lisp/ob-screen.el

   1 ;;; ob-screen.el --- Babel Support for Interactive Terminal -*- lexical-binding: t; -*-
   2
   3 ;; Copyright (C) 2009-2019 Free Software Foundation, Inc.
   4
   5 ;; Author: Benjamin Andresen
   6 ;; Keywords: literate programming, interactive shell
   7 ;; Homepage: https://orgmode.org
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Org-Babel support for interactive terminals.  Mostly shell scripts.
  27 ;; Heavily inspired by 'eev' from Eduardo Ochs
  28 ;;
  29 ;; Adding :cmd and :terminal as header arguments
  30 ;; :terminal must support the -T (title) and -e (command) parameter
  31 ;;
  32 ;; You can test the default setup. (xterm + sh) with
  33 ;; M-x org-babel-screen-test RET
  34
  35 ;;; Code:
  36 (require 'ob)
  37
  38 (defvar org-babel-screen-location "screen"
  39   "The command location for screen.
  40 In case you want to use a different screen than one selected by your $PATH")
  41
  42 (defvar org-babel-default-header-args:screen
  43   '((:results . "silent") (:session . "default") (:cmd . "sh") (:terminal . "xterm"))
  44   "Default arguments to use when running screen source blocks.")
  45
  46 (defun org-babel-execute:screen (body params)
  47   "Send a block of code via screen to a terminal using Babel.
  48 \"default\" session is used when none is specified."
  49   (message "Sending source code block to interactive terminal session...")
  50   (save-window-excursion
  51     (let* ((session (cdr (assq :session params)))
  52            (socket (org-babel-screen-session-socketname session)))
  53       (unless socket (org-babel-prep-session:screen session params))
  54       (org-babel-screen-session-execute-string
  55        session (org-babel-expand-body:generic body params)))))
  56
  57 (defun org-babel-prep-session:screen (_session params)
  58   "Prepare SESSION according to the header arguments specified in PARAMS."
  59   (let* ((session (cdr (assq :session params)))
  60          (cmd (cdr (assq :cmd params)))
  61          (terminal (cdr (assq :terminal params)))
  62          (process-name (concat "org-babel: terminal (" session ")")))
  63     (apply 'start-process process-name "*Messages*"
  64            terminal `("-T" ,(concat "org-babel: " session) "-e" ,org-babel-screen-location
  65                       "-c" "/dev/null" "-mS" ,(concat "org-babel-session-" session)
  66                       ,cmd))
  67     ;; XXX: Is there a better way than the following?
  68     (while (not (org-babel-screen-session-socketname session))
  69       ;; wait until screen session is available before returning
  70       )))
  71
  72 ;; helper functions
  73
  74 (defun org-babel-screen-session-execute-string (session body)
  75   "If SESSION exists, send BODY to it."
  76   (let ((socket (org-babel-screen-session-socketname session)))
  77     (when socket
  78       (let ((tmpfile (org-babel-screen-session-write-temp-file session body)))
  79         (apply 'start-process (concat "org-babel: screen (" session ")") "*Messages*"
  80                org-babel-screen-location
  81                `("-S" ,socket "-X" "eval" "msgwait 0"
  82                  ,(concat "readreg z " tmpfile)
  83                  "paste z"))))))
  84
  85 (defun org-babel-screen-session-socketname (session)
  86   "Check if SESSION exists by parsing output of \"screen -ls\"."
  87   (let* ((screen-ls (shell-command-to-string "screen -ls"))
  88          (sockets (delq
  89                    nil
  90                    (mapcar
  91                     (lambda (x)
  92                       (when (string-match (rx (or "(Attached)" "(Detached)")) x)
  93                         x))
  94                     (split-string screen-ls "\n"))))
  95          (match-socket (car
  96                         (delq
  97                          nil
  98                          (mapcar
  99                           (lambda (x)
 100                             (when (string-match
 101                                    (concat "org-babel-session-" session) x)
 102                               x))
 103                           sockets)))))
 104     (when match-socket (car (split-string match-socket)))))
 105
 106 (defun org-babel-screen-session-write-temp-file (_session body)
 107   "Save BODY in a temp file that is named after SESSION."
 108   (let ((tmpfile (org-babel-temp-file "screen-")))
 109     (with-temp-file tmpfile
 110       (insert body)
 111
 112       ;; org-babel has superfluous spaces
 113       (goto-char (point-min))
 114       (delete-matching-lines "^ +$"))
 115     tmpfile))
 116
 117 (defun org-babel-screen-test ()
 118   "Test if the default setup works.
 119 The terminal should shortly flicker."
 120   (interactive)
 121   (let* ((random-string (format "%s" (random 99999)))
 122          (tmpfile (org-babel-temp-file "ob-screen-test-"))
 123          (body (concat "echo '" random-string "' > " tmpfile "\nexit\n"))
 124          tmp-string)
 125     (org-babel-execute:screen body org-babel-default-header-args:screen)
 126     ;; XXX: need to find a better way to do the following
 127     (while (not (file-readable-p tmpfile))
 128       ;; do something, otherwise this will be optimized away
 129       (format "org-babel-screen: File not readable yet."))
 130     (setq tmp-string (with-temp-buffer
 131                        (insert-file-contents-literally tmpfile)
 132                        (buffer-substring (point-min) (point-max))))
 133     (delete-file tmpfile)
 134     (message (concat "org-babel-screen: Setup "
 135                      (if (string-match random-string tmp-string)
 136                          "WORKS."
 137                        "DOESN'T work.")))))
 138
 139 (provide 'ob-screen)
 140
 141
 142
 143 ;;; ob-screen.el ends here