Configuring a library

[Jona Gold]

I have an argument with a senior programmer here. He says
I shouldn't have special configuration for the part of
the code that's in the library. But isn't that the whole
point of libraries: that you can separate concerns, that
you can change the library, without needing to recompile
all the applications that use it?

My library needs a database DSN. Why should application
initialize it with DSN, instead of special configuration
object? If requirements change, I can simply change or
add settings in the configuration, recompile the library
and leave the applications untouched.

What should I say on the next meeting so that this guy will
stop pushing his twisted design on me? Please help.

Regards, Jona

 

[Marc Gravell]

Since you mention recompiling, it isn't clear where you are planning
on putting this configuration...

But: use a setting in a .config file (web.config/app.config); that way
you don't have to recompile the library or the application - you just
change the .config. For database, configuration/connectionStrings
would be the obvious place...

Marc

 

[Family Tree Mike]

You should not have a separate config file for the dll, but rather let the
calling application set configuration items for your dll. In your example,
it would be good to have a method called SetDSN(string connString); which
replaces the need for the config file you describe. This gets arround
recompiling, and aleviates the need for the application to have a separate
config file to worry about during installation.

 

[Jona Gold]

But: use a setting in a .config file (web.config/app.config); that way
you don't have to recompile the library or the application - you just
change the .config. For database, configuration/connectionStrings
would be the obvious place...

Thanks Marc. There will be couple applications on the server. We
don't want to force admins to use regedit or notepad, so we prepared
a fool-proof configuration editor.

With this editor there comes a library, so that all the applications
can access the configuration uniformly, no matter if it resides in a
..config file, registry or where ever.

Thinking about it again - it's plain stupid, but there is a windows
service and a web application part of one and the same application, and
I'd like to have the configuration in one place. Do I have another option?

Regards,
Jona

 

[Jona Gold]

You should not have a separate config file for the dll, but rather let the
calling application set configuration items for your dll. In your example,
it would be good to have a method called SetDSN(string connString); which
replaces the need for the config file you describe. This gets arround
recompiling, and aleviates the need for the application to have a separate
config file to worry about during installation.

Thanks Mike for taking your time. But what if I have to suddenly connect
to another database? I could just change the dll and some options in the
config file. If I followed your advice, I'd have to convert all the
SetDSN calls in all the applications to something like SetDB(user, pass,
IP) and recompile. Isn't that just much more work and a bad design anyway?

Regards,
Jona

 

[gaurav sharma]

private void DisplayWebConfig()
{ // Reads in the contents of Web.config and displays them in the
TextBox
StreamReader webConfigStream =
File.OpenText(Path.Combine(Request.PhysicalApplicationPath,
"Web.config"));
string configContents = webConfigStream.ReadToEnd();
webConfigStream.Close();
TextBoxWebConfigContent.Text = configContents;
}

 

[gaurav sharma]

private void DisplayWebConfig()
{ // Reads in the contents of Web.config and displays them in the
TextBox
StreamReader webConfigStream =
File.OpenText(Path.Combine(Request.PhysicalApplicationPath,
"Web.config"));
string configContents = webConfigStream.ReadToEnd();
webConfigStream.Close();
TextBoxWebConfigContent.Text = configContents;
}

 

[Jona Gold]

Thanks for the code but it's not what I'm
looking for.

Regards, Jona

 

[Family Tree Mike]

Thanks Mike for taking your time. But what if I have to suddenly connect
to another database? I could just change the dll and some options in the
config file. If I followed your advice, I'd have to convert all the
SetDSN calls in all the applications to something like SetDB(user, pass,
IP) and recompile. Isn't that just much more work and a bad design anyway?

Regards,
Jona

Your main application would likely have the settings in a config file. It
(the application) uses these settings with the DLL API to configure the DLL.