undefined index warning in PHP for LDAP attribute / associative array?

Question

I am having trouble retrieving some data out of an LDAP attribute in PHP.

I connect to LDAP, perform my query, and store the results in a var like so:

$info = ldap_get_entries($connect, $sr);

Now, I can store most of the LDAP attributes I need in sessions vars, like so:

        $_SESSION['accountFirstName'] = $info[0]['givenname'][0];
        $_SESSION['accountLastName'] = $info[0]['sn'][0];
        $_SESSION['accountEmail'] = $info[0]['mail'][0];

These work fine.. No problems. However, there is another var I need to store. I believe It is an associative array. For some reason, no matter what I do, I am getting an NOTICE: Undefined index warning for that specific attribute. I have tried storing it like the above demonstration, but to be honest I'm not entirely sure what the [0] indices on either ends of the attribute name mean.. I'm not familiar with LDAP and frankly the setup is very confusing.

So I guess my questions are:

• how do you access associative arrays that are returned from an LDAP query?

• what does 'undefined index' mean? Does it mean that that attribute does not exist, or it does not exist at the index provided?

• How can I test my LDAP query to see if the variable even exists?

• There is a possibility that the account performing the query does not have adequate LDAP access privileges (the project is for a university and there is a lot of red tape). Is there any way for me to verify that through code?

Thank you! And my apologies for the vagueness of the information provided, I can't be too open-mouthed right now.

Answer 1

The issue doesn't reside with the ldap_get_entries() method, or LDAP at all - it's the data that's being returned.

The NOTICE: Undefined index error is stating that an index in your array doesn't exist. In this case, it is most likely that the data you're receiving doesn't have a value such as givenname or mail, but it could also be the [0] (or, "first record") in one of those arrays.

The textual/string index value, such as givenname or sn, is what would be defined as the "associative array". You are correctly accessing that data with $info[0]['givenname'];

To check if an index exists in PHP, you can use isset(), such as:

if (isset($info[0]['givenname'])) {
    // process data here
}

As a quick way to do your assignments, you can use something like this:

if (count($info) > 0) {
    $_SESSION['accountFirstName'] = (isset($info[0]['givenname']) && isset($info[0]['givenname'][0])) ? $info[0]['givenname'][0] : '';
}

If you have a long list of values you need, I would suggest writing something similar to the following to auto-process it for you:

$fields = array(
    'accountFirstName' => 'givenname',
    'accountLastName' => 'sn',
    'accountEmail' => 'mail'
);

$info = $info[0];
foreach ($fields as $field => $ldapField) {
    // check if the value exists; otherwise set it to an empty-string
    $_SESSION[$field] = (isset($info[$ldapField]) && isset($info[$ldapField][0])) ? $info[$ldapField][0] : '';
}