def read_number(reader, ch):
u"""用于读取数字内容，ch表示上一个被读取到的字符"""
num_str = ch
isfloat = False
while reader.has_next():
ch = reader.get_next()
if ch.isspace():
break
# 读取到逗号,冒号或结束符('}', ']')需要回退一个位置,交给后面的方法处理
elif ch in (',', ':', '}', ']'):
reader.get_prev()
break
elif ch in ('e', '.'):
isfloat = True
num_str += ch
elif ch.isdigit() or ch == '-':
num_str += ch
else:
raise JsonFormatError("Invalid char when read number : %s" % ch)
# 根据标记位进行对应转换
try:
if isfloat:
return float(num_str)
else:
return int(num_str)
except ValueError:
log.warning("Json num format error, string:%s", string)
raise JsonFormatError("Invalid num format, num string:%s" % string)
def _process_escape_char(reader, next_ch):
u"""用于处理，并返回一个合法转义字符"""
if next_ch == '"':
escape_char = '"'
elif next_ch == '\'':
escape_char = '\''
elif next_ch == 'n':
escape_char = '\n'
elif next_ch == 't':
escape_char = '\t'
elif next_ch == 'r':
escape_char = '\r'
elif next_ch == 'b':
escape_char = '\b'
elif next_ch == 'f':
escape_char = '\f'
elif next_ch == '\\':
escape_char = '\\'
elif next_ch == 'u':
# 处理Unicode编码
unicode_char = '\u'
for i in range(4):
ch = reader.get_next()
if ch not in hexdigits:
raise JsonFormatError("Invalid hex char : %s" % ch)
unicode_char += ch
escape_char = unicode_char.decode("raw_unicode_escape")
else:
raise JsonFormatError("Invalid escape char : %s" % next_ch)
return escape_char
def read_array(reader):
json_array = []
while reader.has_next():
ch = reader.get_next()
if ch.isspace():
continue
if ch == ']':
break
# 前移一位，在read_value中获取值
reader.get_prev()
json_array.append(read_value(reader))
# 读取下一个非空字符，判断是否 , 或者 ]
non_space_char = read_non_space_char(reader)
if non_space_char == ']':
break
elif non_space_char == ',':
continue
else:
log.warning("Char after array value must be ',' or ']', ch:%s", ch)
raise JsonFormatError(
"Next char after array value must be ',' or ']', ch:%s" % ch)
else:
log.warning("Invalid json array format, lost ']'")
raise JsonFormatError("Json array lost ']'")
return json_array
def read_object(reader):
json_obj = {}
while reader.has_next():
ch = reader.get_next()
if ch.isspace():
continue
elif ch == '}':
break
# 按照 key , : , value顺序读取数据
key = read_key(reader, ch)
ch = read_non_space_char(reader)
if ch != ":":
raise JsonFormatError("After key must be colon ':'")
value = read_value(reader)
# 忽略非字符串类型的key
if not isinstance(key, (str, unicode)):
log.info("Key must be str, key:%s, ignore it.", key)
else:
json_obj[key] = value
# 读取下一个非空字符，判断是否 , 或者 }
non_space_char = read_non_space_char(reader)
if non_space_char == '}':
break
elif non_space_char == ',':
continue
else:
log.warning("Char after value must be ',' or '}'")
raise JsonFormatError(
"Char after value must be ',' or '}', ch:%s" % ch)
else:
log.warning("Invalid json obj format, lost '}'")
raise JsonFormatError("Json obj lost '}'")
return json_obj
def read_identifier(reader, identifier_chars, ret_val):
u"""
读取Json中的标识符，比如：null，则传入：('u', 'l', 'l'), None
头一个字符可以忽略，因为头个字符在判断时已经被读取
:param reader:
:param identifier_chars:
:param ret_val:
:return:
"""
length = len(identifier_chars)
for i in range(length):
ch = reader.get_next()
if ch is None or ch != identifier_chars[i]:
raise JsonFormatError("Invalid identifier value when read %s"
% str(ret_val))
else:
return ret_val
def json_to_object(json):
if not isinstance(json, (str, unicode)):
log.debug("Argument type was not str, argument:%s", json)
raise TypeError("Argument must be str type")
json = json.strip()
res_obj = None
reader = StringReader(json)
while reader.has_next():
ch = reader.get_next()
if ch == '{':
res_obj = read_object(reader)
elif ch == '[':
res_obj = read_array(reader)
else:
log.debug("Invalid json format, json string should start with "
"start with '{' or '[', argument:%s", json)
raise JsonFormatError("Json string must start with '{' or '['")
return res_obj
def read_value(reader):
while reader.has_next():
ch = reader.get_next()
if ch.isspace():
continue
elif ch == '"':
return read_string(reader)
elif ch == '-' or ch.isdigit():
return read_number(reader, ch)
elif ch in ('i',):
return read_inf(reader)
elif ch in ('n',):
return read_null(reader)
elif ch in ('t',):
return read_true(reader)
elif ch in ('f',):
return read_false(reader)
elif ch == '{':
return read_object(reader)
elif ch == '[':
return read_array(reader)
else:
raise JsonFormatError("Invalid value format, read char:%s" % ch)
def read_key(reader, ch):
if ch == '"':
return read_string(reader)
else:
log.warning("Key must be string type")
raise JsonFormatError("Invalid key type")