待读取的配置文件 config.yaml 内容如下：
blog_name: 我们的博客
allow_comment: False
masters:
- name: Pickerel Yee
account: [email protected]
- name: 王二
account: [email protected]
建立配置验证读取文件 config.py
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import os, sys
from google.appengine.api import validation
from google.appengine.api import yaml_listener
from google.appengine.api import yaml_builder
from google.appengine.api import yaml_object
from simple_blog import *
class BlogMaster(validation.Validated):
ATTRIBUTES = {
'name': validation.TYPE_UNICODE,
'account': r'^\S+@[a-zA-Z0-9._-]+\.[a-zA-Z0-9._-]+$'
}
class ConfigExternal(validation.Validated):
ATTRIBUTES = {
'blog_name': validation.TYPE_UNICODE,
'allow_comment': validation.Type(bool, default=False),
'masters': validation.Optional(validation.Repeated(BlogMaster))
}
#配置类
class Config(object): # subclassing from object for 2.2, unnecessary after that
instance = None
def __init__(self):
self.blog_name = 'blog'
self.blog_masters = []
self.allow_comment = True
@staticmethod
def get_instance():
if Config.instance == None:
Config.instance = Config.load()
return Config.instance
@staticmethod
def load():
"""parses the config.yaml file"""
_BASE_PATH = os.path.abspath(os.path.dirname(__file__))
config_file = os.path.join(_BASE_PATH, "config.yaml")
fh = open(config_file, "r")
try:
builder = yaml_object.ObjectBuilder(ConfigExternal)
handler = yaml_builder.BuilderHandler(builder)
listener = yaml_listener.EventListener(handler)
listener.Parse(fh)
return handler.GetResults()[0]
finally:
fh.close()
GAE中内置了基本数据类型的验证方法，更复杂的验证可以通过正则式或者自定义验证方法来实现。
使用
print config.get_instance().blog_name
附件是一个完整的演示例子。