Combines specified |base_url| and |relative_url| into |resolved_url|. Returns false if one of the URLs is empty or invalid. Parse the specified |url| into its component parts. Returns false if the URL is empty or invalid. Creates a URL from the specified |parts|, which must contain a non-empty spec or a non-empty host and path (at a minimum), but not both. Returns false if |parts| isn't initialized as described. This is a convenience function for formatting a URL in a concise and human- friendly way to help users make security-related decisions (or in other circumstances when people need to distinguish sites, origins, or otherwise- simplified URLs from each other). Internationalized domain names (IDN) may be presented in Unicode if the conversion is considered safe. The returned value will (a) omit the path for standard schemes, excepting file and filesystem, and (b) omit the port if it is the default for the scheme. Do not use this for URLs which will be parsed or sent to other applications. Returns the mime type for the specified file extension or an empty string if unknown. Get the extensions associated with the given mime type. This should be passed in lower case. There could be multiple extensions for a given mime type, like "html,htm" for "text/html", or "txt,text,html,..." for "text/*". Any existing elements in the provided vector will not be erased. Encodes |data| as a base64 string. Decodes the base64 encoded string |data|. The returned value will be NULL if the decoding fails. Escapes characters in |text| which are unsuitable for use as a query parameter value. Everything except alphanumerics and -_.!~*'() will be converted to "%XX". If |use_plus| is true spaces will change to "+". The result is basically the same as encodeURIComponent in Javacript. Unescapes |text| and returns the result. Unescaping consists of looking for the exact pattern "%XX" where each X is a hex digit and converting to the character with the numerical value of those digits (e.g. "i%20=%203%3b" unescapes to "i = 3;"). If |convert_to_utf8| is true this function will attempt to interpret the initial decoded result as UTF-8. If the result is convertable into UTF-8 it will be returned as converted. Otherwise the initial decoded result will be returned. The |unescape_rule| parameter supports further customization the decoding process. Parses the specified |json_string| and returns a dictionary or list representation. If JSON parsing fails this method returns NULL. Parses the specified UTF8-encoded |json| buffer of size |json_size| and returns a dictionary or list representation. If JSON parsing fails this method returns NULL. Parses the specified |json_string| and returns a dictionary or list representation. If JSON parsing fails this method returns NULL and populates |error_msg_out| with a formatted error message. Generates a JSON string from the specified root |node| which should be a dictionary or list value. Returns an empty string on failure. This method requires exclusive access to |node| including any underlying data.