Posting File Input as FileReader Binary Data through AJAX Post

Question

I am trying to post an attachment uploaded to an HTML file input to a web page through a rest API. The API documentation states that the post is a straight binary content as

Answer 1

Simply sending the file reference as data (with processData: false) did the job for me at least:

$('#_testButton').bind('click', function () {
    var file = document.getElementById('_testFile').files[0];

    $.ajax({
        url: "/attachmentURL",
        type: "POST",
        data: file,
        processData: false
    });
});

It is described here: https://developer.mozilla.org/en/DOM/XMLHttpRequest/Sending_and_Receiving_Binary_Data#section_3

Sending a string (even if that string represents binary data) will not work because the browser will forcibly turn it into unicode and encode as utf-8 as specified which will corrupt the binary data:

If data is a string Let encoding be UTF-8.

Let mime type be "text/plain;charset=UTF-8".

Let the request entity body be data converted to Unicode and encoded as UTF-8.

Sending a file reference (blob) will do this:

If data is a Blob If the object's type attribute is not the empty string let mime type be its value.

Let the request entity body be the raw data represented by data.

Answer 2

var file;

        $('#_testFile').on("change", function (e) {
            file = e.target.files[0];
        });
        $('#_testButton').click(function () {
            var serverUrl = '/attachmentURL';

            $.ajax({
                type: "POST",
                beforeSend: function (request) {
                    request.setRequestHeader("Content-Type", file.type);
                },
                url: serverUrl,
                data: file,
                processData: false,
                contentType: false,
                success: function (data) {
                    console.log("File available at: ", data);
                },
                error: function (data) {
                    var obj = jQuery.parseJSON(data);
                    alert(obj.error);
                }
            });
        });