如何在Nodejs中将缓冲区转换为流

Question

我遇到了在 Nodejs 中将缓冲区转换为流的问题。代码如下：

var fs = require('fs');
var b = Buffer([80,80,80,80]);
var readStream = fs.createReadStream({path:b});

代码引发异常：

TypeError: path must be a string or Buffer

但是Nodejs的文档说Buffer可以通过fs.createReadStream()接受。

fs.createReadStream(路径[,选项])
  路径 | |
  选项 |

Answer 1

NodeJS 8+ 版本。 将缓冲区转换为流

const { Readable } = require('stream');

/**
 * @param binary Buffer
 * returns readableInstanceStream Readable
 */
function bufferToStream(binary) {

    const readableInstanceStream = new Readable({
      read() {
        this.push(binary);
        this.push(null);
      }
    });

    return readableInstanceStream;
}

将 chunk 作为 null 传递表示流的结束 (EOF)，其行为与 Read.push(null) 相同，之后不能再写入任何数据。 EOF 信号被放置在缓冲区的末尾，任何缓冲的数据仍将被刷新

Answer 2

节点0.10+

将缓冲区转换为流

var Readable = require('stream').Readable; 

function bufferToStream(buffer) { 
  var stream = new Readable();
  stream.push(buffer);
  stream.push(null);

  return stream;
}

Answer 3

const { Readable } = require('stream');

class BufferStream extends Readable {
    constructor ( buffer ){
        super();
        this.buffer = buffer;
    }

    _read (){
        this.push( this.buffer );
        this.push( null );
    }
}

function bufferToStream( buffer ) {
    return new BufferStream( buffer );
}

Answer 4

我用函数式风格重写了 Alex Dykyi 的解决方案：

var Readable = require('stream').Readable;

[file_buffer, null].reduce(
    (stream, data) => stream.push(data) && stream,
    new Readable()
)