Re: [Bitcoin-development] Error handling in payment protocol (BIP-0070 and BIP-0072)
Keep in mind that links don't always come embedded in html. Think of native mobile apps. On Sat, Apr 26, 2014 at 10:43 AM, Ross Nicoll j...@jrn.me.uk wrote: I'd be very cautious of security implications of embedding files into the payment request. Even file formats one would presume safe, such as images, have had security issues (i.e. https://technet.microsoft.com/library/security/ms11-006 ) Longer term I was wondering about embedding the PaymentRequest into web pages directly via the object tag, which could eliminate need for BIP0072 and potentially improve user interface integration that way. Obviously this would require browser plugins, however. Ross On 26/04/14 18:36, Mike Hearn wrote: PaymentRequests are limited to 50,000 bytes. I can't think of a reason why Payment messages would need to be any bigger than that. Submit a pull request to the existing BIP. In future it might be nice to have images and things in the payment requests, to make UIs look prettier. But with the current version 50kb should be plenty indeed. -- Start Your Social Network Today - Download eXo Platform Build your Enterprise Intranet with eXo Platform Software Java Based Open Source Intranet - Social, Extensible, Cloud Ready Get Started Now And Turn Your Intranet Into A Collaboration Platform http://p.sf.net/sfu/ExoPlatform ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development -- Start Your Social Network Today - Download eXo Platform Build your Enterprise Intranet with eXo Platform Software Java Based Open Source Intranet - Social, Extensible, Cloud Ready Get Started Now And Turn Your Intranet Into A Collaboration Platform http://p.sf.net/sfu/ExoPlatform___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Error handling in payment protocol (BIP-0070 and BIP-0072)
The main area of concern is handling unexpected problems while sending the Payment message, or receiving the corresponding PaymentACK message. For example, in case of a transport layer failure or non-200 HTTP status code while sending the Payment message, what should the wallet software do next? Is it safe to re-send the Payment message? I'd propose that for any transport failure or 500 status code, the client retries after a delay (suggested at 30-60 seconds). For 400 status codes, the request should not be repeated, and as such the user should be alerted and a copy of the Payment message saved to be resent later. Why does error handling have to be standardized? I generally think that wallet software should be free to do whatever gives the user the best experience, so I'm in favor of restricting BIPs to things that must be standardized so that different implementations inter-operate. For 300 (redirect and similar) status codes, is it considered safe to follow redirects? I think we have to, but good to make it clear in the specification. Referencing whatever RFCs defines how to fetch URLs would be the best way to do this. Submit a pull request. On the merchant's side; I think it would be useful for there to be guidance for handling of errors processing Payment messages. I'd suggest that Payment messages should have a fixed maximum size to avoid merchant systems theoretically having to accept files of any size; 10MB would seem far larger than in any way practical, and therefore a good maximum size? PaymentRequests are limited to 50,000 bytes. I can't think of a reason why Payment messages would need to be any bigger than that. Submit a pull request to the existing BIP. A defined maximum time to wait (to avoid DDoS via connection holding) might be useful too, although I'd need to do measurements to find what values are tolerable. Implementation detail that doesn't belong in the spec, in my humble opinion. I would like to have the protocol state that merchant systems should handle repeatedly receiving the same Payment message, and return an equivalent (if not identical) PaymentACK to each. This is important in case of a network failure while the client is sending the Payment message, as outlined above. I think this should be left to implementations to work out. Lastly, I'm wondering about potential timing issues with transactions; if a merchant system wants to see confirmation of a transaction before sending a PaymentACK... not a good idea. The user should get feedback right away. Poking a pay now button and then waiting more than a second or three to get your payment has been received and is being processed is terrible UI. -- -- Gavin Andresen -- Start Your Social Network Today - Download eXo Platform Build your Enterprise Intranet with eXo Platform Software Java Based Open Source Intranet - Social, Extensible, Cloud Ready Get Started Now And Turn Your Intranet Into A Collaboration Platform http://p.sf.net/sfu/ExoPlatform___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Error handling in payment protocol (BIP-0070 and BIP-0072)
Dear Gavin, Andreas, I'd see standardisation (or at least suggested standards) for error handling as positive for consistency of user experience. I do see what you mean about over-specification, however. Thanks for the feedback, I've taken the main points and created two pull requests: BIP-0070: https://github.com/bitcoin/bips/pull/54/ BIP-0072: https://github.com/bitcoin/bips/pull/55/ Please tell me if these need any further work. Ross On 26/04/14 14:23, Gavin Andresen wrote: The main area of concern is handling unexpected problems while sending the Payment message, or receiving the corresponding PaymentACK message. For example, in case of a transport layer failure or non-200 HTTP status code while sending the Payment message, what should the wallet software do next? Is it safe to re-send the Payment message? I'd propose that for any transport failure or 500 status code, the client retries after a delay (suggested at 30-60 seconds). For 400 status codes, the request should not be repeated, and as such the user should be alerted and a copy of the Payment message saved to be resent later. Why does error handling have to be standardized? I generally think that wallet software should be free to do whatever gives the user the best experience, so I'm in favor of restricting BIPs to things that must be standardized so that different implementations inter-operate. For 300 (redirect and similar) status codes, is it considered safe to follow redirects? I think we have to, but good to make it clear in the specification. Referencing whatever RFCs defines how to fetch URLs would be the best way to do this. Submit a pull request. On the merchant's side; I think it would be useful for there to be guidance for handling of errors processing Payment messages. I'd suggest that Payment messages should have a fixed maximum size to avoid merchant systems theoretically having to accept files of any size; 10MB would seem far larger than in any way practical, and therefore a good maximum size? PaymentRequests are limited to 50,000 bytes. I can't think of a reason why Payment messages would need to be any bigger than that. Submit a pull request to the existing BIP. A defined maximum time to wait (to avoid DDoS via connection holding) might be useful too, although I'd need to do measurements to find what values are tolerable. Implementation detail that doesn't belong in the spec, in my humble opinion. I would like to have the protocol state that merchant systems should handle repeatedly receiving the same Payment message, and return an equivalent (if not identical) PaymentACK to each. This is important in case of a network failure while the client is sending the Payment message, as outlined above. I think this should be left to implementations to work out. Lastly, I'm wondering about potential timing issues with transactions; if a merchant system wants to see confirmation of a transaction before sending a PaymentACK... not a good idea. The user should get feedback right away. Poking a pay now button and then waiting more than a second or three to get your payment has been received and is being processed is terrible UI. -- Start Your Social Network Today - Download eXo Platform Build your Enterprise Intranet with eXo Platform Software Java Based Open Source Intranet - Social, Extensible, Cloud Ready Get Started Now And Turn Your Intranet Into A Collaboration Platform http://p.sf.net/sfu/ExoPlatform ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Error handling in payment protocol (BIP-0070 and BIP-0072)
PaymentRequests are limited to 50,000 bytes. I can't think of a reason why Payment messages would need to be any bigger than that. Submit a pull request to the existing BIP. In future it might be nice to have images and things in the payment requests, to make UIs look prettier. But with the current version 50kb should be plenty indeed. -- Start Your Social Network Today - Download eXo Platform Build your Enterprise Intranet with eXo Platform Software Java Based Open Source Intranet - Social, Extensible, Cloud Ready Get Started Now And Turn Your Intranet Into A Collaboration Platform http://p.sf.net/sfu/ExoPlatform___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Error handling in payment protocol (BIP-0070 and BIP-0072)
I'd be very cautious of security implications of embedding files into the payment request. Even file formats one would presume safe, such as images, have had security issues (i.e. https://technet.microsoft.com/library/security/ms11-006 ) Longer term I was wondering about embedding the PaymentRequest into web pages directly via the object tag, which could eliminate need for BIP0072 and potentially improve user interface integration that way. Obviously this would require browser plugins, however. Ross On 26/04/14 18:36, Mike Hearn wrote: PaymentRequests are limited to 50,000 bytes. I can't think of a reason why Payment messages would need to be any bigger than that. Submit a pull request to the existing BIP. In future it might be nice to have images and things in the payment requests, to make UIs look prettier. But with the current version 50kb should be plenty indeed. -- Start Your Social Network Today - Download eXo Platform Build your Enterprise Intranet with eXo Platform Software Java Based Open Source Intranet - Social, Extensible, Cloud Ready Get Started Now And Turn Your Intranet Into A Collaboration Platform http://p.sf.net/sfu/ExoPlatform ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
[Bitcoin-development] Error handling in payment protocol (BIP-0070 and BIP-0072)
Dear Gavin, all, Going over the payment protocol specifications, I've noticed that there's appears to be a lack of specificity on handling of error states. In most cases there are reasonably obvious solutions, however it would seem positive to formalise processes to ensure consistency. I'm wondering therefore if either you'd be willing to edit the existing BIP, or advise on whether this is useful to write up as a new BIP? The main area of concern is handling unexpected problems while sending the Payment message, or receiving the corresponding PaymentACK message. For example, in case of a transport layer failure or non-200 HTTP status code while sending the Payment message, what should the wallet software do next? Is it safe to re-send the Payment message? I'd propose that for any transport failure or 500 status code, the client retries after a delay (suggested at 30-60 seconds). For 400 status codes, the request should not be repeated, and as such the user should be alerted and a copy of the Payment message saved to be resent later. For 300 (redirect and similar) status codes, is it considered safe to follow redirects? I think we have to, but good to make it clear in the specification. On the merchant's side; I think it would be useful for there to be guidance for handling of errors processing Payment messages. I'd suggest that Payment messages should have a fixed maximum size to avoid merchant systems theoretically having to accept files of any size; 10MB would seem far larger than in any way practical, and therefore a good maximum size? A defined maximum time to wait (to avoid DDoS via connection holding) might be useful too, although I'd need to do measurements to find what values are tolerable. I would like to have the protocol state that merchant systems should handle repeatedly receiving the same Payment message, and return an equivalent (if not identical) PaymentACK to each. This is important in case of a network failure while the client is sending the Payment message, as outlined above. Lastly, I'm wondering about potential timing issues with transactions; if a merchant system wants to see confirmation of a transaction before sending a PaymentACK, any thoughts on whether it should hold the connection, or send a PaymentACK with a memo indicating payment has been seen on the relay network but is not yet confirmed, or something else? Happy to write this up as a new BIP if that's more appropriate than editing the original, and please do tell me if I've missed anything obvious/prior discussion on this topic. Ross -- Start Your Social Network Today - Download eXo Platform Build your Enterprise Intranet with eXo Platform Software Java Based Open Source Intranet - Social, Extensible, Cloud Ready Get Started Now And Turn Your Intranet Into A Collaboration Platform http://p.sf.net/sfu/ExoPlatform ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
