149 lines
6 KiB
Markdown
149 lines
6 KiB
Markdown
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## Follow Redirects
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Drop-in replacement for Node's `http` and `https` modules that automatically follows redirects.
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[](https://www.npmjs.com/package/follow-redirects)
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[](https://github.com/follow-redirects/follow-redirects/actions)
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[](https://coveralls.io/r/follow-redirects/follow-redirects?branch=master)
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[](https://www.npmjs.com/package/follow-redirects)
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[](https://github.com/sponsors/RubenVerborgh)
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`follow-redirects` provides [request](https://nodejs.org/api/http.html#http_http_request_options_callback) and [get](https://nodejs.org/api/http.html#http_http_get_options_callback)
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methods that behave identically to those found on the native [http](https://nodejs.org/api/http.html#http_http_request_options_callback) and [https](https://nodejs.org/api/https.html#https_https_request_options_callback)
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modules, with the exception that they will seamlessly follow redirects.
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```javascript
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const { http, https } = require('follow-redirects');
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http.get('http://bit.ly/900913', response => {
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response.on('data', chunk => {
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console.log(chunk);
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});
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}).on('error', err => {
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console.error(err);
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});
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```
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You can inspect the final redirected URL through the `responseUrl` property on the `response`.
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If no redirection happened, `responseUrl` is the original request URL.
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```javascript
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const request = https.request({
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host: 'bitly.com',
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path: '/UHfDGO',
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}, response => {
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console.log(response.responseUrl);
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// 'http://duckduckgo.com/robots.txt'
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});
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request.end();
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```
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## Options
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### Global options
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Global options are set directly on the `follow-redirects` module:
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```javascript
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const followRedirects = require('follow-redirects');
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followRedirects.maxRedirects = 10;
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followRedirects.maxBodyLength = 20 * 1024 * 1024; // 20 MB
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```
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The following global options are supported:
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- `maxRedirects` (default: `21`) – sets the maximum number of allowed redirects; if exceeded, an error will be emitted.
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- `maxBodyLength` (default: 10MB) – sets the maximum size of the request body; if exceeded, an error will be emitted.
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### Per-request options
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Per-request options are set by passing an `options` object:
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```javascript
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const url = require('url');
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const { http, https } = require('follow-redirects');
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const options = url.parse('http://bit.ly/900913');
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options.maxRedirects = 10;
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options.beforeRedirect = (options, { headers }) => {
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// Use this to adjust the request options upon redirecting,
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// to inspect the latest response headers,
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// or to cancel the request by throwing an error
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if (options.hostname === "example.com") {
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options.auth = "user:password";
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}
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};
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http.request(options);
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```
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In addition to the [standard HTTP](https://nodejs.org/api/http.html#http_http_request_options_callback) and [HTTPS options](https://nodejs.org/api/https.html#https_https_request_options_callback),
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the following per-request options are supported:
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- `followRedirects` (default: `true`) – whether redirects should be followed.
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- `maxRedirects` (default: `21`) – sets the maximum number of allowed redirects; if exceeded, an error will be emitted.
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- `maxBodyLength` (default: 10MB) – sets the maximum size of the request body; if exceeded, an error will be emitted.
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- `beforeRedirect` (default: `undefined`) – optionally change the request `options` on redirects, or abort the request by throwing an error.
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- `agents` (default: `undefined`) – sets the `agent` option per protocol, since HTTP and HTTPS use different agents. Example value: `{ http: new http.Agent(), https: new https.Agent() }`
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- `trackRedirects` (default: `false`) – whether to store the redirected response details into the `redirects` array on the response object.
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### Advanced usage
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By default, `follow-redirects` will use the Node.js default implementations
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of [`http`](https://nodejs.org/api/http.html)
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and [`https`](https://nodejs.org/api/https.html).
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To enable features such as caching and/or intermediate request tracking,
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you might instead want to wrap `follow-redirects` around custom protocol implementations:
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```javascript
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const { http, https } = require('follow-redirects').wrap({
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http: require('your-custom-http'),
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https: require('your-custom-https'),
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});
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```
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Such custom protocols only need an implementation of the `request` method.
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## Browser Usage
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Due to the way the browser works,
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the `http` and `https` browser equivalents perform redirects by default.
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By requiring `follow-redirects` this way:
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```javascript
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const http = require('follow-redirects/http');
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const https = require('follow-redirects/https');
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```
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you can easily tell webpack and friends to replace
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`follow-redirect` by the built-in versions:
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```json
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{
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"follow-redirects/http" : "http",
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"follow-redirects/https" : "https"
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}
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```
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## Contributing
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Pull Requests are always welcome. Please [file an issue](https://github.com/follow-redirects/follow-redirects/issues)
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detailing your proposal before you invest your valuable time. Additional features and bug fixes should be accompanied
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by tests. You can run the test suite locally with a simple `npm test` command.
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## Debug Logging
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`follow-redirects` uses the excellent [debug](https://www.npmjs.com/package/debug) for logging. To turn on logging
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set the environment variable `DEBUG=follow-redirects` for debug output from just this module. When running the test
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suite it is sometimes advantageous to set `DEBUG=*` to see output from the express server as well.
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## Authors
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- [Ruben Verborgh](https://ruben.verborgh.org/)
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- [Olivier Lalonde](mailto:olalonde@gmail.com)
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- [James Talmage](mailto:james@talmage.io)
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## License
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[MIT License](https://github.com/follow-redirects/follow-redirects/blob/master/LICENSE)
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