int xml_set_external_entity_ref_handler(int parser, string handler);Sets the notation declaration handler function for the XML parser parser. handler is a string containing the name of a function that must exist when xml_parse() is called for parser.
The function named by handler must accept five parameters, and should return an integer value. If the value returned from the handler is false (which it will be if no value is returned), the XML parser will stop parsing and xml_get_error_code() will return XML_ERROR_EXTERNAL_ENTITY_HANDLING.
int handler(int parser, string openEntityNames, string base, string systemId, string publicId);The first parameter, parser, is a reference to the XML parser calling the handler.
The second parameter, openEntityNames, is a space-separated list of the names of the entities that are open for the parse of this entity (including the name of the referenced entity).
This is the base for resolving the system identifier (systemid) of the external entity. Currently this parameter will always be set to an empty string.
The fourth parameter, systemId, is the system identifier as specified in the entity declaration.
The fifth parameter, publicId, is the public identifier as specified in the entity declaration, or an empty string if none was specified; the whitespace in the public identifier will have been normalized as required by the XML spec.
If a handler function is set to an empty string, or false, the handler in question is disabled.
True is returned if the handler is set up, false if parser is not a parser.
There is currently no support for object/method handlers.