PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

712 Chapter 30 Building a Mailing List Manager
n
n $list[n][2] and $list[n][3] are optional.You use them to convey that
there is more information.They correspond to the more information text
and the more information ID, respectively.We look at an example using
these two parameters when we come to the View Mail action in the
“Implementing Administrative Functions” section.
The optional third, fourth, and fifth parameters to the function are used to pass in
three actions that will be displayed on buttons corresponding to each item. In
Figure 30.7, they are the three action buttons shown as Information, Show
Archive, and Subscribe.
You get these three buttons for the Show All Lists page by passing in the action names
information, show-archive, and subscribe.When you use the display_button()
function, these actions are turned into buttons with those words on them and the appropriate
action assigned to them.
Each of the Show actions calls the display_items() function in a different way, as
you can see by looking back at their actions. In addition to having different titles and
action buttons, each of the three uses a different function to build the array of items to
display. Show All Lists uses the function get_all_lists(), Show Other Lists uses
the function get_unsubscribed_lists(), and Show My Lists uses the function
get_subscribed_lists(). All these functions work in a similar fashion and are all
from the mlm_fns.php function library.
Let’s look at get_unsubscribed_lists() because that’s the example we’ve followed
so far.The code for the get_unsubscribed_lists() function is shown in Listing 30.8.
Listing 30.8 get_unsubscribed_lists()Function from mlm_fns.php—This
Function Builds an Array of Mailing Lists That a User Is Not Subscribed To
function get_unsubscribed_lists($email) {
$list = array();
$query = "select lists.listid, listname, email from lists
left join sub_lists on lists.listid = sub_lists.listid
and email='".$email."' where email is NULL
order by listname";
if($conn=db_connect()) {
$result = $conn->query($query);
if(!$result) {
echo 'Unable to get list from database.';
return false;
}
$num = $result->num_rows;