98 lines
2.6 KiB
Markdown
98 lines
2.6 KiB
Markdown
# duplexify
|
|
|
|
Turn a writeable and readable stream into a single streams2 duplex stream.
|
|
|
|
Similar to [duplexer2](https://github.com/deoxxa/duplexer2) except it supports both streams2 and streams1 as input
|
|
and it allows you to set the readable and writable part asynchronously using `setReadable(stream)` and `setWritable(stream)`
|
|
|
|
```
|
|
npm install duplexify
|
|
```
|
|
|
|
[](http://travis-ci.org/mafintosh/duplexify)
|
|
|
|
## Usage
|
|
|
|
Use `duplexify(writable, readable, streamOptions)` (or `duplexify.obj(writable, readable)` to create an object stream)
|
|
|
|
``` js
|
|
var duplexify = require('duplexify')
|
|
|
|
// turn writableStream and readableStream into a single duplex stream
|
|
var dup = duplexify(writableStream, readableStream)
|
|
|
|
dup.write('hello world') // will write to writableStream
|
|
dup.on('data', function(data) {
|
|
// will read from readableStream
|
|
})
|
|
```
|
|
|
|
You can also set the readable and writable parts asynchronously
|
|
|
|
``` js
|
|
var dup = duplexify()
|
|
|
|
dup.write('hello world') // write will buffer until the writable
|
|
// part has been set
|
|
|
|
// wait a bit ...
|
|
dup.setReadable(readableStream)
|
|
|
|
// maybe wait some more?
|
|
dup.setWritable(writableStream)
|
|
```
|
|
|
|
If you call `setReadable` or `setWritable` multiple times it will unregister the previous readable/writable stream.
|
|
To disable the readable or writable part call `setReadable` or `setWritable` with `null`.
|
|
|
|
If the readable or writable streams emits an error or close it will destroy both streams and bubble up the event.
|
|
You can also explicitly destroy the streams by calling `dup.destroy()`. The `destroy` method optionally takes an
|
|
error object as argument, in which case the error is emitted as part of the `error` event.
|
|
|
|
``` js
|
|
dup.on('error', function(err) {
|
|
console.log('readable or writable emitted an error - close will follow')
|
|
})
|
|
|
|
dup.on('close', function() {
|
|
console.log('the duplex stream is destroyed')
|
|
})
|
|
|
|
dup.destroy() // calls destroy on the readable and writable part (if present)
|
|
```
|
|
|
|
## HTTP request example
|
|
|
|
Turn a node core http request into a duplex stream is as easy as
|
|
|
|
``` js
|
|
var duplexify = require('duplexify')
|
|
var http = require('http')
|
|
|
|
var request = function(opts) {
|
|
var req = http.request(opts)
|
|
var dup = duplexify(req)
|
|
req.on('response', function(res) {
|
|
dup.setReadable(res)
|
|
})
|
|
return dup
|
|
}
|
|
|
|
var req = request({
|
|
method: 'GET',
|
|
host: 'www.google.com',
|
|
port: 80
|
|
})
|
|
|
|
req.end()
|
|
req.pipe(process.stdout)
|
|
```
|
|
|
|
## License
|
|
|
|
MIT
|
|
|
|
## Related
|
|
|
|
`duplexify` is part of the [mississippi stream utility collection](https://github.com/maxogden/mississippi) which includes more useful stream modules similar to this one.
|