我已成功使用以下命令将文件上传到节点服务器multer
通过使用输入文件对话框选择文件然后提交表单来模块,但现在我需要创建一个FormData
对象,并使用发送文件XMLHttpRequest
,但它不起作用,文件总是undefined
在服务器端(路由器)。
执行 AJAX 请求的函数是:
function uploadFile(fileToUpload, url) {
var form_data = new FormData();
form_data.append('track', fileToUpload, fileToUpload.name);
// This function simply creates an XMLHttpRequest object
// Opens the connection and sends form_data
doJSONRequest("POST", "/tracks/upload", null, form_data, function(d) {
console.log(d);
})
}
注意fileToUpload
被定义并且url
是正确的,因为调用了正确的路由器方法。fileToUpload
is a File
通过将文件从文件系统拖放到 dropzone,然后访问dataTransfer
drop 事件的属性。
doJSONRequest
是一个创建一个函数XMLHttpRequest
对象并发送文件等(如评论中所述)。
function doJSONRequest(method, url, headers, data, callback){
//all the arguments are mandatory
if(arguments.length != 5) {
throw new Error('Illegal argument count');
}
doRequestChecks(method, true, data);
//create an ajax request
var r = new XMLHttpRequest();
//open a connection to the server using method on the url API
r.open(method, url, true);
//set the headers
doRequestSetHeaders(r, method, headers);
//wait for the response from the server
r.onreadystatechange = function () {
//correctly handle the errors based on the HTTP status returned by the called API
if (r.readyState != 4 || (r.status != 200 && r.status != 201 && r.status != 204)){
return;
} else {
if(isJSON(r.responseText))
callback(JSON.parse(r.responseText));
else if (callback !== null)
callback();
}
};
//set the data
var dataToSend = null;
if (!("undefined" == typeof data)
&& !(data === null))
dataToSend = JSON.stringify(data);
//console.log(dataToSend)
//send the request to the server
r.send(dataToSend);
}
这是doRequestSetHeaders
:
function doRequestSetHeaders(r, method, headers){
//set the default JSON header according to the method parameter
r.setRequestHeader("Accept", "application/json");
if(method === "POST" || method === "PUT"){
r.setRequestHeader("Content-Type", "application/json");
}
//set the additional headers
if (!("undefined" == typeof headers)
&& !(headers === null)){
for(header in headers){
//console.log("Set: " + header + ': '+ headers[header]);
r.setRequestHeader(header, headers[header]);
}
}
}
我的路由器上传文件如下
// Code to manage upload of tracks
var multer = require('multer');
var uploadFolder = path.resolve(__dirname, "../../public/tracks_folder");
function validTrackFormat(trackMimeType) {
// we could possibly accept other mimetypes...
var mimetypes = ["audio/mp3"];
return mimetypes.indexOf(trackMimeType) > -1;
}
function trackFileFilter(req, file, cb) {
cb(null, validTrackFormat(file.mimetype));
}
var trackStorage = multer.diskStorage({
// used to determine within which folder the uploaded files should be stored.
destination: function(req, file, callback) {
callback(null, uploadFolder);
},
filename: function(req, file, callback) {
// req.body.name should contain the name of track
callback(null, file.originalname);
}
});
var upload = multer({
storage: trackStorage,
fileFilter: trackFileFilter
});
router.post('/upload', upload.single("track"), function(req, res) {
console.log("Uploaded file: ", req.file); // Now it gives me undefined using Ajax!
res.redirect("/"); // or /#trackuploader
});
我的猜测是multer
不明白fileToUpload
是一个带有名称的文件track
(不是吗?),即中间件upload.single("track")
无法正常工作/解析或什么都没有,或者可能根本无法与FormData
,那样的话那就乱了。继续使用 multer 会有什么替代方案?
如何使用 AJAX 和 multer 上传文件?
如果您需要更多详细信息,请随时询问。