Phát triển web với PHP và MySQL - p 67 doc

LISTING 27.5 store_account_settings() Function from mail_fns.php—Function to Save
New Account Details for a User
function store_account_settings($auth_user, $settings)
{
if(!filled_out($settings))
{
echo “All fields must be filled in. Try again.<br><br>”;
return false;
}
else
{
if($settings[‘account’]>0)
$query = “update accounts set server = ‘$settings[server]’,
port = $settings[port], type = ‘$settings[type]’,
remoteuser = ‘$settings[remoteuser]’,
remotepassword = ‘$settings[remotepassword]’
where accountid = $settings[account]
and username = ‘$auth_user’”;
else
$query = “insert into accounts values (‘$auth_user’,
‘$settings[server]’, $settings[port],
‘$settings[type]’, ‘$settings[remoteuser]’,
‘$settings[remotepassword]’, NULL)”;
if(db_connect() && mysql_query($query))
{
return true;
}
else
{
echo “could not store changes.<br><br><br><br><br><br>”;
return false;

}
}
}
As you can see, two choices within this function correspond to inserting a new account or
updating an existing account. The function executes the appropriate query to save the account
details.
After storing the account details, we go back to index.php, to the main body stage:
case ‘store-settings’ :
case ‘account-setup’ :
case ‘delete-account’ :
{
display_account_setup($auth_user);
break;
}
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As you can see, we then execute the display_account_setup() function as before to list the
user’s account details. The newly added account will now be included.
Modifying an Existing Account
The process for modifying an existing account is very similar. The user can change the account
details and click the Save Changes button. Again this will trigger the store-settings action,
but this time it will update the account details instead of inserting them.

Deleting an Account
To delete an account, the user can click the Delete Account button that is shown under each
account listing. This activates the
delete-account action.
In the preprocessing section of the index.php script, we will execute the following code:
case ‘delete-account’ :
{
delete_account($auth_user, $account);
break;
}
This code calls the delete_account() function. The code for this function is shown in Listing
27.6. Deleting accounts needs to be handled before the header because a choice of which
account to use is inside the header. The account list needs to be updated before this can be cor-
rectly drawn.
LISTING 27.6 delete_account() Function from mail_fns.php—Function to Delete a Single
Account’s Details
function delete_account($auth_user, $accountid)
{
//delete one of this user’s accounts from the DB
$query = “delete from accounts where
accountid=’$accountid’ and
username = ‘$auth_user’”;
if(db_connect())
{
$result = mysql_query($query);
}
return $result;
}
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After execution returns to index.php, the body stage will run the following code:
case ‘store-settings’ :
case ‘account-setup’ :
case ‘delete-account’ :
{
display_account_setup($auth_user);
break;
}
You will recognize this as the same code we ran before—it just displays the list of the user’s
accounts.
Reading Mail
After the user has set up some accounts, we can move on to the main game: connecting to
these accounts and reading mail.
Selecting an Account
We need to select one of the user’s accounts to read mail from. The currently selected account
is stored in the $selected_account session variable.
If the user has a single account registered in the system, it will be automatically selected when
he logs in, as follows:
if(number_of_accounts($auth_user)==1)
{
$accounts = get_account_list($auth_user);
$selected_account = $accounts[0];
session_register(“selected_account”);
}
The number_of_accounts() function, from mail_fns.php, is used to work out whether the
user has more than one account. The
get_account_list() function retrieves an array of the

names of the user’s accounts. In this case there is exactly one, so we can access it as the
array’s
0 value.
The number_of_accounts() function is shown in Listing 27.7.
LISTING 27.7 number_of_accounts() Function from mail_fns.php—Function to Work Out
How Many Accounts a User Has Registered
function number_of_accounts($auth_user)
{
// get the number of accounts that belong to this user
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$query = “select count(*) from accounts where username = ‘$auth_user’”;
if(db_connect())
{
$result = mysql_query($query);
if($result)
return mysql_result($result, 0, 0);
}
return 0;
}
The get_account_list() function is similar to the get_accounts() function we looked at
before except that it only retrieves the account names.

If a user has multiple accounts registered, he will need to select one to use. In this case, the
headers will contain a SELECT that lists the available mailboxes. Choosing the appropriate one
will automatically display the mailbox for that account. You can see this in Figure 27.5.
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LISTING 27.7 Continued
FIGURE 27.5
After the localhost account is selected from the SELECT box, the mail from that account is downloaded and displayed.
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This SELECT option is generated in the do_html_header() function from output_fns.php,as
shown in the following code fragment:
<?
// include the account select box only if the user has more than one account
if(number_of_accounts($auth_user)>1)
{
echo “<form target=’index.php?action=open-mailbox’ method=post>”;
echo ‘<td bgcolor = “#ff6600” align = right valign = middle>’;
display_account_select($auth_user, $selected_account);
echo ‘</td>’;
echo “</form>”;
}
?>
We have generally avoided discussing the HTML used in the examples in this book, but the
HTML generated by the function display_account_select() bears a visit.
Depending on the accounts the current user has, display_account_select() will generate
HTML like this:
<select onchange=window.location=this.options[selectedIndex].value name=account>
<option value = 0 selected>

Choose Account</a>
<option value = ‘index.php?action=select-account&account=10’>
mail.domain.com
</option>
<option value = ‘index.php?action=select-account&account=11’>
mail.server.com
</option>
<option value = ‘index.php?action=select-account&account=9’>
localhost
</option>
</select>
Most of this code is just an HTML select element, but it also includes a little JavaScript. In the
same way that PHP can generate HTML, it can also be used to generate client-side scripts.
Whenever a change event happens to this element, JavaScript will set window.location to the
value of the option. If your user selects the first option in the select, window.location will be
set to ‘index.php?action=select-account&account=10’. This will result in this URL being
loaded. Obviously, if the user has a browser that does not support JavaScript or has JavaScript
disabled, this code will have no effect.
The display_account_select() function, from output_fns.php, is used to get the available
account list and display the SELECT. It also uses the get_account_list() function we dis-
cussed previously.
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Choosing one of the options in the SELECT activates the select_account event. If you look at
the URL in Figure 27.5, you can see this appended to the end of the URL, along with the
account ID of the chosen account.
This has two effects. First, in the preprocessing stage of index.php, the chosen account will be
stored in the session variable $selected_account, as follows:
case ‘select-account’ :
{
// if have chosen a valid account, store it as a session variable
if($account&&account_exists($auth_user, $account))
{
$selected_account = $account;
session_register(‘selected_account’);
}
}
Second, when the body stage of the script is executed, the following code will be executed:
case ‘select-account’ :
case ‘view-mailbox’ :
{
// if mailbox just chosen, or view mailbox chosen, show mailbox
display_list($auth_user, $selected_account);
break;
}
As you can see, we take the same action here as if the user had chosen the View Mailbox
option. We’ll look at that next.
Viewing Mailbox Contents
Mailbox contents can be viewed with the display_list() function. This displays a list of all
the messages in the mailbox. The code for this function is shown in Listing 27.8.
LISTING 27.8 display_list() Function from output_fns.php—Function to Display All
Mailbox Messages

function display_list($auth_user, $accountid)
{
// show the list of messages in this mailbox
global $table_width;
if(!$accountid)
{
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echo “No mailbox selected<br><br><br><br><br><br>.”;
}
else
{
$imap = open_mailbox($auth_user, $accountid);
if($imap)
{
echo “<table width = $table_width cellspacing = 0
cellpadding = 6 border = 0>”;
$headers = imap_headers($imap);
// we could reformat this data, or get other details using
// imap_fetchheaders, but this is not a bad summary so we just echo each
$messages = sizeof($headers);
for($i = 0; $i<$messages; $i++)
{
echo “<tr><td bgcolor = ‘“;
if($i%2)
echo “#ffffff”;
else

echo “#ffffcc”;
echo “‘><a href =’index.php?action=view-
message&messageid=”.($i+1).”’>”;
echo $headers[$i];
echo “</a></td></tr>\n”;
}
echo “</table>”;
}
else
{
$account = get_account_settings($auth_user, $accountid);
echo “could not open mail box “.$account[‘server’].”.<br><br><br><br>”;
}
}
}
In this function, we actually begin to use PHP’s IMAP functions. The two key parts of this
function are opening the mailbox and reading the message headers.
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LISTING 27.8 Continued
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We open the mailbox for a user account with a call to the open_mailbox() function that we
have written in mail_fns.php. This function is shown in Listing 27.9.

LISTING 27.9 open_mailbox() Function from mail_fns.php—This Function Connects to a
User Mailbox
function open_mailbox($auth_user, $accountid)
{
// select mailbox if there is only one
if(number_of_accounts($auth_user)==1)
{
$accounts = get_account_list($auth_user);
$selected_account = $accounts[0];
session_register(“selected_account”);
$accountid = $selected_account;
}
// connect to the POP3 or IMAP server the user has selected
$settings = get_account_settings($auth_user, $accountid);
if(!sizeof($settings)) return 0;
$mailbox = “{“.$settings[server];
if($settings[type]==’POP3’)
$mailbox .= ‘/pop3’;
$mailbox .= “:”.$settings[port].”}INBOX”;
// suppress warning, remember to check return value
@ $imap = imap_open($mailbox, $settings[remoteuser],
$settings[remotepassword]);
return $imap;
}
We actually open the mailbox with the imap_open() function. This function has the following
prototype:
int imap_open (string mailbox, string username, string password [, int flags])
The parameters you need to pass to it are as follows:
• mailbox—This string should contain the server name and mailbox name, and optionally
a port number and protocol. The format of this string is

{hostname/protocol:port}boxname
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If the protocol is not specified, it defaults to IMAP. In the code we have written, you can
see that we specify POP3 if the user has specified that protocol for a particular account.
For example, to read mail from the local machine using the default ports, we would use
the following mailbox name for IMAP
{localhost:143}INBOX
and this one for POP3
{localhost/pop3:110}INBOX
• username—The username for the account
• password—The password for the account
You can also pass it optional flags to specify options such as “open mailbox in read-only
mode”
.
One thing to note is that we have constructed the mailbox string piece by piece with the con-
catenation operator before passing it to
imap_open(). You need to be careful how you construct
this string because strings containing {$ cause problems in PHP 4.
This function call returns an IMAP stream if the mailbox can be opened, and false if it cannot.
When you are finished with an IMAP stream, you can close it using imap_close(imap_stream).
In our function, the IMAP stream is passed back to the main program. We then use the
imap_headers() function to get the email headers for display:
$headers = imap_headers($imap);
This function returns header information for all mail messages in the mailbox we have con-
nected to. The information is returned as an array, one line per message. We haven’t formatted
this. It just outputs one line per message, so you can see from looking at Figure 27.5 what the

output looks like.
You can get more information about email headers using the confusing, similarly named
imap_header(). In this case, the imap_headers() function gives us enough detail for our
purpose.
Reading a Mail Message
We have set up each of the messages in the previous display_list() function to link to
specific email messages.
Each link is of the form
index.php?action=view-message&messageid=6
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The messageid is the sequence number used in the headers we retrieved earlier. Note that
IMAP messages are numbered from 1, not 0.
If the user clicks one of these links, he will see output like that shown in Figure 27.6.
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FIGURE 27.6
Using the view-message action shows us a particular message—in this case, it’s a piece of spam.
When we enter these parameters into the index.php script, we execute the following code:
case ‘show-headers’ :

case ‘hide-headers’ :
case ‘view-message’ :
{
// if we have just picked a message from the list, or were looking at
// a message and chose to hide or view headers, load a message
$fullheaders = ($action==’show-headers’);
display_message($auth_user, $selected_account, $messageid,
$fullheaders)
break;
}
You’ll notice that we’re checking the value of the $action being equal to ‘show-headers’. In
this case, it will be false, and $fullheaders will be set equal to false. We’ll look at the
‘show-headers’ action in a moment.
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