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some problems with biztalk's ftp adapter

there are two issues you need to be aware of when using the ftp as a receive location:

1. ftp does not have a way to lock files while you're reading them; under some conditions, you could have more than one machine pick up the file and you could end up with duplicate messages. obviously then, you cannot have the host running the ftp adapter live on more than one machine. the receive function of the ftp adapter MUST run under a singleton host.
   
2. the biztalk adapter closes the ftp connection after 3 minutes of inactivity. this means that you must process your files promptly. if you're processing a large file, and it takes more than 3 minutes for your process to commit the message(s) to the message box, you will not be able to delete the file from the ftp receive location once your process finishes. this means that next time your receive location runs again, you'll pick up the same file!

we've encountered both of these issues recently, and both are easy to solve:

1. like i've already mention, have your ftp receive location run under a singleton host.
2. just bring the file down (without processing it) through ftp, and put it on some file folder. have the process that would normally work on the file pick the file up from this new location.

the "guaranteed delivery" nature is a really nice feature, but you have to be aware of the problems it can create. hopefully this will help you in your development; i know i was scratching my head for a while trying to figure out why the ftp adapter wouldn't delete the files it had processed.