tra-analysis/website/functions/node_modules/retry-request

Retry a request with built-in exponential backoff.

$ npm install --save request
$ npm install --save retry-request

var request = require('retry-request', {
  request: require('request')
});

It should work the same as request in both callback mode and stream mode.

Note: This module only works when used as a readable stream, i.e. POST requests aren't supported (#3).

Do I need to install request?

Yes! You must independently install request and provide it to this library:

var request = require('retry-request', {
  request: require('request')
});

The code will actually look for the request module automatically to save you this step. But, being explicit like in the example is also welcome.

Callback

urlThatReturns503 will be requested 3 total times before giving up and executing the callback.

request(urlThatReturns503, function (err, resp, body) {});

Stream

urlThatReturns503 will be requested 3 total times before giving up and emitting the response and complete event as usual.

request(urlThatReturns503)
  .on('error', function () {})
  .on('response', function () {})
  .on('complete', function () {});

request(requestOptions, [opts], [cb])

requestOptions

Passed directly to request. See the list of options supported: https://github.com/request/request/#requestoptions-callback.

opts (optional)

opts.noResponseRetries

Type: Number

Default: 2

The number of times to retry after a response fails to come through, such as a DNS resolution error or a socket hangup.

var opts = {
  noResponseRetries: 0
};

request(url, opts, function (err, resp, body) {
  // url was requested 1 time before giving up and
  // executing this callback.
});

opts.objectMode

Type: Boolean

Default: false

Set to true if your custom opts.request function returns a stream in object mode.

opts.retries

Type: Number

Default: 2

var opts = {
  retries: 4
};

request(urlThatReturns503, opts, function (err, resp, body) {
  // urlThatReturns503 was requested a total of 5 times
  // before giving up and executing this callback.
});

opts.currentRetryAttempt

Type: Number

Default: 0

var opts = {
  currentRetryAttempt: 1
};

request(urlThatReturns503, opts, function (err, resp, body) {
  // urlThatReturns503 was requested as if it already failed once.
});

opts.shouldRetryFn

Type: Function

Default: Returns true if http.incomingMessage.statusCode is < 200 or >= 400.

var opts = {
  shouldRetryFn: function (incomingHttpMessage) {
    return incomingHttpMessage.statusMessage !== 'OK';
  }
};

request(urlThatReturnsNonOKStatusMessage, opts, function (err, resp, body) {
  // urlThatReturnsNonOKStatusMessage was requested a
  // total of 3 times, each time using `opts.shouldRetryFn`
  // to decide if it should continue before giving up and
  // executing this callback.
});

opts.request

Type: Function

Default: try { require('request') }

If we cannot locate request, we will throw an error advising you to provide it explicitly.

NOTE: If you override the request function, and it returns a stream in object mode, be sure to set opts.objectMode to true.

var originalRequest = require('request').defaults({
  pool: {
    maxSockets: Infinity
  }
});

var opts = {
  request: originalRequest
};

request(urlThatReturns503, opts, function (err, resp, body) {
  // Your provided `originalRequest` instance was used.
});

cb (optional)

Passed directly to request. See the callback section: https://github.com/request/request/#requestoptions-callback.