Can you create workflows using only c#, no designer

[faesel]

Hi,

I had a question on whether you could create a workflow using c# that appears on the dashboard without using the designer. I noticed there is a brief mention of the Workflow Definition Store in the docs which can be used to create new workflows.

I patched together some code below to create a workflow, which I can see creates something on the dashboard. However

1. This doesn't seem like the right place for me to be doing this, is there some way to gather all the c# workflows on startup and sync them up with the database.
2. Running this is also crashing out the dashboard for me with an error JsonReaderException: Error reading JObject from JsonReader. Current JsonReader item is not an object: Null. Path 'Exception', line 1, position 91. Am I missing some properties or something?

Is there an example of this floating around somewhere?

public class HelloWorldHttpWorkflow : IWorkflow
    {
        private readonly IWorkflowDefinitionStore workflowDefinitionStore;

        public HelloWorldHttpWorkflow(
            IWorkflowDefinitionStore workflowDefinitionStore)
        {
            this.workflowDefinitionStore = workflowDefinitionStore;
        }

        public void Build(IWorkflowBuilder builder)
        {
            builder.WithId("workflow1");
            builder.WithName("hello world test");
            builder.WithVersion(1);
            builder.WithDescription("hello world test");

            builder
                .StartWith<ReceiveHttpRequest>(
                    x =>
                    {
                         x.Id = "123-Recieve";
                        x.Method = HttpMethod.Get.Method;
                        x.Path = new Uri("/hello-world", UriKind.Relative);
                    }
                )
                .Then<WriteHttpResponse>(
                    x =>
                    {
                        x.Id = "123-Respond";
                        x.Content = new LiteralExpression("<h1>Hello World back!</h1>");
                        x.ContentType = "text/html";
                        x.StatusCode = HttpStatusCode.OK;
                        x.ResponseHeaders = new LiteralExpression("X-Powered-By=Elsa Workflows");
                    }
                );

//Create a connection between the two jobs
            builder.Connect(
                builder.Activities.First(x => x.Id == "123-Recieve"), 
                builder.Activities.First(x => x.Id == "123-Respond"), 
                outcome: "Done");

            var workflow = builder.Build();

            //This should be async which makes me thing this is the wrong place
            var workflowTask = workflowDefinitionStore.SaveAsync(workflow);
            workflowTask.Wait();
        }
    }

Below is the full stack for the error:

JsonReaderException: Error reading JObject from JsonReader. Current JsonReader item is not an object: Null. Path 'Exception', line 1, position 92.

    Newtonsoft.Json.Linq.JObject.Load(JsonReader reader, JsonLoadSettings settings)
    Newtonsoft.Json.Linq.JObject.Load(JsonReader reader)
    Elsa.Serialization.Converters.ExceptionConverter.ReadJson(JsonReader reader, Type objectType, Exception existingValue, bool hasExistingValue, JsonSerializer serializer)
    Newtonsoft.Json.JsonConverter<T>.ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(JsonConverter converter, JsonReader reader, Type objectType, object existingValue)
    Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, object target)
    Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, string id)
    Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, object existingValue)
    Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, object existingValue)
    Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, bool checkAdditionalContent)
    Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)
    Newtonsoft.Json.JsonConvert.DeserializeObject(string value, Type type, JsonSerializerSettings settings)
    Newtonsoft.Json.JsonConvert.DeserializeObject<T>(string value, JsonSerializerSettings settings)
    Elsa.Persistence.EntityFrameworkCore.DbContexts.ElsaContext.Deserialize<T>(string json)
    lambda_method632(Closure , QueryContext , DbDataReader , ResultContext , SingleQueryResultCoordinator )
    Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable<T>+AsyncEnumerator.MoveNextAsync()
    Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ToListAsync<TSource>(IQueryable<TSource> source, CancellationToken cancellationToken)
    Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ToListAsync<TSource>(IQueryable<TSource> source, CancellationToken cancellationToken)
    Elsa.Persistence.EntityFrameworkCore.Services.EntityFrameworkCoreWorkflowInstanceStore.ListByDefinitionAsync(string definitionId, CancellationToken cancellationToken)
    Elsa.Extensions.AsyncEnumerableExtensions.ToListAsync<T>(Task<IEnumerable<T>> task)
    Elsa.Dashboard.Areas.Elsa.Controllers.WorkflowDefinitionController.CreateWorkflowDefinitionListItemModelAsync(WorkflowDefinitionVersion workflowDefinition, CancellationToken cancellationToken)
    Elsa.Dashboard.Areas.Elsa.Controllers.WorkflowDefinitionController.Index(CancellationToken cancellationToken)
    lambda_method593(Closure , object )
    Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor+TaskOfActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, object controller, object[] arguments)
    System.Threading.Tasks.ValueTask<TResult>.get_Result()
    System.Runtime.CompilerServices.ValueTaskAwaiter<TResult>.GetResult()
    Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask<IActionResult> actionResultValueTask)
    Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)
    Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
    Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
    Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeInnerFilterAsync>g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
    Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
    Microsoft.AspNetCore.Builder.Extensions.MapMiddleware.Invoke(HttpContext context)
    Elsa.Activities.Http.Middleware.RequestHandlerMiddleware<THandler>.InvokeAsync(HttpContext httpContext, THandler handler)
    Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

[sfmskywalker]

Hi Faesel,

1. In Elsa 1, there is no way to display workflows written using the C# Workflow Builder API in the designer.
   With Elsa 2 on the other hand this will work by default (in readonly mode).
2. This might very well be a bug. Elsa 1 has a number of known issues when it comes to serialization. These have been fixed in Elsa 2. One thing you could try however is remove the call to builder.Connect - there is no need to connect these activities explicitly, since the workflow builder will already create these connections for you (by virtue of using .Then<>). If you declared activities as standalone variables, then you would have to connect them manually.

Elsa 2 is currently in preview and is planned to be released end of Q1.