|By Ben Forta||
|September 11, 2003 12:00 AM EDT||
One of the most used tags in CFML is <CFMAIL>. It is definitely the most used of all the Internet protocol tags, and as one of the original CFML tags (it was actually one of the DBML tags and originally named <DBMAIL>), it has also been slowly enhanced and updated with each new release of ColdFusion. Slowly. Maybe a little too slowly.
ColdFusion MX 6.1 introduces a whole new <CFMAIL>, a much better and much more powerful <CFMAIL>, and this month I'd like to walk you through these important changes.
Let's start with performance. <CFMAIL> was never designed to be a high-performance mass mailer, and yet many developers have tried using it as just that. <CFMAIL> has always been very capable of delivering hundreds, even thousands, of messages, but that's about as far as the tag could be pushed.
ColdFusion MX 6.1 introduces important changes to the <CFMAIL> engine that facilitate dramatically increased mail-delivery performance. In fact, in testing, we clocked <CFMAIL> on a fairly typical box delivering mail at over 1,000,000 messages an hour (so fast that the bottleneck became the network and mail server rather than ColdFusion).
So what changed? Two things:
<CFMAIL> performance has been improved in all versions of ColdFusion, but if you need high-volume mail delivery, then you should be using ColdFusion MX Enterprise. The two changes just described apply to ColdFusion MX Enterprise only.
One frequently requested <CFMAIL> enhancement is support for backup SMTP servers so that if a mail server is down, a backup SMTP server would be used. Support for redundant (backup) SMTP servers has been added to ColdFusion MX 6.1 Enterprise (this too is an Enterprise-only feature).
ColdFusion Administrator contains a new field (in the Mail page) named "Backup mail servers". You may specify as many servers as you like here (DNS names or IP addresses) in a comma-delimited format (you may also list backup servers right in the <CFMAIL> tag SERVER attribute). The specified servers are the backup servers, and will be used automatically if the primary SMTP server is unavailable.
It is important to note that <CFMAIL> does not support multiple mail server delivery. These additional servers are backup servers and are used only if the primary server is unavailable. If a server (any server) is unavailable, then ColdFusion will attempt to use the next server in the list. Once a server has been flagged as unavailable, ColdFusion will not attempt to use it again for 60 seconds. If all servers are unavailable, then an error is logged.
Like the high-performance features discussed above, the ability to specify backup SMTP servers is an Enterprise-only feature. (From this point on, however, everything discussed applies to all versions of ColdFusion, including ColdFusion MX Standard).
SMTP was never designed to a be a secure protocol. As we are all painfully aware, you can never really be sure who mail comes from and whether or not a FROM field contains the actual sender address. It's all too easy to submit fake SMTP e-mail to mail servers for processing.
In recent years, mail administrators have started taking steps to prevent their servers from being used to deliver unauthorized mail (commonly known as relaying). One technique that has gained popularity is to require an SMTP login. Unlike POP, which always requires a login, SMTP usually does not, but many SMTP servers now do require that login credentials be passed in in order to deliver outbound mail. If enabled, this security prevented the use of <CFMAIL>, as <CFMAIL> provided no way to specify login information.
ColdFusion MX 6.1 supports SMTP logins in two ways:
The ability to use SMTP logins is an important enhancement, and one that will make many server administrators very happy.
Multiple MIME Types
One of the most eagerly anticipated <CFMAIL> enhancements is the ability to include multiple bodies of different MIME types all in a single message. What does this mean? Consider the following:
You deliver reports via <CFMAIL>. Your reports are detailed, have columns, colors and fonts, use images, and more, and so you tell <CFMAIL> to deliver the e-mail in HTML, as most mail clients, including Outlook and Outlook Express, support HTML e-mail. The problem, however, is that not all users have mail clients capable of displaying HTML e-mail, so you also need to generate a plain-text version of your report for those users. Of course, this then requires that you maintain a record of which version to send to which user (probably a flag in your database). You'd need a way for users to specify the message type they'd like, and then mail generation code that might look a bit like this:
<!--- Check HTML mail flag --->
<!--- Send HTML version --->
<!--- Send text version --->
You'd need to repeat everything, not to mention maintaining the user mail preferences. You'd also not be able to use the <CFMAIL> query attribute easily, or you'd need two queries - one for text message recipients and one for HTML message recipients - and then you'd need two <CFMAIL> tags (one for each query).
There's a better way to do this. E-mail messages can actually contain multiple bodies, each of a different MIME type. The problem is that <CFMAIL> did not support the use of this feature. Until now, that is. Here's the ColdFusion MX 6.1 version of the previous example:
<!--- Generate mail message --->
<!--- Generate text body --->
Text body goes here
<!--- Generate HTML body --->
<B>HTML body goes here</B>
As you can see, a single <CFMAIL> tag is being used along with two instances of a new tag named <CFMAILPART>. This new tag allows you to embed multiple bodies in a single message, as long as each has a different MIME type. This way it is the mail client that decides which body to display, and this makes your life a bit simpler. (It also means that your mail messages will be bigger; you'll need to decide whether or not this is acceptable.)
Any and all MIME types are supported, although in practice you'll probably use only TEXT and HTML.
Note: Although we're just covering <CFMAIL> in this column, it's worth noting that <CFPOP> has been similarly enhanced and now supports the retrieval of multiple bodies as well.
In addition to all the changes listed thus far, <CFMAIL> also features lots of little enhancements. Some worth noting are:
<CFMAIL> is an important ColdFusion tag and ranks as one of the most used tags in the CFML language. For high performance and high-availability mail delivery you should definitely consider using ColdFusion MX Enterprise. For all users, the enhancements to this tag in ColdFusion MX 6.1 provide yet another compelling reason to upgrade.
On a totally separate note, this is my 50th CFDJ <BF> on <CF> column - that's 50 back-to-back columns (with only one exception, and I'll try not to let that happen again). While writing this column, I glanced at the topics covered since way back when, and was reminded of just how far ColdFusion has come in such a short time. It's been a great ride thus far, here's to another 50!
|ant 10/09/03 12:10:35 PM EDT|
While much of the new cfmail functionality is great, it comes at a price - The inability to write a text file into email directly from a database or other source. All I had to do was create a boundary and header and add that text in between my cfmail call like so:
After the "upgrade" only cfmailparam worked - back to cfdirectory/cffile calls - more overhead and unnecesary code. The new cfmailpart doesn't allow for attachements like this - ONLY inline content. Oh well, 2 steps forward, one step back...
|Craig Overpeck 09/24/03 12:51:24 PM EDT|
It cut our hardware scaling solution in half. BF is right - a long awaited but noteworthy accomplishment by Alliare...I mean Macromedia. Congrats on number 50 BF!
|prethi 09/24/03 08:33:59 AM EDT|
can i have a sample of cfmail. I have hosted with cfmresources but am not able to send mails.
|Fran Garland 09/24/03 08:31:25 AM EDT|
Yes CFMail has come a long way.
I intend to use some of this new functionalily on my companies web site.
In addition it give me more fodder to upgrade the one server not on the CFMX 6.0 En since the setting staying connected in only available in this version. Enjoyed the article
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