Can i make a DLL file auto run and keep working?

Question

I just saw in some wordpress plugins, there are auto tag plugin, auto RSS fetch, just you install the plugin and it keep working for ever without calling it.

What i want to do is to put a dll file inside my Images folder and it will monitor the uploaded files and edit them based on some options, i want this dll to work automatically just when uploaded in the right folder, and keep running forever

This can be done?
If no, there is another options to do so?
"i know that i can use a windows service or startup applciation, i mean other options"

UPDATE: i want any other options, because the server may be shared so have no access on its windows to make a service or a start up.

Answer 1

"You just install the plugin and it keeps working for ever without calling it"

You install the plugin which will have been written against a published interface, and then wordpress will automatically call that plug-in as appropriate when needed.

A dll can't run on its own, it's a library, you need something else to call it - check the running processes on an XP or Win2k3 server and you'll see a number of instances of rundll32 - an executable used to host a dll.

Depending on what you want to do, and what constraints you have, you might be able to do something the Shell Extensions, but I think that a windows service would be the best way to go in all honesty.

Answer 2

Since you didn't include any links, I can only assume you're thinking of WP-o-Matic. From the FAQ, it sets up a cron job - it does not run automagically.

The Windows equivalent would be a scheduled task. You could either write an EXE to host the DLL and call it. Or, use wget to call a URL that would do the work. Obviously, as you mention, a Windows Service with a FileSystemWatcher would have less latency.

That being said, there are various hacks abusing ASP.NET's cache service, timers, or threads to avoid a Windows Service or Scheduled Task. Personally, I endorse none of them. ;)

Answer 3

Can you share the directory? If you can make it a share, you could have a service from another box (or BizTalk for example) monitor it for changes.