一、前言
确定了渐进式增强的上传方式，接下来我们需要将上传功能从具体的业务逻辑中剥离出来，作为公共组件供业务层调用。这就要求我们必须对业务层隐藏上传细节，只暴露统一的上传API。这时候大家是不是跟我一样想到了Facade模式？
二、Facade模式实现文件上传，代码示例：
/*
上传组件，IE浏览器默认flash上传，其它浏览器html5
示例:
var fileUpload = new FileUpload({
container: document.getElementById("uploadBtn"),
onselect: function (files) {
var self = this;
$(files).each(function (i, n) {
updateUI(n);
});
setTimeout(function () { //异步，等待onselect函数return后才能调用upload
self.upload();
}, 10);
},
onprogress: function (fileInfo) {
updateUI(fileInfo);
},
oncomplete: function (fileInfo, responseText) {
updateUI(fileInfo);
}
});
*/
function FileUpload(options) {
var uploader=null;
if (options) {
//为什么要多创建一级div容器？flash 的activex创建后，再改变位置会引起activex对象失效，所以要在创建前就定好位
var div = document.createElement("div");
div.id = "flashUploadDiv";
document.body.appendChild(div);
var c = $(options.container);
//绝对定位到上传按钮的坐标，flash本身为透明遮罩
$(div).css({
position: "absolute",
left: c.offset().left + "px",
opacity:0,
top: c.offset().top + "px"
});
if ($.browser.msie || options.uploadType == "flash") {
//flash上传方式
var url = "Richinfo_annex_upload.swf";
var so = new SWFObject(url, "flashupload", c.width(), c.height());
so.addParam("wmode", "transparent");
so.write("flashUploadDiv");
options.activexObj = document.getElementById("flashupload");
window.JSForFlashUpload = new FlashUpload(options);
uploader = JSForFlashUpload;
} else {
$(div).html([‘<form style="" enctype="multipart/form-data" id="fromAttach" method="post" action="" target="frmAttachTarget">‘,
‘<input style="height: ‘, c.height(), ‘px;width:‘, c.width(), ‘px" type="file" name="uploadInput" id="uploadInput" multiple="true">‘,
‘</form>‘,
‘<iframe id="frmAttachTarget" style="display: none" name="frmAttachTarget"></iframe>‘].join(""));
options.uploadInput = document.getElementById("uploadInput");
uploader = new Html5Upload(options);
}
}
this.upload = function () {//触发上传请求
//alert("uploader.load");
uploader.upload();
},
this.cancel = function () {//取消上传
uploader.cancel();
}
this.getUploadFiles = function () {//获取上传队列
uploader.getUploadFiles();
}
$.extend(options, this);//继承FileUpload的能力
}
var FlashUpload = function(options){
var resultObject = {
activexObj: options.activexObj,
upload:function(){
this.activexObj.uploadAll();
},
cancel: function () {
this.activexObj.cancel();
},
getUploadUrl: function () {
return this.agent.getUploadUrl();
},
getUploadFiles: function () {
return this.uploadFiles;
},
onload: function (param) {
this.agent = {};
if (options) {
this.agent = options;
}
param["filter"] = ["images图片(*.jpg;*.png;*.bmp)", "video(*.flv;*.avi;*.rmvb)"];
param["uploadFieldName"] = "filedata";
//options["filter"] = ["eml邮件(*.eml)"];
//options["filter"] = ["所有文件(*.*)"];
return param;
},
onselect: function (xmlFileList, jsonFileList) {
for (var i = 0; i < jsonFileList.length; i++) {
jsonFileList[i].fileName = decodeURIComponent(jsonFileList[i].fileName);
jsonFileList[i].state = "waiting";
/*if (jsonFileList[i].fileSize > 100000) { //大于100K不上传
jsonFileList.splice(i, 1);
i--;
}*/
}
//uploadView.onselect(jsonFileList);
this.agent.onselect && this.agent.onselect(jsonFileList);
this.uploadFiles = jsonFileList;
return jsonFileList;
},
onprogress: function (taskId, sendedSize, uploadSpeed, fileInfo) {
fileInfo.taskId = taskId;
fileInfo.sendedSize = sendedSize;
fileInfo.percent = Math.round((sendedSize / fileInfo.fileSize) * 100);
fileInfo.state = "uploading";
fileInfo.fileName = decodeURIComponent(fileInfo.fileName);//防止乱码，flash里面做了encode
//alert(fileInfo.percent);
this.agent.onprogress && this.agent.onprogress(fileInfo);
},
oncomplete: function (taskId, responseText, fileInfo) {
fileInfo.taskId = taskId;
fileInfo.state = "complete";
fileInfo.fileName = decodeURIComponent(fileInfo.fileName);//防止乱码，flash里面做了encode
this.agent.oncomplete && this.agent.oncomplete(fileInfo, responseText);
},
onerror: function (taskId, errorCode, errorMsg) {
alert("文件上传失败：" + errorMsg);
this.agent.onerror && this.agent.onerror(errorMsg);
},
onmouseover: function () {
},
onmouseout: function () {
},
onclick: function () {
return true;//返回false不会弹出文件选择框
//alert("onclick");
}
}
return resultObject;
}
var Html5Upload = function (options) {
var resultObject = {
uploadInput: null,
currentFile: null,
uploadFiles:[],//待上传的文件
completeFiles:[],//已完成的文件
init: function () {
var self = this;
this.agent = options;
this.uploadInput = options.uploadInput;
this.uploadInput.onclick = this.onclick;
this.uploadInput.onchange = function () {
var files = this.files;
var result = [];
for (var i = 0; i < files.length; i++) {
console.log(files[i]);
result.push({
fileName: files[i].name,
fileSize: files[i].size,
fileData: files[i],
state : "waiting",
taskId: Math.random().toString().substr(2)
});
}
self.uploadFiles = result;
self.onselect(result);
}
},
getFileUploadXHR: function () { //单例
if (!window.fileUploadXHR) {
fileUploadXHR = new XMLHttpRequest();
}
this.xhr = window.fileUploadXHR;
return fileUploadXHR;
},
getUploadUrl: function () { //获取上传地址
return this.agent.getUploadUrl();
},
getUploadFiles:function(){ //获取上传队列
return this.uploadFiles.concat(this.completeFiles);
},
upload: function () {//开始上传请求
this.uploadNextFile();
},
cancel:function(){ //取消上传
this.xhr.abort();
},
uploadNextFile: function () { //每个上传文件会触发
var fileInfo = this.uploadFiles.shift();
this.completeFiles.push(fileInfo); //存入已完成列表
this.currentFile = fileInfo;
if (fileInfo) {
var self = this;
var xhr = this.getFileUploadXHR();
xhr.upload.onabort = function (oEvent) { };
xhr.upload.onerror = function (oEvent) { self.onerror(oEvent); };
xhr.upload.onload = function (oEvent) { self.onload(oEvent); };
xhr.upload.onloadend = function (oEvent) { };
xhr.upload.onloadstart = function (oEvent) { };
xhr.upload.onprogress = function (oEvent) {
console.log(oEvent);
fileInfo.state = "uploading";
fileInfo.sendedSize = oEvent.position;
fileInfo.percent = Math.round((oEvent.position / oEvent.total) * 100);
self.onprogress(fileInfo);
};
//xhr.ontimeout = function(oEvent){This.ontimeout(oEvent);};
xhr.onreadystatechange = function (oEvent) {
if (xhr.readyState == 4) {
if (xhr.status == 200) {
var responseText = xhr.responseText;
self.oncomplete(fileInfo);
}
}
};
var url = this.getUploadUrl();
xhr.open("POST", url, true);
//xhr.timeout = this.timeout; //timeout
function getFormData(fileInfo) {
var formData = new FormData();
formData.append("filedata", fileInfo.fileData);
return formData;
}
var fd = getFormData(fileInfo);
xhr.send(fd);
}
},
onclick: function () {
},
onselect:function(files){
this.agent.onselect && this.agent.onselect(files);
},
onload:function(e){
},
onprogress: function (fileInfo) {
this.agent.onprogress && this.agent.onprogress(fileInfo);
},
oncomplete: function (fileInfo) {
fileInfo.state = "complete";
this.agent.oncomplete && this.agent.oncomplete(fileInfo);
this.uploadNextFile();
}
}
resultObject.init();
return resultObject;
}
三、调用示例：
<html>
<head>
<script src="jquery-1.8.3.js"></script>
<script src="swfobject.js"></script>
<script src="upload.js"></script>
</head>
<body>
<div style="position:absolute">
</div>
<ul id="uploadList"></ul>
</body>
<script>
function updateUI(fileInfo) {
var ul = $("#uploadList");
switch (fileInfo.state) {
case "waiting":
ul.append("<li taskId=‘" + fileInfo.taskId + "‘>" + fileInfo.fileName + "(等待上传...)</li>");
break;
case "uploading":
ul.find("li[taskId=" + fileInfo.taskId + "]").html(fileInfo.fileName + "(" + fileInfo.percent + "%)");
break;
case "complete":
ul.find("li[taskId=" + fileInfo.taskId + "]").html(fileInfo.fileName + "(完成)");
break;
}
}
var fileUpload = new FileUpload({
container: document.getElementById("uploadBtn"),
//uploadType:"flash",
getUploadUrl: function () {
return "upload.ashx";
},
onselect: function (files) {
var self = this;
$(files).each(function (i, n) {
updateUI(n);
});
setTimeout(function () { //异步，等待onselect函数return后才能调用upload
self.upload();
}, 10);
},
onprogress: function (fileInfo) {
updateUI(fileInfo);
},
oncomplete: function (fileInfo, responseText) {
updateUI(fileInfo);
console.log(this.getUploadFiles());
}
});
</script>
</html>
四、结束语
以上源码仅提供上传组件化思路，实际应用中要考虑更多，比如：弱网络环境下需要分块上传，断点续传，异常情况下的日志上报等等。
以上源码非本人原创，代码来源于139邮箱前端团队内部分享。希望对大家有所帮助。
五、参考资料
百度前端上传组件：http://fex.baidu.com/blog/2014/04/html5-uploader/?qq-pf-to=pcqq.group
时间： 2024-08-11 18:34:18