kronos-interceptor

introspects / modifies requests as they pass between endpoints

``javascript
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

$3

- 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

$3

- request

Returns Promise<Error>

ConnectorMixin

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

$3

- superclass

Interceptor

Extends ConnectorMixin(class {})

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

$3

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

$3

use endpoint owner as logger

$3

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

Returns string

$3

Meta description of the configuration

Returns Object

$3

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

$3

Deliver the json representation

Returns Object json representation

$3

forget all accumulated information

$3

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

$3

Meta description of the configuration

Returns Object

TimeoutInterceptor

Extends Interceptor

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

$3

Returns string 'timeout'

rejectUnlessResolvedWithin

$3

- promise Promise
- timeout number in miliseconds
- name string

Returns Promise

StatsCollectorInterceptor

Extends Interceptor

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

$3

Logs the time the requests takes

#### Parameters

- request
- oldRequest

$3

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

$3

- config
- endpoint

$3

Returns string 'request-limit'

install

With npm do:

`shell
npm install kronos-interceptor
``

license

BSD-2-Clause