Question

I’m trying to create a remote job for scheduling in Quartz.net. When I have a copy of the assembly containing the job locally I can do something like this

    JobDetail job = new JobDetail("remotelyAddedJob", "default", typeof(DummyJob.DummyJob));

This requires that I have a copy of the assembly containing the class DummyJob both on the server and on the computer I am creating the schedule from.

What I’d like to do is be able to create the schedule without a client-side copy of the assebmly, by sending the job-type information the way it is stored in the quartz_jobs.xml file

  <job-type>Quartz.Job.NoOpJob, Quartz</job-type>

I have not been able to figure out how to send the class type information without having a local copy. Does anyone have a good solution to this?

Answer 1

This problem was really bugging me. I knew that I could generate classes on the fly, so I looked into how.

Step 1: Create this class

using System;
using Quartz;
using System.Reflection;
using System.Reflection.Emit;

namespace TestQuartzTaskCreator {
    public class FakeJob {
        public static Type Create(string assemblyName, string typeName){
            AssemblyName aName = new AssemblyName(assemblyName);
            AssemblyBuilder ab = AppDomain.CurrentDomain.DefineDynamicAssembly(
                    aName,
                    AssemblyBuilderAccess.RunAndSave);

            ModuleBuilder mb = ab.DefineDynamicModule(aName.Name, aName.Name + ".dll");

            TypeBuilder tb = mb.DefineType(typeName, TypeAttributes.Public);

            tb.AddInterfaceImplementation(typeof(IJob));

            MethodBuilder meth = tb.DefineMethod(
                "Execute",
                MethodAttributes.Public | MethodAttributes.Virtual,
                typeof(void),
                new Type[] { typeof(JobExecutionContext) });

            meth.DefineParameter(1,
                ParameterAttributes.In,
                "context");

            ILGenerator methIL = meth.GetILGenerator();
            methIL.Emit(OpCodes.Ldarg_0);

            Type t = null;
            try {
                // Finish the type.
                t = tb.CreateType();
            }
            catch (Exception ex) {
                System.Console.WriteLine(ex.ToString());
            }

//            ab.Save(aName.Name + ".dll");

            return t;
        }
    }
}

Step 2: Change from this

JobDetail job = new JobDetail("remotelyAddedJob", "default", typeof(TestType));

to this

JobDetail job = new JobDetail("remotelyAddedJob", "default", FakeJob.Create("TestAss", "TestType"));

Step 3: Run as before (but without a copy of your job assembly being referenced in the client)

— Edit —
While this did what I originally wanted it to, it doesn’t resolve all of the issues when using Quartz.Net from a client environment. Retrieving the job requires that the assembly be available.

My current approach is to create a web-service interface that will reside on the same server as the service and present a more disconnected interface.