/// <summary>
/// Creates a new message scope. This scope becomes
/// the current scope. Use inside a using(...) clause.
/// </summary>
public ExecMsgScope()
{
OuterContext = Current;
Current = this;
Messages = new HashSet <ExecMsg>();
}
/// <summary>
/// Raise one or more messages.
/// </summary>
public static void RaiseMsg(IEnumerable <ExecMsg> Msgs)
{
ExecMsgScope Ctx = Current;
if (Ctx == null)
{
ThrowMsgs(Msgs);
return;
}
HashSet <ExecMsg> ToThrow = new HashSet <ExecMsg>();
HashSet <ExecMsg> ToHold = new HashSet <ExecMsg>();
foreach (ExecMsg Msg in Msgs)
{
if (Msg.Severity >= MinThrowImmediatelySeverity)
{
ToThrow.Add(Msg);
}
else
{
ToHold.Add(Msg);
}
}
Ctx.Messages.UnionWith(ToHold);
ThrowMsgs(ToThrow);
}
/// <summary>
/// Extract messages from the current scope, based on criteria specified.
/// </summary>
public static IEnumerable <ExecMsg> ExtractMessages(Func <ExecMsg, bool> where)
{
ExecMsgScope Ctx = Current;
if (Ctx != null)
{
IEnumerable <ExecMsg> Msgs = Ctx.Messages.Where(where);
Ctx.Messages = new HashSet <ExecMsg>(Ctx.Messages.Except(Msgs));
return(Msgs);
}
return(new ExecMsg[0]);
}
/// <summary>
/// Pops a scope off the stack.
/// </summary>
public void Dispose()
{
Current = OuterContext;
RaiseMsg(Messages);
}
/// <summary>
/// Certain external components, such as data stores or web services, may throw
/// error or exception conditions that are converted by .NET into undifferentiated
/// Exceptions. To allow them to raise ExecMsgs, we've provided a special string
/// tagging system; this method detects those string tags and converts the exceptions
/// into the appropriate ExecMsgs, if present.
/// </summary>
/// <param name="toRun">The code to execute with ExecMsg tag support. If a tagged
/// exception is thrown by this code, it will be converted to an ExecMsg and raised
/// into the current ExecMsgScope automatically.</param>
public static void ConvertTaggedMsgs(Action toRun)
{
try
{
toRun.Invoke();
}
catch (ExecMsgException)
{
// Pass-through any ExecMsgExceptions, which are already in the correct format.
throw;
}
catch (Exception ex)
{
// If any unexpected internal exception happens while processing the
// original exception, make sure we don't lose the original exception;
// it will be attached to the processing error message.
List <ExecMsg> Msgs = new List <ExecMsg>();
try
{
// Regex for the special tag to identify errors that are meant to be
// converted to ExecMsgs. This is because some external components,
// such as web services or data stores, may be unable to throw ExecMsgs
// directly through the channel we're using to communicate with them.
Regex Rx = new Regex(Regex.Escape(@"{{ExecMsg:") + @"(\S+)"
+ Regex.Escape(@":") + @"(\S+)" + Regex.Escape(@":")
+ @"(.*?)" + Regex.Escape(@"}}"));
// Loop through the exception stack (recurse into inner exceptions) and
// process each for ExecMsgs.
for ( ; ex != null; ex = ex.InnerException)
{
foreach (Match M in Rx.Matches(ex.Message).OfType <Match>().Where(M => M.Success))
{
// Separate out the groups from the regex match. Sometimes it seems that special
// groups (such as the "whole match" group) get added to the start of the groups
// list, so we're only interested in the last 3. There should always be at least
// these three groups.
Group[] SelectedGroups = M.Groups.OfType <Group>().Where(G => G.Value != null).ToArray();
if (SelectedGroups.Length < 3)
{
throw new Exception("Incorrect number of groups in " + (M.Value ?? string.Empty));
}
SelectedGroups = SelectedGroups.Skip(SelectedGroups.Count() - 3).ToArray();
// Try to parse out the message severity, as either a case-insensitive name from
// the enum, or as an integer equivalent. Throw an exception on an invalid value.
ExecMsgSeverity Sev;
if (!Enum.TryParse(SelectedGroups[0].Value.Trim(), true, out Sev))
{
int SevValue;
if (int.TryParse(SelectedGroups[0].Value.Trim(), out SevValue) &&
Enum.IsDefined(typeof(ExecMsgSeverity), SevValue))
{
Sev = (ExecMsgSeverity)SevValue;
}
else
{
throw new Exception("Invalid severity level in " + (M.Value ?? string.Empty));
}
}
// Try to parse out the message ID, as either a case-insensitive name from
// the enum, or as an integer equivalent. Throw an exception on an invalid value.
SysMsgCode MsgCode;
if (!Enum.TryParse(SelectedGroups[1].Value.Trim(), true, out MsgCode))
{
int MsgCodeValue;
if (int.TryParse(SelectedGroups[1].Value.Trim(), out MsgCodeValue) &&
Enum.IsDefined(typeof(ExecMsgSeverity), MsgCodeValue))
{
MsgCode = (SysMsgCode)MsgCodeValue;
}
else
{
throw new Exception("Invalid SysMsgCode in " + (M.Value ?? string.Empty));
}
}
// Add the message to the list of messages to be raised.
Msgs.Add(new ExecMsg(Sev, MsgCode, SelectedGroups[2].Value ?? string.Empty));
}
}
}
catch (Exception ey)
{
throw new Exception("Exception while processing an exception for ExecMsg tags: " + ey.ToString(), ex);
}
// If we were able to transform any exceptions into ExecMsgs, then we
// assume that any other content in the exception is just noise from rethrowing
// and rewrapping, and only raise the messages. If we didn't find any messages,
// then continue to treat this as an internal error and re-raise it.
if ((Msgs != null) && Msgs.Any())
{
ExecMsgScope.RaiseMsg(Msgs);
}
else
{
throw;
}
}
}
