fetch-rate-limit-util

Handle fetch errors and rate limits and caching.

Waits and retry after rate limit rest time has reached.

• auth0 API
• github API
• Zalando API
• Retry-After

import { stateActionHandler } from "fetch-rate-limit-util";

const response = await stateActionHandler(someURL, options);

// if rate limit occurs waits and retires

API

Table of Contents

• HandlerResult
  • Properties
• RequestReporter
  • Properties
• wait
  • Parameters
• stateActionHandler
  • Parameters
• calculateRepeatAfter
  • Parameters
• rateLimitHandler
  • Parameters
• retryTimes
• retryHandler
  • Parameters
• defaultHandler
  • Parameters
• errorHandler
  • Parameters
• cacheHandler
  • Parameters
• DEFAULT_MIN_WAIT_MSECS
• DEFAULT_MAX_RETRIES

HandlerResult

Type: Object

Properties

• url URL? what to fetch next
• repeatAfter number? of milliseconds to wait befor next try
• message string to report
• done boolean op is finished return
• response Response
• postprocess boolean exec postprocess

RequestReporter

Function to provide progress report.

Type: Function

Properties

• url String to be requested
• method String http method name
• status (String | Error) result of the last request
• nthTry number how often have we retried

wait

Parameters

• url (URL | string)
• options Object
• result Object

stateActionHandler

Executes fetch operation and handles response.

Parameters

• url (string | URL)

• options Object

  • options.reporter RequestReporter
  • options.cache Object?
  • options.maxRetries number?
  • options.method string?
  • options.headers Object?
  • options.body string?
  • options.postprocess Function
  • options.stateActions Object

Returns Promise<Response> from fetch

calculateRepeatAfter

Parameters

• response any

Returns (number | undefined) msecs to wait

rateLimitHandler

• See: https://auth0.com/docs/policies/rate-limit-policy
• See: https://developer.github.com/v3/#rate-limiting
• See: https://opensource.zalando.com/restful-api-guidelines/#153

Waits and retries after rate limit reset time has reached.

Parameters

• response Response from fetch
• options Object
• nthTry number

Returns HandlerResult

retryTimes

Retry timeouts with increasing delay for each retry. Values in msecs.

retryHandler

Try several times with a increasing delay.

Parameters

• response Response from fetch
• options Object
• nthTry number

Returns HandlerResult

defaultHandler

Postprocessing if response is ok.

Parameters

• response Response from fetch
• options Object
• nthTry number

Returns HandlerResult

errorHandler

No postprocessing.

Parameters

• response Response from fetch
• options Object
• nthTry number

Returns HandlerResult

cacheHandler

Provide cached data.

Parameters

• response Response from fetch
• options Object
• nthTry number

Returns Promise<HandlerResult>

DEFAULT_MIN_WAIT_MSECS

Minimum wait time in msecs.

Type: number

DEFAULT_MAX_RETRIES

Max # of retries.

Type: number

install

With npm do:

npm install fetch-rate-limit-util

license

BSD-2-Clause