json_formatter.py

# -*- encoding: utf-8 -*-


class JsonFormatter:
	def __init__(self, intend=4, name="", encoding="utf-8"):
		self.name = name
		self.intend = intend
		self.encoding = encoding
		self.stack = []
		self.obj = None
		self.source = self.get_source(name, self.encoding)
		self.prepare()

	@staticmethod
	def json_str(s):
		return '"' + s + '"'

	@staticmethod
	def get_source(name, encoding="utf-8"):
		with open(name, 'r', encoding=encoding) as f:
			return ''.join(f.read().split())

	def prepare(self):
		try:
			self.source = self.source.replace("null", "None").replace("true", "True").replace("false", "False")
			self.obj = eval(self.source)
		except:
			raise Exception('Invalid json string!')

	def line_intend(self, level=0):
		return '\n' + ' ' * self.intend * level

	def parse_dict(self,obj=None,intend_level=0):
		if intend_level == 0:
			# 这个判断是为了防止文件开头出现空行
			self.stack.append('{')
		else:
			self.stack.append(self.line_intend(intend_level)+'{')
		intend_level += 1
		i = 0
		for key, value in obj.items():
			key = self.json_str(str(key))
			self.stack.append(self.line_intend(intend_level)+key+':')
			self.parse(value, intend_level)
			if i != len(obj.items())-1:
				# 这个处理是为了防止最后一对kv后面还有个逗号，这样会造成json.load()函数无法读取
				self.stack.append(',')
			i += 1
		self.stack.append(self.line_intend(intend_level-1)+'}')

	def parse_list(self, obj=None, intend_level=0):
		if intend_level == 0:
			self.stack.append('[')
		else:
			self.stack.append(self.line_intend(intend_level)+'[')
		intend_level += 1
		for i, item in zip(range(0, len(obj)), obj):
			self.parse(item, intend_level)
			if i != len(obj)-1:
				self.stack.append(',')
		self.stack.append(self.line_intend(intend_level-1)+']')

	def parse(self, obj, intend_level=0):
		if obj is None:
			self.stack.append('null')
		elif obj is True:
			self.stack.append('true')
		elif obj is False:
			self.stack.append('false')
		elif isinstance(obj, (int, float)):
			self.stack.append(str(obj))
		elif isinstance(obj, str):
			self.stack.append(self.json_str(obj))
		elif isinstance(obj, (list, tuple)):
			self.parse_list(obj, intend_level)
		elif isinstance(obj, dict):
			self.parse_dict(obj, intend_level)
		else:
			raise Exception('Invalid json type %s!' % obj)

	def render(self):
		self.parse(self.obj, 0)
		res_file = self.name
		res = ''.join(self.stack)
		with open(res_file, 'w', encoding=self.encoding) as f:
			f.write(res)

if __name__ == "__main__":
	jf = JsonFormatter(name="/Users/Mac/Desktop/w2o/tst/tst.json")
	jf.render()