koa-json-rpc2

Yet another JSON-RPC2 middleware implementation for koa-js.

Installation

npm install koa-json-rpc2

Usage

var koa = require('koa');
var app = koa();

var koaJsonRpc2 = require('koa-json-rpc2');

// Create rpc router instance
// Option 'limit' to set maximum post size
// Limit is 1mb by default
var jrpc2 = koaJsonRpc2({ limit: '20mb' });

// Register new rpc function
jrpc2.use('user', function* user() {
  return 'root'
});

// Register new rpc function
jrpc2.use('sum', function* sum(params) {
  return params.reduce(
    function (prev, curr) {
      return prev + curr;
    },
    0);
});

// Add context information that's useful throughout the lifetime of application 
app.context.some_string = 'context string';

jrpc2.use('ctx', function* ctx() {
  // Get access to context information inside rpc method
  return this.app.context.some_string;
});


// Exception handling

jrpc2.use('internal', function* internal() {
  // Return JSON-RPC2 Internal Error response as result of exception inside RPC method
  throw new Error();
});

jrpc2.use('checkParams', function* checkParams(params) {
  if (params && Object.prototype.hasOwnProperty.call(params, 'foo')) {
    return params.foo;
  }
  // Return JSON-RPC2 Invalid Parameters Error response 
  // as result of InvalidParamsError exception inside RPC method
  throw new koaJsonRpc2.InvalidParamsError('Param foo omitted');
});

// Register rpc router as koa middleware
app.use(jrpc2.app());

app.listen(3000);

Debug

Set variable DEBUG to koa-json-rpc2 to enable debug output. For instance:

DEBUG=koa-json-rpc2 npm server.js

History

HISTORY.md

Authors

Dmytro Ryzhykov dark81@gmail.com

License

The MIT License