This is the first checked-in completely working version. It contains

nearly all concepts and simple implementations thereof needed to get a
simple HTTP/0.9 "compliant" server working (there are some hacks
needed that we don't yet provide, since the correct things will be
added shortly, like complete HTTP/1.1 request parsing.  The hacks
needed are provided as part of the basic HTTP/0.9 server demo in
src/test/basic-demo.cl).

Further work is needed to clean up some things, Entity and Resource
handling needs to be implemented right and less "naive" (the current
implementations are just simple place-holders to get things up and
running).  Connections need to have knowledge of client identity
(passed from the driver, this is implementation-specific stuff).
Logging needs to be implemented (probably as server mixins).
Condition handling needs to generate better responses for HTTP/0.9,
and the division between condition handling and normal handling needs
to be documented/rethought.  Content generation is totally missing
currently and needs to be implemented.  If this is all in place, an
HTTP/1.0 conforming server should be possible, and after porting the
drivers to ACL and LW, we can make a first release.

src/main/entity.cl

@@ -0,0 +1,112 @@
+;;;; CLASH --- The Common Lisp Adaptable Simple HTTP server
+;;;; This is copyrighted software.  See documentation for terms.
+;;;; 
+;;;; entity.cl --- Entity Handling
+;;;; 
+;;;; Checkout Tag: $Name$
+;;;; $Id$
+
+(in-package :CLASH)
+
+;;;; %File Description:
+;;;; 
+;;;; 
+;;;; 
+
+(defclass entity ()
+  ())
+
+(defgeneric render-entity-headers (entity stream))
+
+(defgeneric render-entity-body (entity stream))
+
+(defclass entity-header-mixin/1.1 ()
+  ((allow :initarg :allow :reader entity-allow)
+   (content-base :initarg :content-base :reader entity-content-base)
+   (content-encoding :initarg :content-encoding
+		     :reader entity-content-encoding)
+   (content-language :initarg :content-language
+		     :reader entity-content-language)
+   (content-length :initarg :content-length :reader entity-content-length)
+   (content-location :initarg :content-location
+		     :reader entity-content-location)
+   (content-md5 :initarg :content-md5 :reader entity-content-md5)
+   (content-range :initarg :content-range :reader entity-content-range)
+   (content-type :initarg :content-type :reader entity-content-type)
+   (etag :initarg :etag :reader entity-etag)
+   (expires :initarg :expires :reader entity-expires)
+   (last-modified :initarg :last-modified :reader entity-last-modified)))
+
+(defmacro render-slots ((obj stream) &rest clauses)
+  (loop with obj-sym = (gensym)
+	with stream-sym = (gensym)
+	for (slot-spec string . body) in clauses
+	for slot = (if (consp slot-spec) (car slot-spec) slot-spec)
+	for slot-var = (if (consp slot-spec) (cadr slot-spec) slot-spec)
+	collect
+	`(when (slot-boundp ,obj-sym (quote ,slot))
+	   (with-slots ((,slot-var ,slot)) ,obj-sym
+	     (write-string ,string ,stream-sym)
+	     (write-char #\: ,stream-sym)
+	     (write-char #\Space ,stream-sym)
+	     ,@body
+	     (write-char #\Return ,stream-sym)
+	     (write-char #\Newline ,stream-sym)))
+	into clause-list
+	finally
+	(return `(let ((,stream-sym ,stream)
+		       (,obj-sym ,obj))
+		   ,@clause-list))))
+
+(defmethod render-entity-headers ((e entity-header-mixin/1.1) stream)
+  (render-slots (e stream)
+    (allow "Allow"
+      (write-http-element-list-1 allow stream))
+    (content-base "Content-Base"
+      (princ content-base stream))
+    (content-encoding "Content-Encoding"
+      (write-http-element-list-1 content-encoding stream))
+    (content-language "Content-Language"
+      (write-http-element-list-1 content-language stream))
+    (content-length "Content-Length"
+      (format stream "~D" content-length))
+    (content-location "Content-Location"
+      (princ content-location stream))
+    #+NIL
+    (content-md5 "Content-MD5"
+      (write-string (base64-encode-string content-md5) stream))
+    #+NIL
+    (content-range "Content-Range"
+      (princ content-range stream))
+    #+NIL
+    (content-type "Content-Type"
+      (princ content-type stream))
+    #+NIL
+    (etag "ETag"
+      (princ etag stream))
+    #+NIL
+    (expires "Expires"
+      (princ expires stream))
+    #+NIL
+    (last-modified "Last-Modified"
+      (princ last-modified stream))))
+
+
+
+(defclass simple-entity (entity entity-header-mixin/1.1)
+  ((body :initarg :body :reader entity-body :initform nil)))
+
+(defmethod render-entity-body ((entity simple-entity) stream)
+  (etypecase (entity-body entity)
+    (string
+     (with-input-from-string (in-stream (entity-body entity))
+       (loop for line = (read-line in-stream nil nil)
+	     while line
+	     do (write-http-line line stream))))
+    (pathname
+     (with-open-file (in-stream (entity-body entity))
+       (let ((buffer (make-string (file-length in-stream))))
+	 (+ (read-sequence buffer in-stream)
+	    (length (write-sequence buffer stream))))))
+    (function
+     (funcall (entity-body entity) stream))))