Best way to call a POP3 server at an interval?

[Mike Doty]

I've written a POP3 checker and wonder what is the best way to check for email every so often.
Is it better to use a timer, a thread, or just call the program at an interval from another program?

Calling from another program actually has some advantage as it can also be used to launch/monitor multiple programs.
Using a thread is easy, but may not be the best way.

[Michael Mattias]

Depends if you want your program running all the time and when/how it's supposed to tell you, "You've got mail to pick up."

If you don't need the program running all the time,Windows Scheduler works just fine.

If you do need/Want the program running all the time, a simple timer sounds promising.

If the program is running all the time, using a timer, has a persistent UI (tray?) and this this 'checking" takes more than one-tenth second, then you at least want to think about performing that check in a separate thread of execution.... and this demo sounds like it might be useful for that purpose:

GUI + Worker Thread + Abort Demo 11-24-07

MCM

[Mike Doty]

How do you call Windows scheduler to call a program every so often?

http://en.wikipedia.org/wiki/Task_Scheduler

Create a job file. This looks promising.
Thank you, Michael.

[Michael Mattias]

I know Scheduler has a COM-based API, but I don't know if anyone has tried using it.

I was thinking to just hit Start/Programs/Accessories/System Tools/Schduled Tasks and defining one.

NOTE: if you want something to run every 'X' minutes, on specific days, you have to start by defining the task to Windows Scheduler as a "weekly" task. (I was not in the room when that design decision was made.)

Me and one of my clients - also a technical/programmer type - together wasted about an hour trying to set this up "intuitively" using the provided screens, prompts and help files, only succeeding when one of us hit "weekly" by mistake and lo and behold the screen we wanted came up!

[Mike Doty]

It sure could be used for a lot of things (not that I don't like programming.)
I'll try to see if I can find examples on the net and in the forum.
I'm looking at some VB stuff, now.

[Michael Mattias]

I was driven to try Scheduler by client requirements... we needed something which could run every 15 minutes, Monday thru Friday, from 7:00 AM to 10:00 PM.

I could have written it myself, but it would have cost my client mucho dinero.

However, I knew Scheduler existed, and I knew that there are commercial products to do this (eg, Ground Control, a referral I got here many years ago), and I figured why not look for an existing product to meet our needs? Even if we could not have gotten Windows Scheduler to work, fifty or sixty bucks for an off-the-shelf solution had to be a better decision than writing something from scratch.


MCM

[John Petty]

Why would it be expensive for about 10 lines of code.
Mike yes a timer is ideal, as I said in the other post my code is in a DLL and called from another program( VB) every 2 minutes from 8am to 8pm. If the mail server is very slow then you might consider a thread and if it is very slow then and you are calling very regularly obviously a flag to ensure you don't call it twice without a return from the functions or as I do, turn the timer off until there is a return from the functions, then restart it.

[Michael Mattias]

>Why would it be expensive for about 10 lines of code.

Oh, really?

Perhaps without any error handling, requires recode/recompile to change anything, no auditing or control it could be done in ten lines of code.

Unfortunately, in the Real World you need these other things, as my clients' customers ofter have alternate vendors they could use.

FWIW, if you have an automobile and ocassionally go to the parts counter at Napa, Autozone, Carquest or Summit Racing (Atech) and have to order a part (for my 1996 Mercury nothing is in stock anymore), depending on the part you order you are using what IS installed at this client, making YOU one of my users.

When you need that part, aren't you glad I didn't just hack this thing together in, say, ten lines of code?


MCM

[Michael Mattias]

While automobile repair parts are hardly life-and-death matters, this got me thinking.

I wonder how much "execution speed" or "development time" we'd all be willing to trade for more/better error handing, audit control, editing, and ease of restart/re-do if we forced ourselves to think beyond the confines of the IT office to the ultimate end-users of our software?

I did some work for a manufacturer of medical devices two years ago. Same kind of thing I do a lot of: customer sends orders to my client electronically, I have to get them into my client's ERP system so they can be picked, shipped and invoiced.

This particular client took orders from hospitals for operating room supplies... for scheduled surgeries.

Just imagine how you'd feel if the doctor told you, "We'll have to postpone your child's procedure because of a software screwup by one of our supplies vendors."

Or maybe you've been bugged by a doctor or collection agency because your health insurance company failed to pay a bill on time ... because of a software screwup by the payer's software developer?


How about rescheduling a week's worth of production (about 30 people) because a vendor could not send a proper advance ship notice for the steel he shipped yesterday... and because you don't have enough to start a production run unless you know that steel is going to arrive on Tuesday, you have to postpone the production run (not to mention upset your customers who were counting on you making those items next week)?

Whether you are an outside consultant/contractor or an employee, you'll create better software if you think about what kind of bad things can happen to you, your family or friends if your software fails.

[John Petty]

>Why would it be expensive for about 10 lines of code.

Oh, really?

Perhaps without any error handling, requires recode/recompile to change anything, no auditing or control it could be done in ten lines of code.

Unfortunately, in the Real World you need these other things, as my clients' customers ofter have alternate vendors they could use.

FWIW, if you have an automobile and ocassionally go to the parts counter at Napa, Autozone, Carquest or Summit Racing (Atech) and have to order a part (for my 1996 Mercury nothing is in stock anymore), depending on the part you order you are using what IS installed at this client, making YOU one of my users.

When you need that part, aren't you glad I didn't just hack this thing together in, say, ten lines of code?


MCM

What does any of that have to do with the question of "how to call at a regular interval" I assure you my entire program is not a "hack" and is used by a multi million dollar coporation. Yes it has audit trails, automatically sends email back to the customers of errors, rejects spam and viruses. As it is in a different country from me I can click on a button on my computer and it will send me the last 64K bytes of the audit trail. All again has nothing to do with the few lines of code that control the frequency of checking for mail. Surprise, you are not the only professional programmer in the world.

[John Petty]

MCM
Seems while I was typing my reply you posted more pontifical cr*p which has nothing to do with the question. I do not "hack" commercial code.
John
PS I have been President of a Multi National, multi million dollar life saving medical company in the USA so am well aware of the requirements and the legal implications of dealing with the FDA so don't need any advice from you on the subject

[Michael Mattias]

All again has nothing to do with the few lines of code that control the frequency of checking for mail

As you point out youself, the 'ten lines' is ONLY to control the frequency. I inferred you were suggesting the entire program could be done in 'ten lines.'

Oh, well, at least I got to excercise Ye Olde Braine Celles.

[Gösta H. Lovgren-2]

Ye Olde Braine Celles.

Defined in some (non-programming) dictionaries as "n. - Bloviated balderdash". adj. "imaginary implied self-important grandiosity"


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Admiration, n.:
A polite recognition of another's
resemblance to ourselves.
Ambrose Bierce (1842-1914)
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[Michael Mattias]

>Defined in some (non-programming) dictionaries ....

I think you forgot "condescending egoism."

But you also forgot, it's my opinion; and AFIAK as long as I stay within the sponsor's rules I am welcome to share it here.

You, of course, are free to agree, disagree or ignore it.

In the case at hand, asking Mr. Petty to show us just what ten lines could accomplish the task was likely a fool's errand, since he has yet to grace us with even one demo in the source code forum.

Call me old-fashioned, but seems to me the only valid 'coin of the realm' in the field of programming is one's code.

[Gösta H. Lovgren-2]

>Defined in some (non-programming) dictionaries ....

I think you forgot "condescending egoism."

Thank you. I will update the definitions accordingly.

But you also forgot, it's my opinion; and AFIAK as long as I stay within the sponsor's rules I am welcome to share it here.

I am unaware of any implication otherwise. A reader's inference is, of course, not in my control. Egotists often feel others are out to "get them".

You, of course, are free to agree, disagree or ignore it.

Thank you for your permission.

In the case at hand, asking Mr. Petty to show us just what ten lines could accomplish the task was likely a fool's errand, since he has yet to grace us with even one demo in the source code forum.

Call me old-fashioned, but seems to me the only valid 'coin of the realm' in the field of programming is one's code.

Ah yes, the old "Put up or Shut Up" ploy. Well played, my man. I am somewhat surprised though you would call yourself a likely fool, however (in?)appropriate it may be.

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Anger is never without a reason
but seldom a good one.
Ben Franklin
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[Michael Mattias]

Not to , but I think providing a little "business context" in the form of a narrative sometimes - no, make that often - serves the developer as well or even better than does twenty or thirty sterile lines of source code.

However, I will agree such narrative is probably of far more interest to "developers" and "consultants" than to "contractors" ... or those who are now "contractors" but wish to become "developers" or "consultants."


MCM

[John Petty]

That is the biggest load of codswalop I have read from you yet Michael.. PB is a language for programmers, its speed is partly based on the concept that the user is proficient enough to write code that only does error checking when needed.
What do you want? Some honorary degree from a university on programming? You won’t get it you have posted too much erroneous information.
I post on the basis that there are better more experienced programmers on this site than me, so only offer a few lines of sterile code if I think it might help, and on occasions it is wrong or not helpful.
I have found this site very useful over the years and in my own small way tried to repay. There is no way I have the time to make 22,000 posts so please leave me out of any of your discussions of what a contributor should do.

[Michael Mattias]

>That is the biggest load of codswalop I have read from you yet Michael

Hmm... I guess that's not "total agreement. "

I'll put you down for "undecided."

[John Petty]

OK?