是否有一种普遍接受的技术可以有效地将JavaScript字符串转换为arraybuffer,反之亦然?具体来说,我希望能够将ArrayBuffer的内容写入localStorage,然后再将其读回来。
当前回答
对我来说,这很有效。
static async hash(message) {
const data = new TextEncoder().encode(message);
const hashBuffer = await crypto.subtle.digest('SHA-256', data)
const hashArray = Array.from(new Uint8Array(hashBuffer))
const hashHex = hashArray.map((b) => b.toString(16).padStart(2, '0')).join('')
return hashHex
}
其他回答
Just
const buffer = thisReturnsBuffers();
const blob = new Blob([buffer], {type: 'text/plain; charset=utf-8'});
blob.text().then(text => console.log(text));
Or
const stringVal = "string here";
const blob = new Blob([stringVal], {type: 'text/plain; charset=utf-8'});
blob.arrayBuffer().then(buffer => console.log(buffer));
你们为什么要把事情搞得这么复杂?
我不建议使用已弃用的api,如BlobBuilder
Blob对象早已弃用了BlobBuilder。将Dennis回答中的代码(其中使用了BlobBuilder)与下面的代码进行比较:
function arrayBufferGen(str, cb) {
var b = new Blob([str]);
var f = new FileReader();
f.onload = function(e) {
cb(e.target.result);
}
f.readAsArrayBuffer(b);
}
请注意,与已弃用的方法相比,这是多么干净和不那么臃肿……是的,这绝对是需要考虑的。
对我来说,这很有效。
static async hash(message) {
const data = new TextEncoder().encode(message);
const hashBuffer = await crypto.subtle.digest('SHA-256', data)
const hashArray = Array.from(new Uint8Array(hashBuffer))
const hashHex = hashArray.map((b) => b.toString(16).padStart(2, '0')).join('')
return hashHex
}
请看这里:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays/StringView (基于JavaScript ArrayBuffer接口的类似c语言的字符串接口)
我发现这种方法有问题,主要是因为我试图将输出写入一个文件,而它没有正确编码。由于JS似乎使用UCS-2编码(源,源),我们需要进一步扩展这个解决方案,这是我的增强解决方案,对我来说是有效的。
我对一般文本没有任何困难,但当它变成阿拉伯语或韩语时,输出文件没有所有字符,而是显示错误字符
文件输出: ”、“单位”:“10 K”:“O©iuY喜爱”、“遵循% % {screen_name} {screen_name}”:“U”“O©iu“推特:“¤问题”、“推%{标签}”:“%{标签}’一个¤uEY喜爱”,“推特%{名称}”:“%{名称}U”xA¤uEY喜爱”},柯:{“% {followers_count}的追随者”:“% {followers_count}…X \”,“100 K +”:“100我助教”,“10 K单位”:“我e”,遵循:“\°”,“跟着% {screen_name}”:“% {screen_name}Ø\°X0”,凯西:“œ”,男:“我”,推特:“¸”,“推特%{标签}”:“%{标签}
original: ", " 10 k unit ": "万",follow: "关注"," follow百分之百分之;screen _ name} ": " {screen _ name}先生圆场,tweet: "推特"," tweet百分之百分之{hashtag} ": " {hashtag},推特的"," tweet to百分之百分之{name} ": " {name}先生推到百分之":{},ko " {followers _ count}百分之followers ": " {followers _ count}명의팔로워100 k + ": " 100 ", "만이상"," 10 k unit ": "만단위",follow: "팔로우"," follow百分之百分之{screen _ name} ": " {screen _ name}님팔로우하기",k: "천",米:"백만",tweet: "트윗"," tweet百分之百分之{hashtag} ": " {hashtag}
我从dennis的解决方案和我发现的这个帖子中获取了信息。
这是我的代码:
function encode_utf8(s) {
return unescape(encodeURIComponent(s));
}
function decode_utf8(s) {
return decodeURIComponent(escape(s));
}
function ab2str(buf) {
var s = String.fromCharCode.apply(null, new Uint8Array(buf));
return decode_utf8(decode_utf8(s))
}
function str2ab(str) {
var s = encode_utf8(str)
var buf = new ArrayBuffer(s.length);
var bufView = new Uint8Array(buf);
for (var i=0, strLen=s.length; i<strLen; i++) {
bufView[i] = s.charCodeAt(i);
}
return bufView;
}
这允许我将内容保存到一个文件,而没有编码问题。
How it works: It basically takes the single 8-byte chunks composing a UTF-8 character and saves them as single characters (therefore an UTF-8 character built in this way, could be composed by 1-4 of these characters). UTF-8 encodes characters in a format that variates from 1 to 4 bytes in length. What we do here is encoding the sting in an URI component and then take this component and translate it in the corresponding 8 byte character. In this way we don't lose the information given by UTF8 characters that are more than 1 byte long.