【发布时间】：2019-07-16 03:57:43
【问题描述】：
我正在尝试简单地将文件上传到 node.js 服务器。
为此，我使用了文件 API 和 readAsArrayBuffer。这是触发输入文件“更改”事件时调用的代码，以及一些 hepler 函数（我使用COBY 库进行套接字发送和其他事件设置，binaryType 设置为 arraybuffer）：
COBY.events = {
"file": (e) => {
files = Array.from(e.target.files);
startReadingFile(files[0]);
}
};
function startReadingFile(file) {
readFileFrom(file, 0, chunkSize, (array, r) => {
COBY.socketSend({"start uploading a file": {
name:file.name,
type:file.type,
size:file.size,
data:(array)
}});
console.log("didnt something?", r, Array.from(r));
});
}
function readFileFrom(file, start, end, callback) {
var sliced = file.slice(start, end);
var reader = new FileReader();
reader.onload = (event) => {
result = (event.target.result);
var arr = Array.from(new Uint8Array(result));
if(callback && callback.constructor == Function) {
currentPosition = end;
callback(arr, result);
}
}
reader.readAsArrayBuffer(sliced);
}
在我的服务器上（我正在使用 coby-node 库，它是 COBY 客户端库的 node.js 版本）：
var coby = require("coby-node");
var fs = require("fs");
var files = {};
var kilobyte = 1024;
function makeBigFile(name, number) {
var test = fs.createWriteStream("./" + name, {flags: "w+"});
console.log("OK?",name);
[...Array(number)].forEach((x, i) => test.write(i+"\n"));
}
//makeBigFile("OKthere.txt", 12356);
coby.startAdanServer({
onOpen:(cs) => {
console.log("something just connected! Let's send it something");
// cs.send({"Whoa man !":1234});
cs.send({asdf :3456789});
},
onAdanMessage: (cs, msg) => {
// console.log("HMM weird just got this message...", msg);
},
adanFunctions: {
"do something important": (cs, data) => {
console.log("I just got some message:", data);
console.log(cs.server.broadcast);
cs.server.broadcast({"look out":"here I am"}, {
current: cs
});
cs.send({message:"OK I did it I think"});
},
"start uploading a file": (cs, data) => {
if(data.data && data.data.constructor == Array) {
var name = data["name"]
files[name] = {
totalSize:data.size,
downloadedSize:0
};
files[name]["handler"] = fs.createWriteStream("./" + data.name, {
flags: "w+"
});
files[name]["handler"].on("error", (err) => {
console.log("OY vay", err);
});
cs.send({"ok dude I need more": {
name:name,
bytePositionToWriteTo:0,
totalLength:files[name]["totalSize"]
}});
}
},
"continue uploading file": (cs, data) => {
var name = data.name;
if(files[name]) {
var handler = files[name]["handler"];
var uint = Uint8Array.from(data.bufferArray);
var myBuffer = Buffer.from(uint.buffer);
var start = data.startPosition || 0,
end = myBuffer.byteLength + start;
files[name].downloadedSize += myBuffer.byteLength;
if(files[name].downloadedSize < files[name]["totalSize"]) {
cs.send({"ok dude I need more": {
name:name,
bytePositionToWriteTo:files[name].downloadedSize,
totalLength:files[name]["totalSize"]
}});
try {
handler.write(myBuffer);
} catch(e) {
console.log("writing error: ", e);
}
} else {
end = files[name]["totalSize"];
handler.write(myBuffer);
console.log("finished, I think?");
console.log(files[name].downloadedSize, "total: ", files[name]["totalSize"]);
console.log(" start: ", start, "end: ", end);
}
}
}
},
intervalLength:1000
});
function startUnity() {
coby.cmd(`./MyUnity/Editor/Unity.exe -batchmode -quit -projectPath "./MyUnity/totally empty" -executeMethod COBY.Start -logfile ./new123folder/wow.txt`, {
onData:(data) => {
console.log(data);
},
onError:(data) => {
console.log(data);
},
onExit:(exitCode) => {
console.log("exitted with code: " + exitCode);
},
onFail:(msg) => {
console.log(msg);
}
});
}
到目前为止，这实际上上传了一个文件，您可以使用 npm install coby-node 对其进行测试，但它需要更多时间，因为我正在 JSON.stringifing 一个 Array.from(new Uint8Array(/* the ArrayBuffer result */)) 然后在服务器端我重新 JSON解析它，但我如何将实际的 ArrayBuffer 发送到 websocket？我想将arraybuffer 连同文件的名称和其他数据一起发送，所以我想将它包含在一个JSON对象中，但是当我 JSON.stringify(/an ArrayBuffer em>/) 结果总是[]，IDK怎么用我自己的数据发送一个ArrayBuffer？？？
另外，使用 Array.from(new Uint8Array(arrayBufer)) 似乎要花费很多时间，您认为 readAsDataURL 会更快吗？
顺便说一句，我能够通过 websocket 使用 binayType="arraybuffer" 由 ITSELF 发送一个数组缓冲区，但是如何在其中包含文件名？？
【问题讨论】：
标签： javascript arrays node.js json fileapi