Javascript Web Workers文件上传 [英] Javascript Web Workers File Upload
本文介绍了Javascript Web Workers文件上传的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试使用HTML5和Web Workers为非常大的文件制作html上传器。它上传缓慢但消耗大量内存。我认为它将整个文件添加到表单时将其传输到内存中。下面是代码：
jswebworker.js：
I am trying to make a html uploader for very large files using HTML5 and Web Workers. Atm it uploads slowly but consumes alot of memory. I think it is transferring the whole file to the memory when it adds it to the form. Heres the code: jswebworker.js:
/*importScripts('webworkerFormData.js');*/
(function() {
// Export variable to the global scope
(this == undefined ? self : this)['FormData'] = FormData;
var ___send$rw = XMLHttpRequest.prototype.send;
XMLHttpRequest.prototype['send'] = function(data) {
if (data instanceof FormData) {
if (!data.__endedMultipart) data.__append('--' + data.boundary + '--\r\n');
data.__endedMultipart = true;
this.setRequestHeader('Content-Type', 'multipart/form-data; boundary=' + data.boundary);
data = new Uint8Array(data.data).buffer;
}
// Invoke original XHR.send
return ___send$rw.call(this, data);
};
function FormData() {
// Force a Constructor
if (!(this instanceof FormData)) return new FormData();
// Generate a random boundary - This must be unique with respect to the form's contents.
this.boundary = '------RWWorkerFormDataBoundary' + Math.random().toString(36);
var internal_data = this.data = [];
/**
* Internal method.
* @param inp String | ArrayBuffer | Uint8Array Input
*/
this.__append = function(inp) {
var i=0, len;
if (typeof inp === 'string') {
for (len=inp.length; i<len; i++)
internal_data.push(inp.charCodeAt(i) & 0xff);
} else if (inp && inp.byteLength) {/*If ArrayBuffer or typed array */
if (!('byteOffset' in inp)) /* If ArrayBuffer, wrap in view */
inp = new Uint8Array(inp);
for (len=inp.byteLength; i<len; i++)
internal_data.push(inp[i] & 0xff);
}
};
}
/**
* @param name String Key name
* @param value String|Blob|File|Uint8Array|ArrayBuffer Value
* @param filename String Optional File name (when value is not a string).
**/
FormData.prototype['append'] = function(name, value, filename) {
if (this.__endedMultipart) {
// Truncate the closing boundary
this.data.length -= this.boundary.length + 6;
this.__endedMultipart = false;
}
var valueType = Object.prototype.toString.call(value),
part = '--' + this.boundary + '\r\n' +
'Content-Disposition: form-data; name="' + name + '"';
if (/^\[object (?:Blob|File)(?:Constructor)?\]$/.test(valueType)) {
return this.append(name,
new Uint8Array(new FileReaderSync().readAsArrayBuffer(value)),
filename || value.name);
} else if (/^\[object (?:Uint8Array|ArrayBuffer)(?:Constructor)?\]$/.test(valueType)) {
part += '; filename="'+ (filename || 'blob').replace(/"/g,'%22') +'"\r\n';
part += 'Content-Type: application/octet-stream\r\n\r\n';
this.__append(part);
this.__append(value);
part = '\r\n';
} else {
part += '\r\n\r\n' + value + '\r\n';
}
this.__append(part);
};
})();
movies = [];
var timeStarted = 0;
uploadingVar = false;
const BYTES_PER_CHUNK = 64 * 1024 * 1024;
function toTitleCase(str)
{
return str.replace(/\w\S*/g, function(txt){return txt.charAt(0).toUpperCase() + txt.substr(1);});
}
function newUpload(blobOrFile, moviename, filename, i, fileType, sizeFile) {
var xhr = new XMLHttpRequest();
path = '/moviehtml/newmupload.php? moviename='+escape(moviename)+'&filename='+escape(filename)+'&num='+escape(i);
xhr.open('POST', path, false);
self.postMessage(blobOrFile.size);
var fd = new FormData();
//xhr.setRequestHeader('Content-Type', fileType)
//blobOrFile2 = FileReaderSync.readAsArrayBuffer(blobOrFile);
fd.append("files1", blobOrFile);
//fd.append("moviename", moviename);
//fd.append("filename", filename);
//fd.append("num",i);
seconds = new Date() / 1000;
xhr.send(fd);
self.postMessage(xhr.responseText)
self.postMessage({'type':'partial','done':i*BYTES_PER_CHUNK, 'started':timeStarted, 'total':sizeFile});
var finish = Date()/1000;
if (finish >= (seconds+100)){
return false;
}
return true;
}
function newFileUpload(file, movieName, fileType, filename, exten){
if (movieName == movieName.match(/[a-zA-Z0-9\. \:]+/)){
timeStarted = new Date().getTime();
var blob = file;// this.files[0];
//var filename = blob.name;
var moviename = toTitleCase(movieName);
// 1MB chunk sizes.
const SIZE = blob.size;
//alert(SIZE + ' '+document.getElementById('fileToUpload').files[0].size)
var start = 0;
var end = BYTES_PER_CHUNK;
//alert(SIZE/BYTES_PER_CHUNK)
var i = 1;
while(start < SIZE) {
wow = newUpload(blob.slice(start, end), moviename, filename, i, fileType, SIZE);
start = end;
end = start + BYTES_PER_CHUNK;
i++;
}
var xhr = new XMLHttpRequest();
var fd2 = new FormData();
typeFile = filename.split('.').pop()
fd2.append("type", blob.type);
fd2.append("exten", typeFile);
fd2.append("moviename", moviename);
xhr.open('POST', '/moviehtml/finishedupload.php', false);
xhr.send(fd2);
}
}
function process(){
uploadingVar = true;
while(movies.length > 0) {
upMovie = movies.pop();
var file = upMovie[0];
var movieName = upMovie[1];
var fileType = upMovie[2];
var filename = upMovie[3];
var exten = upMovie[4];
self.postMessage({'type':'start','size':file.size, 'name':movieName});
newFileUpload(file, movieName, fileType, filename, exten);
self.postMessage({'type':'finish','name':movieName})
self.postMessage(movieName + " Uploaded Succesfully");
}
uploadingVar = false;
}
self.addEventListener('message', function(e) {
movies.push(e.data);
if (!uploadingVar){
process();
}
}, false);
我的函数调用它：
var worker = new Worker('jswebworker.js');
function testUpload(){
//newFileUpload();
var file = document.getElementById('fileToUpload').files[0];
worker.postMessage([file,toTitleCase(document.getElementById('movieName').value), file.type, file.name, file.name.split('.').pop()]);
}
这是我单位的媒体服务器的网页。
我希望有一种方法可以创建一个blob，而无需将所有原始内容加载到内存中。
感谢您的帮助，Nick
This is the web page for a media server for my flat. I am hoping that there is a way to create a blob without loading all of the original into memory. Thanks for any help, Nick
推荐答案
我认为这个库（这里是 resumable的github页面.js 也可能已经做了你想要完成的事情。由于我不知道你要上传的文件有多大，我无法提供任何有关基准测试的见解。我希望这会帮助你。
I think that this library (here is the github page for resumable.js as well) may already be doing what you are trying too accomplish. Since I don't know how big the files are that you are tying to upload I can't provide any insight as far as benchmarks go. I hope this helps you out.
这篇关于Javascript Web Workers文件上传的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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