使用Flask Cache與發電機功能

Question

我正在嘗試使用Flask-Cache來緩存發電機功能。燒瓶緩存需要酸洗，並且由於發生器不能被酸洗，這是一個問題。是否有任何解決方案使用Flask-Cache生成器？

Answer 1

如果您想緩存結果只需在生成器上調用list，然後存儲即可。如果結果太大而無法安全地存儲在內存中（即使是暫時的），然後將結果包含在類實例中，該實例可以：restore itself when unpickled：

# Warning: This is terribly tightly bound together 
# There are better ways to do this - this is just by way of example 

def some_generator(identifier): 
    """This could be anything 
     * A database wrapper 
     * A permutation generator 
     * Something that streams (and transforms) data from disk 
     * The possibilities are endless""" 
    if identifier == "result_set_1": 
     results = [(x, y) for x in range(10) for y in range(x)] 
    elif identifier == "result_set_2": 
     results = [(x, 0) for x in range(20)] 
    else: 
     results = [(1, 2), (3, 4)] 

    for row in results: 
     yield row 


class GeneratorWrapper(object): 
    """ 
    Use:: 

     @cache 
     some_function(identifier): 
      return GeneratorWrapper(identifier) 
    """ 

    def __init__(self, identifier=None): 
     self.identifier = identifier 
     if identifier is not None: 
      self.data = some_generator(identifier) 

    def __getstate__(self): 
     """When pickled return the key to rebuilding the generator""" 
     return self.identifier 

    def __setstate__(self, state): 
     """When unpickled, restore the generator using the pickled key""" 
     self.identifier = state 
     if state is not None: 
      self.data = some_generator(state) 

    def __iter__(self): 
     return self.data