Node.js流

Question

Im using the zlib component of node js to deflate data, using

var stream = zlib.createDeflate({ "level": level });                             
stream.write(string);                                                            
stream.on('data', function(data) {console.log(data.toString())});

However, the the data callback is only run once with a buffer 'x'. What I want is to extract the deflated data from the stream into a variable, asynchronous or not. All examples of streams that I have found are writing data between streams.

Answer 1

Try this

var stream = zlib.createDeflate({ "level": level });             
var buffers = [];
var result;                
stream.on('data', function(data) {buffers.push(data)});
stream.on('close', function() {  
    result = Buffer.concat(buffers);
    console.log('COMPRESSED DATA:', result);  
})

stream.write(string);
stream.end();

Answer 2

I ended up using

  function deflate(string, level) {

  var fiber = fibers.current;

  var result = [];

  var out = new stream.Stream();

  out.write = function(data) {
    result.push(data);
  }

  out.end = function() {
    result = Buffer.concat(result);
    fiber.run(result.toString('base64'));
  }

  var deflate = zlib.createDeflate({ "level": level });
  deflate.end(string, 'utf8');
  deflate.pipe(out);

  return fibers.yield();
}