91 lines
2.3 KiB
Markdown
91 lines
2.3 KiB
Markdown
# on-finished
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[](https://www.npmjs.org/package/on-finished)
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[](http://nodejs.org/download/)
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[](https://travis-ci.org/jshttp/on-finished)
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[](https://coveralls.io/r/jshttp/on-finished)
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Execute a callback when a request closes, finishes, or errors.
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## Install
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```sh
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$ npm install on-finished
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```
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## API
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```js
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var onFinished = require('on-finished')
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```
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### onFinished(res, listener)
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Attach a listener to listen for the response to finish. The listener will
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be invoked only once when the response finished. If the response finished
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to to an error, the first argument will contain the error.
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Listening to the end of a response would be used to close things associated
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with the response, like open files.
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```js
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onFinished(res, function (err) {
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// clean up open fds, etc.
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})
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```
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### onFinished(req, listener)
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Attach a listener to listen for the request to finish. The listener will
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be invoked only once when the request finished. If the request finished
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to to an error, the first argument will contain the error.
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Listening to the end of a request would be used to know when to continue
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after reading the data.
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```js
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var data = ''
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req.setEncoding('utf8')
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res.on('data', function (str) {
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data += str
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})
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onFinished(req, function (err) {
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// data is read unless there is err
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})
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```
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### onFinished.isFinished(res)
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Determine if `res` is already finished. This would be useful to check and
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not even start certain operations if the response has already finished.
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### onFinished.isFinished(req)
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Determine if `req` is already finished. This would be useful to check and
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not even start certain operations if the request has already finished.
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### Example
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The following code ensures that file descriptors are always closed
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once the response finishes.
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```js
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var destroy = require('destroy')
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var http = require('http')
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var onFinished = require('finished')
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http.createServer(function onRequest(req, res) {
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var stream = fs.createReadStream('package.json')
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stream.pipe(res)
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onFinished(res, function (err) {
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destroy(stream)
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})
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})
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```
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## License
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[MIT](LICENSE)
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