context in input parameters

Author: danielgerlag

src/WorkflowCore/Interface/IStepBuilder.cs

@@ -62,6 +62,15 @@ public interface IStepBuilder<TData, TStepBody>
         /// <returns></returns>
         IStepBuilder<TData, TStepBody> Input<TInput>(Expression<Func<TStepBody, TInput>> stepProperty, Expression<Func<TData, TInput>> value);
 
+        /// <summary>
+        /// Map properties on the step to properties on the workflow data object before the step executes
+        /// </summary>
+        /// <typeparam name="TInput"></typeparam>
+        /// <param name="stepProperty"></param>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        IStepBuilder<TData, TStepBody> Input<TInput>(Expression<Func<TStepBody, TInput>> stepProperty, Expression<Func<TData, IStepExecutionContext, TInput>> value);
+
         /// <summary>
         /// Map properties on the workflow data object to properties on the step after the step executes
         /// </summary>

src/WorkflowCore/Services/StepBuilder.cs

@@ -82,6 +82,15 @@ public IStepBuilder<TData, TStepBody> Input<TInput>(Expression<Func<TStepBody, T
             return this;
         }
 
+        public IStepBuilder<TData, TStepBody> Input<TInput>(Expression<Func<TStepBody, TInput>> stepProperty, Expression<Func<TData, IStepExecutionContext, TInput>> value)
+        {
+            var mapping = new DataMapping();
+            mapping.Source = value;
+            mapping.Target = stepProperty;
+            Step.Inputs.Add(mapping);
+            return this;
+        }
+
         public IStepBuilder<TData, TStepBody> Output<TOutput>(Expression<Func<TData, TOutput>> dataProperty, Expression<Func<TStepBody, TOutput>> value)
         {
             var mapping = new DataMapping();

src/WorkflowCore/Services/WorkflowExecutor.cs

@@ -75,9 +75,7 @@ public WorkflowExecutorResult Execute(WorkflowInstance workflow, WorkflowOptions
                             });
                             continue;
                         }
-
-                        ProcessInputs(workflow, step, body);
-
+                        
                         IStepExecutionContext context = new StepExecutionContext()
                         {
                             Workflow = workflow,
@@ -87,6 +85,8 @@ public WorkflowExecutorResult Execute(WorkflowInstance workflow, WorkflowOptions
                             Item = pointer.ContextItem
                         };
 
+                        ProcessInputs(workflow, step, body, context);
+
                         switch (step.BeforeExecute(wfResult, context, pointer, body))
                         {
                             case ExecutionPipelineDirective.Defer:
@@ -198,12 +198,26 @@ private void ProcessExecutionResult(WorkflowInstance workflow, WorkflowDefinitio
             }
         }
 
-        private void ProcessInputs(WorkflowInstance workflow, WorkflowStep step, IStepBody body)
+        private void ProcessInputs(WorkflowInstance workflow, WorkflowStep step, IStepBody body, IStepExecutionContext context)
         {
+            //TODO: Move to own class
             foreach (var input in step.Inputs)
             {
                 var member = (input.Target.Body as MemberExpression);
-                var resolvedValue = input.Source.Compile().DynamicInvoke(workflow.Data);
+                object resolvedValue = null;
+
+                switch (input.Source.Parameters.Count)
+                {
+                    case 1:
+                        resolvedValue = input.Source.Compile().DynamicInvoke(workflow.Data);
+                        break;
+                    case 2:
+                        resolvedValue = input.Source.Compile().DynamicInvoke(workflow.Data, context);
+                        break;
+                    default:
+                        throw new ArgumentException();
+                }
+                
                 step.BodyType.GetProperty(member.Member.Name).SetValue(body, resolvedValue);
             }
         }

src/samples/WorkflowCore.Sample09/ForEachWorkflow.cs

@@ -18,6 +18,7 @@ public void Build(IWorkflowBuilder<object> builder)
                 .ForEach(data => new List<int>() { 1, 2, 3, 4 })
                     .Do(x => x
                         .StartWith<DisplayContext>()
+                            .Input(step => step.Item, (data, context) => context.Item)
                         .Then<DoSomething>())
                 .Then<SayGoodbye>();
         }        

src/samples/WorkflowCore.Sample09/Steps/DisplayContext.cs

@@ -8,9 +8,12 @@ namespace WorkflowCore.Sample09
 {
     public class DisplayContext : StepBody
     {        
+
+        public object Item { get; set; }
+
         public override ExecutionResult Run(IStepExecutionContext context)
         {
-            Console.WriteLine($"Working on item {context.Item}");
+            Console.WriteLine($"Working on item {Item}");
             return ExecutionResult.Next();
         }
     }