Creating An Online Photo Album with PHP and GD: Part 3

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Creating An Online Photo Album with PHP and GD: Part 3

By: Frank Manno	Search For More Articles! Disclaimer Author Terms
Rating: / 16
2003-09-03

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Part 3 is here! It is time to learn how to create an upload area as well as developing the php code so that the details about the photo are updatable.We need to determine what our requirements for the upload section will be. I’ve decided that I would first like to indicate the number of images to upload. Next, we select the album we’d like to upload our images to, and proceed on. An added option that we’ll add to the image uploads is a checkbox that will allow us to specify which photo we’d like to be the album cover for our selected album.

I would also like the option of not only providing a description for the albums, but also for each individual photo. Descriptions can contain EXIF information (Exchangeable Image File Format), photo date, and anything of value.

EXIF stands for Exchangeable Image File Format, and is a standard for storing interchange information in image files, especially those using JPEG compression. Most digital cameras now use the EXIF format. – EXIF.org

Our first form will be very simple. One field, which will indicate the number of images we would like to upload, and the other, a drop-down, to select the album to which the images will belong. We’ll call this page upload_images.php:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Gallery - Upload Images</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<body leftmargin="0" topmargin="0" marginwidth="0" marginheight="0">
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td><form action="image_upload.php" method="post">
<p> </p>
<table width="60%" border="0" align="center" cellpadding="3" cellspacing="0">
<tr>
<td><h1>Image Upload Area</h1></td>
</tr>
</table>
<table width="60%" border="0" align="center" cellpadding="5" cellspacing="0">
<tr>
<td colspan="2"><p>Please indicate the number of
images you wish to upload to your album(s). If you would like
to create a new album, click the Create New Album link below.</p>
</td>
</tr>
<tr>
<td> </td>
<td> </td>
</tr>
<tr>
<td>Number of Images:<br>
(JPEG / PNG)</td>
<td><input name="num_images" type="text" id="num_images" size="10">
</td>
</tr>
<tr>
<td>Photo Album:</td>
<td><select name="albums" id="albums">
<?php
include("../include/config.php");
db_connect();
$sql = "SELECT album_id, album_name FROM albums";
$result = @mysql_query( $sql ) or die("Error retrieving records: " . mysql_error());
while ( $row = mysql_fetch_array($result) ){
echo("<option value=" . $row['album_id'] . ">" . $row['album_name'] . "</option>");
}
?>
</select>
</td>
</tr>
<tr>
<td> </td>
<td><input name="submit" type="submit" id="submit" value="Continue">
</td>
</tr>
</table>
<table width="60%" border="0" align="center" cellpadding="3" cellspacing="0" >
<tr>
<td><a href="index.php">Main Menu</a> | <a href="new_album.php">Create
New Album</a> | <a href="../gallery.php">View Gallery</a></td>
</tr>
</table>
</form>
</td>
</tr>
</table>
</body>
</html>

The PHP code for our form is quite simple:

db_connect();
$sql = "SELECT album_id, album_name FROM albums";
$result = @mysql_query( $sql ) or die("Error retrieving records: " . mysql_error());
while ( $row = mysql_fetch_array($result) ){
echo("<option value=’" . $row['album_id'] . "’>" . $row['album_name'] . "</option>\n");
}

We connect to our database, retrieve the album name and ID, and display the values in a drop-down form. The album ID is the value of each option, and the album name is the text that is displayed in the drop-down menu:

Once we indicate the number of photos we’d like to upload, our upload form is displayed. Our image upload form will contain the following fields: a field to store the filename (chosen by the browse button), an image title field, and image description field, and a radio button indicating whether or not the photo is the album cover. We’ll call this page image_upload.php:

<?php
if (!$_POST['num_images']){
echo("Please specify the # of images you wish to upload!<br />");
echo("Click <a href='javascript:history.go(-1)'>here</a> to go back.");
die();
} else {
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Gallery - Image Upload</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"></head>
<body leftmargin="0" topmargin="0" marginwidth="0" marginheight="0">
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td><form action="create_thumbnails.php" method="post" enctype="multipart/form-data">
<p> </p>
<table width="60%" border="0" align="center" cellpadding="3" cellspacing="0">
<tr>
<td><h1>Image Upload Area</h1>
</td>
</tr>
</table>
<table width="60%" border="0" align="center" cellpadding="5" cellspacing="0">
<?php
for ($i = 0; $i < $_POST['num_images']; $i++){
// Determine alternate row colours
if($i % 2 == 0){
$style = "bgcolor=\"#FFFFFF\"";
$bottomstyle = "bgcolor=\"#FFFFFF\"";
} else {
$style = "bgcolor=\"#EFEFEF\"";
$bottomstyle = "bgcolor=\"#EFEFEF\"";
}
echo("\n<tr>\n<td $style width='15%'>Image #" . ($i + 1) . ": </td>\n<td $style><input type='file' name='image[]'></td>\n</tr>");
echo("\n<tr>\n<td $style width='15%'>Image Title : </td>\n<td $style><input type='text' name='photo_title'></td>\n</tr>");
echo("\n<tr>\n<td $style valign=\"top\">Photo Description: </td>\n<td $style><textarea name='photo_desc' cols='30' rows='6' wrap='default'></textarea></td>\n</tr>");
echo("\n<tr>\n<td $style valign=\"top\">Album Cover? </td>\n<td $style><input type=\"radio\" name=\"album_cover\" value=\"$i\">");
}
echo("
<tr>
<td $style> </td>
<td $style>
<input name='process' type='hidden' value='1'>
<input name='album_id' type='hidden' value='" . $_POST['albums'] . "'>
<input name='submit' type='submit' id='submit' value='Continue'>
</td>
</tr>");
?>
</table>
<table width="60%" border="0" align="center" cellpadding="3" cellspacing="0" class="bottommenu">
<tr>
<td class="bottommenu"><a href="index.php">Main Menu</a> | <a href="new_album.php">Create
New Album</a> | <a href="../gallery.php">View Gallery</a></td>
</tr>
</table>
</form>
</td>
</tr>
</table>
</body>
</html>
<?php
}
?>

The HTML code is straight-forward. We have a simple form, which allows us to indicate the file we want to upload, our image title and description, as well as a radio button allowing us to specify which photo to make our cover.

<?php
for ($i = 0; $i < $_POST['num_images']; $i++){
// Determine alternate row colours
if($i % 2 == 0){
$style = "bgcolor=\"#FFFFFF\"";
$bottomstyle = "bgcolor=\"#FFFFFF\"";
} else {
$style = "bgcolor=\"#EFEFEF\"";
$bottomstyle = "bgcolor=\"#EFEFEF\"";
}
echo("\n<tr>\n<td $style width='15%'>Image #" . ($i + 1) . ": </td>\n<td $style><input type='file' name='image[]'></td>\n</tr>");
echo("\n<tr>\n<td $style width='15%'>Image Title : </td>\n<td $style><input type='text' name='photo_title'></td>\n</tr>");
echo("\n<tr>\n<td $style valign=\"top\">Photo Description: </td>\n<td $style><textarea name='photo_desc' cols='30' rows='6' wrap='default'></textarea></td>\n</tr>");
echo("\n<tr>\n<td $style valign=\"top\">Album Cover? </td>\n<td $style><input type=\"radio\" name=\"album_cover\" value=\"$i\">");
}
echo("
<tr>
<td $style> </td>
<td $style>
<input name='process' type='hidden' value='1'>
<input name='album_id' type='hidden' value='" . $_POST['albums'] . "'>
<input name='submit' type='submit' id='submit' value='Continue'>
</td>
</tr>");
?>

Our PHP code is quite simple as well. We first start off by creating a loop, which will create our upload form. The number of times we loop is determined by the number of images we indicated on the previous page.

// Determine alternate row colours
if($i % 2 == 0){
$style = "bgcolor=\"#FFFFFF\"";
$bottomstyle = "bgcolor=\"#FFFFFF\"";
} else {
$style = "bgcolor=\"#EFEFEF\"";
$bottomstyle = "bgcolor=\"#EFEFEF\"";
}

The code above is simply used to allow an easy screen-flow. We create alternating row colours making use of the modulus (%) operator. We’re simply stating: If the remainder of our loop’s counter, divided by 2, returns 0, use white as the background colour; otherwise, use grey.

The rest of the form is built using the loop. When we submit the form, the values of the form are sent to our processing page, create_thumbnails.php:

<?php
include("GallerySizer.php");
include("../include/config.php");
DEFINE("IMAGE_FULL", '../photos/');
// Album cover
$cover = $_FILES['image']['name'][$_POST['album_cover']];
if (!$_REQUEST['process']){
echo("Error! No images chosen for processing. <br />");
echo("Click <a href='index.php'>here</a> to start processing your images.");
die();
} elseif (!$_POST['album_id']){
echo("No album selected. Please <a href=\"\">choose an album</a> to upload images to.");
die();
} else {
for($i = 0; $i < count($_FILES['image']['tmp_name']); $i++){
$fileName = $_FILES['image']['name'][$i];
copy($_FILES['image']['tmp_name'][$i], IMAGE_FULL . $fileName);
$thumb = new GallerySizer();
if($thumb->getLocation($_FILES['image']['name'][$i])){
if($thumb->loadImage()){
echo("Still here!");
if($thumb->getSize()){
if($thumb->setThumbnail()){
if($thumb->copyImage()){
if($thumb->resizeImage()){
$thumb->copyResize();
$thumb->display();
}
}
}
}
} else {
echo("Invalid image/file has been uploaded. Please upload a supported file-type (JPEG/PNG)");
unlink(IMAGE_FULL . $fileName);
die();
}
insert_location($thumb);
} else {
echo("Error processing images: " . mysql_error());
}
// If image matches cover selection, update album cover
if($cover == $_FILES['image']['name'][$i]){
$sql = "UPDATE albums SET album_cover = '" . $thumb->getThumbLocation() . "' WHERE album_id = " . $_POST['album_id'];
$result = @mysql_query($sql) or die("Error inserting records: " . mysql_error());
}
}
}
function insert_location($thumb_obj){
$image_location = $thumb_obj->getImageLocation();
$thumb_location = $thumb_obj->getThumbLocation();
$dbcnx = mysql_connect("localhost", "root", "");
mysql_select_db("album", $dbcnx);
$sql = "INSERT INTO photos values(0, '$_POST[photo_title]', '$_POST[photo_desc]', NOW(), '$image_location', '$thumb_location', $_POST[album_id])";
$result = mysql_query($sql, $dbcnx) or die("Error inserting record(s) into the database: " . mysql_error());
if ($result){
echo("Images successfully converted and stored! <br />Click <a href='../admin'>here</a> to continue.");
}
}
?>

The code is as follows:

// Album cover
$cover = $_FILES['image']['name'][$_POST['album_cover']];

We store the value of our chosen album, which will be used later on in the script.

if (!$_REQUEST['process']){
echo("Error! No images chosen for processing. <br />");
echo("Click <a href='upload_images.php'>here</a> to start processing your images.");
die();
} elseif (!$_POST['album_id']){
echo("No album selected. Please <a href=\"upload_images.php\">choose an album</a> to upload images to.");
die();

Here we simply check to see if the form has been properly submitted via the image_upload script. If the script isn’t properly submitted, we offer a link back to the upload_images script.

We also check to see if an album ID has been selected, which is determined by the album name drop-down. If no album has been selected, we notify the user, and provide a link back to the upload_images script.

for($i = 0; $i < count($_FILES['image']['tmp_name']); $i++){
$fileName = $_FILES['image']['name'][$i];
copy($_FILES['image']['tmp_name'][$i], IMAGE_FULL . $fileName);
$thumb = new GallerySizer();
if($thumb->getLocation($_FILES['image']['name'][$i])){
if($thumb->loadImage()){
echo("Still here!");
if($thumb->getSize()){
if($thumb->setThumbnail()){
if($thumb->copyImage()){
if($thumb->resizeImage()){
$thumb->copyResize();
$thumb->display();
}
}
}
}
} else {
echo("Invalid image/file has been uploaded. Please upload a supported file-type (JPEG/PNG)");
unlink(IMAGE_FULL . $fileName);
die();
}
insert_location($thumb);
} else {
echo("Error processing images: " . mysql_error());
}
// If image matches cover selection, update album cover
if($cover == $_FILES['image']['name'][$i]){
$sql = "UPDATE albums SET album_cover = '" . $thumb->getThumbLocation() . "' WHERE album_id = " . $_POST['album_id'];
$result = @mysql_query($sql) or die("Error inserting records: " . mysql_error());
}
}

This here is the chunk of our script. This is also where we finally make use of our GallerySizer class file. We first loop through the files that have been uploaded. We make use of PHP’s global array $_FILES, which allows us to access file information, including: file name, file size, etc.

In dealing with our files, we first retrieve actual name of the file, and store it into our $fileName variable. When then use PHP’s copy() function, and create a copy of the temporary uploaded file, and store it in our image directory (a constant defined at the top of our script).

Next, we create an object reference to GallerySizer class. We’ll call our object $thumb. We use our $thumb object to call the getLocation() method (function), and pass to it our the file uploaded from the form. If the function returns a true value, we proceed by calling the loadImage() method, which will then determine if the type of file uploaded is supported by our gallery. If the file uploaded is of an invalid type (not supported), an error message is displayed to the user. If the file is supported, the method returns true, and we then call the getSize() method.

The getSize() method will determine the dimensions of our uploaded photo, determine the scale for our thumbnail and resized image conversions. If the method returns true, we proceed by calling the setThumbnail() method, which will then convert our uploaded image into a thumbnail. If the method returns true, we call the copyImage() method, which will copy the newly created thumbnail into our specified thumbnail directory. If the copyImage() method operates successfully, it will return true.

If a true value is returned, we call the resizeImage() method, which will now resize our uploaded image. The size of the image will be less than or equal to our maximum-desired dimensions (set in our GallerySizer class file). If a true value is returned, we then call our last method, copyResize(), which will simply place our newly-resized image into the specified photo directory.

Because our method-calls are nested, a single failure would cause the entire hierarchy to fail, resulting in the error message – “Error processing image(s)…” – to be displayed.

Assuming our pass-through into the hierarchy yields a successful conversion process, we call the insert_location() function and pass to it our object reference, $thumb.

The insert_location() function accepts an object reference, and creates an SQL INSERT statement, which creates a new record of the image in the photos table of our database.

Our last condition statement:

if($cover == $_FILES['image']['name'][$i])

simply checks to see whether or not the current image (in our loop iteration) matches the image chosen as the album cover from the previous image upload page. If the current image is the album cover, we simply create an SQL EDIT statement, which sets the value of the album_cover field to the path of the current image’s thumbnail; thus, resulting in a complete conversion process.

We then display a message to the user, notifying them that the conversion process was successful.

Image Editing, Please!

Well, after we’ve uploaded our images, we may decide that our photo descriptions aren’t what we originally intended. No problem! We’ll add our edit_photos.php script, and making changes to our photo titles and descriptions will be a breeze:

<?php
include_once("../include/config.php");
// Has album been updated?
if ( $_POST['edit'] ){
if ( empty($_POST['photo_title']) || empty($_POST['photo_desc'])){
$msg = "Please complete all required fields!<br /><a href='edit_photos.php'>Go Back</a>";
displayPage( $msg, "Error Updating Photo!");
die();
}
db_connect();
// Insert updated record into DB
$sql = "UPDATE photos SET photo_title = '" . addslashes($_POST['photo_title']) . "', photo_desc = '" . addslashes($_POST['photo_desc']) . "' WHERE photo_id = " . $_POST['photo_id'];
$result = @mysql_query( $sql ) or die("Error inserting record: " . mysql_error());
if ($result){
$msg = "Photo updated successfully!<br /><a href='index.php'>Return to Admin Menu</a>";
displayPage($msg, "Photo Updated Successfully!");
die();
}
} else if ( !$_POST['edit'] && !empty($_GET['photo_id'])){
db_connect();
// Retrieve album information
$sql = "SELECT photo_id, photo_title, photo_desc FROM photos WHERE photo_id = " . addslashes($_GET['photo_id']);
$result = @mysql_query( $sql ) or die("Error retrieving record: " . mysql_error());
while($row = mysql_fetch_array( $result )){
// Display edit page
$msg .= "<form action=\"edit_photos.php\" method=\"post\">\n";
$msg .= "<table width=\"60%\" border=\"0\" cellpadding=\"5\" cellspacing=\"0\">\n";
$msg .= "<tr>\n<td>Photo Title:</td>\n<td><input name=\"photo_title\" type=\"text\" id=\"photo_title\" size=\"40\" value=\"" . $row['photo_title'] . "\"></td>\n</tr>\n";
$msg .= "<tr>\n<td>Photo Description:</td>\n<td><textarea name=\"photo_desc\" cols=\"30\" rows=\"4\" id=\"photo_desc\">" . $row['photo_desc'] . "</textarea></td>\n</tr>\n";
$msg .= "<tr>\n<td><input type=\"hidden\" name=\"edit\" value=\"1\"><input type=\"hidden\" name=\"photo_id\" value=\"" . addslashes($_GET['photo_id']) . "\"></td>\n";
$msg .= "<td><input name=\"submit\" type=\"submit\" id=\"submit\" value=\"Continue\">";
$msg .= "<a href=\"del_photos.php?photo_id=" . addslashes($_GET['photo_id']) . "\">Delete</a>";
$msg .= "</td>\n</tr>\n</table>\n</form>";
$photo_title = $row['photo_title'];
}
displayPage($msg, "Editing Photo " . $photo_title . ":");
// Display album summaries
} elseif ( !$_GET['photo_id'] ){
db_connect();
// Retrieve all album information
$sql = "SELECT photos.photo_id, photos.photo_title, albums.album_cover FROM photos, albums
WHERE photos.album_id = albums.album_id";
$result = @mysql_query( $sql ) or die( "Error retrieving records: " . mysql_error() );
$i = 0;
while($row = mysql_fetch_array($result)){
if (( $i % IMAGE_DISPLAY ) == 0 && ( $i != 0 )){
$msg .= ("</tr>\n<tr>");
}
$msg .= ("<td>" . ($i + 1) . ". <a href='edit_photos.php?photo_id=" . $row['photo_id'] . "'>");
$msg .= ($row['photo_title'] . "<br /><img src=\"../" . $row['album_cover'] . "\" /></td>\n");
$i++;
}
displayPage( $msg, "Edit Photos", false );
}
?>

The code is identical to our edit_album.php script, except that rather than using our album data, we take the photo data into consideration.

include_once("../include/config.php");
// Has album been updated?
if ( $_POST['edit'] ){
if ( empty($_POST['photo_title']) || empty($_POST['photo_desc'])){
$msg = "Please complete all required fields!<br /><a href='edit_photos.php'>Go Back</a>";
displayPage( $msg, "Error Updating Photo!");
die();
}

We first check to see whether or not the edited photo information has been submitted. If it has, we check to see whether or not the fields were completed. If not, we display an error message to the user. If the fields have been completed, we create an SQL UPDATE statement, and make changes to the photo’s information in the DB:

$sql = "UPDATE photos SET photo_title = '" . addslashes($_POST['photo_title']) . "', photo_desc = '" . addslashes($_POST['photo_desc']) . "' WHERE photo_id = " . $_POST['photo_id'];
$result = @mysql_query( $sql ) or die("Error inserting record: " . mysql_error());
if ($result){
$msg = "Photo updated successfully!<br /><a href='index.php'>Return to Admin Menu</a>";
displayPage($msg, "Photo Updated Successfully!");
die();
}

If successful, we notify the user.

} else if ( !$_POST['edit'] && !empty($_GET['photo_id'])){
db_connect();
// Retrieve album information
$sql = "SELECT photo_id, photo_title, photo_desc FROM photos WHERE photo_id = " . addslashes($_GET['photo_id']);
$result = @mysql_query( $sql ) or die("Error retrieving record: " . mysql_error());
while($row = mysql_fetch_array( $result )){
// Display edit page
$msg .= "<form action=\"edit_photos.php\" method=\"post\">\n";
$msg .= "<table width=\"60%\" border=\"0\" cellpadding=\"5\" cellspacing=\"0\">\n";
$msg .= "<tr>\n<td>Photo Title:</td>\n<td><input name=\"photo_title\" type=\"text\" id=\"photo_title\" size=\"40\" value=\"" . $row['photo_title'] . "\"></td>\n</tr>\n";
$msg .= "<tr>\n<td>Photo Description:</td>\n<td><textarea name=\"photo_desc\" cols=\"30\" rows=\"4\" id=\"photo_desc\">" . $row['photo_desc'] . "</textarea></td>\n</tr>\n";
$msg .= "<tr>\n<td><input type=\"hidden\" name=\"edit\" value=\"1\"><input type=\"hidden\" name=\"photo_id\" value=\"" . addslashes($_GET['photo_id']) . "\"></td>\n";
$msg .= "<td><input name=\"submit\" type=\"submit\" id=\"submit\" value=\"Continue\">";
$msg .= "<a href=\"del_photos.php?photo_id=" . addslashes($_GET['photo_id']) . "\">Delete</a>";
$msg .= "</td>\n</tr>\n</table>\n</form>";
$photo_title = $row['photo_title'];
}
displayPage($msg, "Editing Photo " . $photo_title . ":");

Next, we verify whether or not the photo information has been edited, and whether or not the photo ID has been submitted. If the page has not been edited, and a photo ID _has_ been specified, we present the user with a form that allows them to edit the pre-existing photo information (title and description). We also provide a link for the image to be deleted from the database. If the user chooses to delete the photo, the photo ID is passed onto our del_photos.php script, which we’ll discuss in a bit.

// Display album summaries
} elseif ( !$_GET['photo_id'] ){
db_connect();
// Retrieve all album information
$sql = "SELECT photos.photo_id, photos.photo_title, albums.album_cover FROM photos, albums
WHERE photos.album_id = albums.album_id";
$result = @mysql_query( $sql ) or die( "Error retrieving records: " . mysql_error() );
$i = 0;
while($row = mysql_fetch_array($result)){
if (( $i % IMAGE_DISPLAY ) == 0 && ( $i != 0 )){
$msg .= ("</tr>\n<tr>");
}
$msg .= ("<td>" . ($i + 1) . ". <a href='edit_photos.php?photo_id=" . $row['photo_id'] . "'>");
$msg .= ($row['photo_title'] . "<br /><img src=\"../" . $row['album_cover'] . "\" /></td>\n");
$i++;
}
displayPage( $msg, "Edit Photos", false );
}

Lastly, we check to see whether or not a photo ID has been passed to the page. If not, we list all the photos in our database, in a tabular format. Again, we make use of the modulus (%) operator, to determine how many images to display in each row. We then provide a link to edit the photo.

Our del_photos.php script is very similar to our del_album.php script. The difference, again, is that we take the photo data into consideration, rather than the album data. Our script is as follows:

<?php
include_once("../include/config.php");
// No album id has been selected
if( !$_GET['photo_id'] ){
// Display error message to user
$msg .= "Photo not selected. Please choose a photo you wish to delete!";
$msg .= "<br /><a href=\"edit_photos.php\">Edit photos</a>";
displayPage($msg, "Error Selecting Photo");
} else {
db_connect();
// Retrieve image and thumbnail path information
$sql = "SELECT photo_location, thumbnail_location FROM photos WHERE photo_id = " . addslashes($_GET['photo_id']);
$result = @mysql_query($sql) or die("Error retrieving records: " . mysql_error());
while ($row = mysql_fetch_array($result)){
$photo_location = $row['photo_location'];
$thumb_location = $row['thumbnail_location'];
}
if (@unlink("../" . $photo_location)){
} else {
die("Error deleting photo!<br /><a href=\"index.php\">Please try again</a>.");
}
if (@unlink("../" . $thumb_location)){
} else {
die("Error deleting thumbnail!<br /><a href=\"index.php\">Please try again</a>.");
}
// Delete specified album
$sql = "DELETE FROM photos WHERE photo_id = " . addslashes($_GET['photo_id']);
$result = @mysql_query($sql) or die("Error deleting record: " . mysql_error());
// Display success to user
$msg .= "Photo has been successfully deleted!<br /><a href='index.php'>Return to Admin Menu</a>";
displayPage($msg, "Photo Deleted!");
}
?>

The code breakdown is as follows:

include_once("../include/config.php");
// No album id has been selected
if( !$_GET['photo_id'] ){
// Display error message to user
$msg .= "Photo not selected. Please choose a photo you wish to delete!";
$msg .= "<br /><a href=\"edit_photos.php\">Edit photos</a>";
displayPage($msg, "Error Selecting Photo");
die();

We first check to see if a photo ID has been submitted. If not, we notify the user by displaying an error message.

If a photo ID has been specified, we first retrieve the path information for our full-sized image and our thumbnail, which relate to the photo ID specified. Not only do we want to delete the database record, but we also want to delete the actual photo files that reside in the filesystem.

db_connect();
// Retrieve image and thumbnail path information
$sql = "SELECT photo_location, thumbnail_location FROM photos WHERE photo_id = " . addslashes($_GET['photo_id']);
$result = @mysql_query($sql) or die("Error retrieving records: " . mysql_error());
while ($row = mysql_fetch_array($result)){
$photo_location = $row['photo_location'];
$thumb_location = $row['thumbnail_location'];
}
if (@unlink("../" . $photo_location)){
} else {
die("Error deleting photo!<br /><a href=\"index.php\">Please try again</a>.");
}
if (@unlink("../" . $thumb_location)){
} else {
die("Error deleting thumbnail!<br /><a href=\"index.php\">Please try again</a>.");
}

We create an SQL SELECT statement, and retrieve the path information. We then proceed to use PHP’s unlink() function, which performs a delete operation on the file specified as the argument. If there are any errors in the deletion, we echo out an error message, and execution of the script is halted. The user can then try again.

If both deletions are successful, we create an SQL DELETE statement, and remove the photo record from our database:

// Delete specified album
$sql = "DELETE FROM photos WHERE photo_id = " . addslashes($_GET['photo_id']);
$result = @mysql_query($sql) or die("Error deleting record: " . mysql_error());
// Display success to user
$msg .= "Photo has been successfully deleted!<br /><a href='index.php'>Return to Admin Menu</a>";
displayPage($msg, "Photo Deleted!");

If our query is successful, our photo has now been removed both from the filesystem, as well as the database.

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