ethermacs/etherpad.el

280 lines
10 KiB
EmacsLisp

;;; etherpad.el --- Interface to the Etherpad API -*- coding: utf-8; lexical-binding: t -*-
;; Copyright 2020 FoAM
;;
;; Author: nik gaffney <nik@fo.am>
;; Created: 2020-08-08
;; Version: 0.1
;; Package-Requires: ((emacs "26.3") (request "0.3") (let-alist "0.0") (websocket "1.12") (parsec "0.1") (0xc "0.1"))
;; Keywords: comm, etherpad, collaborative editing
;; URL: https://github.com/zzkt/ethermacs
;; This file is not part of GNU Emacs.
;; This program 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.
;; This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; Etherpad is a highly customizable Open Source online editor providing
;; collaborative editing in really real-time.
;;
;; This package enables read-write access to pads on an Etherpad server
;; as if they were filelike but is not (yet) suitable for use as a
;; collaborative Etherpad client.
;;
;; details -> https://etherpad.org/doc/v1.8.5/#index_http_api
;; known bugs, limitations, shortcomings, etc
;; - various problems with realtime editing using easysync
;; - the server and api key could be buffer local to enable editing on more than one server
;; - doesn't automate API interface generation from openapi.json
;; - not much in the way of error checking or recovery
;; - etc
;;; Code:
(add-to-list 'load-path ".")
(require 'let-alist)
(require 'ethersync)
(require 'request)
(require 'cl-lib)
(defgroup etherpad nil
"Etherpad edits."
:prefix "etherpad-"
:group 'external)
(defcustom etherpad-apikey "request an API key"
"API key for the etherpad server."
:type 'string)
(defcustom etherpad-server "https://example.org"
"URL of the etherpad server."
:type 'string)
(defcustom etherpad-autosync nil
"Sync with etherpad server whenever the local buffer changes."
:type 'boolean)
(defcustom etherpad-idlesync nil
"Sync with etherpad server whenever auto-save is triggered."
:type 'boolean)
(defvar etherpad--local-pad-name ""
"Buffer local pad details.")
(defvar etherpad--local-pad-revision ""
"Buffer local pad details.")
(define-minor-mode etherpad-mode
"Minor mode to sync changes with etherpad."
:lighter " etherpad"
:keymap (make-sparse-keymap)
(if etherpad-mode
(ethersync--add-change-hooks)
(ethersync--remove-change-hooks)))
;; API functions
(defun etherpad-openapi ()
"Find API details using openAPI endpoint.
Should be available at https://<host>/api/1/openapi.json"
(interactive)
(request
(format "%s/api/1/openapi.json" etherpad-server)
:sync t
:parser 'json-read
:success (cl-function
(lambda (&key data &allow-other-keys)
(message "200: %s" data)))
:error (cl-function
(lambda (&rest args &key error-thrown &allow-other-keys)
(message "etherpad API error: %s" error-thrown)))))
(defun etherpad--api-pad-revision (pad-id)
"Current revision number for the pad with PAD-ID."
(catch 'rev
(request
(format "%s/api/1/getRevisionsCount?padID=%s&apikey=%s" etherpad-server pad-id etherpad-apikey)
:sync t
:parser 'json-read
:success (cl-function
(lambda (&key data &allow-other-keys)
(let-alist data (throw 'rev .data.revisions))))
:error (cl-function
(lambda (&rest args &key error-thrown &allow-other-keys)
(error "Etherpad API error: %s" error-thrown))))))
(defun etherpad--api-get-text (pad-id)
"Get the text of a pad with PAD-ID."
(catch 'text
(request
(format "%s/api/1/getText?padID=%s&apikey=%s" etherpad-server pad-id etherpad-apikey)
:sync t
:parser 'json-read
:success (cl-function
(lambda (&key data &allow-other-keys)
(let-alist data (throw 'text .data.text))))
:error (cl-function
(lambda (&rest args &key error-thrown &allow-other-keys)
(error "Etherpad API error: %s" error-thrown))))))
(defun etherpad--api-set-text (pad-id text)
"Overwrite the contents of the pad PAD-ID with some TEXT."
(request
(format "%s/api/1/setText" etherpad-server)
:type: "POST"
:data `(("apikey" . ,etherpad-apikey) ("padID" . ,pad-id) ("text" . ,text))
:parser 'json-read
:success (cl-function
(lambda (&key data &allow-other-keys)
(message "written to %s: %s\ndata: %s\n" pad-id text data)))
:error (cl-function
(lambda (&rest args &key error-thrown &allow-other-keys)
(error "Etherpad API error: %s" error-thrown)))))
;;;###autoload
(defun etherpad-edit (&optional pad-id)
"Edit a pad with the given PAD-ID."
(interactive "sName of the pad to edit: ")
;; note: check if pad-id exists and/or create new pad as required
(let* ((pad-remote-revision (etherpad--api-pad-revision pad-id))
(pad-buffer (get-buffer-create (format "%s:%s at %s" pad-id pad-remote-revision etherpad-server)))
(pad-text (etherpad--api-get-text pad-id)))
(with-current-buffer pad-buffer
(setq-local etherpad--local-pad-name pad-id
etherpad--local-pad-revision (etherpad--api-pad-revision pad-id))
(goto-char (point-min))
(erase-buffer)
(insert pad-text)
(message "opening pad: %s rev: %s" etherpad--local-pad-name etherpad--local-pad-revision)
(goto-char (point-max))
(display-buffer pad-buffer)
(make-local-variable 'etherpad-autosync)
(when etherpad-autosync (etherpad-autosync-enable))
(when etherpad-idlesync (etherpad-idlesync-enable)))
(set-buffer pad-buffer)))
(defun etherpad-update (&optional pad-id)
"Update current buffer with text from a remote pad (PAD-ID)."
(interactive "sName of the pad to sync from: ")
(when (not pad-id) (setq pad-id etherpad--local-pad-name))
(message "pad-id: %s etherpad--local-pad-name: %s (buffer local)" pad-id etherpad--local-pad-name)
;; note: check if pad-id exists and/or create new pad as required
(let* ((pad-remote-revision (etherpad--api-pad-revision pad-id))
(pad-buffer (current-buffer))
(pad-text (etherpad--api-get-text pad-id)))
(with-current-buffer pad-buffer
(setq-local etherpad--local-pad-name pad-id
etherpad--local-pad-revision pad-remote-revision)
(rename-buffer (format "%s:%s at %s" etherpad--local-pad-name etherpad--local-pad-revision etherpad-server))
(goto-char (point-min))
(erase-buffer)
(insert pad-text)
(message "synced from pad: %s rev: %s" etherpad--local-pad-name etherpad--local-pad-revision)
(goto-char (point-max))
(display-buffer pad-buffer)
pad-buffer)))
;;;###autoload
(defun etherpad-save ()
"Write a buffer to an etherpad.
'etherpad--local-pad-name' and 'etherpad--local-pad-revision' are buffer local"
(interactive)
;; show diffs, merge, update, etc+
;; and save...
(message "preparing to write %s revision %s (from '%s')" etherpad--local-pad-name (1+ etherpad--local-pad-revision) (current-buffer))
;; check for version drift & update revision
(let* ((remote-revision (etherpad--api-pad-revision etherpad--local-pad-name))
(local-revision etherpad--local-pad-revision))
(if (> remote-revision local-revision)
(when (y-or-n-p
(format "Text is out of sync with pad on the server (revision %s > %s) resync? "
remote-revision local-revision))
(etherpad-update etherpad--local-pad-name))
(progn
(etherpad--api-set-text etherpad--local-pad-name (buffer-string))
(message "wrote to pad: %s revision %s" etherpad--local-pad-name (etherpad--api-pad-revision etherpad--local-pad-name))
(setq etherpad--local-pad-revision (etherpad--api-pad-revision etherpad--local-pad-name))
(message "new revision? %s" etherpad--local-pad-revision)
(rename-buffer (format "%s:%s at %s" etherpad--local-pad-name etherpad--local-pad-revision etherpad-server))
(message "pad has been synced (at revision %s)" etherpad--local-pad-revision)))))
(defun etherpad-before-change-function (_begin _end)
"Function to run before etherpad update (buffer BEGIN and END).
should be specific to minor mode and buffer local."
(let* ((remote-revision (etherpad--api-pad-revision etherpad--local-pad-name))
(local-revision etherpad--local-pad-revision))
(when (> remote-revision local-revision)
(etherpad-update))))
(defun etherpad-after-change-function (_begin _end _length)
"Function to run after buuffer has changed (buffer BEGIN, END & LENGTH).
should be specific to minor mode and buffer local."
(etherpad-save))
(defun etherpad-autosync-toggle ()
"Toggle autosync."
(interactive)
(if etherpad-autosync
(progn (setq etherpad-autosync nil)
(etherpad-autosync-disable))
(progn (setq etherpad-autosync t)
(etherpad-autosync-enable))))
(defun etherpad-autosync-enable ()
"Enable autosync."
(interactive)
(message "enabled autosync with etherpad server.")
(make-local-variable 'after-change-functions)
(make-local-variable 'before-change-functions)
(add-hook 'after-change-functions #'etherpad-after-change-function)
(add-hook 'before-change-functions #'etherpad-before-change-function))
(defun etherpad-autosync-disable ()
"Disable autosync."
(interactive)
(message "disabled autosync with etherpad server.")
(remove-hook 'after-change-functions #'etherpad-after-change-function)
(remove-hook 'before-change-functions #'etherpad-before-change-function))
(defun etherpad-idlesync-enable ()
"Sync pad whenever auto-save would."
(interactive)
(make-local-variable 'auto-save-hook)
(make-local-variable 'auto-save-mode)
(auto-save-mode t)
(add-hook 'auto-save-hook #'etherpad-save))
(defun etherpad-idlesync-disable ()
"Disable idle syncing."
(interactive)
(remove-hook 'auto-save-hook #'etherpad-save))
(provide 'etherpad)
;;; etherpad.el ends here