This used to be httpd.el but there are already several of these out there already of varying usefulness. Since the name change, it's been stripped down to simply serve files and directory listings. Client requests are sanitized so this should be safe, but I make no guarantees.

This package is available on MELPA.

Once loaded, there are only two interactive functions to worry about: httpd-start and httpd-stop. Files are served from httpd-root (can be changed at any time) on port httpd-port. Directory listings are enabled by default but can be disabled by setting httpd-listings to nil.

(require 'simple-httpd)
(setq httpd-root "/var/www")
(httpd-start)

Servlets can be defined with defservlet. This one creates at servlet at /hello-world that says hello.

(defservlet hello-world text/plain (path)
  (insert "hello, " (file-name-nondirectory path)))

See the comment header in simple-httpd.el for full details.

There's a fork out there but it's been GPLed. Like the rest of my software I want to keep this public domain.

The unit tests can (and should usually) be run like so,

emacs -batch -L . -l simple-httpd-test.el -f ert-run-tests-batch

It does some mocking to avoid using network code during testing.