90 lines
3.2 KiB
Markdown
90 lines
3.2 KiB
Markdown
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# EventSource [](http://browsenpm.org/package/eventsource)[](https://travis-ci.org/EventSource/eventsource)[](http://npm-stat.com/charts.html?package=eventsource&from=2015-09-01)[](https://david-dm.org/EventSource/eventsource)
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This library is a pure JavaScript implementation of the [EventSource](https://html.spec.whatwg.org/multipage/server-sent-events.html#server-sent-events) client. The API aims to be W3C compatible.
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You can use it with Node.js or as a browser polyfill for
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[browsers that don't have native `EventSource` support](http://caniuse.com/#feat=eventsource).
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## Install
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npm install eventsource
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## Example
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npm install
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node ./example/sse-server.js
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node ./example/sse-client.js # Node.js client
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open http://localhost:8080 # Browser client - both native and polyfill
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curl http://localhost:8080/sse # Enjoy the simplicity of SSE
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## Browser Polyfill
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Just add `example/eventsource-polyfill.js` file to your web page:
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```html
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<script src=/eventsource-polyfill.js></script>
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```
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Now you will have two global constructors:
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```javascript
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window.EventSourcePolyfill
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window.EventSource // Unchanged if browser has defined it. Otherwise, same as window.EventSourcePolyfill
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```
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If you're using [webpack](https://webpack.github.io/) or [browserify](http://browserify.org/)
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you can of course build your own. (The `example/eventsource-polyfill.js` is built with webpack).
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## Extensions to the W3C API
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### Setting HTTP request headers
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You can define custom HTTP headers for the initial HTTP request. This can be useful for e.g. sending cookies
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or to specify an initial `Last-Event-ID` value.
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HTTP headers are defined by assigning a `headers` attribute to the optional `eventSourceInitDict` argument:
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```javascript
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var eventSourceInitDict = {headers: {'Cookie': 'test=test'}};
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var es = new EventSource(url, eventSourceInitDict);
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```
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### Allow unauthorized HTTPS requests
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By default, https requests that cannot be authorized will cause the connection to fail and an exception
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to be emitted. You can override this behaviour, along with other https options:
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```javascript
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var eventSourceInitDict = {https: {rejectUnauthorized: false}};
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var es = new EventSource(url, eventSourceInitDict);
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```
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Note that for Node.js < v0.10.x this option has no effect - unauthorized HTTPS requests are *always* allowed.
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### HTTP status code on error events
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Unauthorized and redirect error status codes (for example 401, 403, 301, 307) are available in the `status` property in the error event.
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```javascript
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es.onerror = function (err) {
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if (err) {
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if (err.status === 401 || err.status === 403) {
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console.log('not authorized');
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}
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}
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};
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```
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### HTTP/HTTPS proxy
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You can define a `proxy` option for the HTTP request to be used. This is typically useful if you are behind a corporate firewall.
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```javascript
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var es = new EventSource(url, {proxy: 'http://your.proxy.com'});
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```
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## License
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MIT-licensed. See LICENSE
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