Using HTML5 file uploads with AJAX and jQuery

Solution 1:

It's not too hard. Firstly, take a look at FileReader Interface.

So, when the form is submitted, catch the submission process and

var file = document.getElementById('fileBox').files[0]; //Files[0] = 1st file
var reader = new FileReader();
reader.readAsText(file, 'UTF-8');
reader.onload = shipOff;
//reader.onloadstart = ...
//reader.onprogress = ... <-- Allows you to update a progress bar.
//reader.onabort = ...
//reader.onerror = ...
//reader.onloadend = ...


function shipOff(event) {
    var result = event.target.result;
    var fileName = document.getElementById('fileBox').files[0].name; //Should be 'picture.jpg'
    $.post('/myscript.php', { data: result, name: fileName }, continueSubmission);
}

Then, on the server side (i.e. myscript.php):

$data = $_POST['data'];
$fileName = $_POST['name'];
$serverFile = time().$fileName;
$fp = fopen('/uploads/'.$serverFile,'w'); //Prepends timestamp to prevent overwriting
fwrite($fp, $data);
fclose($fp);
$returnData = array( "serverFile" => $serverFile );
echo json_encode($returnData);

Or something like it. I may be mistaken (and if I am, please, correct me), but this should store the file as something like 1287916771myPicture.jpg in /uploads/ on your server, and respond with a JSON variable (to a continueSubmission() function) containing the fileName on the server.

Check out fwrite() and jQuery.post().

On the above page it details how to use readAsBinaryString(), readAsDataUrl(), and readAsArrayBuffer() for your other needs (e.g. images, videos, etc).

Solution 2:

With jQuery (and without FormData API) you can use something like this:

function readFile(file){
   var loader = new FileReader();
   var def = $.Deferred(), promise = def.promise();

   //--- provide classic deferred interface
   loader.onload = function (e) { def.resolve(e.target.result); };
   loader.onprogress = loader.onloadstart = function (e) { def.notify(e); };
   loader.onerror = loader.onabort = function (e) { def.reject(e); };
   promise.abort = function () { return loader.abort.apply(loader, arguments); };

   loader.readAsBinaryString(file);

   return promise;
}

function upload(url, data){
    var def = $.Deferred(), promise = def.promise();
    var mul = buildMultipart(data);
    var req = $.ajax({
        url: url,
        data: mul.data,
        processData: false,
        type: "post",
        async: true,
        contentType: "multipart/form-data; boundary="+mul.bound,
        xhr: function() {
            var xhr = jQuery.ajaxSettings.xhr();
            if (xhr.upload) {

                xhr.upload.addEventListener('progress', function(event) {
                    var percent = 0;
                    var position = event.loaded || event.position; /*event.position is deprecated*/
                    var total = event.total;
                    if (event.lengthComputable) {
                        percent = Math.ceil(position / total * 100);
                        def.notify(percent);
                    }                    
                }, false);
            }
            return xhr;
        }
    });
    req.done(function(){ def.resolve.apply(def, arguments); })
       .fail(function(){ def.reject.apply(def, arguments); });

    promise.abort = function(){ return req.abort.apply(req, arguments); }

    return promise;
}

var buildMultipart = function(data){
    var key, crunks = [], bound = false;
    while (!bound) {
        bound = $.md5 ? $.md5(new Date().valueOf()) : (new Date().valueOf());
        for (key in data) if (~data[key].indexOf(bound)) { bound = false; continue; }
    }

    for (var key = 0, l = data.length; key < l; key++){
        if (typeof(data[key].value) !== "string") {
            crunks.push("--"+bound+"\r\n"+
                "Content-Disposition: form-data; name=\""+data[key].name+"\"; filename=\""+data[key].value[1]+"\"\r\n"+
                "Content-Type: application/octet-stream\r\n"+
                "Content-Transfer-Encoding: binary\r\n\r\n"+
                data[key].value[0]);
        }else{
            crunks.push("--"+bound+"\r\n"+
                "Content-Disposition: form-data; name=\""+data[key].name+"\"\r\n\r\n"+
                data[key].value);
        }
    }

    return {
        bound: bound,
        data: crunks.join("\r\n")+"\r\n--"+bound+"--"
    };
};

//----------
//---------- On submit form:
var form = $("form");
var $file = form.find("#file");
readFile($file[0].files[0]).done(function(fileData){
   var formData = form.find(":input:not('#file')").serializeArray();
   formData.file = [fileData, $file[0].files[0].name];
   upload(form.attr("action"), formData).done(function(){ alert("successfully uploaded!"); });
});

With FormData API you just have to add all fields of your form to FormData object and send it via $.ajax({ url: url, data: formData, processData: false, contentType: false, type:"POST"})