Network Working Group S. Ferguson Internet-Draft Caucho Intended status: Standards Track April 6, 2011 Expires: October 8, 2011 The JSON Message Protocol draft-ferg-jsmp-v0 Abstract The JSON Message Protocol defines a bidirectional messaging protocol using JSON as a payload serialization format. Messages are typed and addressed. Both unidirectional messages and bidirectional queries are supported. JSMP is expected to be built on top of a framing protocol like WebSockets. Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on October 8, 2011. Ferguson Expires October 8, 2011 [Page 1] Internet-Draft The JSON Message Protocol April 2011 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 5 4. General Requirements . . . . . . . . . . . . . . . . . . . . . 6 4.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 6 4.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 6 4.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6 4.4. Basic Rules . . . . . . . . . . . . . . . . . . . . . . . 7 5. Packets . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.1. message . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.2. message-error . . . . . . . . . . . . . . . . . . . . . . 8 5.3. query . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.4. response . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.5. query-error . . . . . . . . . . . . . . . . . . . . . . . 10 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 7. Normative References . . . . . . . . . . . . . . . . . . . . . 12 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . . . . 14 Ferguson Expires October 8, 2011 [Page 2] Internet-Draft The JSON Message Protocol April 2011 1. Introduction The goal of JSMP is to provide structure for a JSON-based messaging over a WebSockets connection. JSON supports: o typed messages, allowing for an object-oriented messaging style. o addressable actors on the client and servers, enabling encapsulation of services. o unidirectional messages and bidirectional query-response pairs for both major messaging styles. o payloads encoded using JSON. Ferguson Expires October 8, 2011 [Page 3] Internet-Draft The JSON Message Protocol April 2011 2. Requirements 1. JSMP must support unidirectional messages. 2. JSMP must support query-response pairs. 3. JSMP responses may be unordered to the querires or messages. 4. JSMP must support typed messages. 5. JSMP must support services, using addresses for routing. Ferguson Expires October 8, 2011 [Page 4] Internet-Draft The JSON Message Protocol April 2011 3. Protocol Overview _This section is non-normative._ A unidirectional message looks as follows: message to@target.example.com from@source.example.com com.example.MyMessageType {"value", "my-payload-value"} Bidirectional queries consist of a "query" packet and a corresponding "response" packet. The query and response are correlated with a correlation-id, which is a 64-bit integer. A service MUST response to a "query" with either a "response" or a "query_error" because the client will be waiting for the response. A query looks as follows: query to@target.example.com from@source.example.com com.example.MyQueryType 12345 {"value", "my-payload-value"} The corresponding response looks as follows: response from@source.example.com to@target.example.com com.example.MyResponseType 12345 {"value", "my-payload-value"} Ferguson Expires October 8, 2011 [Page 5] Internet-Draft The JSON Message Protocol April 2011 4. General Requirements 4.1. Requirements 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]. An implementation is not compliant if it fails to satisfy one or more of the MUST or REQUIRED level requirements for the protocols it implements. An implementation that satisfies all the MUST or REQUIRED level and all the SHOULD level requirements for its protocols is said to be "unconditionally compliant"; one that satisfies all the MUST level requirements but not all the SHOULD level requirements for its protocols is said to be "conditionally compliant." 4.2. Syntax Notation This specification uses the Augmented Backus-Naur Form (ABNF) notation of [RFC5234]. The following core rules are included by reference, as defined in [RFC5234], Appendix B.1: ALPHA (letters), CR (carriage return), CRLF (CR LF), DIGIT (decimal 0-9), OCTET (any 8-bit sequence of data), SP (space), VCHAR (any visible [USASCII] character), and WSP (whitespace). 4.3. Terminology This specification the following JSMP address: An address of a JSMP actor/service. payload: A JSON value. type: A string representing a message type. Ferguson Expires October 8, 2011 [Page 6] Internet-Draft The JSON Message Protocol April 2011 4.4. Basic Rules The following basic rules follow the definitions in HTTP [RFC2616]. token = 1*tchar tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA ; any VCHAR, except special type_name = 1* ( ALPHA / DIGIT / "_" / "." ) correlation_id = 1* DIGIT payload = JSON error_payload = JSON The following is the format of a JSMP address. address = [user '@'] domain [ '/' resource ] Ferguson Expires October 8, 2011 [Page 7] Internet-Draft The JSON Message Protocol April 2011 5. Packets The following 5 packets are the only packets allowed for JSMP: message, message_error, query, response, query_error. The stream consists of a sequence of packets. stream = *( packet ) packet = message / message-error / query / response / query-error 5.1. message message is a unidirectional message. message grammar message ::= "message" LF address LF address LF type LF payload LF A unidirectional message looks as follows: message to@target.example.com from@source.example.com com.example.MyMessageType {"value", "my-payload-value"} 5.2. message-error message is an error response to a message. message error grammar message_error ::= "message_error" LF address LF address LF type LF payload LF error_payload LF Ferguson Expires October 8, 2011 [Page 8] Internet-Draft The JSON Message Protocol April 2011 A unidirectional message looks as follows: message_error from@source.example.com to@target.example.com com.example.MyMessageType {"value", "my-payload-value"} {"code", "zomg"} 5.3. query query is a bidirectional request for a response. A receiver MUST response with either a "response" or a "queryError" query grammar query ::= "query" LF address LF address LF type LF correlation_id LF payload LF Example: A query looks as follows: query to@target.example.com from@source.example.com com.example.MyQueryType 12345 {"value", "my-payload-value"} 5.4. response "response" is a bidirectional response to a query. response grammar response ::= "response" LF address LF address LF type LF correlation_id LF payload LF Ferguson Expires October 8, 2011 [Page 9] Internet-Draft The JSON Message Protocol April 2011 Example: A response looks as follows: response to@target.example.com from@source.example.com com.example.MyQueryType 12345 {"value", "my-payload-value"} 5.5. query-error query-error is an error response to a message. query-error grammar query_error ::= "query_error" LF address LF address LF type LF correlation_id LF payload LF error_payload LF A unidirectional message looks as follows: messageError from@source.example.com to@target.example.com com.example.MyMessageType {"value", "my-payload-value"} {"code", "zomg"} Ferguson Expires October 8, 2011 [Page 10] Internet-Draft The JSON Message Protocol April 2011 6. Security Considerations This section is meant to inform application developers and users of security issues related to JSMP. This list is unlikely to be complete. Ferguson Expires October 8, 2011 [Page 11] Internet-Draft The JSON Message Protocol April 2011 7. Normative References [RFC2616] Fielding, R., Gettys, J., Mogul, J., Mainter, L., Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, November 2003. [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, January 2008. Ferguson Expires October 8, 2011 [Page 12] Internet-Draft The JSON Message Protocol April 2011 Author's Address Scott Ferguson Caucho Technology Ferguson Expires October 8, 2011 [Page 13] Internet-Draft The JSON Message Protocol April 2011 Full Copyright Statement Copyright (C) The IETF Trust (2011). 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