JSON-RPC node.js implementation

JSON-RPC official spec.

Extremely fast and simple Node.js JSON-RPCv2 router middleware.
Handle incoming request and apply to controller functions.
Validation available.

Note As Router require body-parser which must be used before router.

Installation

``sh
$ npm install express express-json-rpc-router
`
or

`sh
$ yarn add express express-json-rpc-router
`

Examples

$3

`js
const express = require('express')
const jsonRouter = require('express-json-rpc-router')
const app = express()

const controller = {
testMethod({ username }) {
console.log('username: ', username)
return ['example data 1', 'example data 2']
}
}

app.use(express.json())
app.use(jsonRouter({ methods: controller }))
app.listen(3000, () => console.log('Example app listening on port 3000'))
`

and
`bash
curl -X POST \
http://localhost:3000 \
-H 'Content-Type: application/json' \
-d '{
"jsonrpc": "2.0",
"method": "testMethod",
"params": {
"username": "valeron"
},
"id": 1
}'
`
will return:
`json
{
"jsonrpc": "2.0",
"result": [
"example data 1",
"example data 2"
],
"id": 1
}
`

$3

`js
const controller = {
// You have access to raw express req/res object as raw.res and raw.req
testMethod({ username }, raw) {
console.log('username: ', username)
return ['example data 1', 'example data 2']
}
}

const beforeController = {
// You have access to raw express req/res object as raw.res and raw.req
testMethod(params, _, raw) {
if (Math.random() >= 0.5) { // Random error
const error = new Error('Something going wrong')
error.data = { hello: 'world' } // its optional
throw error
}
}
}

const afterController = {
testMethod: [
// You have access to result and to raw express req/res object as raw.res and raw.req.
(params, result, raw) => console.log('testMethod executed 1!'), () => console.log('testMethod executed 2!')
]
}

app.use(bodyParser.json())
app.use(jsonRouter({
methods: controller,
beforeMethods: beforeController,
afterMethods: afterController,
onError(err) {
console.log(err) // send report
}
}))
app.listen(3000, () => console.log('Example app listening on port 3000'))
`

and
`bash
curl -X POST \
http://localhost:3000 \
-H 'Content-Type: application/json' \
-d '{
"jsonrpc": "2.0",
"method": "testMethod",
"params": {
"username": "valeron"
},
"id": 1
}'
`
will return:
`json
{
"jsonrpc": "2.0",
"error": {
"code": -32603,
"message": "Something going wrong",
"data": { "hello": "world" }
},
"id": 1
}
`

$3


- v1.2.0
* Added raw { req, res } native express object to controller and hooks as last argument.
* Passed next arguments: params, null, raw to beforeController actions and params, result, raw to afterController
* Passed additional second argument params, raw to controller actions
- v1.3.0
* Added optional err.data payload to comply with JSON RPC specification: "5.1 Error object".
#### Options

The express-json-rpc-router function takes an optional options object that may contain any of the following keys:

##### methods type: Object
You can pass the object of your methods that will be called when a match is made via JSON-RPC method field.

##### beforeMethods type: Object>
You can provide function or array of functions, which will be called before main method with same name are called.
This is the best place for validation.
beforeMethods names should be the same as methods names.
Request params will be passed as first argument.

##### afterMethods type: Object>
You can provide function or array of functions, which will be called after main method with same name are called.
This is the best place to write logs.
afterMethods names should be the same as methods names.
Method execution result will be passed as second argument.
Request params will be passed as first argument.

##### onError type: function(err, params)`
callback(err, params) {}
Optionally you can pass onError callback which will be called when json-rpc middleware error occurred.

License

MIT