CODEWITHSUNDEEP
c#app-configclass-libraryaspnet-regiis.exe
Sniipe
Sniipe

Reputation: 1296

c# configuration for class library

I have a class library which by default doesn't have an app.config. The calling app for this library is "explorer.exe" and I won't be able to use explorer.exe.config to add my settings.

Is there any way I can have my class library read an app.config? It needs to be an app.config because I intend on encrypting it during deployment using aspnet_regiis (I'll rename it web.config, encrypt it and rename it back to app.config).

Upvotes: 0

Views: 3257

Answers (2)

Sniipe
Sniipe

Reputation: 1296

In the end (as per @Stand__Sure and @tigerswithguitars I created a new project within my solution which will be a console App. It will be executed at deployment. Thanks to Stand__Sure for his link to https://learn.microsoft.com/en-us/dotnet/standard/security/how-to-use-data-protection

The console app does the following: 

private static void Run()
{
    try
    {
        // Get unencrypted data from Settings.dat
        string[] unencrypted = File.ReadAllLines("C:\\Program Files (x86)\\theAPPSettings\\Settings.dat");

        string unencryptedGuid = unencrypted[0]; //its only 1 setting that I'm interested in

        // Create a file.
        FileStream fStream = new FileStream("C:\\Program Files (x86)\\theAPPSettings\\ProtectedSettings.dat", FileMode.OpenOrCreate);

        byte[] toEncrypt = UnicodeEncoding.ASCII.GetBytes(unencryptedGuid);                

        byte[] entropy = UnicodeEncoding.ASCII.GetBytes("A Shared Phrase between the encryption and decryption");

        // Encrypt a copy of the data to the stream.
        int bytesWritten = Protection.EncryptDataToStream(toEncrypt, entropy, DataProtectionScope.CurrentUser, fStream);

        fStream.Close();

        File.Delete("C:\\Program Files (x86)\\theAPPSettings\\Settings.dat");

        //Console.ReadKey();
    }
    catch (Exception e)
    {
        Console.WriteLine("ERROR: " + e.Message);
    }
}

The calling app decrypts it as follows:

FileStream fStream = new FileStream("C:\\Program Files (x86)\\theAPPSettings\\ProtectedSettings.dat", FileMode.Open);

byte[] entropy = UnicodeEncoding.ASCII.GetBytes("A Shared Phrase between the encryption and decryption");

// Read from the stream and decrypt the data.
byte[] decryptData = Protection.DecryptDataFromStream(entropy, DataProtectionScope.CurrentUser, fStream, Length_of_Stream);

fStream.Close();

string temp = UnicodeEncoding.ASCII.GetString(decryptData);

Upvotes: 0

tigerswithguitars
tigerswithguitars

Reputation: 2547

In C# the only config that matters really is the app.config of the output project. In the case of a console app this will be the .exe config. Which will appear in the bin as {your app name}.exe.config.

You can read this file using the ConfigurationManager in the System.Configuration DLL. All the uses of this will point to the executing code's configuration file, even in a class library. So any additional configuration needed in an imported class library will need to be added to this file. This is the canonical way of dealing with config.

If you really want to have some other configuration file, you can use:

ConfigurationManager.OpenMappedExeConfiguration(
            new ExeConfigurationFileMap
            {
                ExeConfigFilename = overrideConfigFileName
            }, 
            ConfigurationUserLevel.None)

Where overrideConfigFileName points to your other app.config file. You can set the file in the class library as Content and ensure it is copied into the output directory at build time. Then you will have to ensure that it is included in the final deploy package and all the paths match.

Upvotes: 2

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