svc-facs-tcp

This facility implements a promise based tcp client and a simple tcp rpc client with support of different encodings.

Config

This facility does not support config file and doesn't have any additional option beside default ones required by base facility.

API

fac.getClient

Initiates a tcp client instance for specific server.

Params:

• host<string> - server host
• port<int> - server port
• encoding<string?> - optional, encoding, e.g. utf-8

Result:

• TcpClient

Example:

const tcp = fac.getClient({
  host: '127.0.0.1',
  port: 7070,
  encoding: 'utf-8'
})

fac.getRPC

Initiates a RPC client instance for specific server.

Params:

• tcp<TcpClient?> - tcp client instance, use either tcp or tcpOpts
• tcpOpts<object> - new tcp client config
  • host<string> - server host
  • port<int> - server port
  • encoding<string?> - optional, encoding, e.g. utf-8
• readStrategy<string?> - optional, response read strategy, default: TcpFacility.TCP_READ_STRATEGY.ON_DATA
• json<boolean?> - optional, flag specifying that rpc requests/responses should be using json serialization, default: false
• timeout<int?> - optional, rpc response timeout, default: 500ms
• delay<int?>- optional, delay between two rpc requests, default: 50ms, useful when server closes connection on response

Result:

• TcpRpcClient

Example:

const rpc1 = fac.getRPC({
  tcpOpts: {
    host: '127.0.0.1',
    port: 7070,
    encoding: 'utf-8'
  },
  readStrategy: TcpFacility.TCP_READ_STRATEGY.ON_DATA,
  json: true,
  timeout: 3000,
  delay: 50
})

// or with existing tcp client

const tcp2 = fac.getClient({
  host: '127.0.0.1',
  port: 7080,
  encoding: 'utf-8'
})
const rpc2 = fac.getRPC({
  tcp: tcp2,
  readStrategy: TcpFacility.TCP_READ_STRATEGY.ON_DATA,
  json: true,
  timeout: 3000,
  delay: 50
})

rpc.request

Performs a TCP request and waits for response.

Params:

• payload<string|JSON|Buffer> - request payload

Result:

• Promise<string|JSON|Buffer> - response from server

Example:

const rcp = fac.getRPC({ ... })
const res = await rpc.request({ ping: 1 })
console.log(res) // { pong: 2 }

tcp.write

Sends data to tcp server

Params:

• data<string|Buffer> - data that will be sent to server

Reponse:

• Promise<void>

Example:

const tcp = fac.getClient({ ... })
await tcp.write('{"ping":1}')

tcp.read

Waits and returns the data from the server

Params:

• opts<Object>
  • strategy<int> - read strategy, 1 (TcpFacility.TCP_READ_STRATEGY.ON_DATA) - on('data') event, 2 (TcpFacility.TCP_READ_STRATEGY.ON_END) - on('end') event
  • timeout<int> - response timeout

Result:

• Promise<string|Buffer>

Example:

const tcp = fac.getClient({ ... })
const res = await tcp.read({ strategy: TcpFacility.TCP_READ_STRATEGY.ON_DATA })
console.log(res) // '{"pong":2}'