EOL> @ register_hook <EOL> class SongHook ( MPDHook ) : <EOL> name = '<STR_LIT>' <EOL> def fetch ( self , client ) : <EOL> return client . current_song <EOL> def extract_key ( self , data , key = '<STR_LIT>' ) : <EOL> """<STR_LIT>""" <EOL> current_song = data <EOL> if not current_song : <EOL> return None <EOL> if key == self . name : <EOL> return current_song . id <EOL> return getattr ( current_song , key , '<STR_LIT>' ) </s>
