From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Daniel Mendler Newsgroups: gmane.emacs.devel Subject: Re: emacsclient in elisp Date: Wed, 19 May 2021 16:13:11 +0200 Message-ID: <6fed43bb-d880-bcd5-6f6f-004b6182e539@daniel-mendler.de> References: <00ce8ae3-bb21-c58f-cd32-c196f146842b@daniel-mendler.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="23867"; mail-complaints-to="usenet@ciao.gmane.io" Cc: "emacs-devel@gnu.org" To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed May 19 16:14:22 2021 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1ljMxi-0005pH-4c for ged-emacs-devel@m.gmane-mx.org; Wed, 19 May 2021 16:14:14 +0200 Original-Received: from localhost ([::1]:39246 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ljMxh-0003Ta-4u for ged-emacs-devel@m.gmane-mx.org; Wed, 19 May 2021 10:14:13 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:53372) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ljMws-0002nf-NV for emacs-devel@gnu.org; Wed, 19 May 2021 10:13:22 -0400 Original-Received: from server.qxqx.de ([2a01:4f8:121:346::180]:36437 helo=mail.qxqx.de) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ljMwn-00077L-0n for emacs-devel@gnu.org; Wed, 19 May 2021 10:13:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=qxqx.de; s=mail1392553390; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:Cc:From:References:To:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=K96nfwmRyP/DHihKpv2dqEa7DMKnQky7JaKuV7xd/wg=; b=QU7+8EUrb6HdlC5lU81W/B3RYp pdmOL+GWCbQVGmG9n6T7VOHNohAggnaLQk71TUZFq/sat3gOvD3E13UlUGYM9qbhFBAdhUbbW3Lft Zd66pbQpntg6Pd+cH54Z3u98yWJO7y+a2m+/40gvAsSSNp4ZxvU/PeQuy3L9gtBhYE58=; In-Reply-To: Content-Language: en-US Received-SPF: pass client-ip=2a01:4f8:121:346::180; envelope-from=mail@daniel-mendler.de; helo=mail.qxqx.de X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:269482 Archived-At: On 5/19/21 3:41 PM, Stefan Monnier wrote: > No. I think the reason goes as follows: for the intended purpose of > `emacsclient`, the time needed to start Emacs itself makes an ELisp > implementation useless... Of course. > and for other purposes you can generally have > a separate server process per client process and it's just as easy if > not easier to then use `start-process` and a ad-hoc communication > protocol... When I a start an Emacs process in the background, which IPC protocol do you recommend to communicate with it? Should I start a separate custom TCP server on the daemon and then communicate with it using a TCP client (inventing my own protocol and with the implied security issues)? I cannot start the Emacs in the background and communicate with it by sending/receiving data via stdin/stdout, since Emacs does not offer an asynchronous facility to read from stdin. Asynchronous reading would be needed on the daemon. If I am calling `read-from-minibuffer` there it reads from stdin but blocks the process. Is this correct? For my use case it is necessary that I start an Emacs process in the background, which stays alive for some time, maintaining some state. Then this process should be controlled asynchronously. There exists the async package, which starts a new Emacs process per future if I understood correctly. This is not sufficient for what I am trying. > rather than having to reuse the protocol used for `emacsclient` > (which is neither very convenient nor very extensible). I am not sure I agree. I can send sexps and return sexps which I consider a sufficiently extensible protocol. But from what I've seen the client is buggy - it is for example not possible to send strings containing \0 bytes. Daniel