upload.php

<?php
$target_dir = "uploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$fileType = pathinfo($target_file,PATHINFO_EXTENSION);
// Check if image file is a actual image or fake image
if(isset($_POST["submit"])) {
    //$check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
    $check = filesize($_FILES["fileToUpload"]["tmp_name"]);
    if($check !== false) {
        echo "This is a CSV format file - " . $check["mime"] . ".";
        $uploadOk = 1;
    } else {
        echo "This is not a CSV format file.";
        $uploadOk = 0;
    }
}
// Check if file already exists
if (file_exists($target_file)) {
    echo "File already exists! Upload a new file";
    $uploadOk = 0;
}
// Check file size
//check with WonHwa, what size limit are we looking at?
if ($_FILES["fileToUpload"]["size"] > 500000) {
    echo "Sorry, your file is too large.";
    $uploadOk = 0;
}
// Allow certain file formats
//if($imageFileType != "csv" && $imageFileType != "png" && $imageFileType != "jpeg"
//&& $imageFileType != "gif" ) {
if($fileType != "csv" ) {
    echo "Sorry! Only CSV files can be uploaded!!";
    $uploadOk = 0;
}
// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
    echo "Sorry, your file was not uploaded.";
// if everything is ok, try to upload file
} else {
    if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
        echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.";
    } else {
        echo "Sorry, there was an error uploading your file.";
    }
}

?>