> * Would be nice to also include the writable side in the spec, with a
symmetrical API (a write / abort pair).
For simplicity you can get away with a Writable stream to just be `function
(simpleStream) { /* consume it */ }`
Then you don't need a central `pipe()` or `pump()` implementation and each
writable stream can implement it's own
consumption & back pressure algorithm.
> * Spec does not say what item is, I'm assuming it can be a Buffer or a
string. Can it also be an object? why not?
I believe it's an arbitrary value including another simple stream
On Thu, Aug 15, 2013 at 3:05 AM, Bruno Jouhier <[email protected]> wrote:
> Isaac's message is clear. Simple streams won't make it into core.
>
> So the solution is probably in userland. Tim's module looks like a good
> starting point and if it gets popular it could become a de facto "simple
> stream" standard API.
>
> My comments on it:
>
> * Would be nice to also include the writable side in the spec, with a
> symmetrical API (a write / abort pair).
> * Why not rename abort close?
> * Spec does not say what item is, I'm assuming it can be a Buffer or a
> string. Can it also be an object? why not?
> * The "Related Interfaces" part should be left out. If we want it to be
> popular, we have to keep it as simple as possible.
>
> Streamline's streams interface is very similar and provides wrappers
> around most of node's steams (HTTP and TCP, client and server). It can also
> be used as source of inspiration (but I'll remap it to simple-streams if
> simple-streams catches up).
>
> Bruno
>
>
>
> On Wednesday, August 14, 2013 7:02:19 PM UTC+2, Eldar wrote:
>>
>> Node completely shutdowns because emitter.emit('error') triggers
>> exception when there is no listeners for error event.
>> The ".pipe()" listens for errors but doesn't change that behavior.
>>
>> So strictly speaking above server will shutdown on file error because of
>> uncaught exception
>> and leak on socket hang up, because "close" not an "error" event will be
>> emitted.
>>
>> среда, 14 августа 2013 г., 13:47:14 UTC+4 пользователь Floby написал:
>>>
>>> file.pipe(res) does clean the resources on error because node completely
>>> shuts down, doesn't it?
>>>
>>> On Tuesday, 13 August 2013 12:08:30 UTC+2, Eldar wrote:
>>>>
>>>> file.pipe(res)
>>>>
>>>> On response error (say client clicked close window button) the file
>>>> will remain open.
>>>> And vice versa on file error response will hang. So the correct way to
>>>> pipe is
>>>>
>>>> file.pipe(res)
>>>> file.on('error', res.destroy.bind(res))
>>>> res.on('error', file.destroy.bind(res))
>>>>
>>>> вторник, 13 августа 2013 г., 12:58:09 UTC+4 пользователь Floby написал:
>>>>>
>>>>> ok.
>>>>> I didn't understand the part about " `.pipe()` doesn't cleanup any
>>>>> resources.
>>>>> Everything works fine until the streaming process completes
>>>>> successfully. "
>>>>>
>>>>> Is there an example where that becomes obvious?
>>>>>
>>>>> On Monday, 12 August 2013 18:05:02 UTC+2, Eldar wrote:
>>>>>>
>>>>>> If you want to create some function which accepts a stream and can affect
>>>>>> it's state you should be able to destroy the given stream on demand
>>>>>> e.g. when something went wrong and/or you are not interested in
>>>>>> receiving data anymore.
>>>>>> Unfortunately that's impossible with current node readable streams
>>>>>> because they:
>>>>>>
>>>>>> 1. Support multiple consumers
>>>>>> 2. Don't have common cleanup interface
>>>>>>
>>>>>> So you can't touch another's stream because someone else may use it
>>>>>> and if you could you don't know how.
>>>>>>
>>>>>> The absence of ability to pass streams as arguments is a huge flow. You
>>>>>> can build almost nothing
>>>>>> without that. Now someone may wonder: but there are so many useful
>>>>>> modules about streams in npm!?
>>>>>> Right. They all rely on `.pipe()`. For some reason all kind of blog
>>>>>> posts, tutorials and even node's
>>>>>> own documentation teach that for passing readable you can do
>>>>>> `readable.pipe(writable)`.
>>>>>> E.g. http file server could be:
>>>>>>
>>>>>> ```javascript
>>>>>> var http = require('http')
>>>>>> var fs = require('fs')
>>>>>> http.createServer(function(**req, res) {
>>>>>> res.writeHead(200, {'Content-Type': 'text/plain'})
>>>>>> fs.createReadStream(req.url.**slice(1)).pipe(res)
>>>>>> }).listen(3000)
>>>>>> ```
>>>>>>
>>>>>> That's a lie. Exactly for the reasons above `.pipe()` doesn't cleanup
>>>>>> any resources.
>>>>>> Everything works fine until the streaming process completes successfully.
>>>>>> But if something fails you get horrible leaks and hangs.
>>>>>> Almost every module doing stream processing have this flow. Obvious or
>>>>>> not.
>>>>>>
>>>>>> That all is sad. We need another, simpler API. Although I believe
>>>>>> incompatible changes should be made
>>>>>> to node core that is not what I am calling about (at least not at the
>>>>>> first place).
>>>>>> But we definitely should stop to expose node streams in userland modules,
>>>>>> stop to extend "stream base classes", just stop to use it in userland.
>>>>>>
>>>>>> Now the constructive part. Tim Caswell proposed recently simple-stream
>>>>>> <https://github.com/creationix/js-git/blob/master/specs/simple-stream.md>
>>>>>> and build many things on top of it.
>>>>>>
>>>>>> Let's just peek this API as a standard and start using it.
>>>>>> Here is readable-to-simple-stream
>>>>>> <https://github.com/eldargab/stream-simple> converter which can be used
>>>>>> for dealing with node core.
>>>>>>
>>>>>> It also contains slightly more detailed version of original spec which
>>>>>> could be discussed.
>>>>>>
>>>>>> That's it.
>>>>>>
>>>>>> --
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