This is not funny now. I am not able to make such simple thing. Now I am getting swapped chunks of data.
https://gist.github.com/xdenser/8887437 when new read stream starts first 2 chunks of data are swapped. How is it possible? 2014-02-11 11:50 GMT+02:00 Denys Khanzhyiev <[email protected]>: > Or maybe I understand it wrong. > When I call fs.ReadStream.read should I expect it will emit 'end' during > call? > Ok it is better to look in sources. > > > > 2014-02-11 11:27 GMT+02:00 Denys Khanzhyiev <[email protected]>: > > Looks like it is not solved. >> >> Sometimes I get situation when fs.ReadStrem neither emit 'readable' nor >> 'end' when used on growing file in non flow mode. And I have no event to >> resume reading. Except maybe some timeout. >> >> >> 2014-02-08 19:53 GMT+02:00 Denys Khanzhyiev <[email protected]>: >> >> Solved by creating actual stream implementing _read. >>> The trick is to call push on each _read. >>> When there is no data, delay pull until data available. >>> >>> In my stream `_read` i call `read` of fs.ReadStream. >>> >>> As I understand I should either rely on `fs.ReadStream.read` and 'end' >>> event. >>> Or 'data' and 'end' events and `fs.ReadStream.pause/resume`, but not >>> mix them. >>> >>> here is gist >>> https://gist.github.com/xdenser/8887437 >>> >>> it needs more details to handle errors >>> and also I have doubts about resume event >>> maybe it is better to `watch` file instead of listening for 'data' event >>> on download stream. >>> >>> >>> >>> >>> >>> 2014-02-08 2:12 GMT+02:00 Denys Khanzhyiev <[email protected]>: >>> >>> Hello, >>>> >>>> I have a task where one slow stream is piped to fs.writeStream and >>>> after some event I need to read from that writen file, i.e. read from >>>> growing file from some position. A have seen `node-growing-file`, and >>>> `tailing-stream` nothing seems to solve my problem. >>>> >>>> It looks like I do not understand how streams work >>>> Here is my helper object (though it is called PxyStream it is not >>>> stream in fact), >>>> >>>> var >>>> fs = require('fs'); >>>> >>>> function PxyStream(path,readStream,writeStream,start,end){ >>>> this.path = path; >>>> this.readStream = readStream; >>>> this.writeStream = writeStream; >>>> this._offset = start; >>>> this.endPos = end; >>>> this.writeStream.on('finish',function(){ >>>> this._writeStreamFinished = true; >>>> this.nextStream(); >>>> }.bind(this)) >>>> } >>>> >>>> >>>> PxyStream.prototype.pipe = function(destination){ >>>> this.destination = destination; >>>> this.nextStream(); >>>> } >>>> >>>> PxyStream.prototype.nextStream = function(){ >>>> if(!this._stream){ >>>> var options = { >>>> start: this._offset >>>> }; >>>> var last = this._writeStreamFinished; >>>> console.log('new read stream',this._offset, last); >>>> this._stream = fs.createReadStream(this.path,options); >>>> this._stream.pipe(this.destination,{end: false}); >>>> this._stream.on('data',function(data){ >>>> this._offset += data.length; >>>> }.bind(this)); >>>> >>>> this._stream.on('end',function(){ >>>> console.log('read stream end',this._offset, last); >>>> this._stream.unpipe(); >>>> this._stream = null; >>>> if(last) { >>>> this.destination.emit('end'); >>>> } >>>> this._watch(); >>>> }.bind(this)); >>>> } >>>> } >>>> >>>> PxyStream.prototype._watch = function(){ >>>> this.readStream.once('data',function(){ >>>> this.nextStream(); >>>> }.bind(this)) >>>> } >>>> >>>> exports.PxyStream = PxyStream; >>>> >>>> >>>> I am using it as >>>> >>>> pxyStream = new PxyStream(filePath,<slowReadStream>, >>>> <fsWriteStream>,start,null); >>>> // i need end position too but lets skip it for now >>>> pxyStream.pipe(<otherSlowStream>); >>>> >>>> my problem is I see 'read stream end' message far before >>>> otherSlowStream ends. >>>> In fact it never ends, but i can see its progress. >>>> Actually destination is http.response stream. >>>> I thought stream.pipe should slow down reading in order to keep buffers >>>> short. >>>> Maybe attached 'data' event makes it read fast, but how can I count >>>> bytes then? >>>> The other problem is I can not end destination properly. >>>> >>>> >>>> >>>> >>> >> > -- -- Job Board: http://jobs.nodejs.org/ Posting guidelines: https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines You received this message because you are subscribed to the Google Groups "nodejs" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/nodejs?hl=en?hl=en --- You received this message because you are subscribed to the Google Groups "nodejs" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
