Python - 通過PyYaml庫操作YAML文件

PyYaml簡單介紹

• Python的PyYAML模塊是Python的YAML解析器和生成器
• 它有個版本分水嶺，就是5.1

 

讀取YAML5.1之前的讀取方法

def read_yaml(self, path):
    with open(path, encoding="utf-8") as f:
        result = f.read()
        result = yaml.load(result)
        return result

當你運行的時候，會報一個Warning

 

讀取YAML 5.1之后的讀取方法

因為在5.1之后，直接用load()已經過時了，需要在方法里面加一個 loader 的請求參數，如下：

def read_yaml(self, path):
    with open(path, encoding="utf-8") as f:
         result = f.read()
         result = yaml.load(result, Loader=yaml.FullLoader) #loader可選擇BaseLoader、SafeLoader、FullLoader、UnsafeLoader
         return result

也可以，根據Python語法糖轉換，如下：

def read_yaml(self, path):
    with open(path, encoding="utf-8") as f:
        result = f.read()
        result = yaml.full_load(result)
        return result

針對不同的需要，加載器有如下幾種類型：

1. BaseLoader：僅加載最基本的YAML
2. SafeLoader：安全地加載YAML語言的子集。建議用於加載不受信任的輸入。（safe_load）
3. FullLoader：加載完整的YAML語言。避免任意代碼執行。這是當前（PyYAML 5.1）默認加載器調用 yaml.load(input) （發出警告后）（full_load）
4. UnsafeLoader（也稱為Loader向后兼容性）：原始的Loader代碼，可以通過不受信任的數據輸入輕松利用。（unsafe_load）　

 

存儲數據到YAML的方法

with open(path, "w", encoding="utf-8") as f:
     yaml.dump(data, f, Dumper=yaml.SafeDumper) # 可選BaseDumper、SafeDumper 

 

 封裝成一個操作YAML的工具類

class YamlUtil:
    __instance = None

    def __new__(cls, *args, **kwargs):
        if not cls.__instance:
            print("YamlUtil first init")
            cls.__instance = super(YamlUtil, cls).__new__(cls, *args, **kwargs)
        return cls.__instance

    def read_yaml(self, path):
        with open(path, encoding="utf-8") as f:
            result = f.read()
            result = yaml.load(result, Loader=yaml.FullLoader)
            return result

    def write_yaml(self, path, data):
        with open(path, "w", encoding="utf-8") as f:
            yaml.dump(data, f, Dumper=yaml.SafeDumper)

yamlUtil = YamlUtil()