requestretry

What is requestretry?

The requestretry npm package is a wrapper around the popular request library that adds automatic retry functionality for failed HTTP requests. It allows you to specify retry strategies, including the number of retries, delay between retries, and conditions under which to retry.

What are requestretry's main functionalities?

Basic HTTP Request with Retry

This feature allows you to make an HTTP GET request with automatic retries. You can specify the maximum number of attempts, the delay between retries, and the retry strategy.

const request = require('requestretry');

request({
  url: 'https://api.example.com/data',
  method: 'GET',
  maxAttempts: 5,   // (default) try 5 times
  retryDelay: 5000, // (default) wait for 5s before trying again
  retryStrategy: request.RetryStrategies.HTTPOrNetworkError // (default) retry on 5xx or network errors
}, function (err, response, body) {
  if (err) {
    console.error('Failed:', err);
  } else {
    console.log('Success:', body);
  }
});

Custom Retry Strategy

This feature allows you to define a custom retry strategy. In this example, the request will be retried if there is an error or if the response status code is 502 (Bad Gateway).

const request = require('requestretry');

function myRetryStrategy(err, response, body) {
  // retry the request if we had an error or if the response was a 'Bad Gateway'
  return err || response.statusCode === 502;
}

request({
  url: 'https://api.example.com/data',
  method: 'GET',
  maxAttempts: 3,
  retryDelay: 3000,
  retryStrategy: myRetryStrategy
}, function (err, response, body) {
  if (err) {
    console.error('Failed:', err);
  } else {
    console.log('Success:', body);
  }
});

POST Request with Retry

This feature demonstrates how to make an HTTP POST request with automatic retries. The request includes a JSON body and will retry up to 4 times with a 2-second delay between attempts.

const request = require('requestretry');

request({
  url: 'https://api.example.com/data',
  method: 'POST',
  json: true,
  body: { key: 'value' },
  maxAttempts: 4,
  retryDelay: 2000,
  retryStrategy: request.RetryStrategies.HTTPOrNetworkError
}, function (err, response, body) {
  if (err) {
    console.error('Failed:', err);
  } else {
    console.log('Success:', body);
  }
});

Other packages similar to requestretry

axios-retry

axios-retry is a plugin for the axios HTTP client that adds retry functionality. It allows you to specify the number of retries, delay between retries, and conditions for retrying. Compared to requestretry, axios-retry is built on top of axios, which is a more modern and widely-used HTTP client than request.

got-retry

got-retry is a plugin for the got HTTP client that adds retry functionality. It provides a flexible retry mechanism with customizable options for retry count, delay, and conditions. got-retry is built on top of got, which is known for its simplicity and performance, making it a good alternative to requestretry.

superagent-retry

superagent-retry is a plugin for the superagent HTTP client that adds retry functionality. It allows you to specify the number of retries and conditions for retrying requests. superagent-retry is useful if you are already using superagent and need retry capabilities similar to those provided by requestretry.

README

Request-retry

When the connection fails with one of ECONNRESET, ENOTFOUND, ESOCKETTIMEDOUT, ETIMEDOUT, ECONNREFUSED, EHOSTUNREACH, EPIPE, EAI_AGAIN or when an HTTP 5xx error occurrs, the request will automatically be re-attempted as these are often recoverable errors and will go away on retry.

Usage

Request-retry is a drop-in replacement for request but adds two new options maxAttempts and retryDelay. It also adds one property to the response, attempts. It supports callbacks or promises.

With callbacks

var request = require('requestretry');

request({
  url: 'https://api.domain.com/v1/a/b'
  json:true,

  // The below parameters are specific to request-retry
  maxAttempts: 5,   // (default) try 5 times
  retryDelay: 5000,  // (default) wait for 5s before trying again
  retryStrategy: request.RetryStrategies.HTTPOrNetworkError // (default) retry on 5xx or network errors
}, function(err, response, body){
  // this callback will only be called when the request succeeded or after maxAttempts or on error
  if (response) {
    console.log('The number of request attempts: ' + response.attempts);
  }
});

With promises

When you're using promises, you can pass the two following options:

• fullResponse (default true) - To resolve the promise with the full response or just the body
• promiseFactory (default whenjs) - A function to allow the usage of a different promise implementation library

request({
  url: 'https://api.domain.com/v1/a/b'
  json:true,

  fullResponse: true // (default) To resolve the promise with the full response or just the body
})
.then(function (response) {
  // response = The full response object or just the body
})
.catch(function(error) {
  // error = Any occurred error
})

Using promiseFactory option to use a different promise implementation library

// See the tests for different libraries usage examples

/**
 * @param  {Function} resolver The promise resolver function
 * @return {Object} The promise instance
 */
function customPromiseFactory(resolver) {
  // With when.js
  return require('when').promise(resolver);

  // With RSVP.js
  var Promise = require('rsvp').Promise;

  return new Promise(resolver);
}

request({
  url: 'https://api.domain.com/v1/a/b'
  json:true,

  // Custom promise factory function
  promiseFactory: customPromiseFactory
})
.then(function (response) {
  // response = The full response object or just the body
})
.catch(function(error) {
  // error = Any occurred error
})

Installation

Install with npm.

npm install --save requestretry

How to define your own retry strategy

/**
 * @param  {Null | Object} err
 * @param  {Object} response
 * @return {Boolean} true if the request should be retried
 */
function myRetryStrategy(err, response){
  // retry the request if we had an error or if the response was a 'Bad Gateway'
  return err || response.statusCode === 502;
}

request({
  url: 'https://api.domain.com/v1/a/b'
  json:true,
  retryStrategy: myRetryStrategy
}, function(err, response, body){
  // this callback will only be called when the request succeeded or after maxAttempts or on error
});

Modifying request options

You can use the defaults method to provide default options like so:

var request = require('requestretry').defaults({ json: true, retryStrategy: myRetryStrategy });

Convenience methods

As with request, several helpers are provided for various HTTP methods:

• request.get(url) - same as request(options, callback) or request(options).
• request.head(url) - same as request(options, callback) or request(options), but it defaults options.method to HEAD.
• request.post(url) - same as request(options, callback) or request(options), but it defaults options.method to POST.
• request.put(url) - same as request(options, callback) or request(options), but it defaults options.method to PUT.
• request.patch(url) - same as request(options, callback) or request(options), but it defaults options.method to PATCH.
• request.del(url) - same as request(options, callback) or request(options), but it defaults options.method to DELETE.
• request.delete(url) - same as request(options, callback) or request(options), but it defaults options.method to DELETE.

Changelog

Donate

I maintain this project in my free time, if it helped you please support my work via paypal or Bitcoins, thanks a lot!

Copyright 2014, Francois-Guillaume Ribreau ([e-mail])

Changelog

1.8.0 (2016-05-11)

• Release v1.8.0. (6767b49)
• docs(changelog): updated (97d6429)