land of lisp src webserver.lisp - webdev.webserver

Question

while I was learning in "land of lisp" chapter 12 and 13 about "socket".
I use lispbox, so I need install a socket.At last, I found usocket available.
this is a sample about how to use usocket, to bulid a webserver.
(defun serve (request-handler)
"serve as a web server,used to handle request
like 'http://127.0.0.1:8080/greeting'"
(let ((socket (usocket:socket-listen "0.0.0.0" 8080 :reuse-address t)))
(unwind-protect
(loop (with-open-stream (stream
(usocket:socket-stream
(usocket:socket-accept socket)))
(let* ((url (parse-url (read-line stream)))
(path (car url))
(header (get-header stream))
(params (append (cdr url)
(get-content-params stream header)))
(*standard-output* stream))
(funcall request-handler path header params))))
(usocket:socket-close socket))))
the origin ‘serve’ function in http://landoflisp.com/webserver.lisp
(defun serve (request-handler)
(let ((socket (socket-server 8080)))
(unwind-protect
(loop (with-open-stream (stream (socket-accept socket))
(let* ((url (parse-url (read-line stream)))
(path (car url))
(header (get-header stream))
(params (append (cdr url)
(get-content-params stream header)))
(*standard-output* stream))
(funcall request-handler path header params))))
(socket-server-close socket))))

Answer 1

API definition
usocket (class)
stream-usocket (class; usocket derivative)
stream-server-usocket (class; usocket derivative)
socket-connect (function) [ to create an active/connected socket ]
socket-connect host port &key element-type
where `host' is a vectorized ip
or a string representation of a dotted ip address
or a hostname for lookup in the DNS system
socket-listen (function) [ to create a passive/listening socket ]
socket-listen host port &key reuseaddress backlog element-type
where `host' has the same definition as above
socket-accept (method) [ to create an active/connected socket ]
socket-accept socket &key element-type
returns (server side) a connected socket derived from a
listening/passive socket.
socket-close (method)
socket-close socket
where socket a previously returned socket
socket (usocket slot accessor),
the internal/implementation defined socket representation
socket-stream (usocket slot accessor),
socket-stream socket
the return value of which satisfies the normal stream interface