From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on starla X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 Received: from nue.mailmanlists.eu (nue.mailmanlists.eu [94.130.110.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 62EA71F405 for ; Thu, 1 Feb 2024 14:59:38 +0000 (UTC) Authentication-Results: dcvr.yhbt.net; dkim=pass (1024-bit key; secure) header.d=ml.ruby-lang.org header.i=@ml.ruby-lang.org header.a=rsa-sha256 header.s=mail header.b=V2xeNi62; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=ruby-lang.org header.i=@ruby-lang.org header.a=rsa-sha256 header.s=s1 header.b=fUGAG8DK; dkim-atps=neutral Received: from nue.mailmanlists.eu (localhost [127.0.0.1]) by nue.mailmanlists.eu (Postfix) with ESMTP id E93D3826DE; Thu, 1 Feb 2024 14:59:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ml.ruby-lang.org; s=mail; t=1706799568; bh=0latS+zNMjF0ksIpyYW+QKEnTytjVTldYLg0jcTe0AQ=; h=Date:References:To:Reply-To:Subject:List-Id:List-Archive: List-Help:List-Owner:List-Post:List-Subscribe:List-Unsubscribe: From:Cc:From; b=V2xeNi62+rsSLOq8lGaa1FTFK36/HiW33N0GgTnUsSSc0jqyA5b2YZ2I6q2ugFYdt tGAAuRybmlaD3yG9v3yoa0L11pUWWr6VWx43jaUkY3whKeu/sL5jWvyg+l8z8IigIu diSr2GeM7d432SbSa+to123gRkY50ugb7a980tUY= Received: from wrqvtvvn.outbound-mail.sendgrid.net (wrqvtvvn.outbound-mail.sendgrid.net [149.72.120.130]) by nue.mailmanlists.eu (Postfix) with ESMTPS id EE0887FAB5 for ; Thu, 1 Feb 2024 14:59:24 +0000 (UTC) Authentication-Results: nue.mailmanlists.eu; dkim=pass (2048-bit key; unprotected) header.d=ruby-lang.org header.i=@ruby-lang.org header.a=rsa-sha256 header.s=s1 header.b=fUGAG8DK; dkim-atps=neutral DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ruby-lang.org; h=from:references:subject:mime-version:content-type: content-transfer-encoding:list-id:to:cc:content-type:from:subject:to; s=s1; bh=0HIFt5TFx5O/LKIG6jDR2j55GUVj6Z0B27xrAaQDn0A=; b=fUGAG8DK8xW0c1uFI1+xS22qmqAu2rj+QV03R21/YmpX1sm/uNChC8k9RLfRMFdBPWDg na9Hbm2La5scOItD9rgOiDhHMYE+693dk0T2xLs8+/Xdt0EvAnwbQkw4I78gTvTbCU2pyp nvsy8RusEBxUE2xA1/IQeD0LmZouYGVj5vn0YqWy5QNSGWJVsqmEbF/jpwvplA0YmXmYcS T3GZI0newTlQTDPEQdJBicZCFlEeqCBJrrrb6jN+5s+TkwKBN9+z80NZXgSK2FjbYsv4mW tRXzTQCFodvoCkoPyEYwEWgS3jTybSr+mBhYyTFVEB3507IS6qeQGKqMJxJTafAA== Received: by recvd-578d4fc675-9r9pm with SMTP id recvd-578d4fc675-9r9pm-1-65BBB1CB-1A 2024-02-01 14:59:23.719361223 +0000 UTC m=+581530.107083892 Received: from herokuapp.com (unknown) by geopod-ismtpd-22 (SG) with ESMTP id 2vPW6csyThiN0plkBwsLEQ for ; Thu, 01 Feb 2024 14:59:23.691 +0000 (UTC) Date: Thu, 01 Feb 2024 14:59:23 +0000 (UTC) Message-ID: References: Mime-Version: 1.0 X-Redmine-Project: ruby-master X-Redmine-Issue-Tracker: Feature X-Redmine-Issue-Id: 20215 X-Redmine-Issue-Author: ioquatix X-Redmine-Sender: Dan0042 X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-Redmine-MailingListIntegration-Message-Ids: 93103 X-SG-EID: =?us-ascii?Q?9vnO9kNFlf1pwhty1clU3mt9eNWYniufdXqocdsQQtaDTWZk4+b5g5js0Akvaj?= =?us-ascii?Q?32LW=2F+fGSAom3tt8Jo+=2FGW3uDD0ktbmu7qAbln0?= =?us-ascii?Q?uJrjIA379QZrbLjQfihx+jq4gxCeWk6Pf=2FfFOFP?= =?us-ascii?Q?F=2FV+2Q31FWjBAPB8TQP7rsh1pFZ+2I=2FoH0W47tL?= =?us-ascii?Q?e9XtrlVBxWgCANPi0sHo0bRIvlXBEc+Md86kiN0?= =?us-ascii?Q?i8Mam7u2ADbLfJBgpf1dtR59xiI4afnNBetQTJw?= =?us-ascii?Q?O0hcQ0s3gU1MOMp0Wcsmg=3D=3D?= To: ruby-core@ml.ruby-lang.org X-Entity-ID: b/2+PoftWZ6GuOu3b0IycA== Message-ID-Hash: 4KHFOFF4GFXQ5OY7XUQQ7DMF4MYX47FA X-Message-ID-Hash: 4KHFOFF4GFXQ5OY7XUQQ7DMF4MYX47FA X-MailFrom: bounces+313651-b711-ruby-core=ml.ruby-lang.org@em5188.ruby-lang.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.3 Precedence: list Reply-To: Ruby developers Subject: [ruby-core:116547] [Ruby master Feature#20215] Introduce `IO#readable?` List-Id: Ruby developers Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: "Dan0042 (Daniel DeLorme) via ruby-core" Cc: "Dan0042 (Daniel DeLorme)" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Issue #20215 has been updated by Dan0042 (Daniel DeLorme). I'm interested in this. I previously had to implement a "nonblocking gets" which was a bit tricky. ```ruby def gets_nonblock(io) str = io.read_nonblock(1, exception: false) return :no_data if str == :wait_readable if str == $/ enc = $/.encoding else str2 = io.gets.to_s enc = str2.encoding str << str2.force_encoding(Encoding::ASCII_8BIT) end str.force_encoding(enc) rescue EOFError nil end ``` It would have been nice to just write `io.gets if io.readable?` But I want to confirm this is the expected behavior: `#readable?` should return true if there is data immediately available for `#read` Based on the BasicSocket implementation above, it seems like `#readable?` could return true even if no data is available? ---------------------------------------- Feature #20215: Introduce `IO#readable?` https://bugs.ruby-lang.org/issues/20215#change-106564 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal ---------------------------------------- There are some cases where, as an optimisation, it's useful to know whether more data is potentially available. We already have `IO#eof?` but the problem with using `IO#eof?` is that it can block indefinitely for sockets. Therefore, code which uses `IO#eof?` to determine if there is potentially more data, may hang. ```ruby def make_request(path = "/") client = connect_remote_host # HTTP/1.0 request: client.write("GET #{path} HTTP/1.0\r\n\r\n") # Read response client.gets("\r\n") # => "HTTP/1.0 200 OK\r\n" # Assuming connection close, there are two things the server can do: # 1. peer.close # 2. peer.write(...); peer.close if client.eof? # <--- Can hang here! puts "Connection closed" # Avoid yielding as we know there definitely won't be any data. else puts "Connection open, data may be available..." # There might be data available, so yield. yield(client) end ensure client&.close end make_request do |client| puts client.read # <--- Prefer to wait here. end ``` The proposed `IO#readable?` is similar to `IO#eof?` but rather than blocking, would simply return false. The expectation is the user will subsequently call `read` which may then wait. The proposed implementation would look something like this: ```ruby class IO def readable? !self.closed? end end class BasicSocket # Is it likely that the socket is still connected? # May return false positive, but won't return false negative. def readable? return false unless super # If we can wait for the socket to become readable, we know that the socket may still be open. result = self.recv_nonblock(1, MSG_PEEK, exception: false) # No data was available - newer Ruby can return nil instead of empty string: return false if result.nil? # Either there was some data available, or we can wait to see if there is data avaialble. return !result.empty? || result == :wait_readable rescue Errno::ECONNRESET # This might be thrown by recv_nonblock. return false end end ``` For `IO` itself, when there is buffered data, `readable?` would also return true immediately, similar to `eof?`. This is not shown in the above implementation as I'm not sure if there is any Ruby method which exposes "there is buffered data". -- https://bugs.ruby-lang.org/ ______________________________________________ ruby-core mailing list -- ruby-core@ml.ruby-lang.org To unsubscribe send an email to ruby-core-leave@ml.ruby-lang.org ruby-core info -- https://ml.ruby-lang.org/mailman3/postorius/lists/ruby-core.ml.ruby-lang.org/