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Burned by CodePages

I've worked with out-sourced developers from other countries and recently had a situation that had me completely dumbfounded until I found it.

In our user table, we stored encrypted passwords. When I ran the system using a standard startup process, it recognized the passed password without a problem.

Then I ran it with an automated scheduling tool and it came back with an invalid user.

So then I ran the automated scheduling tool directly from within FoxPro and it worked.

I put code coverage on it, I put in message boxes and tracking (since you can't really bring up the debugger from within a runtime app) all to no avail. The passwords used in the development or standard approach simply didn't match the ones from the automated scheduling tool.

What could the problem be?
I knew it had to be the codepage.

I tried checking the various code pages on the open files. They all appeared to be the same but then I saw the problem. The automated scheduling tool was including its own CONFIG.FPW in the project.

For those who aren't familiar with this technique, if you include the CONFIG.FPW in the VFP project file, you can provide your own settings for startup, such as SCREEN=OFF and other settings.

The code had been written by a development group from the Ukraine and when I reviewed the CONFIG.FPW, it was marked with CODEPAGE=1251 and CPCOMPILE=1251.

As a result, any of the tables opened afterwards would translate the fields incorrectly. So the character that was stored as Chr(65) was actually being read by the automated tool as Chr(192).

Simple to resolve, but frustrating to track down - I KNEW what the problem was but I forgot they had included the CONFIG.FPW in the file.

In addition, it's a good idea to verify configuration files (like the CONFIG.FPW) when dealing with remote developers, especially from countries who will use different codepages. I've been in the position before when dealing with remote developers but most of them are North American. As developers start to share work with other developers around the world, be aware of the codepage issues.


Anonymous said…
Here's a requirement to include in the assignment for the contracter:
must be put in the Config.fpw that's included in the compiled app
That way you can overrule all settings they are putting in there.

Sietse Wijnker

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