Close, but not quite finished (MySQL, BLOB, pics)

[Anon]

Hi there,

I am writing some website that allows some-one to see thumbnails of an image, after which he/she can click on the image to see the full picture. As I dont want to do parameter passing on the url, I am using session variables to pass parameters.

I have written a small script in PHP4 that retrieves data from a MySQL DataBase, processes it and sends it out. It's almost working as I want it to, but there's one little thing I can't solve.

In the calling script I retrieve some IDs from a table and then start to loop through the pics I want to display

---

$cSql = "SELECT photoID FROM photos WHERE sessionID = " . $sessID;
$link = mysql_connect("localhost", "UID", "PW");
$QueryRes = mysql_db_query($database, $cSql, $link);
while($row = mysql_fetch_array($QueryRes)) {
$nPicID = $row["photoID"];
if(session_is_registered(nPicID)) {
session_unregister(nPicID);
}
session_register(nPicID);
echo "<img src=\"getthumb.php\"><br>" . $nPicID . "<br>";
} // while

mysql_close($link);

The getthumb.php is as follows:

---

            if($nPicID == "") {
                    header("Location: sessionselector.php");
            } else {
                    $cSql = "SELECT strFileType, strFileName, blobPhoto FROM photos WHERE photoID = " . $nPicID;
                    $lnk = mysql_connect("localhost", "UID", "PW");
                    $QueryRes = mysql_db_query($database, $cSql, $lnk);
                    $row = mysql_fetch_array($QueryRes);
                    $data = $row["blobPhoto"];
                    $type = $row["strFileType"];
                    $fnam=$row["strFileName"];
                    mysql_close($lnk);
                    // todo: resize image
                    Header("Content-disposition: filename=gekloot");
                    //header( "Content-Disposition: filename=gekloot");
                    header("Content-type: " . $type);
                    print $data;
                    session_unregister(nPicID);
                    exit();
            } // if2
    } // if1

---

The problem is that on the calling page I get the result of n times the first image in the DB, all called getthumbs.php.

I think this is because the header info sent by getthumbs.php is disregarded by the calling page as some output was already sent to the browser. The brouwser in its turn, recognises n times the same file and displays it as such.

Does anybody have a workaround???

[Anon]

This is not quite the way I would have done this. I'm sorry that this is not an answer to your question, but, and sugestion to how to do it otherwise...

Insted of saving all images in the database, why not store them in singel files. The database will wery quickly become wery large and that is not a good thing. And if you store them in files you just need to pass the url to the file in the first script instead of running an extra script. Now for the tumbnails. Why not use a server side application that generates the thumbnail automaticly if they don't exsist and saves them with just a modifyed name (123.jpg -> 123tumb.jpg)... I'm not sure if this something you would feel comfortable with but if you would like to try I would recomend Image Alchemy for thumbnail generating

Andreas Bernhardsen

[Anon]

header ("Expires: Mon, 26 Jul 1997 05:00:00 GMT"); // Date in the past
header ("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
// always modified
header ("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
header ("Pragma: no-cache"); // HTTP/1.0

[Anon]

Thank you.
I now have the intended behaviour.

[Anon]

expire header don't seem to work on image content types on MSIE. found a new workaround:

<?
$rnd = rand();
echo "<img height=200 width=200 src=showpic.php?ref=$rnd&id=" . $row['ID'] . ">";
?>

now it should be something like:

<img height=200 width=200 src=showpic.php?ref=1093&id=1>

where ref is a random number so it will not be cached.