PowerBASIC Gazette CyberEdition #19
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RE:  PowerBASIC for just $99?


June
Fourteenth
2001

From: Bob Zale, President, PowerBASIC, Inc.

To:   Henk Broekhuizen, Cust#66902

Dear Henk,

There's lots of exciting news this month!  PowerBASIC for just $99?
You bet it's true!  But more about that later...  Right now, there
are other important things to talk about.  You know, our latest Win32
compilers, PB/CC 2 and PB/DLL 6, offer full support for TCP and UDP
communications.  They'll let you send an email from any program, in
just a few lines of code.  You can add attachments, check incoming
email, even access an FTP site or download a web page.

Great stuff...  But how does it really work?  You'll get all the
inside information, right here in the PowerBASIC Gazette.  We've
prepared a series of articles on just these topics.  The first
installment, an overview, was published in a previous Gazette, and
can be found at www.powerbasic.com.  The second article in the
series, "Sending E-mail with PB/DLL", follows below.  Stay tuned
right here, and you'll be a TCP/IP expert in no time at all!

If you haven't yet upgraded to PB/CC 2, or PB/DLL 6, now is
certainly the time to do so.  Check out all of the product
details at www.powerbasic.com and join in the fun!   {smile}
Pricing and ordering information can be found at the very end
of this Gazette.  Questions?   Just email info@powerbasic.com
We'll do our very best to help.

                                      Regards,
                                      Bob Zale, President
                                      PowerBASIC, Inc.

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Sending E-Mail With PB/DLL


Developing Internet applications is usually at the top of most
programmers' "want to do" list.  Often, the first type of
application they want to develop is an e-mail program.

A quick search on the Internet reveals a lot of example code for
e-mail clients, however, few of these examples provide any clear
explanation as to how an e-mail program actually works.  Well, we
think it's time that we shed some light on the subject at hand.
Don't you?

Say HELO To SMTP

SMTP, or the Simple Mail Transport Protocol, provides a way for
the exchange of Internet e-mail.  As suggested by its name, the
SMTP protocol is actually very simple to implement because it uses
plain ASCII commands.

Whenever an e-mail program, or SMTP client, wishes to send e-mail,
it starts out by contacting the SMTP server on port 25.  Using
PowerBASIC DLL 6.0 we would initiate a session with an SMTP server
with the following lines of code:

 ERRCLEAR
 nTCP = FREEFILE
 TCP OPEN "smtp" AT $SMTPServer AS nTCP
 IF ERR THEN MSGBOX "SMTP server could not be reached!"
 TCP LINE nTCP, sBuffer$

Here, we are simply opening the SMTP service for communication,
where $SMTPServer is the name of the server, or host, we wish to
communicate with.  This usually takes the form "mail.myserver.com".

The TCP LINE statement receives the reply from the server.  If the
TCP OPEN is successful, then the variable sBuffer$ contains a string
that begins with a three-character numeric reply code, usually
followed by a verbose text description of the reply code.  If the
numeric reply code is 220, then the connection to the server was
established successfully.

Now that communications between the client and the server have been
established, we need to introduce ourselves to the mail server using
the HELO command.  The HELO command takes one parameter, which is
the fully qualified domain name of the client, as illustrated in the
following example:

 TCP PRINT nTCP, "HELO " & "someplace.com"
 TCP LINE nTCP, sBuffer

If the HELO command is successful, the reply code is 250.

The next step is to initiate the actual transfer of the message by
issuing the MAIL FROM command. This command was originally designed
to tell the SMTP server the reverse-path that the message has taken
from its original source up until this point.  In reality though,
the reverse-path is rarely an actual path.  It's normally the fully
qualified domain name of the original sender, as shown in the below
example:

 TCP PRINT nTCP, "MAIL FROM: <someone@someplace.com>"
 TCP LINE nTCP, sBuffer

If the MAIL FROM command is successful, the reply code is 250.

Now that the mail server knows who the message is from, we need to
let the server know who the message is for (the recipient).  This
is accomplished with the RCPT TO command:

 TCP PRINT nTCP, "RCPT TO: <someoneelse@somewhere.com>"
 TCP LINE nTCP, sBuffer

If the RCPT TO command is successful, the reply code is 250.

For messages that must be sent to multiple recipients, it's simply a
matter of issuing the RCPT TO command repeatedly, and in sequence,
with each command designating a final recipient.  Of course, you
still need to get the return code for each recipient.


Now that all of the recipients have been specified, we can issue the
DATA command to tell the server that we are now going to send the
actual message.  For example:

 TCP PRINT nTCP, "DATA"
 TCP LINE nTCP, sBuffer

If the DATA command is successful, the reply code is 354.

Once the server indicates that it is ready to receive the message,
we can send our message line by line.  But first, let's take a brief
look at exactly what an Internet mail message is.

Simply put, a mail message consists of lines of ASCII characters
terminated with <CR><LF> characters. The first set of lines are the
message header, the remaining lines are the message body, with the
header being separated from the body, by a single blank line.  Let's
look at some example code to illustrate sending the message header:

 TCP PRINT nTCP, "From: someone@someplace.com"
 TCP PRINT nTCP, "To: someoneelse@somewhere.com"
 TCP PRINT nTCP, "Subject: E-Mail With PB/DLL!"
 TCP PRINT nTCP, "X-Mailer: PowerBASIC E-Mail Demo"
 TCP PRINT nTCP, ""

As demonstrated above, a header in its simplest form consists of
basic information, such as who the message is from, who it is for,
the subject of the message, the client program used to send the
message and a single, blank line to signal the end of the message
header.  Once we've sent the header, we can then go ahead and send
the actual message body:

 TCP PRINT nTCP, "This is the body of our test message."

Simple as that.  We just repeat the above statement for each line
in the message, until the entire message has been sent.  No reply
code is received from the server for each of these message lines.
Note that individual lines should be less than 1000 characters wide.

Next, We tell the server that the message body is complete by
sending a line containing a single period character followed by
<CR><LF>.  Since it is possible that a message could actually
contain a line with nothing but a period character, care must be
taken to avoid sending this line unchanged or the message body will
be truncated prematurely.  You can fix this potential problem by
sending two periods instead of one.

 TCP PRINT nTCP, "."
 TCP LINE nTCP, sBuffer

The mail server will then reply with a code indicating whether or
not the transfer was a success (code 250) or a failure (code <> 250).

Now that we've sent our mail message, we need to politely terminate
the session with the SMTP server by sending the QUIT command.

 TCP PRINT nTCP, "QUIT"
 TCP LINE nTCP, sBuffer

Upon issuing the QUIT command, the mail server will reply with code
221, indicating success, or code 500, indicating an error.  It will
then close the TCP connection.

And there you have it - the basics of sending Internet e-mail via
the Simple Mail Transfer Protocol.  Like I stated at the beginning of
this article, it's all fairly simple and straightforward stuff.  For
further information on sending Internet e-mail you may want to take a
look at RFC 2821, which describes the SMTP protocol, and RFC 2822,
which describes the format of electronic mail messages:

 http://www.powerbasic.com/files/pub/docs/rfc/2800/

For a complete sample program that illustrate how errors are to be
handled, please see SMTP.bas which is installed in the PB/DLL
Samples\Tcp folder.  You may also wish to look at TCP32.inc in the
same folder for some ideas.

==============================================================================

PowerBASIC for just $99?  Absolutely!

That's right, PowerBASIC 3.5 for Dos is now priced at just $99, with
all documentation in electronic format.  A new lower price, and more
convenience, too!.   The entire 2-volume documentation set is now
included in Adobe PDF format.  It's easy to use, easy to search, and
provides every bit of information you need to get the most from our
Dos compiler.  And, since it's 100% electronic, you can download
everything you need to start programming for Dos today!  Of course,
the book version is still available for those prefer that classic
format -- A 2-volume printed manual set, over 700 pages in all, is
optional at just $29 plus shipping.

==============================================================================
                      PowerBASIC Price List
------------------------------------------------------------------------------
 PowerBASIC Compiler v3.5 for DOS                            $99.00
    Add PB 3.5 Printed Documentation                         $29.00
 PB/CC Console Compiler 2.0 - Full Product                  $159.00
    Add PB/CC Printed Documentation                           29.00
 PB/DLL 32/16 GUI Compiler 6.0 - Full Product                189.00
    Add PB/DLL Printed Documentation                          29.00
 PowerGEN Visual Designer for PB/DLL                         $39.00
 PowerTree BTree Manager for Windows (Win16/32)             $129.00
 PowerTree Index Manager for DOS                             $89.00
 QuickPak Professional for DOS                              $129.00
 PB/Vision for DOS                                           $20.00
 "Learning Basic" Book for DOS                               $39.95
 PB/Xtra III for DOS and Windows                             $49.00
-------------------------------------------------------------------
PerfectSync Graphics Tools (Requires CT to use with PB/CC) $ 49.95
PerfectSync Console Tools Standard Version                    49.95
PerfectSync Console Tools Professional Version                99.95
PerfectSync Console Tools Professional Version                99.95
PerfectSync SQL Tools Standard Version                        69.95
PerfectSync SQL Tools Professional Version                   199.95
PerfectSync DOS Box                                           35.00
-------------------------------------------------------------------
 Shipping/Handling for above:
                    Software        Software+book    Addl Books
 Email                  $6               N/A              N/A
 Std: US/Can/Mex       $6                $6               $6
 Fedex US 2-day       $12               $12               $6
 Fedex US 1-day       $22               $22               $6
 Air Mail Intl        $12               $22               $6
 Fedex Intl           $28               $38               $8

International Air Mail is $28 for DOS products with books, Fedex
is $38.  Fedex International Rates are for Western Europe, Pacific
Rim, Asia, and North America.  Others please request a quotation.
-------------------------------------------------------------------

Order online at www.powerbasic.com/shop/   or just send an email
with all pertinent information to  sales@powerbasic.com
We'll take it from there!
-------------------------------------------------------------------

Most PowerBASIC products (those without printed books) can now be
delivered by electronic mail.  No wait for a package to arrive...
No high shipping costs...  For just $6 per order, no matter how
many products, we'll deliver directly to your computer.  If you're
outside the U.S., savings might be greater.  You won't pay taxes or
duties to a freight company or postal service, because they aren't
involved in the delivery.  Check your tax code to be sure, but some
countries charge no tax at all on transactions of this type.  It
could just be your lucky day!

====================================================================

PowerBASIC, Inc.                               (800) 780-7707 Sales
316 Mid Valley Center                          (831) 659-8000 Voice
Carmel, CA 93923                               (831) 659-8008 Fax

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All contents Copyright (c) 2001 by PowerBASIC, Inc.  All Rights
Reserved.  PowerBASIC is a registered trademark of PowerBASIC, Inc.
PB/CC, PB/DLL, PowerGEN, and PowerTREE are trademarks of
PowerBASIC, Inc.  All other brand names are trademarks or registered
trademarks of their respective owners.

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                PowerBASIC Gazette - Electronic Edition
                          Volume 1 - Issue 19


PowerBASIC, Inc.                               (800) 780-7707 Sales
316 Mid Valley Center                          (831) 659-8000 Voice
Carmel, CA 93923                               (831) 659-8008 Fax

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