/// <summary>
/// Reads or creates an XmlConfiguration from a name, path, and/or a handler function to provide structure to a new configuration.
/// </summary>
/// <param name="name">The name that will be given to the configuration</param>
/// <param name="path">The path to the file where the configuration is stored</param>
/// <param name="configuration">The configuration that will be returned after creation or reading has finished</param>
/// <param name="encryptionEngine">The encryption engine to use when reading the file</param>
/// <param name="handler">The event handler to call if structure is needed for a new configuration</param>
/// <returns>True if a configuration was created or read</returns>
public static bool ReadOrCreateConfiguration(
bool verbose,
string name,
string path,
out XmlConfiguration configuration,
FileEncryptionEngine encryptionEngine,
XmlConfigurationEventHandler handler)
{
configuration = null;
Log.WriteLineIf(verbose, "Checking to see if the path '" + path + "' exists.");
/// if the file exists, we need to try and read it
if (System.IO.File.Exists(path))
{
Log.WriteLineIf(verbose, "The path '" + path + "' exists.");
try
{
/// but first see if we have permissions to read it
using (SecurityAccessRight right = new SecurityAccessRight(path))
{
Log.WriteLineIf(verbose, "Checking to see if the path '" + path + "' has read access.");
/// if we don't have rights to the file
if (!right.AssertReadAccess())
{
Log.WriteLineIf(verbose, "The path '" + path + "' does not have write access.");
Log.WriteLineIf(verbose, "Prompting for user intervention for the path '" + path + "'.");
/// prompt to see what we should do about this
DialogResult result = ExceptionUtilities.DisplayException(
null,
"Read access denied - Unable to read from file",
MessageBoxIcon.Error,
MessageBoxButtons.AbortRetryIgnore,
null,
"Read access has been denied for the '" + name + "'.",
"Ignoring this exception will result in a default set of options to be loaded in the '" + name + "' for this application instance.",
"If the file has write access enabled, it will be overwritten with the loaded options when the application exits.",
"WARNING: Aborting this operation will exit the application!");
switch (result)
{
case DialogResult.Abort:
Log.WriteLineIf(verbose, "Aborting attempt to read from the path '" + path + "' because of user intervention.");
return false;
case DialogResult.Retry:
Log.WriteLineIf(verbose, "Retrying attempt to read from the path '" + path + "' because of user intervention.");
return ReadOrCreateConfiguration(verbose, name, path, out configuration, encryptionEngine, handler);
case DialogResult.Ignore:
Log.WriteLineIf(verbose, "Ignoring attempt to read from the path '" + path + "' because of user intervention.");
return true;
//break;
};
}
else
{
Log.WriteLineIf(verbose, "The path '" + path + "' has read access, preparing to read the configuration.");
/// rights to read the file
/// ask the configuration engine to read our configuration file for us into our configuration
if (!ReadConfiguration(encryptionEngine, out configuration, path))
{
Log.WriteLineIf(verbose, "Failed to write the configuration, throwing exception from the last operation.");
throw _lastException;
}
/// let the configuration know where it lives
// configuration.Path = path;
/// ensure that the configuration has no changes visible
if (configuration != null)
{
Log.WriteLineIf(verbose, "Succeeded in reading the configuration, accepting changes .");
configuration.AcceptChanges();
}
return true;
}
}
}
catch (Exception ex)
{
Log.WriteLineIf(verbose, "An unexpected exception was encountered while reading the configuration, dumping exception.");
Log.WriteLine(ex);
Log.WriteLineIf(verbose, "Prompting for user intervention for the path '" + path + "'.");
/// failed for some reason reading the file
/// prompt to see what we should do about this
DialogResult result = ExceptionUtilities.DisplayException(
null,
"Exception encountered - Unable to read from file",
MessageBoxIcon.Error,
MessageBoxButtons.AbortRetryIgnore,
ex,
"An exception was encountered while trying to read '" + name + "'.",
"Ignoring this exception will result in a default set of options to be loaded in the '" + name + "' for this application instance.",
"If the file has write access enabled, it will be overwritten with the loaded options when the application exits.",
"WARNING: Aborting this operation will exit the application!");
switch (result)
{
case DialogResult.Abort:
Log.WriteLineIf(verbose, "Aborting attempt to read from the path '" + path + "' because of user intervention.");
return false;
case DialogResult.Retry:
Log.WriteLineIf(verbose, "Retrying attempt to read from the path '" + path + "' because of user intervention.");
return ReadOrCreateConfiguration(verbose, name, path, out configuration, encryptionEngine, handler);
case DialogResult.Ignore:
Log.WriteLineIf(verbose, "Ignoring attempt to read from the path '" + path + "' because of user intervention.");
break;
};
}
}
else
{
Log.WriteLineIf(verbose, "The path '" + path + "' does not exist.");
}
/// if for some reason the configuration hasn't been loaded yet
if (configuration == null)
{
Log.WriteLineIf(verbose, "Creating new configuration named '" + name + "'.");
configuration = new XmlConfiguration();
configuration.ElementName = name;
Log.WriteLineIf(verbose, "Checking for formatting callback for the configuration named '" + name + "'.");
if (handler != null)
{
Log.WriteLineIf(verbose, "Formatting callback found for the configuration named '" + name + "', calling formatting callback to apply structure to the configuration.");
try
{
XmlConfigurationEventArgs e = new XmlConfigurationEventArgs(configuration, XmlConfigurationElementActions.None);
handler(null, e);
configuration = e.Element;
}
catch (Exception ex)
{
Log.WriteLineIf(verbose, "An unexpected exception was encountered while reading the configuration named '" + name + "', dumping exception.");
Log.WriteLine(ex);
}
}
}
Log.WriteLineIf(verbose, "Setting the path for the configuration named '" + name + "' and accepting changes to the configuration.");
/// let the configuration know where it lives
configuration.Path = path;
/// ensure that the configuration has no changes visible
configuration.AcceptChanges();
return true;
}
/// <summary>
/// Reads a configuration using the specified encryption engine from the specified path
/// </summary>
/// <param name="encryptionEngine">The encryption engine to use while reading the configuration, null if no decryption is desired</param>
/// <param name="configuration">The configuration to be read into</param>
/// <param name="path">The path to be read from</param>
/// <returns></returns>
public static bool ReadConfiguration(FileEncryptionEngine encryptionEngine, out XmlConfiguration configuration, string path)
{
Stream stream = null;
_lastException = null;
try
{
configuration = new XmlConfiguration();
stream = (encryptionEngine != null ? encryptionEngine.CreateDecryptorStream(path) : new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.None));
XmlConfigurationReader reader = new XmlConfigurationReader();
configuration = reader.Read(stream);
configuration.Path = path;
configuration.SetHasUnpersistedChanges(false);
return true;
}
catch (Exception ex)
{
Log.WriteLine(ex);
_lastException = ex;
}
finally
{
if (stream != null)
stream.Close();
}
configuration = null;
return false;
}
/// <summary>
/// Writes a configuration to a path using the specified encryption engine. Takes windows security into account and checks for write access before trying to write to the path.
/// </summary>
/// <param name="path"></param>
/// <param name="configuration"></param>
/// <param name="encryptionEngine"></param>
/// <returns></returns>
public static bool WriteConfiguration(bool verbose, string path, XmlConfiguration configuration, FileEncryptionEngine encryptionEngine)
{
try
{
Log.WriteLineIf(verbose, "Checking to see if the path '" + path + "' exists.");
/// if the file exists, we need to try and read it
if (System.IO.File.Exists(path))
{
Log.WriteLineIf(verbose, "The path '" + path + "' exists.");
/// but first see if we have permissions to read it
using (SecurityAccessRight right = new SecurityAccessRight(path))
{
Log.WriteLineIf(verbose, "Checking to see if the path '" + path + "' has write access.");
/// if we don't have rights to the file
if (!right.AssertWriteAccess())
{
Log.WriteLineIf(verbose, "The path '" + path + "' does not have write access.");
Log.WriteLineIf(verbose, "Prompting for user intervention for the path '" + path + "'.");
if (verbose)
{
/// prompt to see what we should do about this
DialogResult result = ExceptionUtilities.DisplayException(
null,
"Write access denied - Unable to write to file",
MessageBoxIcon.Error,
MessageBoxButtons.AbortRetryIgnore,
null,
"Write access has been denied for the file '" + path + "'.",
"Ignoring this exception may result in a loss of data if any options in this file were changed.");
switch (result)
{
case DialogResult.Abort:
Log.WriteLineIf(verbose, "Aborting attempt to write to the path '" + path + "' because of user intervention.");
return false;
case DialogResult.Retry:
Log.WriteLineIf(verbose, "Retrying attempt to write to the path '" + path + "' because of user intervention.");
return WriteConfiguration(verbose, path, configuration, encryptionEngine);
case DialogResult.Ignore:
Log.WriteLineIf(verbose, "Ignoring attempt to write to the path '" + path + "' because of user intervention.");
return true;
//break;
};
}
else
{
/// it failed, but we're not in verbose mode so who cares?
return true;
}
}
else
{
Log.WriteLineIf(verbose, "The path '" + path + "' has write access, preparing to write the configuration.");
/// rights to write to the file
/// ask the configuration engine to write our configuration file for us into our configuration
if (!WriteConfiguration(encryptionEngine, configuration, path))
{
Log.WriteLineIf(verbose, "Failed to write the configuration, throwing exception from the last operation.");
throw _lastException;
}
/// ensure that the configuration has no changes visible
if (configuration != null)
{
Log.WriteLineIf(verbose, "Succeeded in writing the configuration, accepting changes .");
configuration.AcceptChanges();
}
return true;
}
}
}
else
{
Log.WriteLineIf(verbose, "The path '" + path + "' does not exist, preparing to write the configuration for the first time.");
/// ask the configuration engine to write our configuration file for us into our configuration
if (!WriteConfiguration(encryptionEngine, configuration, path))
{
Log.WriteLineIf(verbose, "Failed to write the configuration, throwing exception from the last operation.");
throw _lastException;
}
/// ensure that the configuration has no changes visible
if (configuration != null)
{
Log.WriteLineIf(verbose, "Succeeded in writing the configuration, accepting changes .");
configuration.AcceptChanges();
}
return true;
}
}
catch (Exception ex)
{
Log.WriteLineIf(verbose, "An unexpected exception was encountered while writing the configuration, dumping exception.");
Log.WriteLine(ex);
Log.WriteLineIf(verbose, "Prompting for user intervention for the path '" + path + "'.");
if (verbose)
{
/// failed for some reason writing the file
/// prompt to see what we should do about this
DialogResult result = ExceptionUtilities.DisplayException(
null,
"Exception encountered - Unable to write to file",
MessageBoxIcon.Error,
MessageBoxButtons.AbortRetryIgnore,
ex,
"An exception was encountered while trying to write to the file '" + path + "'.",
"Ignoring this exception may result in a loss of data if any options in this file were changed");
switch (result)
{
case DialogResult.Abort:
Log.WriteLineIf(verbose, "Aborting attempt to write to the path '" + path + "' because of user intervention.");
return false;
case DialogResult.Retry:
Log.WriteLineIf(verbose, "Retrying attempt to write to the path '" + path + "' because of user intervention.");
return WriteConfiguration(verbose, path, configuration, encryptionEngine);
case DialogResult.Ignore:
Log.WriteLineIf(verbose, "Ignoring attempt to write to the path '" + path + "' because of user intervention.");
return true;
};
}
}
return true;
}
/// <summary>
/// Writes a configuration using the specified encryption engine to the specified path
/// </summary>
/// <param name="encryptionEngine">The encryption engine to use while writing the configuration, null if no encryption is desired</param>
/// <param name="configuration">The confiruration to write</param>
/// <param name="path">The path to write it to</param>
/// <returns></returns>
public static bool WriteConfiguration(FileEncryptionEngine encryptionEngine, XmlConfiguration configuration, string path)
{
Stream stream = null;
_lastException = null;
try
{
if (configuration != null)
{
if (configuration.HasUnpersistedChanges())
{
configuration.AcceptChanges();
stream = (encryptionEngine != null ? encryptionEngine.CreateEncryptorStream(path) : new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.None));
XmlConfigurationWriter writer = new XmlConfigurationWriter();
writer.Write(configuration, stream, false);
configuration.SetHasUnpersistedChanges(false);
}
return true;
}
}
catch (Exception ex)
{
Log.WriteLine(ex);
_lastException = ex;
}
finally
{
if (stream != null)
stream.Close();
}
return false;
}