Python API来设计

Question

我的目标是设计一个Python API，允许客户端执行以下操作：

md = MentalDisorders() 
print(md.disorders['eating']) 

得到饮食相关疾病的名单。

这里是我的攻击，认为FAKE_DATABASE将是一个真正的数据库，我只是将这个问题集中在接口的“感觉”/“可用性”上，特别是在Python环境中，我是外星人：

#!/usr/bin/env python2.7 

FAKE_DATABASE = { 
    'anxiety': ['phobia', 'panic'], 
    'personality': ['borderline', 'histrionic'], 
    'eating': ['bulimia', 'anorexia'], 
} 

class MentalDisorders(object): 
    # ... some methods and fields that make it worthwhile having a container class ... 
    class DisorderCollection(object): 
    def __getitem__(self, key): 
     if key in FAKE_DATABASE: 
     return FAKE_DATABASE[key] 
     else: 
     raise KeyError('Key not found: {}.'.format(key)) 
    def __init__(self): 
    self.disorders = self.DisorderCollection() 

def main(): 
    md = MentalDisorders() 
    print(md.disorders['anxiety']) 
    print(md.disorders['personality']) 
    print(md.disorders['eating']) 
    try: 
    print(md.disorders['conduct']) 
    except KeyError as exception: 
    print(exception) 

if __name__ == '__main__': 
    main() 

1. 是具有DisorderCollection建议呢？
2. DisorderCollection应该在MentalDisorders之内还是在其外面定义？
3. 正在实例化self.disorders通过self.DisorderCollection正确吗？
4. 实例化DisorderCollection作为字段发生在 内__init__方法MentalDisorders？
5. 或许应该这样的DisorderCollection没有字段实例都存在，上述 被实现为一个简单的“转移呼叫”从__getattribute__到数据库中的一个关键 查找？在这种情况下，简单的md.disorders（没有指定键） 会返回什么？

Answer 1

以下是我可能会写它：

class DisorderCollection(object): 
    def __getitem__(self, key): 
     if key in FAKE_DATABASE: 
      return FAKE_DATABASE[key] 
     else: 
      raise KeyError('Key not found: {}.'.format(key)) 

class MentalDisorders(DisorderCollection): 
    # ... some methods and fields that make it worthwhile having a container class ... 

class PhysicalDisorders(DisorderCollection): 
    # Unless you plan to have multiple types of disorder collections with different methods, I struggle to see a point in the extra layer of classes. 

def main(): 
    md = MentalDisorders() 
    print(md['anxiety']) 
    print(md['personality']) 
    print(md['eating']) 
    try: 
     print(md['conduct']) 
    except KeyError as exception: 
     print(exception) 

if __name__ == '__main__': 
    main()