Question

I am writing a PHP program that downloads a pdf from a backend and save to a local drive. Now how do I check whether the file exists before downloading?

Currently I am using curl (see code below) to check and download but it still downloads the file which is 1KB in size.

$url = "http://wedsite/test.pdf";
$path = "C:\\test.pdf;"
downloadAndSave($url,$path);

function downloadAndSave($urlS,$pathS)
    {
        $fp = fopen($pathS, 'w');

        $ch = curl_init($urlS);

        curl_setopt($ch, CURLOPT_FILE, $fp);
        $data = curl_exec($ch);

        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        echo $httpCode;
        //If 404 is returned, then file is not found.
        if(strcmp($httpCode,"404") == 1)
        {
            echo $httpCode;
            echo $urlS; 
        }

        fclose($fp);

    }

I want to check whether the file exists before even downloading. Any idea how to do it?

Answer 1

You can do this with a separate curl HEAD request:

curl_setopt($ch, CURLOPT_NOBODY, true);
$data = curl_exec($ch);

$httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

When you actually want to download you can use set NOBODY to false.