Implement Dispatch Workflow Definition endpoint

src/core/Elsa.Abstractions/Services/IWorkflowLaunchpad.cs

@@ -73,6 +73,11 @@ namespace Elsa.Services
         /// Executes the specified startable workflow.
         /// </summary>
         Task<RunWorkflowResult> ExecuteStartableWorkflowAsync(StartableWorkflow startableWorkflow, object? input, CancellationToken cancellationToken = default);
+        
+        /// <summary>
+        /// Dispatches the specified startable workflow.
+        /// </summary>
+        Task<PendingWorkflow> DispatchStartableWorkflowAsync(StartableWorkflow startableWorkflow, object? input, CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Collects and executes workflows that are ready for execution. This takes into account both resumable (suspended) workflows as well as startable workflows.

src/core/Elsa.Core/Services/WorkflowLaunchpad.cs

@@ -212,9 +212,13 @@ namespace Elsa.Services
         public async Task DispatchPendingWorkflowAsync(PendingWorkflow pendingWorkflow, object? input, CancellationToken cancellationToken = default) =>
             await _workflowInstanceDispatcher.DispatchAsync(new ExecuteWorkflowInstanceRequest(pendingWorkflow.WorkflowInstanceId, pendingWorkflow.ActivityId, input), cancellationToken);
 
-        public async Task<RunWorkflowResult> ExecuteStartableWorkflowAsync(StartableWorkflow startableWorkflow, object? input, CancellationToken cancellationToken = default)
+        public async Task<RunWorkflowResult> ExecuteStartableWorkflowAsync(StartableWorkflow startableWorkflow, object? input, CancellationToken cancellationToken = default) => await _workflowRunner.RunWorkflowAsync(startableWorkflow.WorkflowBlueprint, startableWorkflow.WorkflowInstance, startableWorkflow.ActivityId, input, cancellationToken);
+
+        public async Task<PendingWorkflow> DispatchStartableWorkflowAsync(StartableWorkflow startableWorkflow, object? input, CancellationToken cancellationToken = default)
         {
-            return await _workflowRunner.RunWorkflowAsync(startableWorkflow.WorkflowBlueprint, startableWorkflow.WorkflowInstance, startableWorkflow.ActivityId, input, cancellationToken);
+            var pendingWorkflow = new PendingWorkflow(startableWorkflow.WorkflowInstance.Id, startableWorkflow.ActivityId);
+            await ExecutePendingWorkflowAsync(pendingWorkflow, input, cancellationToken);
+            return pendingWorkflow;
         }
 
         public async Task<IEnumerable<PendingWorkflow>> TriggerWorkflowsAsync(CollectWorkflowsContext context, object? input = default, CancellationToken cancellationToken = default)

src/server/Elsa.Server.Api/Endpoints/WorkflowDefinitions/Dispatch.cs

@@ -0,0 +1,45 @@
+using System.Threading;
+using System.Threading.Tasks;
+using Elsa.Server.Api.ActionFilters;
+using Elsa.Services;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Swashbuckle.AspNetCore.Annotations;
+
+namespace Elsa.Server.Api.Endpoints.WorkflowDefinitions
+{
+    [ApiController]
+    [ApiVersion("1")]
+    [Route("v{apiVersion:apiVersion}/workflow-definitions/{workflowDefinitionId}/dispatch")]
+    [Produces("application/json")]
+    public class Dispatch : Controller
+    {
+        private readonly IWorkflowLaunchpad _workflowLaunchpad;
+
+        public Dispatch(IWorkflowLaunchpad workflowLaunchpad)
+        {
+            _workflowLaunchpad = workflowLaunchpad;
+        }
+
+        [HttpPost]
+        [ElsaJsonFormatter]
+        [ProducesResponseType(StatusCodes.Status200OK, Type = typeof(DispatchWorkflowDefinitionResponse))]
+        [ProducesResponseType(StatusCodes.Status404NotFound)]
+        [SwaggerOperation(
+            Summary = "Executes the specified workflow definition.",
+            Description = "Executes the specified workflow definition.",
+            OperationId = "WorkflowDefinitions.Execute",
+            Tags = new[] { "WorkflowDefinitions" })
+        ]
+        public async Task<IActionResult> Handle(string workflowDefinitionId, DispatchWorkflowDefinitionRequest request, CancellationToken cancellationToken = default)
+        {
+            var startableWorkflow = await _workflowLaunchpad.CollectStartableWorkflowAsync(workflowDefinitionId, request.ActivityId, request.CorrelationId, request.ContextId, default, cancellationToken);
+
+            if (startableWorkflow == null)
+                return NotFound();
+            
+            var result = await _workflowLaunchpad.DispatchStartableWorkflowAsync(startableWorkflow, request.Input, cancellationToken);
+            return Ok(new DispatchWorkflowDefinitionResponse(result.WorkflowInstanceId, result.ActivityId));
+        }
+    }
+}

src/server/Elsa.Server.Api/Endpoints/WorkflowDefinitions/Execute.cs

@@ -26,8 +26,7 @@ namespace Elsa.Server.Api.Endpoints.WorkflowDefinitions
 
         [HttpPost]
         [ElsaJsonFormatter]
-        [ProducesResponseType(StatusCodes.Status200OK, Type = typeof(WorkflowDefinition))]
-        [SwaggerResponseExample(StatusCodes.Status200OK, typeof(WorkflowDefinitionExample))]
+        [ProducesResponseType(StatusCodes.Status200OK, Type = typeof(WorkflowDefinitionExecuteResponse))]
         [ProducesResponseType(StatusCodes.Status404NotFound)]
         [SwaggerOperation(
             Summary = "Executes the specified workflow definition.",
@@ -35,24 +34,23 @@ namespace Elsa.Server.Api.Endpoints.WorkflowDefinitions
             OperationId = "WorkflowDefinitions.Execute",
             Tags = new[] { "WorkflowDefinitions" })
         ]
-        public async Task<IActionResult> Handle(string workflowDefinitionId, ExecuteWorkflowDefinitionModel model, CancellationToken cancellationToken = default)
+        public async Task<IActionResult> Handle(string workflowDefinitionId, ExecuteWorkflowDefinitionRequest request, CancellationToken cancellationToken = default)
         {
-            var startableWorkflow = await _workflowLaunchpad.CollectStartableWorkflowAsync(workflowDefinitionId, model.ActivityId, model.CorrelationId, model.ContextId, default, cancellationToken);
+            var startableWorkflow = await _workflowLaunchpad.CollectStartableWorkflowAsync(workflowDefinitionId, request.ActivityId, request.CorrelationId, request.ContextId, default, cancellationToken);
 
             if (startableWorkflow == null)
                 return NotFound();
-            
-            var result = await _workflowLaunchpad.ExecuteStartableWorkflowAsync(startableWorkflow, model.Input, cancellationToken);
+
+            var result = await _workflowLaunchpad.ExecuteStartableWorkflowAsync(startableWorkflow, request.Input, cancellationToken);
 
             if (Response.HasStarted)
                 return new EmptyResult();
-            
-            return Ok(new
-            {
+
+            return Ok(new WorkflowDefinitionExecuteResponse(
                 result.Executed,
                 result.ActivityId,
                 result.WorkflowInstance
-            });
+            ));
         }
     }
 }

src/server/Elsa.Server.Api/Endpoints/WorkflowDefinitions/Models.cs

@@ -14,5 +14,8 @@ namespace Elsa.Server.Api.Endpoints.WorkflowDefinitions
         bool IsPublished,
         bool IsLatest);
     
-    public record ExecuteWorkflowDefinitionModel(string? ActivityId, string? CorrelationId, string? ContextId, object? Input);
+    public record ExecuteWorkflowDefinitionRequest(string? ActivityId, string? CorrelationId, string? ContextId, object? Input);
+    public record WorkflowDefinitionExecuteResponse(bool Executed, string? ActivityId, WorkflowInstance? WorkflowInstance);
+    public record DispatchWorkflowDefinitionRequest(string? ActivityId, string? CorrelationId, string? ContextId, object? Input);
+    public record DispatchWorkflowDefinitionResponse(string WorkflowInstanceId, string? ActivityId);
 }