Running an asynchronous process within VFP

[rkolva]

Hello all,

I've got a data entry system that transmits data as xml over http ssl with a client certificate. The handshake takes about a second on average and while the data is being sent I display a graphic that lets the user know something is happening. The communication is currently in a custom class that I'm in the process to converting it to a COM dll so that I don't have to include the code with each of my applications (exes) as I typically have more than 1 of my apps running on a given machine. What I would like to do is to initiate the communication process asynchronously so that the user doesn't see a 'hiccup' in using the app. I suppose I could shell the communication to an exe. Any suggestions on a good approach?

Thanks to all.

Ralph

 

[baltman]

Using a seperate exe or a dll should work fine. I would think it would work just like calling a procedure in that you pass paramters either using a shellexecute() or automation.

You might want to leave a file somewhere that the main program can check for using a timer to see if the transfer failed or not so that it can tell the user.

Brian

 

[rkolva]

Thanks for the quick response Brian.

Currently I assign my application object an instance of my communication object which has a failed transmission flag and cache the xml to a flat file it communication fails. In a sence the flat file also acts as a flag, if its empty it worked. If using an exe I suppose it would be better to use a seperate transaction file for each app and pass the file location as an arg.

If I were to use automation how do I make the call telling it launch as an independant process, or does that happen by default or a setting?

Ralph

 

[rgbean]

Ralph,
If you create a VFP .DLL COM server, then you can "automate" it just like any other COM server - see the many examples posted on Tek-Tips - especially those for Outlook, Excel and Word. The only difference, is that you can decide what properties and methods you want to expose in your "server". Note: COM DLLs can't have any UI displays, if you need that capability, then it'll hace to be a .EXE COM server!

I believe there may even be a FAQ on writing a COM server, but if you can't find it, a little program can easily show the concepts.

Rick

 

[rkolva]

Thanks Rick,

Currently my class doesn't have any UI and I don't expect that I'll ever want to give it one, so the DLL sounds like it'll do the trick. I started to port the class from an 'ActiveDoc' to 'Session' (as suggested in 'MegaFox') and got a successful first compile on a laptop machine but on my main development machine it doesn't want to write to the registry properly. I'll take a look at the FAQ.

Thanks for the input. I always find this site a fantastic source of info and input and the contributing programmers top notch. You all are a great bunch of folk!

Thanks again.

Ralph