necroface necroface - 1 month ago 15
Ajax Question

FormData append not working

I wrote this to upload an image to my local Apache webserver using

input
element in HTML. The
file
is logged as not empty, but why is the
form_data
completely empty?

$('#upload-image').change(function(e){
var file = e.target.files[0];
var imageType = /image.*/;
if (!file.type.match(imageType))
return;
console.log(file);
var form_data = new FormData();
form_data.append('file', file);
console.log(form_data);
$.ajax({
url: 'http://localhost/upload.php',
cache: false,
contentType: false,
processData: false,
data: form_data,
type: 'POST',
success: function(response){
console.log(response);
},
error: function(error){
console.log(error);
}
});

});


This is my
upload.php
on local webserver

<?php
header('Access-Control-Allow-Origin: *');
if ( 0 < $_FILES['file']['error'] ) {
echo 'Error: ' . $_FILES['file']['error'] . '<br>';
}
else {
move_uploaded_file($_FILES['file']['tmp_name'], 'uploads/' . $_FILES['file']['name']);
$target_path = $_SERVER['DOCUMENT_ROOT'] . "/uploads/" . $_FILES['file']['name'];
echo $target_path;
}
?>


The
console.log(response)
logs all the code lines of PHP file, instead of the returned result of
echo

Answer

When logging a formData object with just console.log(formData) it always returns empty, as you can't log formData.

If you just have to log it before sending it, you can use entries() to get the entries in the formData object

$('#upload-image').change(function(e) {
    var file = e.target.files[0];
    var imageType = /image.*/;

    if (!file.type.match(imageType)) return;

    var form_data = new FormData();
    form_data.append('file', file);

    for (var key of form_data.entries()) {
        console.log(key[0] + ', ' + key[1]);
    }

    $.ajax({
        url: 'http://localhost/upload.php',
        cache: false,
        contentType: false,
        processData: false,
        data: form_data,
        type: 'POST',
        success: function(response) {
            console.log(response);
        },
        error: function(error) {
            console.log(error);
        }
    });

});