[angularjs] File Upload using AngularJS

I've read all the thread and the HTML5 API solution looked the best. But it changes my binary files, corrupting them in a manner I've not investigated. The solution that worked perfectly for me was :

HTML :

<input type="file" id="msds" ng-model="msds" name="msds"/>
<button ng-click="msds_update()">
    Upload
</button>

JS:

msds_update = function() {
    var f = document.getElementById('msds').files[0],
        r = new FileReader();
    r.onloadend = function(e) {
        var data = e.target.result;
        console.log(data);
        var fd = new FormData();
        fd.append('file', data);
        fd.append('file_name', f.name);
        $http.post('server_handler.php', fd, {
            transformRequest: angular.identity,
            headers: {'Content-Type': undefined}
        })
        .success(function(){
            console.log('success');
        })
        .error(function(){
            console.log('error');
        });
    };
    r.readAsDataURL(f);
}

Server side (PHP):

$file_content = $_POST['file'];
$file_content = substr($file_content,
    strlen('data:text/plain;base64,'));
$file_content = base64_decode($file_content);