kronos-interceptor

introspects / modifies requests as they pass between endpoints

const ki = require('kronos-interceptor');

const endpoint = { get name() { return 'aName'; }, receive() {}};
const interceptor1 = new ki.Interceptor({},endpoint);
const interceptor2 = new ki.Interceptor({},endpoint);

interceptor1.connected = interceptor2

const request = {};
const promise = interceptor1.receive(request);

API

Table of Contents

• rejectingReceiver
  • Parameters
• ConnectorMixin
  • Parameters
• Interceptor
  • Parameters
  • logger
  • type
  • configurationAttributes
  • configure
    • Parameters
  • toJSON
  • reset
  • receive
    • Parameters
  • configurationAttributes
• TimeoutInterceptor
  • name
• rejectUnlessResolvedWithin
  • Parameters
• StatsCollectorInterceptor
  • receive
    • Parameters
  • name
• LimitingInterceptor
  • Parameters
  • name

rejectingReceiver

rejecting receiver used to signal a not present connection when used always delivers a rejecting promise

Parameters

• request

Returns Promise<Error>

ConnectorMixin

Mixin to make endpoints/interceptors connectable Forms a single linked list

Parameters

• superclass

Interceptor

Extends ConnectorMixin(class {})

Base interceptor. The base class for all the interceptors Calls configure() and reset().

Parameters

• config Object The interceptor configuration object.
• endpoint Object the endpoint object this interceptor will be attached to.

logger

use endpoint owner as logger

type

The instance method returning the type. Defaults to the constructors name (class name)

Returns string

configurationAttributes

Meta description of the configuration

Returns Object

configure

Takes attribute values from config parameters and copies them over to the object. Copying is done according to configurationAttributes Which means we loop over all configuration attributes and then for each attribute decide if we use the default, call a setter function or simply assign the attribute value

Parameters

• config Object

toJSON

Deliver the json representation

Returns Object json representation

reset

forget all accumulated information

receive

The receive method. This method receives the request from the leading interceptor and calls the trailing interceptor

Parameters

• request Object the request from the leading interceptor
• oldRequest Object the oldRequest from the leading interceptor. This is a special case. As some interceptors are in charge of copying and creating the request objects, the step will call the interceptor chain with the both requests. At some point of the interceptor chain only the request itself will survive. But all interceptors designed to be inserted early in the interceptor chain of a sending endpoint should pass both requests to the next interceptor.

Returns Promise

configurationAttributes

Meta description of the configuration

Returns Object

TimeoutInterceptor

Extends Interceptor

Rejects a request if it does not resolve in a given time

name

Returns string 'timeout'

rejectUnlessResolvedWithin

Parameters

• promise Promise
• timeout number in miliseconds
• name string

Returns Promise

StatsCollectorInterceptor

Extends Interceptor

Interceptor to collect processing time, number of processed and failed requests

receive

Logs the time the requests takes

Parameters

• request
• oldRequest

name

Returns string 'collect-request-stats'

LimitingInterceptor

Extends Interceptor

Limits the number of concurrent requests. Requests can be delayed or rejected. Sample config: [ { count: 20 }, { count: 10, delay: 100 }, { count: 5, delay: 10 } ] 1 - 4 : no delay 5 - 9 : 10ms delay 10 - 19 : 100ms delay 20 : reject default is to reject when more than 10 requests are on the way

Parameters

• config
• endpoint

name

Returns string 'request-limit'

install

With npm do:

npm install kronos-interceptor

license

BSD-2-Clause