Internet DRAFT - draft-hope-bailie-http-payments
draft-hope-bailie-http-payments
Network Working Group A. Hope-Bailie
Internet-Draft Ripple
Intended status: Standards Track October 31, 2017
Expires: May 4, 2018
HTTP-Payments
draft-hope-bailie-http-payments-00
Abstract
HTTP-Payments describes a mechanism for passing a standardized
payment request in the headers of an HTTP 402 response and the
expected behaviour of HTTP clients that receive such a response.
Feedback
This specification is an early experiment in bringing the work of the
W3C Web Payments working group to the HTTP protocol. It is
maintained at https://github.com/adrianhopebailie/http-payments [1].
The work is inspired by work in the Interledger community on
[HTTP-ILP]
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on May 4, 2018.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Payment Methods . . . . . . . . . . . . . . . . . . . . . . . 3
4. HTTP Status Code 402 . . . . . . . . . . . . . . . . . . . . 3
4.1. The "Pay" Header . . . . . . . . . . . . . . . . . . . . 3
4.2. The "Pay-Token" Header . . . . . . . . . . . . . . . . . 4
4.3. The "Pay-Balance" Header . . . . . . . . . . . . . . . . 4
4.4. Flow . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.5. Example . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.1. Normative References . . . . . . . . . . . . . . . . . . 5
5.2. Informative References . . . . . . . . . . . . . . . . . 6
5.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Appendix A. Security Considerations . . . . . . . . . . . . . . 6
Appendix B. IANA Considerations . . . . . . . . . . . . . . . . 6
B.1. Payment Method Identifier Short-string Registry . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
The W3C Web Payments working group has defined a Web Platform API
that is being widely deployed to browsers for requesting a payment.
The PaymentRequest API [W3C.CR-payment-request-20170921], defines an
interface for a website to pass a payment request to the user agent
via this API.
The user agent will then, through interaction with the user, complete
or reject the requested payment.
HTTP-Payments describes a manner in which an HTTP server can request
payment from a client in the same manner as a website would from a
user agent using the W3C APIs.
The critical portion of the payment request is the set of, one or
more, supported payment methods and associated payment-method-
specific data. HTTP-Payments defines a mechaism by which these are
expressed in the response headers of an HTTP request for which the
server requires a payment.
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In the website and user-agent scenario, when handling the payment
request, the user-agent will prompt the user to pick one of the
supported payment methods and will then handle the payment in a
manner that is appropriate for that payment method. In an HTTP-
Payment, the HTTP client will perform this function, likely with no
user interaction.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119][].
3. Payment Methods
A payment method is a way that the payee can be paid. Examples
include, via credit card, bank wire transfer, or Bitcoin.
A payment method is identified by a payment method identifier as
specified in the Payment Method Identifiers specification [2]. This
is either a standardized short-string, identified in a registry
maintained by the W3C Web Payments WG, or a URL.
The most common case will be for the URL form to be used. In cases
where there is no authority responsible for the payment method that
can host the payment method URL, the WG will consider adding a new
identifier for the payment method to the registry.
Payment methods define the data that the payer and payee need to
exchange, to complete a payment, and the process by which this
occurs.
4. HTTP Status Code 402
The HTTP Status Code, 402 (Payment Required) is currently defined in
[RFC7231] as "reserved for future use". Using HTTP-Payment a service
MAY respond to any request with the 402 response code and use the
"Pay" header to specify the payment request details.
4.1. The "Pay" Header
The body of the "Pay" header is defined as follows:
Pay: <payment-method-identifier> <amount> <address> <payment-method-data>
Multiple "Pay" headers MAY be present in an HTTP 402 response.
The fields in the header are:
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o payment-method: The payment method identifier for the accepted
payment method. Either a standardized short-string or a URL.
o amount: The amount that must be paid, expressed as an integer.
The currency, scale and precision of the destination account are
expected to be expressed in the account address.
o address: A payment-method specific payee address. For example, if
the payment method is Bitcoin this would be a Bitcoin address.
o payment-method-data: Payment method specific data. This is either
a URI identifying the data or, if it is small enough, is the data
itself, BASE64URL encoded as described in [RFC4648], Section 5.
4.2. The "Pay-Token" Header
An HTTP client that makes a paid-HTTP request, after paying for the
request to be processed, MAY attach a "Pay-Token" header with a token
referencing the payment.
This mechanism can be employed by services wishing to accept payments
without binding these to an HTTP session.
4.3. The "Pay-Balance" Header
Ann HTTP Service that accepts payments may respond to any request
with a "Pay-Balance" header. This contains an integer indicating the
current balance of paid credit the client has with the HTTP service.
4.4. Flow
Upon receipt of a 402 response, an HTTP client MUST look for any
"Pay" headers and parse these. The client can discard all headers
for which it is not equipped to make a payment (i.e. filter on
payment-method-identifier)
The client MUST then select the header that is preferred for
processing based upon external interactions (such as with a human
user) or pre-configured rules. The client MUST attempt to make a
payment using the payment method identified in the header, for the
amount specified, and to the destination address specified.
The payment-method specific data SHOULD be sufficient for the system
processing the payment to reconcile the payment with the original
HTTP request.
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The client SHOULD receive a token in return for completeing the
payment. If the payment method used does return a token to the
payer, it MUST pass this token in subsequent HTTP requests.
The token MUST be passed in the "Pay-Token" header, BASE64URL encoded
as described in [RFC4648], Section 5.
The HTTP service MUST process the "Pay-Token" header and use this to
reconcile this HTTP request with the payment received prior.
4.5. Example
Client requests access to a paid resource:
POST /upload HTTP/1.1
Host: myservice.example
Server responds with payment request (and optionally indicates that
the client has a zero balance):
HTTP/1.1 402 Payment Required
Pay: http://interledger.org 10 us.nexus.ankita.~recv.filepay SkTcFTZCBKgP6A6QOUVcwWCCgYIP4rJPHlIzreavHdU
Pay-Balance: 0
Client makes the payment through an appropriate payment side-channel
and then attempts the request again:
POST /upload HTTP/1.1
Host: myservice.example
Pay-Token: 7y0SfeN7lCuq0GFF5UsMYZofIjJ7LrvPvsePVWSv450
Server responds:
HTTP/1.1 200 Success
Pay-Balance: 0
5. References
5.1. Normative References
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/info/rfc4648>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>.
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[W3C.CR-payment-method-id-20170914]
Bateman, A., Koch, Z., McElmurry, R., and M. Caceres,
"Payment Method Identifiers", World Wide Web Consortium
CR CR-payment-method-id-20170914, September 2017,
<https://www.w3.org/TR/2017/
CR-payment-method-id-20170914>.
[W3C.CR-payment-request-20170921]
Bateman, A., Koch, Z., McElmurry, R., Denicola, D., and M.
Caceres, "Payment Request API", World Wide Web Consortium
CR CR-payment-request-20170921, September 2017,
<https://www.w3.org/TR/2017/CR-payment-request-20170921>.
5.2. Informative References
[HTTP-ILP]
Interledger Community Group, "HTTP-ILP", October 2017,
<https://github.com/interledger/rfcs/
blob/58d8dcb015b160a381313126fa3065c64406db05/0014-http-
ilp/0014-http-ilp.md>.
5.3. URIs
[1] https://github.com/adrianhopebailie/http-payments
[2] W3C.CR-payment-method-id-20170914
Appendix A. Security Considerations
TBD
Appendix B. IANA Considerations
B.1. Payment Method Identifier Short-string Registry
The W3C maintains a registry of standardized short-string payment
method identifiers as part of the [Payment Method Identifier]
specification. If standardized short-string identifiers are to be
used for HTTP-Payments this may be better served as an IANA registry.
Author's Address
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Adrian Hope-Bailie
Ripple
315 Montgomery Street
San Francisco, CA 94104
US
Phone: -----------------
Email: adrian@ripple.com
URI: https://www.ripple.com
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