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RPC handler

Purpose

A JSON-RPC messages handler, supporting a stateful context and inputs validation.

Installation

npm install @erebos/rpc-handler

Usage

import { createHandler } from '@erebos/rpc-handler'

const handle = createHandler({
  methods: {
    hello: {
      params: {
        name: 'string'
      },
      handler(ctx, params) => `hello ${params.name}`,
    },
    ping: () => 'pong',
  },
})

const context = {}

const incomingMessage = {
  jsonrpc: '2.0',
  id: 'test',
  method: 'hello',
  params: {
    name: 'bob',
  },
}

const outgoingMessage = await handle(context, incomingMessage)
// outgoingMessage = {jsonrpc: '2.0', id: 'test', result: 'hello bob'}

Interfaces and types

RPCRequest

Imported from @erebos/rpc-base

RPCResponse

Imported from @erebos/rpc-base

ErrorHandler

type ErrorHandler = <C = any, P = any>(
  ctx: C,
  msg: RPCRequest<P>,
  error: Error,
) => void

MethodHandler

type MethodHandler = <C = any, P = any, R = any>(
  ctx: C,
  params: P,
) => R | Promise<R>

NotificationHandler

type NotificationHandler = <C = any, P = any>(
  ctx: C,
  msg: RPCRequest<P>,
) => void

MethodWithParams

interface MethodWithParams {
  params?: Record<string, any> | undefined
  handler: MethodHandler
}

Methods

type Methods = Record<string, MethodHandler | MethodWithParams>

HandlerParams

interface HandlerParams {
  methods: Methods
  onHandlerError?: ErrorHandler | undefined
  onInvalidMessage?: NotificationHandler | undefined
  onNotification?: NotificationHandler | undefined
  validatorOptions?: any | undefined
}

HandlerFunc

type HandlerFunc = <C = any, P = any, R = any, E = any>(
  ctx: C,
  req: RPCRequest<P>,
) => Promise<RPCResponse<R, E>>

API

createHandler()

Arguments

1. params: HandlerParams

Returns HandlerFunc

parseJSON()

Tries to parse a JSON string, or throws a RPCError with code -32700 (parse error)

Arguments

1. input: string

Returns T = any