Handeling application crashes in a bat-file

Question

I have a application (.NET console app) written in C# that I run on a server. From time to time (about 2 times a week) the application crashes, this might for instance be caused by the network going down or something like that, but that's not important, what I want however, is that when the application crash I want it to simply silently restart. I can't rewrite the application to do this as I don't have the source, and I would like a simple solution to this, so I tried to create a bat file like this:

:start
@BotR.TestR.exe
echo sleeping
@ping 123.45.67.89 -n 1 -w %1000 > nul
goto start

However, whenever the application (BotR.TestR.exe) crashes, it pops up with a popup-window telling that the application crashed, witch stops it from continuing and thus stops it from restarting. Is there any simple way I can solve this?

Answer 1

I'm not sure this is the best way, but you can rewrite the application using Mono Cecil to do what you want like this:

ModuleDefinition module = ModuleDefinition.ReadModule(fileName);

var entryPoint = module.EntryPoint.Body;

var corlib = module.TypeSystem.Corlib;

var exceptionTypeReference = new TypeReference(
    "System", "Exception", null, corlib, false);
exceptionTypeReference = module.Import(exceptionTypeReference);

var entryPointIL = entryPoint.GetILProcessor();

var objectTypeReference = new TypeReference(
    "System", "Object", null, corlib, false);
objectTypeReference = module.Import(objectTypeReference);

var writeLineMethod =
    new MethodReference(
        "WriteLine",
        new TypeReference("System", "Void", null, corlib, true),
        new TypeReference("System", "Console", null, corlib, false))
    { Parameters = { new ParameterDefinition(objectTypeReference) } };
writeLineMethod = module.Import(writeLineMethod);

var callWriteLine = entryPointIL.Create(OpCodes.Call, writeLineMethod);
entryPointIL.Append(callWriteLine);

entryPointIL.Emit(OpCodes.Br, entryPoint.Instructions.First());

var exceptionHandler = new ExceptionHandler(ExceptionHandlerType.Catch)
                        {
                            CatchType = exceptionTypeReference,
                            TryStart = entryPoint.Instructions.First(),
                            TryEnd = callWriteLine,
                            HandlerStart = callWriteLine,
                            HandlerEnd = entryPoint.Instructions.Last()
                        };
entryPoint.ExceptionHandlers.Add(exceptionHandler);

module.Write(fileName);

What this code does is to take the entry point of the application (usually the Main() method) and rewrite it from this:

static void Main()
{
    // some code
}

into this:

static void Main()
{
    while (true)
    {
        try
        {
            // some code
        }
        catch (Exception exception)
        {
            Console.WriteLine(exception);
        }
    }
}

EDIT:

If the Main() method and the contain class are public, there is an easier way: create an application that has the other one as a reference and runs its Main(). Something like this:

class Program
{
    void Main()
    {
        while (true)
        {
            try
            {
                OtherApplication.Program.Main();
            }
            catch (Exception exception)
            {
                Console.WriteLine(exception);
            }
        }
    }
}