--- /dev/null
+---
+edit_link: ''
+title: WebSocket protocol x-afb-ws-json1
+origin_url: >-
+ https://git.automotivelinux.org/src/app-framework-binder/plain/docs/protocol-x-afb-ws-json1.md?h=master
+---
+
+<!-- WARNING: This file is generated by fetch_docs.js using /home/boron/Documents/AGL/docs-webtemplate/site/_data/tocs/apis_services/master/app-framework-binder-developer-guides-api-services-book.yml -->
+
+# The websocket protocol x-afb-ws-json1
+
+The WebSocket protocol *x-afb-ws-json1* is used to communicate between
+an application and a binder. It allows access to all registered apis
+of the binder.
+
+This protocol is inspired from the protocol **OCPP - SRPC** as described for
+example here:
+[OCPP transport specification - SRPC over WebSocket](http://www.gir.fr/ocppjs/ocpp_srpc_spec.shtml).
+
+The registration to the IANA is still to be done, see:
+[WebSocket Protocol Registries](https://www.iana.org/assignments/websocket/websocket.xml)
+
+This document gives a short description of the protocol *x-afb-ws-json1*.
+A more formal description has to be done.
+
+## Architecture
+
+The protocol is intended to be symmetric. It allows:
+
+- to CALL a remote procedure that returns a result
+- to push and receive EVENT
+
+## Messages
+
+Valid messages are made of *text* frames that are all valid JSON.
+
+Valid messages are:
+
+Calls:
+
+```txt
+[ 2, ID, PROCN, ARGS ]
+[ 2, ID, PROCN, ARGS, TOKEN ]
+```
+
+Replies (3: OK, 4: ERROR):
+
+```txt
+[ 3, ID, RESP ]
+[ 4, ID, RESP ]
+```
+
+Events:
+
+```txt
+[ 5, EVTN, OBJ ]
+```
+
+Where:
+
+| Field | Type | Description
+|-------|--------|------------------
+| ID | string | A string that identifies the call. A reply to that call use the ID of the CALL.
+| PROCN | string | The procedure name to call of the form "api/verb"
+| ARGS | any | Any argument to pass to the call (see afb_req_json that returns it)
+| RESP | any | The response to the call
+| TOKEN | string | The authorisation token
+| EVTN | string | Name of the event in the form "api/event"
+| OBJ | any | The companion object of the event
+
+Below, an example of exchange:
+
+```txt
+C->S: [2,"156","hello/ping",null]
+S->C: [3,"156",{"response":"Some String","jtype":"afb-reply","request":{"status":"success","info":"Ping Binder Daemon tag=pingSample count=1 query=\"null\"","uuid":"ec30120c-6997-4529-9d63-c0de0cce56c0"}}]
+```
+
+## History
+
+### 14 November 2019
+
+Removal of token returning. The replies
+
+```txt
+[ 3, ID, RESP, TOKEN ]
+[ 4, ID, RESP, TOKEN ]
+```
+
+are removed from the specification.
+
+## Future
+
+Here are the planned extensions:
+
+- add binary messages with cbor data
+- add calls with unstructured replies
+
+This could be implemented by extending the current protocol or by
+allowing the binder to accept either protocol including the new ones.
+
+## Javascript implementation
+
+The file **AFB.js** is a javascript implementation of the protocol.
+
+Here is that code:
+
+```javascript
+/*
+ * Copyright (C) 2017-2019 "IoT.bzh"
+ * Author: José Bollo <jose.bollo@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+AFB = function(base, initialtoken){
+
+if (typeof base != "object")
+ base = { base: base, token: initialtoken };
+
+var initial = {
+ base: base.base || "api",
+ token: base.token || initialtoken || "HELLO",
+ host: base.host || window.location.host,
+ url: base.url || undefined
+};
+
+var urlws = initial.url || "ws://"+initial.host+"/"+initial.base;
+
+/*********************************************/
+/**** ****/
+/**** AFB_context ****/
+/**** ****/
+/*********************************************/
+var AFB_context;
+{
+ var UUID = undefined;
+ var TOKEN = initial.token;
+
+ var context = function(token, uuid) {
+ this.token = token;
+ this.uuid = uuid;
+ }
+
+ context.prototype = {
+ get token() {return TOKEN;},
+ set token(tok) {if(tok) TOKEN=tok;},
+ get uuid() {return UUID;},
+ set uuid(id) {if(id) UUID=id;}
+ };
+
+ AFB_context = new context();
+}
+/*********************************************/
+/**** ****/
+/**** AFB_websocket ****/
+/**** ****/
+/*********************************************/
+var AFB_websocket;
+{
+ var CALL = 2;
+ var RETOK = 3;
+ var RETERR = 4;
+ var EVENT = 5;
+
+ var PROTO1 = "x-afb-ws-json1";
+
+ AFB_websocket = function(on_open, on_abort) {
+ var u = urlws;
+ if (AFB_context.token) {
+ u = u + '?x-afb-token=' + AFB_context.token;
+ if (AFB_context.uuid)
+ u = u + '&x-afb-uuid=' + AFB_context.uuid;
+ }
+ this.ws = new WebSocket(u, [ PROTO1 ]);
+ this.url = u;
+ this.pendings = {};
+ this.awaitens = {};
+ this.counter = 0;
+ this.ws.onopen = onopen.bind(this);
+ this.ws.onerror = onerror.bind(this);
+ this.ws.onclose = onclose.bind(this);
+ this.ws.onmessage = onmessage.bind(this);
+ this.onopen = on_open;
+ this.onabort = on_abort;
+ }
+
+ function onerror(event) {
+ var f = this.onabort;
+ if (f) {
+ delete this.onopen;
+ delete this.onabort;
+ f && f(this);
+ }
+ this.onerror && this.onerror(this);
+ }
+
+ function onopen(event) {
+ var f = this.onopen;
+ delete this.onopen;
+ delete this.onabort;
+ f && f(this);
+ }
+
+ function onclose(event) {
+ for (var id in this.pendings) {
+ try { this.pendings[id][1](); } catch (x) {/*TODO?*/}
+ }
+ this.pendings = {};
+ this.onclose && this.onclose();
+ }
+
+ function fire(awaitens, name, data) {
+ var a = awaitens[name];
+ if (a)
+ a.forEach(function(handler){handler(data);});
+ var i = name.indexOf("/");
+ if (i >= 0) {
+ a = awaitens[name.substring(0,i)];
+ if (a)
+ a.forEach(function(handler){handler(data);});
+ }
+ a = awaitens["*"];
+ if (a)
+ a.forEach(function(handler){handler(data);});
+ }
+
+ function reply(pendings, id, ans, offset) {
+ if (id in pendings) {
+ var p = pendings[id];
+ delete pendings[id];
+ try { p[offset](ans); } catch (x) {/*TODO?*/}
+ }
+ }
+
+ function onmessage(event) {
+ var obj = JSON.parse(event.data);
+ var code = obj[0];
+ var id = obj[1];
+ var ans = obj[2];
+ AFB_context.token = obj[3];
+ switch (code) {
+ case RETOK:
+ reply(this.pendings, id, ans, 0);
+ break;
+ case RETERR:
+ reply(this.pendings, id, ans, 1);
+ break;
+ case EVENT:
+ default:
+ fire(this.awaitens, id, ans);
+ break;
+ }
+ }
+
+ function close() {
+ this.ws.close();
+ this.ws.onopen =
+ this.ws.onerror =
+ this.ws.onclose =
+ this.ws.onmessage =
+ this.onopen =
+ this.onabort = function(){};
+ }
+
+ function call(method, request, callid) {
+ return new Promise((function(resolve, reject){
+ var id, arr;
+ if (callid) {
+ id = String(callid);
+ if (id in this.pendings)
+ throw new Error("pending callid("+id+") exists");
+ } else {
+ do {
+ id = String(this.counter = 4095 & (this.counter + 1));
+ } while (id in this.pendings);
+ }
+ this.pendings[id] = [ resolve, reject ];
+ arr = [CALL, id, method, request ];
+ if (AFB_context.token) arr.push(AFB_context.token);
+ this.ws.send(JSON.stringify(arr));
+ }).bind(this));
+ }
+
+ function onevent(name, handler) {
+ var id = name;
+ var list = this.awaitens[id] || (this.awaitens[id] = []);
+ list.push(handler);
+ }
+
+ AFB_websocket.prototype = {
+ close: close,
+ call: call,
+ onevent: onevent
+ };
+}
+/*********************************************/
+/**** ****/
+/**** ****/
+/**** ****/
+/*********************************************/
+return {
+ context: AFB_context,
+ ws: AFB_websocket
+};
+};
+```
Code Review / AGL / documentation.git / blobdiff