emacs/lisp/url/url-vars.el

;;; url-vars.el --- Variables for Uniform Resource Locator tool  -*- lexical-binding:t -*-

;; Copyright (C) 1996-2024 Free Software Foundation, Inc.

;; Keywords: comm, data, processes, hypermedia

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

(defgroup url nil
  "Uniform Resource Locator tool."
  :version "22.1"
  :link '(custom-manual "(url) Top")
  :link '(info-link "(url) Customization")
  :group 'comm)

(defgroup url-file nil
  "URL storage."
  :prefix "url-"
  :group 'url)

(defgroup url-cache nil
  "URL cache."
  :prefix "url-"
  :prefix "url-cache-"
  :group 'url)

(defgroup url-mime nil
  "MIME options of URL."
  :prefix "url-"
  :group 'url)

(defgroup url-hairy nil
  "Hairy options of URL."
  :prefix "url-"
  :group 'url)


(defvar-local url-current-object nil
  "A parsed representation of the current URL.")

(defvar-local url-current-mime-headers nil
  "A parsed representation of the MIME headers for the current URL.")

(defvar-local url-current-lastloc nil
  "A parsed representation of the URL to be considered as the last location.
Use of this value on outbound connections is subject to
`url-privacy-level' and `url-lastloc-privacy-level'.  This is never set
by the url library, applications are expected to set this
variable in buffers representing a displayed location.")

(defcustom url-honor-refresh-requests t
  "Whether to do automatic page reloads.
These are done at the request of the document author or the server via
the `Refresh' header in an HTTP response.  If nil, no refresh
requests will be honored.  If t, all refresh requests will be honored.
If non-nil and not t, the user will be asked for each refresh request."
  :type '(choice (const :tag "off" nil)
		 (const :tag "on" t)
		 (other :tag "ask" ask))
  :group 'url-hairy)

(defcustom url-automatic-caching nil
  "If non-nil, all documents will be automatically cached to the local disk."
  :type 'boolean
  :group 'url-cache)

(define-obsolete-variable-alias 'url-bug-address
  'report-emacs-bug-address "24.5")

(defcustom url-personal-mail-address nil
  "Your full email address.
This is what is sent to HTTP servers as the FROM field in an HTTP
request."
  :type '(choice (const :tag "Unspecified" nil) string)
  :group 'url)
(make-obsolete-variable 'url-personal-mail-address nil "30.1")

(defcustom url-directory-index-file "index.html"
  "The filename to look for when indexing a directory.
If this file exists, and is readable, then it will be viewed instead of
using `dired' to view the directory."
  :type 'string
  :group 'url-file)

(defcustom url-privacy-level '(email)
  "How private you want your requests to be.
HTTP has header fields for various information about the user, including
operating system information, email addresses, the last page you visited, etc.
This variable controls how much of this information is sent.

This should a symbol or a list.
Valid values if a symbol are:
none     -- send all information
low      -- don't send the last location
high     -- don't send the email address or last location
paranoid -- don't send anything

If a list, this should be a list of symbols of what NOT to send.
Valid symbols are:
email    -- the email address (in Emacs 29 or older)
os       -- the operating system info
emacs    -- the version of Emacs
lastloc  -- the last location (see also `url-lastloc-privacy-level')
agent    -- do not send the User-Agent string
cookies  -- never accept HTTP cookies

Emacs 30 and newer never includes the email address in the
User-Agent string.  If you expect to use older versions of Emacs,
it is recommended to always customize this list to include `email'.

Samples:

 (setq url-privacy-level \\='high)
 (setq url-privacy-level \\='(email lastloc))    ;; equivalent to \\='high
 (setq url-privacy-level \\='(email lastloc os emacs))

::NOTE::
This variable controls several other variables and is _NOT_ automatically
updated.  Call the function `url-setup-privacy-info' after modifying this
variable."
  :initialize #'custom-initialize-default
  :set (lambda (sym val) (set-default sym val) (url-setup-privacy-info))
  :type '(radio (const :tag "None (you believe in the basic goodness of humanity)"
		       :value none)
		(const :tag "Low (do not reveal last location)"
		       :value low)
		(const :tag "High (no email address or last location)"
		       :value high)
		(const :tag "Paranoid (reveal nothing!)"
		       :value paranoid)
		(checklist :tag "Custom"
			   (const :tag "Email address" :value email)
			   (const :tag "Operating system" :value os)
			   (const :tag "Emacs version" :value emacs)
			   (const :tag "Last location" :value lastloc)
			   (const :tag "Browser identification" :value agent)
                           (const :tag "No cookies" :value cookies)))
  :group 'url)

(defcustom url-lastloc-privacy-level 'domain-match
  "Further restrictions on sending the last location.
This value is only consulted if `url-privacy-level' permits
sending last location in the first place.

Valid values are:
none          -- Always send last location.
domain-match  -- Send last location if the new location is within the
                 same domain
host-match    -- Send last location if the new location is on the
                 same host"
  :version "27.1"
  :type '(radio (const :tag "Always send" none)
                (const :tag "Domains match" domain-match)
                (const :tag "Hosts match" host-match))
  :group 'url)

(defvar url-inhibit-uncompression nil "Do not do decompression if non-nil.")

(defcustom url-uncompressor-alist '((".z"  . "x-gzip")
				    (".gz" . "x-gzip")
				    (".uue" . "x-uuencoded")
				    (".hqx" . "x-hqx")
				    (".Z"  . "x-compress")
				    (".bz2" . "x-bzip2")
				    (".xz" . "x-xz"))
  "An alist of file extensions and appropriate content-transfer-encodings."
  :type '(repeat (cons :format "%v"
		       (string :tag "Extension")
		       (string :tag "Encoding")))
  :group 'url-mime)

(defcustom url-mail-command 'compose-mail
  "This function will be called whenever URL needs to send mail.
It should enter a mail-mode-like buffer in the current window.
The commands `mail-to' and `mail-subject' should still work in this
buffer, and it should use `mail-header-separator' if possible."
  :type 'function
  :group 'url)

(defcustom url-proxy-services nil
  "An alist of schemes and proxy servers that gateway them.
Looks like ((\"http\" . \"hostname:portnumber\") ...).  This is set up
from the ACCESS_proxy environment variables."
  :type '(repeat (cons :format "%v"
		       (string :tag "Protocol")
		       (string :tag "Proxy")))
  :group 'url)

(defcustom url-standalone-mode nil
  "Rely solely on the cache?"
  :type 'boolean
  :group 'url-cache)

(defvar url-mime-separator-chars (append "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
					 "abcdefghijklmnopqrstuvwxyz"
					 "0123456789'()+_,-./=?"
					 nil)
  "Characters allowable in a MIME multipart separator.")

(defcustom url-bad-port-list
  '("25" "119" "19")
  "List of ports to warn the user about connecting to.
Defaults to just the mail, chargen, and NNTP ports so you cannot be
tricked into sending fake mail or forging messages by a malicious HTML
document."
  :type '(repeat (string :tag "Port"))
  :group 'url-hairy)

(defvar url-mime-content-type-charset-regexp
  ";[ \t]*charset=\"?\\([^\"]+\\)\"?"
  "Regexp used in parsing `Content-Type' for a charset indication.")

(defvar url-request-data nil "Any data to send with the next request.")

(defvar url-request-extra-headers nil
  "A list of extra headers to send with the next request.
Should be an assoc list of headers/contents.")

(defvar url-request-noninteractive nil
  "If non-nil, the request is done in a noninteractive context.")

(defvar url-request-method nil "The method to use for the next request.")

(defvar url-mime-encoding-string (and (fboundp 'zlib-available-p)
				      (zlib-available-p)
				      "gzip")
  "String to send in the Accept-encoding: field in HTTP requests.")

(defvar mm-mime-mule-charset-alist)

;; Perhaps the first few should actually be given decreasing `q's and
;; the list should be trimmed significantly.
(defun url-mime-charset-string ()
  "Generate a list of preferred MIME charsets for HTTP requests.
Generated according to current coding system priorities."
  (require 'mm-util)
  (let ((ordered (sort-coding-systems
		  (let (accum)
		    (dolist (elt mm-mime-mule-charset-alist)
		      (if (coding-system-p (car elt))
			  (push (car elt) accum)))
		    (nreverse accum)))))
    (concat (format "%s;q=1, " (pop ordered))
	    (mapconcat #'symbol-name ordered ";q=0.5, ")
	    ";q=0.5")))

(defvar url-mime-charset-string nil
  "String to send in the Accept-charset: field in HTTP requests.
The MIME charset corresponding to the most preferred coding system is
given priority 1 and the rest are given priority 0.5.")

(defun url-set-mime-charset-string ()
  (declare (obsolete nil "27.1"))
  (setq url-mime-charset-string (url-mime-charset-string)))

;; Fixme: set from the locale.
(defcustom url-mime-language-string nil
  "String to send in the Accept-language: field in HTTP requests.

Specifies the preferred language when servers can serve documents in
several languages.  Use RFC 1766 abbreviations, e.g.: `en' for
English, `de' for German.  A comma-separated specifies descending
order of preference.  The ordering can be made explicit using `q'
factors defined by HTTP, e.g. `de,en-gb;q=0.8,en;q=0.7'.  `*' means
get the first available language (as opposed to the default)."
  :type '(radio
	  (const :tag "None (get default language version)" :value nil)
	  (const :tag "Any (get first available language version)" :value "*")
	  (string :tag "Other"))
  :group 'url-mime
  :group 'i18n)

(defvar url-mime-accept-string nil
  "String to send to the server in the Accept: field in HTTP requests.")

(defvar url-package-version nil
  "Version number of package using URL.")

(defvar url-package-name nil "Name of package using URL.")

(defvar url-system-type nil
  "What type of system we are on.")
(defvar url-os-type nil
  "What OS we are on.")

(defcustom url-max-password-attempts 5
  "Maximum number of times a password will be prompted for.
Applies when a protected document is denied by the server."
  :type 'natnum
  :group 'url)

(defcustom url-show-status t
  "Whether to show a running total of bytes transferred.
Can cause a large hit if using a remote X display over a slow link, or
a terminal with a slow modem."
  :type 'boolean
  :group 'url)

(defvar url-using-proxy nil
  "Either nil or the fully qualified proxy URL in use, e.g.
https://www.example.com/")

(defcustom url-news-server nil
  "The default news server from which to get newsgroups/articles.
Applies if no server is specified in the URL.  Defaults to the
environment variable NNTPSERVER or \"news\" if NNTPSERVER is
undefined."
  :type '(choice (const :tag "None" :value nil) string)
  :group 'url)

;; From RFC3986: Scheme names consist of a sequence of characters
;; beginning with a letter and followed by any combination of letters,
;; digits, plus ("+"), period ("."), or hyphen ("-").

(defvar url-nonrelative-link
  "\\`\\([a-zA-Z][-a-zA-Z0-9+.]*:\\)"
  "A regular expression that will match an absolute URL.")

(defcustom url-max-redirections 30
  "The maximum number of redirection requests to honor in a HTTP connection.
A negative number means to honor an unlimited number of redirection requests."
  :type 'integer
  :group 'url)

(defcustom url-confirmation-func 'y-or-n-p
  "What function to use for asking yes or no functions.
Possible values are `yes-or-no-p' or `y-or-n-p', or any function that
takes a single argument (the prompt), and returns t only if a positive
answer is given."
  :type '(choice (const :tag "Short (y or n)" :value y-or-n-p)
		 (const :tag "Long (yes or no)" :value yes-or-no-p)
		 (function :tag "Other"))
  :group 'url-hairy)

(defcustom url-gateway-method 'native
  "The type of gateway support to use.
Should be a symbol specifying how to get a connection from the local machine.

Currently supported methods:
`telnet': Run telnet in a subprocess to connect;
`socks': Connect through a socks server;
`tls': Connect with TLS;
`ssl': Connect with SSL (deprecated, use `tls' instead);
`native': Connect directly."
  :type '(radio (const :tag "Telnet to gateway host" :value telnet)
		(const :tag "Use SOCKS proxy" :value socks)
		(const :tag "Use SSL/TLS for all connections" :value tls)
		(const :tag "Use SSL for all connections (obsolete)" :value ssl)
		(const :tag "Direct connection" :value native))
  :group 'url-hairy)

(defcustom url-user-agent 'default
  "User Agent used by the URL package for HTTP/HTTPS requests.
Should be one of:
* A string (not including the \"User-Agent:\" prefix)
* A function of no arguments, returning a string
* `default' (to compute a value according to `url-privacy-level')
* nil (to omit the User-Agent header entirely)"
  :type
  '(choice
    (string :tag "A static User-Agent string")
    (function :tag "Call a function to get the User-Agent string")
    (const :tag "No User-Agent at all" :value nil)
    (const :tag "An string auto-generated according to `url-privacy-level'"
           :value default))
  :version "26.1"
  :group 'url)

(defvar url-setup-done nil "Has setup configuration been done?")

(defconst url-weekday-alist
  '(("Sunday" . 0) ("Monday" . 1) ("Tuesday" . 2) ("Wednesday" . 3)
    ("Thursday" . 4) ("Friday" . 5) ("Saturday" . 6)
    ("Tues" . 2) ("Thurs" . 4)
    ("Sun" . 0) ("Mon" . 1) ("Tue" . 2) ("Wed" . 3)
    ("Thu" . 4) ("Fri" . 5) ("Sat" . 6)))

(defconst url-monthabbrev-alist
  '(("Jan" . 1) ("Feb" . 2) ("Mar" . 3) ("Apr" . 4) ("May" . 5) ("Jun" . 6)
    ("Jul" . 7) ("Aug" . 8) ("Sep" . 9) ("Oct" . 10) ("Nov" . 11)
    ("Dec" . 12)))

(defvar url-lazy-message-time 0)

;; Fixme: We may not be able to run SSL.
(defvar url-extensions-header nil)

(defvar url-parse-syntax-table
  (copy-syntax-table emacs-lisp-mode-syntax-table)
  "A syntax table for parsing URLs.")

(modify-syntax-entry ?' "\"" url-parse-syntax-table)
(modify-syntax-entry ?` "\"" url-parse-syntax-table)
(modify-syntax-entry ?< "(>" url-parse-syntax-table)
(modify-syntax-entry ?> ")<" url-parse-syntax-table)
(modify-syntax-entry ?/ " " url-parse-syntax-table)

(defcustom url-load-hook nil
  "Hook run after initializing the URL library."
  :group 'url
  :type 'hook)
(make-obsolete-variable 'url-load-hook
                        "use `with-eval-after-load' instead." "28.1")

(defconst url-working-buffer " *url-work")

(defvar url-gateway-unplugged nil
  "Non-nil means don't open new network connections.
This should be set, e.g. by mail user agents rendering HTML to avoid
`bugs' which call home.")

(defun url-interactive-p ()
  "Non-nil when the current request is from an interactive context."
  (not (or url-request-noninteractive
           (bound-and-true-p url-http-noninteractive))))

;; Obsolete

(defconst url-version "Emacs" "Version number of URL package.")
(make-obsolete-variable 'url-version 'emacs-version "28.1")

(provide 'url-vars)
;;; url-vars.el ends here