Aurora.Workflows.Tasks.Workflow 0.5.1.22

Aurora Workflows

A versatile C# workflow engine designed to streamline task management. Easily define and execute workflows with built-in tasks or customize your own to fit specific needs. Perfect for automating processes and improving efficiency in any application.

Project website: https://aurora.unex.me/workflows

Features

• Generic Workflow Management: Create and manage workflows with ease.
• Built-in Tasks: Use predefined tasks for common operations.
• Custom Tasks: Define your own tasks to handle specific requirements.
• Extensible: Easily extend the engine to fit your unique use cases.
• Simple Integration: Integrate seamlessly with your existing C# applications.

Getting Started

Installation

You can install the workflow engine via NuGet Package Manager:

dotnet add package Aurora.Workflows
dotnet add package Aurora.Workflows.Tasks     # 70+ built-in tasks
dotnet add package Aurora.Workflows.Fluent    # fluent builder API
dotnet add package Aurora.Workflows.Contracts # only this is needed to write custom tasks

Building and running a workflow (Fluent API)

A root StartTask is created automatically. String arguments are expression-capable: plain text, or a C# expression that is evaluated by Roslyn at runtime.

using Aurora.Workflows.Fluent;
using Aurora.Workflows.Tasks;

var workflow = FluentWorkflow
    .Create("Daily Report")
    .TriggerOnSchedule("0 0 7 * * ?")                        // Quartz cron: every day at 07:00
    .Set("hour", "DateTime.Now.Hour")                          // SetVariableTask – always an expression
    .If("context.Get<int>(\"hour\") < 12",
        then: t => t.Print("Good morning!"),
        @else: t => t.Print("Hello!"))
    .ReadFile(@"C:\data\report.txt", outputVariable: "report")
    .Do<GreetTask>(t => t.Greeting = "=context.Get<string>(\"report\")") // custom task, see below
        .WithOutput("greeting")
        .Retry(TimeSpan.FromSeconds(5), maxRetries: 3)
    .WriteFile(@"C:\data\greeting.txt", inputVariable: "greeting")
    .Build();

await workflow.StartAsync();

// Persist / restore as JSON
string json = FluentWorkflow.Create("Persisted").TriggerOnce().Print("Hi").Persist();
var restored = FluentWorkflow.Load(json).Build();

Writing a custom task

Derive from WorkflowTaskBase. Every string property of a task may contain plain text or a C# expression prefixed with = – the user decides in the designer. Therefore such properties are never read directly but passed through Resolve<T>(), which returns plain text as-is and compiles/evaluates = expressions (e.g. =context.Get<string>("userName")). Data flows between tasks via GetInput<T>() / SetOutput(), which honour scope and variable-name settings.

using System.ComponentModel;
using System.Threading.Tasks;
using Aurora.Workflows.Contracts;
using Aurora.Workflows.Contracts.Attributes;

[WorkflowTaskCategory("My Category")]
[WorkflowTaskInputDefinition(typeof(string), Description = "The name to greet (output of the previous task).")]
[WorkflowTaskOutputDefinition(typeof(string), IsDefault = true, Description = "The composed greeting text.")]
public sealed class GreetTask : WorkflowTaskBase
{
    // Expression-capable: "Hello" (plain text) or
    // "=DateTime.Now.Hour < 12 ? \"Good morning\" : \"Hello\"" (evaluated at runtime).
    [Description("Greeting prefix. Plain text or a '=' prefixed C# expression.")]
    public string Greeting { get; set; } = "Hello";

    // Non-string properties are used directly.
    public bool Exclaim { get; set; } = true;

    public GreetTask() { Name = "Greet Task"; }

    protected override Task<bool> DoAsync(IWorkflowDataContext context)
    {
        var name = GetInput<string>(context) ?? "World";    // previous task's output
        var greeting = Resolve<string>(Greeting, context);   // text or evaluated expression

        SetOutput(context, $"{greeting}, {name}{(Exclaim ? "!" : ".")}");
        return Task.FromResult(true);
    }

    protected override Task<bool> DoSetupAsync() => Task.FromResult(true);     // before first run
    protected override Task<bool> DoTearDownAsync() => Task.FromResult(true);  // on workflow stop
}

Scope tasks with child tasks (loops, conditionals, transactions) derive from TransactionScopeTaskBase instead. Full documentation: https://aurora.unex.me/workflows

Tip: developing custom tasks in a class library? Add a reference to Aurora.Workflows.UI.Host so pressing F5 opens the visual designer with your project already loaded for interactive debugging.

License

Aurora Workflows is free to use in full for non-commercial projects. For commercial use, please get in touch to discuss licensing terms; redistribution, modification, decompilation, reverse-engineering, or publication of the software without explicit written permission is strictly prohibited.