creates a new servlet that implements HTTP basic authentication.
The servlet should be registered with a lower order than the other
servlets that it protects, so that it executes first.
is a pointer to a function having this type:
typedef const char *http_servlet_basicauth_t(void *arg,
struct http_request *req, const char *username,
const char *password);
is the opaque cookie supplied to
is the HTTP request object and
are the credentials supplied with the request, or the empty string
if none were supplied.
to allow access.
Otherwise, it should return the authorization realm string
to deny access.
This string is not freed by the calling function.
this is reversed from usual semantics; returning
indicates success and allows access.
When the servlet is destroyed, if
it will be invoked with
as its parameter.