From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1W7Wzv-0001ou-U0 for bitcoin-development@lists.sourceforge.net; Sun, 26 Jan 2014 21:12:07 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of m.gmane.org designates 80.91.229.3 as permitted sender) client-ip=80.91.229.3; envelope-from=gcbd-bitcoin-development@m.gmane.org; helo=plane.gmane.org; Received: from plane.gmane.org ([80.91.229.3]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1W7Wzu-0006x0-Mf for bitcoin-development@lists.sourceforge.net; Sun, 26 Jan 2014 21:12:07 +0000 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1W7Wzl-0004bR-K3 for bitcoin-development@lists.sourceforge.net; Sun, 26 Jan 2014 22:11:57 +0100 Received: from f052020014.adsl.alicedsl.de ([78.52.20.14]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 26 Jan 2014 22:11:57 +0100 Received: from andreas by f052020014.adsl.alicedsl.de with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 26 Jan 2014 22:11:57 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: bitcoin-development@lists.sourceforge.net From: Andreas Schildbach Date: Sun, 26 Jan 2014 22:11:47 +0100 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: f052020014.adsl.alicedsl.de User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 X-Spam-Score: -0.9 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [80.91.229.3 listed in list.dnswl.org] -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain -0.0 SPF_HELO_PASS SPF: HELO matches SPF record 1.1 DKIM_ADSP_ALL No valid author signature, domain signs all mail -0.0 SPF_PASS SPF: sender matches SPF record -0.5 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Headers-End: 1W7Wzu-0006x0-Mf Subject: [Bitcoin-development] BIP70/71 issue, RFD X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 26 Jan 2014 21:12:08 -0000 I'm experimenting with BIP70/71 (payment protocol) usage in face to face payments (more on that soon). I've excountered an issue with the protobuf format. Protobufs are not self-delimiting. That means if you're reading from an undelimited stream, you will read endlessly because you don't know how much to read. The current BIP70 implementations probably work because they're reading either from a file or from an HTTP resource which sets the Content-Length header. Trouble is the Content-Length header is optional, and also there are many kinds of streams that don't have this built-in delimiting mechanism. The Java protobuf API solves this by offering delimited I/O, like payment.writeDelimitedTo(os); This writes the size of the message as a varint before writing the data. I don't know about protobuf implementations for other languages but I'd expect them to offer something compatible. However, this leading varint is an incompatible change and would need to be added to the spec. I specifically encountered this with PaymentMessage and PaymentACK, but it might be a good idea to apply this to all messages if any. Open for discussion.