xmlhttp 收发二进制数据 （Sending and Receiving Binary Data）

Sending and Receiving Binary Data

使用JavaScript类型数组接受二进制数据Edit

r

esponseType

r

esponse属性的值会根据

r

esponseType属性的值的不同而不同

ArrayBuffer

Blob

Document

NULL(如果请求未完成或失败)

var oReq = new XMLHttpRequest();
oReq.open("GET", "/myfile.png", true);
oReq.responseType = "arraybuffer";

oReq.onload = function (oEvent) {
var arrayBuffer = oReq.response; // 注意:不是oReq.responseText
if (arrayBuffer) {
var byteArray = new Uint8Array(arrayBuffer);
for (var i = 0; i < byteArray.byteLength; i++) {
// 对数组中的每个字节进行操作
}
}
};

oReq.send(null);

var BlobBuilder = window.MozBlobBuilder || window.WebKitBlobBuilder || window.MSBlobBuilder || window.BlobBuilder;
var oReq = new XMLHttpRequest();
oReq.open("GET", "/myfile.png", true);
oReq.responseType = "arraybuffer";

oReq.onload = function(oEvent) {
var blobBuilder = new BlobBuilder();
blobBuilder.append(oReq.response);
var blob = blobBuilder.getBlob("image/png");
// ...
};

oReq.send();

给

添加了一个私有的非标准属性mozResponseArrayBuffer

在老的浏览器中接受二进制数据Edit

load_binary_resource()方法

function load_binary_resource(url) {
var req = new XMLHttpRequest();
req.open('GET', url, false);
//XHR binary charset opt by Marcus Granado 2006 [http://mgran.blogspot.com]
req.overrideMimeType('text/plain; charset=x-user-defined');
req.send(null);
if (req.status != 200) return '';
return req.responseText;
}

var filestream = load_binary_resource(url);
var abyte = filestream.charCodeAt(x) & 0xff; // 扔掉的高位字节(f7)

filestream.length-1

发送二进制数据Edit

send方法

ArrayBuffer

Blob

File

POST方法将该文件发送到了服务器上

var oReq = new XMLHttpRequest();
oReq.open("POST", url, true);
oReq.onload = function (oEvent) {
// 上传完成后.
};

var bb = new BlobBuilder(); // 需要合适的前缀: window.MozBlobBuilder 或者 window.WebKitBlobBuilder
bb.append('abc123');

oReq.send(bb.getBlob('text/plain'));

将类型数组作为二进制数据发送Edit

var myArray = new ArrayBuffer(512);
var longInt8View = new Uint8Array(myArray);

for (var i=0; i< longInt8View.length; i++) {
longInt8View[i] = i % 255;
}

var xhr = new XMLHttpRequest;
xhr.open("POST", url, false);
xhr.send(myArray);

ArrayBuffer

Firefox私有方法Edit

POST

sendAsBinary()

var req = new XMLHttpRequest();
req.open("POST", url, true);
// 这里应该设置适当的MIME请求头
req.setRequestHeader("Content-Length", 741);
req.sendAsBinary(aBody);

sendAsBinary()

nsIFileInputStream

send()

Content-Length请求头

// 新建一个文件流.
var stream = Components.classes["@mozilla.org/network/file-input-stream;1"]
.createInstance(Components.interfaces.nsIFileInputStream);
stream.init(file, 0x04 | 0x08, 0644, 0x04); // file是一个nsIFile对象实例

// 设置文件的MIME类型
var mimeType = "text\/plain";
try {
var mimeService = Components.classes["@mozilla.org/mime;1"]
.getService(Components.interfaces.nsIMIMEService);
mimeType = mimeService.getTypeFromFile(file); // file是一个nsIFile对象实例
}
catch (oEvent) { /* 丢弃异常,使用默认的text/plain类型 */ }

// 发送
var req = Components.classes["@mozilla.org/xmlextras/xmlhttprequest;1"]
.createInstance(Components.interfaces.nsIXMLHttpRequest);
req.open('PUT', url, false); /* 同步模式! */
req.setRequestHeader('Content-Type', mimeType);
req.send(stream);