specials.lisp

;;; -*- Mode: LISP; Syntax: COMMON-LISP; Package: DRAKMA; Base: 10 -*-
;;; $Header: /usr/local/cvsrep/drakma/specials.lisp,v 1.19 2008/01/14 01:57:02 edi Exp $

;;; Copyright (c) 2006-2012, Dr. Edmund Weitz.  All rights reserved.

;;; Redistribution and use in source and binary forms, with or without
;;; modification, are permitted provided that the following conditions
;;; are met:

;;;   * Redistributions of source code must retain the above copyright
;;;     notice, this list of conditions and the following disclaimer.

;;;   * Redistributions in binary form must reproduce the above
;;;     copyright notice, this list of conditions and the following
;;;     disclaimer in the documentation and/or other materials
;;;     provided with the distribution.

;;; THIS SOFTWARE IS PROVIDED BY THE AUTHOR 'AS IS' AND ANY EXPRESSED
;;; OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
;;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
;;; ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
;;; DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
;;; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
;;; GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
;;; INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
;;; WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
;;; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
;;; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

(in-package :drakma)

(defparameter *drakma-version* #.(asdf:component-version (asdf:find-system :drakma))
  "Drakma's version number as a string.")

(defmacro define-constant (name value &optional doc)
  "A version of DEFCONSTANT for, cough, /strict/ CL implementations."
  ;; See <http://www.sbcl.org/manual#Defining-Constants>
  `(defconstant ,name (if (boundp ',name) (symbol-value ',name) ,value)
     ,@(when doc (list doc))))

(define-constant +latin-1+ (make-external-format :latin-1 :eol-style :lf)
  "Default external format when reading headers.")

(define-constant +redirect-codes+ '(301 302 303 307)
  "A list of all HTTP return codes that redirect us to another URI.")

(define-constant +redirect-to-get-codes+ '(302 303)
  "A list of HTTP return codes that redirect using a GET method
(see http://en.wikipedia.org/wiki/Post/Redirect/Get).")

(define-constant +known-methods+ '(:copy
                                   :delete
                                   :get
                                   :head
                                   :lock
                                   :mkcol
                                   :move
                                   :options
                                   :options*
                                   :patch
                                   :post
                                   :propfind
                                   :proppatch
                                   :put
                                   :report
                                   :trace
                                   :unlock)
  "The HTTP methods \(including WebDAV methods) Drakma knows.")

(define-constant +redirect-to-get-methods+ '(:post)
  "A list of HTTP methods that should be changed to GET in case of redirect
(see http://en.wikipedia.org/wiki/Post/Redirect/Get).")

(defconstant +buffer-size+ 8192)

(defvar *drakma-default-external-format* ':latin-1
  "The default value for the external format keyword arguments of
HTTP-REQUEST.  The value of this variable will be interpreted by
FLEXI-STREAMS.  The initial value is the keyword :LATIN-1.
(Note that Drakma binds *DEFAULT-EOL-STYLE* to :LF).")

(defvar *header-stream* nil
  "If this variable is not NIL, it should be bound to a stream to
which incoming and outgoing headers will be written for debugging
purposes.")

(defvar *allow-dotless-cookie-domains-p* nil
  "When this variable is not NIL, cookie domains containing no dots
are considered valid.  The default is NIL, meaning to disallow such
domains except for \"localhost\".")

(defvar *ignore-unparseable-cookie-dates-p* nil
  "Whether Drakma is allowed to treat `Expires' dates in cookie
headers as non-existent if it can't parse them.  If the value of this
variable is NIL \(which is the default), an error will be signalled
instead.")

(defvar *remove-duplicate-cookies-p* t
  "Determines how duplicate cookies in the response are handled,
defaults to T.  Cookies are considered duplicate using COOKIE=.  Valid
values are:

 NIL - duplicates will not be removed,
 T or :KEEP-LAST - for duplicates, only the last cookie value will be kept, based on the
 order of the response header,
 :KEEP-FIRST - for duplicates, only the first cookie value will be kept, based on the order of the response
 header.

Misbehaving servers may send duplicate cookies back in the
 same Set-Cookie header:

HTTP/1.1 200 OK
Server: My-hand-rolled-server
Date: Wed, 07 Apr 2010 15:12:30 GMT
Connection: Close
Content-Type: text/html
Content-Length: 82
Set-Cookie: a=1; Path=/; Secure, a=2; Path=/; Secure

In this case Drakma has to choose whether cookie 'a' has the value '1'
or '2'.  By default, Drakma will choose the last value specified, in
this case '2'.  By default, Drakma conforms to RFC2109 HTTP State
Management Mechanism, section 4.3.3 Cookie Management:

    If a user agent receives a Set-Cookie response header whose NAME
    is the same as a pre-existing cookie, and whose Domain and Path
    attribute values exactly \(string) match those of a pre-existing
    cookie, the new cookie supersedes the old.")

(defvar *text-content-types* '(("text" . nil))
  "A list of conses which are used by the default value of
*BODY-FORMAT-FUNCTION* to decide whether a 'Content-Type' header
denotes text content.  The car and cdr of each cons should each be a
string or NIL.  A content type matches one of these
entries (and thus denotes text) if the type part is STRING-EQUAL
to the car or if the car is NIL and if the subtype part
is STRING-EQUAL
to the cdr or if the cdr is NIL.

The initial value of this variable is the list

\((\"text\" . nil))

which means that every content type that starts with \"text/\" is
regarded as text, no matter what the subtype is.")

(defvar *body-format-function* 'determine-body-format
  "A function which determines whether the content body returned by
the server is text and should be treated as such or not.  The function
is called after the request headers have been read and it must accept
two arguments, headers and external-format-in, where headers is like
the third return value of HTTP-REQUEST while external-format-in is the
HTTP-REQUEST argument of the same name.  It should return NIL if the
body should be regarded as binary content, or a FLEXI-STREAMS external
format \(which will be used to read the body) otherwise.

This function will only be called if the force-binary argument to
HTTP-REQUEST is NIL.

The initial value of this variable is a function which uses
*TEXT-CONTENT-TYPES* to determine whether the body is text and then
proceeds as described in the HTTP-REQUEST documentation entry.")

(defvar *time-zone-map*
  ;; list taken from
  ;; <http://www.timeanddate.com/library/abbreviations/timezones/>
  '(("A" . -1)
    ("ACDT" . -10.5)
    ("ACST" . -9.5)
    ("ADT" . 3)
    ("AEDT" . -11)
    ("AEST" . -10)
    ("AKDT" . 8)
    ("AKST" . 9)
    ("AST" . 4)
    ("AWDT" . -9)
    ("AWST" . -8)
    ("B" . -2)
    ("BST" . -1)
    ("C" . -3)
    ("CDT" . 5)
    ("CEDT" . -2)
    ("CEST" . -2)
    ("CET" . -1)
    ("CST" . -10.5)
    ("CST" . -9.5)
    ("CST" . 6)
    ("CXT" . -7)
    ("D" . -4)
    ("E" . -5)
    ("EDT" . 4)
    ("EEDT" . -3)
    ("EEST" . -3)
    ("EET" . -2)
    ("EST" . -11)
    ("EST" . -10)
    ("EST" . 5)
    ("F" . -6)
    ("G" . -7)
    ("GMT" . 0)
    ("H" . -8)
    ("HAA" . 3)
    ("HAC" . 5)
    ("HADT" . 9)
    ("HAE" . 4)
    ("HAP" . 7)
    ("HAR" . 6)
    ("HAST" . 10)
    ("HAT" . 2.5)
    ("HAY" . 8)
    ("HNA" . 4)
    ("HNC" . 6)
    ("HNE" . 5)
    ("HNP" . 8)
    ("HNR" . 7)
    ("HNT" . 3.5)
    ("HNY" . 9)
    ("I" . -9)
    ("IST" . -1)
    ("K" . -10)
    ("L" . -11)
    ("M" . -12)
    ("MDT" . 6)
    ("MESZ" . -2)
    ("MEZ" . -1)
    ("MST" . 7)
    ("N" . 1)
    ("NDT" . 2.5)
    ("NFT" . -11.5)
    ("NST" . 3.5)
    ("O" . 2)
    ("P" . 3)
    ("PDT" . 7)
    ("PST" . 8)
    ("Q" . 4)
    ("R" . 5)
    ("S" . 6)
    ("T" . 7)
    ("U" . 8)
    ("UTC" . 0)
    ("V" . 9)
    ("W" . 10)
    ("WEDT" . -1)
    ("WEST" . -1)
    ("WET" . 0)
    ("WST" . -9)
    ("WST" . -8)
    ("X" . 11)
    ("Y" . 12)
    ("Z" . 0))
  "An alist which maps time zone abbreviations to Common Lisp
timezones.")

(defvar *default-http-proxy* nil
  "HTTP proxy to be used as default. If not NIL, it should be a string
denoting a proxy server through which the request should be sent.  Or
it can be a list of two values - a string denoting the proxy server
and an integer denoting the port to use \(which will default to 80
otherwise).")

;; stuff for Nikodemus Siivola's HYPERDOC
;; see <http://common-lisp.net/project/hyperdoc/>
;; and <http://www.cliki.net/hyperdoc>
;; also used by LW-ADD-ONS

(defvar *no-proxy-domains* nil
  "A list of domains for which a proxy should not be used.")

(defvar *hyperdoc-base-uri* "http://weitz.de/drakma/")

(let ((exported-symbols-alist
       (loop for symbol being the external-symbols of :drakma
             collect (cons symbol
                           (concatenate 'string
                                        "#"
                                        (string-downcase symbol))))))
  (defun hyperdoc-lookup (symbol type)
    (declare (ignore type))
    (cdr (assoc symbol
                exported-symbols-alist
                :test #'eq))))