if if语句上传文件

Question

I have a simple file uploader on my index.php page which it gets posted to my addnew.php page along with 2 other input fields like this below:

<form action="addnew.php" method="post" enctype="multipart/form-data">
<input type="text" name="title" placeholder="Title">
<input type="text" name="location" placeholder="location">
<input type="file" name="file">
<input type="submit" value="add">
</form>

my question is that when it sends to the file upload, it sends a generateRandomString function to replace the original file name, so if the form field is empty, it still sends a string of 10 random characters to my database. My question is that how can I set a if/else statement so that it does not send the random characters to my database if the upload field is empty. Here's the idea that I have, but it's obviously not working..

if (!empty($_FILES['file'])=="") {
    $sql="INSERT INTO tabletry (title, location)
          VALUES ('".addslashes($title)."', '".addslashes($location)."')";
} else {
    $ext = pathinfo($_FILES['file']['name'])['extension'];
    $nFn = generateRandomString(). ".$ext";
    move_uploaded_file($_FILES['file']['tmp_name'],"pictures/".$nFn);

    function generateRandomString($legnth = 10) {
        return substr(str_shuffle("abcdefghijklmnopqrstuvwxyz"),0, $legnth);
    }

    $sql="INSERT INTO tabletry (title, location, mainimage) 
          VALUES ('".addslashes($title)."', '".addslashes($location)."', '{$nFn}')";  
}

any help would be amazing..

Answer 1

Don't compare empty() with any value this condition is always false and your code enter into else.

You need to change

if (!empty($_FILES['file'])=="") {// wrong use of empty

To

 if (!empty($_FILES['file'])

OR use file upload validation as

 $check = getimagesize($_FILES["file"]["tmp_name"]);
        if($check !== false) {
    /// Your code