data of type application/x-www-form-urlencoded轉換爲字典形式
python官網有解釋：https://docs.python.org/2/library/urlparse.html
urlparse.parse_qs(qs[, keep_blank_values[, strict_parsing]])
Parse a query string given as a string argument (data of type application/x-www-form-urlencoded). Data are returned as a dictionary. The dictionary keys are the unique query variable names and the values are lists of values for each name.
The optional argument keep_blank_values is a flag indicating whether blank values in percent-encoded queries should be treated as blank strings. A true value indicates that blanks should be retained as blank strings. The default false value indicates that blank values are to be ignored and treated as if they were not included.
The optional argument strict_parsing is a flag indicating what to do with parsing errors. If false (the default), errors are silently ignored. If true, errors raise a ValueError exception.
Use the urllib.urlencode() function to convert such dictionaries into query strings.
參考：http://stackoverflow.com/questions/6877497/converting-x-www-form-urlencoded-query-string-to-a-dict