--- /dev/null
+# delayed-stream
+
+Buffers events from a stream until you are ready to handle them.
+
+## Installation
+
+``` bash
+npm install delayed-stream
+```
+
+## Usage
+
+The following example shows how to write a http echo server that delays its
+response by 1000 ms.
+
+``` javascript
+var DelayedStream = require('delayed-stream');
+var http = require('http');
+
+http.createServer(function(req, res) {
+ var delayed = DelayedStream.create(req);
+
+ setTimeout(function() {
+ res.writeHead(200);
+ delayed.pipe(res);
+ }, 1000);
+});
+```
+
+If you are not using `Stream#pipe`, you can also manually release the buffered
+events by calling `delayedStream.resume()`:
+
+``` javascript
+var delayed = DelayedStream.create(req);
+
+setTimeout(function() {
+ // Emit all buffered events and resume underlaying source
+ delayed.resume();
+}, 1000);
+```
+
+## Implementation
+
+In order to use this meta stream properly, here are a few things you should
+know about the implementation.
+
+### Event Buffering / Proxying
+
+All events of the `source` stream are hijacked by overwriting the `source.emit`
+method. Until node implements a catch-all event listener, this is the only way.
+
+However, delayed-stream still continues to emit all events it captures on the
+`source`, regardless of whether you have released the delayed stream yet or
+not.
+
+Upon creation, delayed-stream captures all `source` events and stores them in
+an internal event buffer. Once `delayedStream.release()` is called, all
+buffered events are emitted on the `delayedStream`, and the event buffer is
+cleared. After that, delayed-stream merely acts as a proxy for the underlaying
+source.
+
+### Error handling
+
+Error events on `source` are buffered / proxied just like any other events.
+However, `delayedStream.create` attaches a no-op `'error'` listener to the
+`source`. This way you only have to handle errors on the `delayedStream`
+object, rather than in two places.
+
+### Buffer limits
+
+delayed-stream provides a `maxDataSize` property that can be used to limit
+the amount of data being buffered. In order to protect you from bad `source`
+streams that don't react to `source.pause()`, this feature is enabled by
+default.
+
+## API
+
+### DelayedStream.create(source, [options])
+
+Returns a new `delayedStream`. Available options are:
+
+* `pauseStream`
+* `maxDataSize`
+
+The description for those properties can be found below.
+
+### delayedStream.source
+
+The `source` stream managed by this object. This is useful if you are
+passing your `delayedStream` around, and you still want to access properties
+on the `source` object.
+
+### delayedStream.pauseStream = true
+
+Whether to pause the underlaying `source` when calling
+`DelayedStream.create()`. Modifying this property afterwards has no effect.
+
+### delayedStream.maxDataSize = 1024 * 1024
+
+The amount of data to buffer before emitting an `error`.
+
+If the underlaying source is emitting `Buffer` objects, the `maxDataSize`
+refers to bytes.
+
+If the underlaying source is emitting JavaScript strings, the size refers to
+characters.
+
+If you know what you are doing, you can set this property to `Infinity` to
+disable this feature. You can also modify this property during runtime.
+
+### delayedStream.dataSize = 0
+
+The amount of data buffered so far.
+
+### delayedStream.readable
+
+An ECMA5 getter that returns the value of `source.readable`.
+
+### delayedStream.resume()
+
+If the `delayedStream` has not been released so far, `delayedStream.release()`
+is called.
+
+In either case, `source.resume()` is called.
+
+### delayedStream.pause()
+
+Calls `source.pause()`.
+
+### delayedStream.pipe(dest)
+
+Calls `delayedStream.resume()` and then proxies the arguments to `source.pipe`.
+
+### delayedStream.release()
+
+Emits and clears all events that have been buffered up so far. This does not
+resume the underlaying source, use `delayedStream.resume()` instead.
+
+## License
+
+delayed-stream is licensed under the MIT license.
Code Review / simantics / district.git / blobdiff