Unique URLs in a databse

Question

I am using PHP / MySQL. I want to make a database of
websites, where the website URLs are unique. Let's say '
http://www.adobe.com' exists in
the database...
If someone tries to insert a record with the URL '
http://adobe.com', then script should
find '
http://www.adobe.com' (with the
www in front) in the database and detect that it is the same site,
and prohibit the insertion of the record.
Also, if someone tries to insert '
http://www.adobe.com/' (with that
added / at the end), it should just simply remove the end slash
before inserting it or looking for any records with a similar URL.
Lastly, the '
http://' should be added to the beginning of a
URL automatically if it isn't already provided.
How do I do these three things? Also, is there anything else
I should design the script to look for to make sure the URLs are
unique and duplicates are not being inserted?
Edit:
One other thing, '
http://www.adobe.com/some_page.html'
should be seen as the same thing as '
http://www.adobe.com', and would
prohibited from insertion. I'd actually like it if specific pages
could just be knocked off automatically, leaving just the domain.
Although, URL entries like '
http://some_host.com/user123'
and '
http://user123.some_host.com'
should still work.

Answer 1

AngryCloud wrote:
> I am using PHP / MySQL. I want to make a database of
websites, where the
> website URLs are unique.
How you design your script depends a great deal on who will
be inputting
the material. If this is going to be on an open site, with
anyone free
to input material, you will need to do a lot of checking and
sanitizing
of the user input before submitting it to your database. If
it's going
to be in a protected area where only trusted users are given
permission
to insert new entries, you can be less paranoid.
PHP has a useful function called parse_url() that extracts
the various
elements of a URL:
http://www.php.net/manual/en/function.parse-url.php
You could use it like this:
// check that input field isn't blank
if (isset($_POST['url']) && !empty($_POST['url])) {
// remove magic quotes
$url = get_magic_quotes_gpc() ? stripslashes($_POST['url]) :
$_POST['url];
// parse the URL
$parts = parse_url($url);
// if it looks OK, go ahead
if (isset($parts['scheme']) && $parts['scheme'] ==
'http' &&
isset($parts['host']) {
$host = $parts['host'];
// get the domain name with and without www.
if (strpos($host, 'www.') === 0) {
$www_host = $host;
$no_www = substr($host, 4);
else {
$www_host = 'www.'.$host;
$no_www = $host;
// query the database to see if URL already registered
$sql = "SELECT url FROM myTable
WHERE url = '
http://{$www_host}'
OR url = '
http://{$no_www}'";
$result = mysql_query($sql);
if (mysql_num_rows($result)) {
$error = 'That URL is already registered';
else {
$error = 'URL must begin with
http://';
// if no errors detected, insert into database
if (!$error) {
$site = '
http://'.mysql_real_escape_string($host);
$sql = "INSERT INTO myTable SET url = '$site'";
mysql_query($sql);
This isn't the only way of doing it, and you should probably
add more
checks, but the inline comments should show you how the
script works.
David Powers, Adobe Community Expert
Author, "The Essential Guide to Dreamweaver CS3" (friends of
ED)
Author, "PHP Solutions" (friends of ED)
http://foundationphp.com/