如何在Nodejs

Question

我遇到了在Nodejs中将缓冲区转换为流的问题。这是代码：

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

然而，Nodejs的文档说fs.createReadStream（）可以接受缓冲区。

  

fs.createReadStream（path [，options]）
    路径＆lt; string＆gt; | ＆LT;缓冲液＆GT; | ＆LT; URL＆GT;
    options＆lt; string＆gt; | ＆LT;对象＆gt;

有人可以回答这个问题吗？非常感谢！

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;

  }

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

我用功能样式重写了Alex Dykyi的解决方案：

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

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

Answer 4

noexcept(true)

Answer 5

with hv as ( select hv.*, count(*) over (partition by address, appointment_date order by workno) as cnt from housevisits hv ) select hv.* from hv where cnt = 1; 旨在对文件系统执行操作 fs期望一个路径作为第一个参数，可以是文件名，文件的url或文件缓冲区（因为它很好地解释了here）。您正在传递对象fs.createReadStream()。

如果您尝试使用{path:b}正确的语法，则错误会变得更加明确：

createReadStream()