mirror of
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170 lines
3.9 KiB
Markdown
170 lines
3.9 KiB
Markdown
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|:-:
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|Retry a [request][request] with built-in [exponential backoff](https://developers.google.com/analytics/devguides/reporting/core/v3/coreErrors#backoff).
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```sh
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$ npm install --save request
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$ npm install --save retry-request
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```
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```js
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var request = require('retry-request', {
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request: require('request')
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});
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```
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It should work the same as `request` in both callback mode and stream mode.
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Note: This module only works when used as a readable stream, i.e. POST requests aren't supported ([#3](https://github.com/stephenplusplus/retry-request/issues/3)).
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## Do I need to install `request`?
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Yes! You must independently install `request` and provide it to this library:
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```js
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var request = require('retry-request', {
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request: require('request')
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});
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```
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*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.*
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#### Callback
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`urlThatReturns503` will be requested 3 total times before giving up and executing the callback.
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```js
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request(urlThatReturns503, function (err, resp, body) {});
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```
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#### Stream
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`urlThatReturns503` will be requested 3 total times before giving up and emitting the `response` and `complete` event as usual.
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```js
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request(urlThatReturns503)
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.on('error', function () {})
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.on('response', function () {})
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.on('complete', function () {});
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```
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## request(requestOptions, [opts], [cb])
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### requestOptions
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Passed directly to `request`. See the list of options supported: https://github.com/request/request/#requestoptions-callback.
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### opts *(optional)*
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#### `opts.noResponseRetries`
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Type: `Number`
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Default: `2`
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The number of times to retry after a response fails to come through, such as a DNS resolution error or a socket hangup.
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```js
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var opts = {
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noResponseRetries: 0
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};
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request(url, opts, function (err, resp, body) {
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// url was requested 1 time before giving up and
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// executing this callback.
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});
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```
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#### `opts.objectMode`
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Type: `Boolean`
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Default: `false`
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Set to `true` if your custom `opts.request` function returns a stream in object mode.
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#### `opts.retries`
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Type: `Number`
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Default: `2`
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```js
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var opts = {
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retries: 4
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};
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request(urlThatReturns503, opts, function (err, resp, body) {
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// urlThatReturns503 was requested a total of 5 times
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// before giving up and executing this callback.
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});
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```
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#### `opts.currentRetryAttempt`
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Type: `Number`
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Default: `0`
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```js
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var opts = {
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currentRetryAttempt: 1
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};
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request(urlThatReturns503, opts, function (err, resp, body) {
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// urlThatReturns503 was requested as if it already failed once.
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});
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```
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#### `opts.shouldRetryFn`
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Type: `Function`
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Default: Returns `true` if [http.incomingMessage](https://nodejs.org/api/http.html#http_http_incomingmessage).statusCode is < 200 or >= 400.
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```js
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var opts = {
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shouldRetryFn: function (incomingHttpMessage) {
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return incomingHttpMessage.statusMessage !== 'OK';
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}
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};
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request(urlThatReturnsNonOKStatusMessage, opts, function (err, resp, body) {
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// urlThatReturnsNonOKStatusMessage was requested a
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// total of 3 times, each time using `opts.shouldRetryFn`
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// to decide if it should continue before giving up and
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// executing this callback.
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});
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```
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#### `opts.request`
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Type: `Function`
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Default: `try { require('request') }`
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If we cannot locate `request`, we will throw an error advising you to provide it explicitly.
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*NOTE: If you override the request function, and it returns a stream in object mode, be sure to set `opts.objectMode` to `true`.*
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```js
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var originalRequest = require('request').defaults({
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pool: {
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maxSockets: Infinity
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}
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});
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var opts = {
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request: originalRequest
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};
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request(urlThatReturns503, opts, function (err, resp, body) {
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// Your provided `originalRequest` instance was used.
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});
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```
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### cb *(optional)*
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Passed directly to `request`. See the callback section: https://github.com/request/request/#requestoptions-callback.
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[request]: https://github.com/request/request
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