Phát triển web với PHP và MySQL - p 68 ppt

The line $fullheaders = ($action==’show-headers’); could have been more verbosely—and perhaps more clearly—written as if($action==’show-headers’) $fullheaders = true; else $fullheaders = false; Next, we call the display_message() function. Most of this function outputs plain HTML, so we will not go through it here. It calls the retrieve_message() function to get the appropriate message from the mailbox: $message = retrieve_message($auth_user, $accountid, $messageid, $fullheaders); The retrieve_message() function is in the mail_fns.php library. You can see the code for it in Listing 27.10. LISTING 27.10 retrieve_message() Function from mail_fns.php—This Function Retrieves One Specific Message from a Mailbox function retrieve_message($auth_user, $accountid, $messageid, $fullheaders) { $message = array(); if(!($auth_user && $messageid && $accountid)) return false; $imap = open_mailbox($auth_user, $accountid); if(!$imap) return false; $header = imap_header($imap, $messageid); if(!$header) return false; $message[‘body’] = imap_body($imap, $messageid); if(!$message[‘body’]) $message[‘body’] = ‘[This message has no body]\n\n\n\n\n\n’; if($fullheaders) $message[‘fullheaders’] = imap_fetchheader($imap, $messageid); else $message[‘fullheaders’] = ‘’; Building a Web-Based Email Service C HAPTER 27 27 BUILDING A WEB-BASED EMAIL SERVICE 645 33 7842 CH27 3/6/01 3:41 PM Page 645 $message[‘subject’] = $header->subject; $message[‘fromaddress’] = $header->fromaddress; $message[‘toaddress’] = $header->toaddress; $message[‘ccaddress’] = $header->ccaddress; $message[‘date’] = $header->date; // note we can get more detailed information by using from and to // rather than fromaddress and toaddress, but these are easier imap_close($imap); return $message; } Again we have used open_mailbox() to open the user’s mailbox. This time, however, we are after a specific message. Using this function library, we download the message headers and message body separately. The three IMAP functions we use here are imap_header(), imap_fetchheader(), and imap_body(). Note that the two header functions are distinct from imap_headers(), the one we used previously. They are somewhat confusingly named. In summary, • imap_headers()—Returns a summary of the headers for all the messages in a mailbox. It returns them as an array with one element per message. • imap_header()—Returns the headers for one specific message in the form of an object. • imap_fetchheader()—Returns the headers for one specific message in the form of a string. In this case we use imap_header() to fill out specific header fields and imap_fetchheader() to show the user the full headers if requested. (We’ll come back to this.) We use imap_header() and imap_body() to build an array containing all the elements of a message that we are interested in. We call imap_header() as follows: $header = imap_header($imap, $messageid); We can then extract each of the fields we require from the object: $message[‘subject’] = $header->subject; We call imap_body() to add the message body to our array as follows: $message[‘body’] = imap_body($imap, $messageid); Building Practical PHP and MySQL Projects P ART V 646 LISTING 27.10 Continued 33 7842 CH27 3/6/01 3:41 PM Page 646 Finally we close the mailbox with imap_close() and return the array we have built. The display_message() function can then display the message’s fields in the form you can see in Figure 27.6. Viewing Message Headers As you can see in Figure 27.6, there is a Show Headers button. This activates the show-headers option, which adds the full message headers to the message display. If the user clicks this button, he will see output similar to that shown in Figure 27.7. Building a Web-Based Email Service C HAPTER 27 27 BUILDING A WEB-BASED EMAIL SERVICE 647 FIGURE 27.7 Using show-headers to see the full headers for this message will help a user to track down the source of the spam. As you probably noticed, the event handling for view-message covers show-headers (and its counterpart hide-headers) too. If this option is selected, we do the same things as before. But in retrieve_message(), we also grab the full text of the headers, as follows: if($fullheaders) $message[‘fullheaders’] = imap_fetchheader($imap, $messageid); We can then display these headers for the user. 33 7842 CH27 3/6/01 3:41 PM Page 647 Deleting Mail If a user clicks the Delete button on a particular email, he will activate the “delete” action. This will execute the following code from index.php: case ‘delete’ : { delete_message($auth_user, $selected_account, $messageid); //note deliberately no ‘break’ - we will continue to the next case } case ‘select-account’ : case ‘view-mailbox’ : { // if mailbox just chosen, or view mailbox chosen, show mailbox display_list($auth_user, $selected_account); break; } As you can see, the message is deleted using the delete_message() function, and then the resulting mailbox is displayed as discussed previously. The code for the delete_message() function is shown in Listing 27.11. LISTING 27.11 delete_message() Function from mail_fns.php—This Function Deletes One Specific Message from a Mailbox function delete_message($auth_user, $accountid, $message_id) { // delete a single message from the server $imap = open_mailbox($auth_user, $accountid); if($imap) { imap_delete($imap, $message_id); imap_expunge($imap); imap_close($imap); return true; } return false; } As you can see, this function uses a number of the IMAP functions. The new ones are imap_delete() and imap_expunge(). Note that imap_delete() only marks messages for dele- tion. You can mark as many messages as you like. The call to imap_expunge() actually deletes the messages. Building Practical PHP and MySQL Projects P ART V 648 33 7842 CH27 3/6/01 3:41 PM Page 648 Sending Mail Finally we come to sending mail. There are a few ways to do this from this script: The user can send a new message, reply to, or forward mail. Let’s see how these work. Sending a New Message The user can choose this option by clicking the New Message button. This activates the “new-message” action, which executes the following code in index.php: case ‘new-message’ : { display_new_message_form($auth_user, $to, $cc, $subject, $body); break; } The new message form is just a form for sending mail. You can see what it looks like in Figure 27.8. This figure actually shows mail forwarding rather than new mail, but the form is the same. We’ll look at forwarding and replies next. Building a Web-Based Email Service C HAPTER 27 27 BUILDING A WEB-BASED EMAIL SERVICE 649 FIGURE 27.8 Using mail forwarding, we can report the spammer. 33 7842 CH27 3/6/01 3:41 PM Page 649 Clicking the Send Message button invokes the “send-message” action, which executes the following code: case ‘send-message’ : { if(send_message($to, $cc, $subject, $message)) echo “Message sent. ”; else echo “Could not send message. ”; break; } This code calls the send_message() function, which actually sends the mail. This function is shown in Listing 27.12. LISTING 27.12 send_message() Function from mail_fns.php—This Function Sends the Message that the User Has Typed In function send_message($to, $cc, $subject, $message) { //send one email via PHP global $auth_user; if (!db_connect()) { return false; } $query = “select address from users where username=’$auth_user’”; $result = mysql_query($query); if (!$result) { return false; } else if (mysql_num_rows($result)==0) { return false; } else { $other = “From: “.mysql_result($result, 0, “address”).”\r\ncc: $cc”; if (mail($to, $subject, $message, $other)) return true; else { return false; Building Practical PHP and MySQL Projects P ART V 650 33 7842 CH27 3/6/01 3:41 PM Page 650 } } } As you can see, this function uses mail() to send the email. First, however, it loads the user’s email address out of the database to use in the From field of the email. Replying To or Forwarding Mail The Reply, Reply All, and Forward functions all send mail in the same way that New Message does. The difference in how they work is that they fill in parts of the new message form before showing it to the user. Look back at Figure 27.8. The message we are forwarding has been indented with the > symbol, and the Subject line prefaced with To. Similarly, the Reply and Reply All options will fill in the recipients, subject line, and indented message. The code to do this is activated in the body section of index.php, as follows: case ‘reply-all’ : { //set cc as old cc line if(!$imap) $imap = open_mailbox($auth_user, $selected_account); if($imap) { $header = imap_header($imap, $messageid); if($header->reply_toaddress) $to = $header->reply_toaddress; else $to = $header->fromaddress; $cc = $header->ccaddress; $subject = ‘Re: ‘.$header->subject; $body = add_quoting(stripslashes(imap_body($imap, $messageid))); imap_close($imap); display_new_message_form($auth_user, $to, $cc, $subject, $body); } break; } case ‘reply’ : { //set to address as reply-to or from of the current message if(!$imap) $imap = open_mailbox($auth_user, $selected_account); if($imap) { Building a Web-Based Email Service C HAPTER 27 27 BUILDING A WEB-BASED EMAIL SERVICE 651 LISTING 27.12 Continued 33 7842 CH27 3/6/01 3:41 PM Page 651 $header = imap_header($imap, $messageid); if($header->reply_toaddress) $to = $header->reply_toaddress; else $to = $header->fromaddress; $subject = ‘Re: ‘.$header->subject; $body = add_quoting(stripslashes(imap_body($imap, $messageid))); imap_close($imap); display_new_message_form($auth_user, $to, $cc, $subject, $body); } break; //note deliberately no ‘break’ } case ‘forward’ : { //set message as quoted body of current message if(!$imap) $imap = open_mailbox($auth_user, $selected_account); if($imap) { $header = imap_header($imap, $messageid); $body = add_quoting(stripslashes(imap_body($imap, $messageid))); $subject = ‘Fwd: ‘.$header->subject; imap_close($imap); display_new_message_form($auth_user, $to, $cc, $subject, $body); } break; } You can see that each of these options sets up the appropriate headers, applies formatting as necessary, and calls the display_new_message_form() function to set up the form. That’s the full set of functionality for our Web mail reader. Extending the Project There are many extensions or improvements you could make to this project. You can look to the mail reader you normally use for inspiration, but some useful additions are the following: • Add the ability for users to register with this site. (You could reuse some of the code from Chapter 24, “Building User Authentication and Personalization,” for this purpose.) • Many users have more than one email address; perhaps a personal address and a work address. By moving their stored email address from the users table to the accounts table, Building Practical PHP and MySQL Projects P ART V 652 33 7842 CH27 3/6/01 3:41 PM Page 652 you could allow them to use many addresses. You would need to change a limited amount of other code too. The send mail form would need a drop-down box to select from which address to use. • Add the ability to send, receive, and view mail with attachments. If users are to be able to send attachments, you will need to build in file upload capabilities as discussed in Chapter 16, “Interacting with the File System and the Server.” Sending mail with attachments is covered in Chapter 28, “Building a Mailing List Manager.” • Add address book capabilities. • Add network news reading abilities. Reading from an NNTP server using the IMAP functions is almost identical to reading from a mailbox. You just need to specify a differ- ent port number and protocol in the imap_open() call. Instead of naming a mailbox like INBOX, you name a newsgroup to read from instead. You could combine this with the thread-building capabilities from the project in Chapter 29, “Building Web Forums,” to build a threaded Web-based newsreader. Next In the next chapter, we’ll build another email-related project—an application to support sending newsletters on multiple topics to people who subscribe through our site. Building a Web-Based Email Service C HAPTER 27 27 BUILDING A WEB-BASED EMAIL SERVICE 653 33 7842 CH27 3/6/01 3:41 PM Page 653 33 7842 CH27 3/6/01 3:41 PM Page 654 . = $header->subject; We call imap_body() to add the message body to our array as follows: $message[‘body’] = imap_body($imap, $messageid); Building Practical PHP and MySQL Projects P ART V 646 LISTING. ‘.$header->subject; imap_close($imap); display_new_message_form($auth_user, $to, $cc, $subject, $body); } break; } You can see that each of these options sets up the appropriate headers, applies. project in Chapter 29, “Building Web Forums,” to build a threaded Web- based newsreader. Next In the next chapter, we’ll build another email-related project—an application to support sending newsletters