将缓冲区转换为数组

问题描述 投票:13回答:6

我正在设置memcached

$memcached->set("item" , ["1" => "hello"]);

任何在PHP中工作,

在带有memcached插件的Node.js中,我得到一个缓冲区而不是结果中的数组

<Buffer 61 3a 25 61 34 3a>

我无法将这种缓冲区转换为数组

在Node.js中:

memcached.get("item" , function(err, data) {
  console.log(data);
}

你有什么办法吗?

javascript node.js memcached
6个回答
34
投票

arr = [...buffer]

除了缓冲区之外,ES6还引入了许多其他功能。

你甚至可以像这样轻松追加:

arr.push(...buffer)

当在数组中使用时,...运算符会扩展数组和缓冲区等可枚举项。它还将它们扩展为单独的函数参数。


是的,它也更快:

...:x100000:835.850ms

来自原型的切片调用:x100000:2118.513ms

var array,
    buffer = new Buffer([1, 4, 4, 5, 6, 7, 5, 3, 5, 67, 7, 4, 3, 5, 76, 234, 24, 235, 24, 4, 234, 234, 234, 325, 32, 6246, 8, 89, 689, 7687, 56, 54, 643, 32, 213, 2134, 235, 346, 45756, 857, 987, 0790, 89, 57, 5, 32, 423, 54, 6, 765, 65, 745, 4, 34, 543, 43, 3, 3, 3, 34, 3, 63, 63, 35, 7, 537, 35, 75, 754, 7, 23, 234, 43, 6, 247, 35, 54, 745, 767, 5, 3, 2, 2, 6, 7, 32, 3, 56, 346, 4, 32, 32, 3, 4, 45, 5, 34, 45, 43, 43]),
    iter = 100000;

array = buffer;

console.time("... : x" + iter);
for (var i = iter; i--;) array = [...buffer]
console.timeEnd("... : x" + iter);

console.time("Apply/call/etc : x" + iter);
for (var i = iter; i--;) array = Array.prototype.slice.call(buffer, 0)
console.timeEnd("Apply/call/etc : x" + iter);

7
投票

干得好:

var buffer = new Buffer([1,2,3])
var arr = Array.prototype.slice.call(buffer, 0)
console.log(arr)

2
投票

我没有使用过memcached,所以我不确定这个缓冲区代表什么或者你想拥有什么。抱歉。这是一个将缓冲区拆分为字节数组的函数。更多在node.js Buffer docs,希望它有所帮助!

var hex = new Buffer("613a2561343a", "hex");
var l = hex.length; // in bytes
var output = [];
for(var i = 0; i < l; i++){
  var char = hex.toString('hex',i,i+1); // i is byte index of hex
  output.push(char);
};
console.log(output);
// output: [ '61', '3a', '25', '61', '34', '3a' ]

2
投票

还有另一种转换为整数数组的方法

使用toJSON()

Buffer.from('Text of example').toJSON()
{ type: 'Buffer',data: [ 84, 101, 120, 116, 32, 111, 102, 32, 101, 120, 97, 109, 112, 108, 101 ] }

// simple get data
Buffer.from('Text of example').toJSON().data
[ 84, 101, 120, 116, 32, 111, 102, 32, 101, 120, 97, 109, 112, 108, 101 ]

基准的例子

// I took this from @user4584267's answer
const buffer = new Buffer([1, 4, 4, 5, 6, 7, 5, 3, 5, 67, 7, 4, 3, 5, 76, 234, 24, 235, 24, 4, 234, 234, 234, 325, 32, 6246, 8, 89, 689, 7687, 56, 54, 643, 32, 213, 2134, 235, 346, 45756, 857, 987, 0790, 89, 57, 5, 32, 423, 54, 6, 765, 65, 745, 4, 34, 543, 43, 3, 3, 3, 34, 3, 63, 63, 35, 7, 537, 35, 75, 754, 7, 23, 234, 43, 6, 247, 35, 54, 745, 767, 5, 3, 2, 2, 6, 7, 32, 3, 56, 346, 4, 32, 32, 3, 4, 45, 5, 34, 45, 43, 43]);
let array = null;
const iterations = 100000;

console.time("...buffer");
for (let i = iterations; i=i-1;) array = [...buffer]
console.timeEnd("...buffer");

console.time("array.prototype.slice.call");
for (let i = iterations; i=i-1;) array = Array.prototype.slice.call(buffer, 0)
console.timeEnd("array.prototype.slice.call");

console.time("toJSON().data");
for (let i = iterations; i=i-1;) array = buffer.toJSON().data
console.timeEnd("toJSON().data");

OUTPUT

...缓冲区:559.932ms array.prototype.slice.call:1176.535ms toJSON()。data:30.571ms

或者如果你想在Buffer中使用更专业和自定义的功能,请使用:

Buffer.prototype.toArrayInteger = function(){
    if (this.length > 0) {
        const data = new Array(this.length);
        for (let i = 0; i < this.length; i=i+1)
            data[i] = this[i];
        return data;
    }
    return [];
}

基准的例子:

const buffer = new Buffer([1, 4, 4, 5, 6, 7, 5, 3, 5, 67, 7, 4, 3, 5, 76, 234, 24, 235, 24, 4, 234, 234, 234, 325, 32, 6246, 8, 89, 689, 7687, 56, 54, 643, 32, 213, 2134, 235, 346, 45756, 857, 987, 0790, 89, 57, 5, 32, 423, 54, 6, 765, 65, 745, 4, 34, 543, 43, 3, 3, 3, 34, 3, 63, 63, 35, 7, 537, 35, 75, 754, 7, 23, 234, 43, 6, 247, 35, 54, 745, 767, 5, 3, 2, 2, 6, 7, 32, 3, 56, 346, 4, 32, 32, 3, 4, 45, 5, 34, 45, 43, 43]);
let array = null;
const iterations = 100000;

console.time("toArrayInteger");
for (let i = iterations; i=i-1;) buffer.toArrayInteger();
console.timeEnd("toArrayInteger");

输出:

toArrayInteger:28.714ms

注意:在最后一个例子中,我从Buffer.toJSON复制了一个函数,并将它自定义为lite


0
投票

我有一个解决方案,虽然我目前正试图找到一个更好的解决方案:

function bufToArray(buffer) {
  let array = new Array();
  for (data of buffer.values()) array.push(data);
  return array;
}

编辑:我发现了一种更简单的方法:

var buffer = Buffer.from('NodeJS rocks!')
var array = new Function(`return [${Array.prototype.slice.call(buffer, 0)}]`)

但是,就像有人已经说过的那样,[...buffer]更快(并且代码效率更高)。

你也可以使用new Uint8Array(buffer [, byteOffset [, length]]);


-2
投票

在互联网上,没有相关的信息,但我找到了修道院的方式

在nodejs中,我必须使用:

var arrayobject = phpjs.unserialize(data.toString());

但是,它是获取数组的非常愚蠢的方式,它似乎在设置memcache时设置了php serilzie数据。

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