simple-jsonrpc-js

Client and server.
Support websocket and http.
Full support for JSON-RPC 2.0 (including auto-incrementing request IDs)

Originally created by jershell / QuickResto. (original Github repo)

Some updates written by Privex Inc. (Privex's simple-jsonrpc fork repo)

Browser Quickstart

For usage in browsers, you can quickly add it to your web application from Privex's CDN - which hosts both the latest Git version (master) of the library, along with official tagged release versions for safe production use.

<script src="https://cdn.privex.io/lib/simple-jsonrpc/master/simple-jsonrpc-js.min.js"></script>

<script>
    // Create a Simple-JsonRPC object which can call HTTP JSON-RPC queries against the remote server https://rpc.example.com
    var jrpc = simple_jsonrpc.connect_xhr('https://rpc.example.com');

    // Equivelent to: {"jsonrpc":"2.0","method":"get_account","id":1,"params":["johndoe"]}
    jrpc.call('get_account', ['johndoe']).then(function(res) {
        console.log("User ID:", res.id);
        console.log("User Email:", res.email);
        console.log("User Name:", res.full_name);
    });
    // Equivelent to: {"jsonrpc":"2.0","method":"find_posts","id":2,"params":{"tag":"python","author":"jane.doe"}}
    jrpc.call('find_posts', {tag: 'python', author: 'jane.doe'}).then(function(posts) {
        for (var p of posts) {
            console.log("Post title:", p.title)
            console.log("Post tags:", p.tags)
            console.log("Post content:", p.content)
        }
    });
    // Equivelent to: {"jsonrpc":"2.0","method":"status","id":3}
    jrpc.call('status').then(function(status) {
        console.log(status);
    });

</script>

For safe production usage, you should use a versioned release of the library, with asset integrity attributes like so:

<script src="https://cdn.privex.io/lib/simple-jsonrpc/1.0.0/simple-jsonrpc-js.min.js" 
        integrity="sha384-AlmC3wzXXhOcKeP42iv0VOyrxth6bLTmu4l4YgK9oii9MArKWpLFBfrFN91OxnEO" 
        crossorigin="anonymous">
</script>

Privex's CDN regularly publishes integrity hashes for the JS and CSS files they host, along with script/link tags with the integrity attributes pre-configured for easy copy pasting: https://cdn.privex.io/integrity.txt (CTRL-F for simple-jsonrpc)

Installing

You can install this package either with

Bower - for HTML web clients

bower install simple-jsonrpc-js

NPM or Yarn - for NodeJS applications

# Installing simple-jsonrpc-js with Yarn (https://yarnpkg.com/)
yarn install simple-jsonrpc-js
# If you don't have / don't want to use Yarn, you can install using NPM normally
npm install simple-jsonrpc-js

Building production JS

# Install the 'gulp' tool globally
npm install -g gulp-cli

git clone https://github.com/jershell/simple-jsonrpc-js.git
cd simple-jsonrpc-js
# Install NodeJS dependencies
yarn install   # or npm install
# Compile simple-jsonrpc-js.js into dist/simple-jsonrpc-js.min.js
yarn build     # or npm build   ||  or just 'gulp compress'

Usage

(over WebSocket) on server:

function add(x, y){
    return x + y;
}

//over ws
var WebSocketServer = new require('ws');
var JsonRPC = require('simple-jsonrpc-js');

var webSocketServer = new WebSocketServer.Server({
    host: '0.0.0.0',
    port: 8090
}).on('connection', function(ws) {
    var jrpc = new JsonRPC();
    ws.jrpc = jrpc;

    ws.jrpc.toStream = function(message){
        ws.send(message);
    };

    ws.on('message', function(message) {
        jrpc.messageHandler(message);
    });

    jrpc.on('add', ['x', 'y'], add);

    jrpc.on('mul', ['x', 'y'], function(x, y){
        return x*y;
    });

    var item_id = 120;

    jrpc.on('create', ['item', 'rewrite'], function(item, rewrite){
        item_id ++;
        item.id = item_id;
        return item;
    });

    jrpc.call('view.setTitle', ["JSONRPC over ws"]);

});

And on client:

        //configure
        var jrpc = new simple_jsonrpc();
        var socket = new WebSocket("ws://localhost:8090");

        //wait of call
        jrpc.on('view.setTitle', function(title){
            document.getElementsByClassName('title')[0].innerHTML = title;
        });

        socket.onmessage = function(event) {
            jrpc.messageHandler(event.data);
        };

        jrpc.toStream = function(_msg){
            socket.send(_msg);
        };

        socket.onerror = function(error) {
            console.error("Error: " + error.message);
        };

        socket.onclose = function(event) {
            if (event.wasClean) {
                console.info('Connection close was clean');
            } else {
                console.error('Connection suddenly close');
            }
            console.info('close code : ' + event.code + ' reason: ' + event.reason);
        };

        //usage
        //after connect
        socket.onopen = function(){

            //calls
            jrpc.call('add', [2, 3]).then(function (result) {
                document.getElementsByClassName('paragraph')[0].innerHTML += 'add(2, 3) result: ' + result + '<br>';
            });

            jrpc.call('mul', {y: 3, x: 2}).then(function (result) {
                document.getElementsByClassName('paragraph')[0].innerHTML += 'mul(2, 3) result: ' + result + '<br>';
            });

            jrpc.batch([
                {call:{method: "add", params: [5,2]}},
                {call:{method: "mul", params: [100, 200]}},
                {call:{method: "create", params: {item: {foo: "bar"}, rewrite: true}}}
            ]);
        };

More examples in directory

API

call(methodName, params) - Remote method invocation. Returned promise object.

notification(methodName, params) - Remote method invocation without response object

batch(calls) - batch invocation. Returned promise object.

on(methodName, paramsName, handler) - Registration local method for incommig invocation

off(methodName) - disable method for incommig invocation

customException(code, message, data) - return exception with implementation-defined server-errors

configuration:

messageHandler(rawMessage) - All incoming messages must be passed as a parameter. Returned promise object.

toStream - The property, a function pointer. It is necessary to determine before use. Will be called for send a message to the remote host

undefinedResult - allow to set default result of locally called function if it returns undefined

usage example:

    jrpc.undefinedResult = null; // or false, or whatever
    jrpc.on('find', function(key) {
        if (db.exists(key))
	    return db.get(key);
	// If there is nothing found then just return nothing
    });

Dependecies

NodeJS <= 8.11.4 (if using within a NodeJS app, or compiling) || Latest browser (if using client side)
(Optional) promise-polyfill for OLD versions of NodeJS and certain older browsers

Specification

http://www.jsonrpc.org/specification

Notification for non-existent method will elicit response which is non-standard

According to JSON RPC 2.0 Section 4.1

Notifications are not confirmable by definition, since they do not have a Response object to be returned. As such, the Client would not be aware of any errors (like e.g. "Invalid params","Internal error").

Sample communication:

{"jsonrpc":"2.0","method":"SetWindowLocked","params":[false]}
{"jsonrpc":"2.0","error":{"code":-32601,"message":"Method not found. The method does not exist / is not available.","data":"SetWindowLocked"}}
{"jsonrpc":"2.0","method":"SetClickthrough","params":[false]}
{"jsonrpc":"2.0","error":{"code":-32601,"message":"Method not found. The method does not exist / is not available.","data":"SetClickthrough"}}
{"jsonrpc":"2.0","method":"SetVisible","params":[false]}
{"jsonrpc":"2.0","error":{"code":-32601,"message":"Method not found. The method does not exist / is not available.","data":"SetVisible"}}

Proposed solution:
In handleRemoteRequest method, change else block into

            else if (request.hasOwnProperty('id')) {
                return _Promise.resolve({
                    "jsonrpc": "2.0",
                    "id": request.id,
                    "error": setError(ERRORS.METHOD_NOT_FOUND, {
                        message: request.method
                    })
                });
            }
            else {
                // Don't return method not found for notifications
                console.warn("Received notification for non-existent method:", request.method);
                return _Promise.resolve();
            }

jershell / simple-jsonrpc-js Goto Github PK