Limit FORM mailer submissions to 5 on website, then pause until reviewed by webmaster

[Lance]

Hi everyone,

I was hoping someone could help or point me in the right direction.

I would like to install an intelligent Form mailer on my up and coming
website.
The purpose of the Form mailer will be to either submit to a database
or send an email. However, I would like the form mailer to pause and
prevent any further submissions after 5 submits. During this period new
users visiting the page should automatically be redirect to another URL
displaying a message similar to '5 forms have already been submitted,
please check back soon'. Once I have reviewed the 5 submitted forms,
I should then be allowed to open the form up again.

Looking forward to your suggestions.

Many thanks,

Lance

P.S - my scripting knowledge is very limited ;-)

 

[Matt Garrish]

Hi everyone,

I was hoping someone could help or point me in the right direction.

I would like to install an intelligent Form mailer on my up and coming
website.
The purpose of the Form mailer will be to either submit to a database
or send an email. However, I would like the form mailer to pause and
prevent any further submissions after 5 submits. During this period new
users visiting the page should automatically be redirect to another URL
displaying a message similar to '5 forms have already been submitted,
please check back soon'. Once I have reviewed the 5 submitted forms,
I should then be allowed to open the form up again.

[realizing this has absolutely nothing to do with Perl...]

Your requirements are a bit vague, but I'm assuming all submissions go
into the database and the email goes out when you confirm the
submissions? If that is the case, the standard approach is to add a
confirmation column to your table. You can then count the number of
unconfirmed entries before displaying the page and if it already equals
five display your alternate text. You just have to bear in mind that
multiple people could see the form while it still only registers 4
submissions, and they could all try to submit to be the fifth, which
might make some users unhappy when they find out they're actually
number 6,7,8,9... and rejected after filling out the form. It also
means that as you confirm the entries new ones will be able to go in.

If you don't want to be counting all the time from your database, there
are other options but they require a good deal of care to implement.
One would be to create a separate table with just the current count and
check it each time (but you'll need to properly lock the tables during
transactions to ensure accuracy). Another would be to use a text file
for the count, holding a lock on it while the database update occurs
and then wrting the new count. You can then review the five submitted
entries at your leisure but until you reset the count table/text file
no one can submit (i.e., your database won't keep filling up as you
review).

With a limit of 5 it doesn't sound like you're dealing with enough
traffic that you'd need to worry yourself about the latter options,
though.

To give this some Perl content, there are many modules available that
make writing a script like you've described very simple. For databases,
have a look at DBI (and probably DBD::MySQL), and for sending emails
there's Net::SMTP, Mail::Mailer, etc.

Just don't post back asking someone here to write it for you, unless
you enjoy being flamed...

Matt

 

[Lance]

Thank you Matt.

Your response and suggestions were amazing and well detailed. It's
given me a lot more to think about and definitely helped me to see the
bigger picture and protection problems.

Although i may not get a large number of posts simultaneously, i will
need to think about either counting the current sessions or applying a
lock on a file, as the type of posts could mean that users spend 30
minutes writing the post before clicking submit. It sounds easier to
have a script that creates a temporary row in a sessions table as soon
as the Form Windows is opened. I would need to include a script just
before that to do a count on the session table. If the count is >= 5,
then don't display the input form and instead display the message,
otherwise show the form.

So to avoid being flamed, could I ask if anyone could recommend a good
place to start and the best programming language to go with? I'll be
very grateful for any links and additional pointers.

Many thanks again Matt for your post..

Lance

 

[Matt Garrish]

Thank you Matt.

Your response and suggestions were amazing and well detailed. It's
given me a lot more to think about and definitely helped me to see the
bigger picture and protection problems.

Happy to help, but please quote context when you reply.

Although i may not get a large number of posts simultaneously, i will
need to think about either counting the current sessions or applying a
lock on a file, as the type of posts could mean that users spend 30
minutes writing the post before clicking submit. It sounds easier to
have a script that creates a temporary row in a sessions table as soon
as the Form Windows is opened. I would need to include a script just
before that to do a count on the session table. If the count is >= 5,
then don't display the input form and instead display the message,
otherwise show the form.

You wouldn't lock the file from the time they come to the page until
the time they submit. That would make your application impossible to
use. All I meant is that the file is locked while the transaction to
the database occurs (fraction of a second), so that no other attempts
to submit can happen while that one is in progress. The same can be
done by writing a proper transaction when you submit to your database
so that the table(s) are locked while that update occurs.

I think you have too much faith in the statefulness of web
applications, though. It's a bad idea to try and stop submissions when
you think you might have reached your limit. What if the person loads
the page and then goes away? What if they fill out some of the form and
go away? You'd then need a way to (somewhat arbitrarily) reap the
unused locks you've written to your database, which is an ugly
approach.

There's no nice way to do what you're after, other than to check your
count however you implement it both before displaying and before
accepting (don't forget a spammer who gets the source for your form can
bypass the first count). And that means that some people may get
rejected. It's just a fact of life if you're going to impose a limit
like you want.

So to avoid being flamed, could I ask if anyone could recommend a good
place to start and the best programming language to go with? I'll be
very grateful for any links and additional pointers.

Yes, Perl, but that's what you get for asking in a Perl newsgroup. I
doubt that you'll find anything prewritten, because these kinds of
multi-faceted applications tend to be use-specific, so there's no good
way to abstract them into something that anyone could plug in. If
you're looking to write it yourself, you might want to start at
learn.perl.org, otherwise you could look for someone to freelance at
jobs.perl.org.

Matt