Complex emailing from webpage

Question

Hi everyone,
I have posted this question in several forums but have had
very littel response. I would greatly appreciate someone letting me
know which direction I should go in to achieve this task.
I want to have a list of contactable people on my webpage,
and for the user to have the option to contact as many or as few as
they like in one go by selecting a checkbox next to their name.
When you have selected the checkboxes, you click "send" and an
automatic email is generated and sent to the people selected.
Pretty simple - but I can't work it out. Once I have worked out
this bit there will be more complex issues to deal with, but for
tge time being I want to have:
1. An automatic email that says - "This is my automatic
email"
2. Users to be able to select froma list of 10 or so
contacts, by ticking checkboxes, and then clicking "send"
3. The automoated email is sent to the selected people.
Please please help me with this, I will learn whatever I have
to learn - but simply do not know where to start!
Thank you
Nathan

Answer 1

NJFuller wrote:
> Thanks again. I have been studying at Killerphp.com -
would be interested to
> know what you think of them.
It's very difficult for me to comment on killerphp.com. I
have been
there before and looked at one of the videos, but I found the
explanation so slow, I was falling asleep. The problem is
that I know
the stuff that is being taught. For someone who's a complete
beginner,
it might be just the right speed. I've just looked at another
video, and
the content was accurate. So, if his teaching style suits
you, it might
be OK.
Without sitting through the whole course, though, it's
impossible to
know whether it pays sufficient attention to security. A
major problem
with a lot of tutorials and books is that they concentrate on
the basic
mechanics of form processing, but pay little or no attention
to
server-side validation, which is essential to guard your site
against
malicious attacks.
In the code I created for you (and which Gary improved), the
user input
is checked to make sure only expected values are inserted
into the
$toAddresses variable. Without those checks, a malicious
attacker could
turn your form into a spam relay.
All user input needs to be checked to make sure it doesn't
contain
anything unexpected. Inexperienced developers often rely on
JavaScript
to do all the checking. That might help the genuine user, but
it's an
open invitation to an attacker. All the attacker needs to do
is turn off
JavaScript, and your form is an open window: all the checks
are by-passed.
> Could you give me an examples of the mail command in
this particular case, once
> I have an overview of the whole process I should be able
to use my noggin to
> work out the rest :)
The PHP mail() command is very simple. It takes a minimum of
three
arguments: the address(es) the mail is being sent to, the
subject line,
and the body of the message.
After processing the addresses as shown before, you build the
body of
the message by creating a single variable that gathers the
information
from the other fields. Let's say your form has three fields
called
"name", "email", and "comments", you could build the message
like this:
$message = "Name: {$_POST['name']}\n\n";
$message .= "Email: {$_POST['email']}\n\n";
$message .= "Comments: {$_POST['comments']}";
You then send the message like this:
$sent = mail($toAddresses, 'Comments from the web page',
$message);
if ($sent) {
echo 'Your message has been sent';
} else {
echo 'Sorry, there was a problem with your message';
I haven't conducted any checks on the content of the three
fields,
because they're simply being put into the body of the
message. However,
in normal circumstances, you should perform some checks. For
example, a
lot of tutorials show how to pass the user's email address to
the mail()
function as a fourth argument, so that you can send a reply
to the user
just by clicking reply in your email program. This leaves a
gaping
security hole that attackers use to turn your site into a
spam relay.
PHP is relatively easy, but it's also easy to make serious
mistakes that
will cause big headaches down the line.
David Powers
Adobe Community Expert, Dreamweaver
http://foundationphp.com