I am implementing a quite simple state-machine order processing application. It is a e-commerce application with a few twists. The users of the application will not be editing workflows by themselves.
Microsoft claims that asp.net and Windows Workflow is possible to combine. How hard is it to install and maintain a combination of asp.net and Windows Workflow? I would be keeping the workflow state in sql-server.
Is it easier for me to roll my own state machine code or is Windows Workflow the right tool for the job?
Asp.net and WF get along just fine, and WF doesn't add much maintenance overhead.
Whether or not this is the right design for you depends a lot on your needs. If you have a lot of event driven actions then WF might be worthwhile, otherwise the overhead of rolling your own tracking would probably add less complexity to the system.
WF is reasonably easy to work with so I'd suggest working up a prototype and experimenting with it.
Also, in my opinion, based on your requirements, I doubt WF would be the right solution for you.
It depends on your needs. How complex is the state machine? Where do you want the state machine to live (e.g. model vs. database)? WWF provides an event based state machine, which is good enough if your state machine is embedded in the model.
Personally I've implemented an e-commerce framework and other workflow based websites and I've have always had a lot of joy from implementing database based state machines. Always worked without a hitch.
On the other hand, some colleagues of mine prefer WWF.
In any case it works perfectly with ASP.NET.
If your state machine is very simple, then I would say that you should just roll your own. You have more control over everything. You can deal with persistence on your own terms and not worry about how they do it.
WF does look pretty cool though, but I think that it's power probably lies in the fact that it is easy to tie it into frameworks like CRM and Sharepoint. If you are going to use these in your application, then I would definitely consider using WF.
Full disclosure: I am definitely not a WF expert.
Related
My team has been tasked with designing a web application that is workflow driven. I need some advice regarding the design.
The workflows need to be dynamic. Meaning, users can define the workflows through some interface and apply those workflows to a given scenario (The definitions will live in a SQL 2008 Database). The scenarios are defined by the business and will never change. So there may be only 2 types of scenarios a workflow can be defined for. The workflows are not necessarily linear. Some sort of state will drive the workflow. States will also be dynamic, but only exist in a workflow.
I have been looking at examples of workflows and state machines and my head is spinning. I am not sure I want o leverage Workflow Foundation or something we develop. I have seen this and think it may work, but I am not sure the state full implementation will work for us.
You can do this using WF4. I have never used Objectflow so I can't really comment on that but it appears to be an in memory solution and with an ASP.NET web site hosted in IIS that means you will occasionally lose state as IIS recycles and AppDomain. Usually not a big problem as it doesn't happen often but a WF4 InstanceStore will take care of that. It will also allow you to run on a web farm without sticky sessions and have the workflow migrate from machine to machine.
Another nice thing is the workflow designer. Its a WPF control you can rehost in your own app. Not in am ASP.NET or Silverlight app but you can provide a smart client to have users update the workflow definition using the sane designer as you use in VS2010.
The biggest problem with WF4 is the asynchronous execution nature. You will need to use a SynchronizationContext to execute the activities and wait for the workflow to go idle in the new state before you return the resulting HTML to the browser.
Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 8 years ago.
Improve this question
Our team is divided on this and I wanted to get some third-party opinions.
We are building an application and cannot decide if we want to use .Net WPF Desktop Application with a WCF server, or ASP.Net web app using jQuery. I thought I'd ask the question here, with some specs, and see what the pros/cons of using either side would be. I have my own favorite and feel I am biased.
Ideally we want to build the initial release of the software as fast as we can, then slow down and take time to build in the additional features/components we want later on. Above all we want the software to be fast. Users go through records all day long and delays in loading records or refreshing screens kills their productivity.
Application Details:
I'm estimating around 100 different screens for initial version, with plans for a lot of additional screens being added on later after the initial release.
We are looking to use two-way communication for reminder and event systems
Currently has to support around 100 users, although we've been told to allow for growth up to 500 users
We have multiple locations
Items to consider (maybe not initially in some cases but in future releases):
Room for additional components to be added after initial release (there are a lot of of these... perhaps work here than the initial application)
Keyboard navigation
Performance is a must
Production Speed to initial version
Low maintenance overhead
Future support
Softphone/Scanner integration
Our Developers:
We have 1 programmer who has been learning WPF the past few months and was the one who suggested we use WPF for this.
We have a 2nd programmer who is familiar with ASP.Net and who may help with the project in the future, although he will not be working on it much up until the initial release since his time is spent maintaining our current software.
There is me, who has worked with both and am comfortable in either
We have an outside company doing the project management, and they are an ASP.Net company.
We plan on hiring 1-2 others, however we need to know what direction we are going in first
Environment:
General users are on Windows 2003 server with Terminal Services. They connect using WYSE thin-clients over an RDP connection. Admin staff has their own PCs with XP or higher. Users are allowed to specify their own resolution although they are limited to using IE as the web browser.
Other locations connects to our network over a MPLS connection
Based on that, what would you choose and why?
I am especially interested in hearing from developers who have experience with both ASP.Net and WPf.
Reasons to choose WPF:
Much faster and easier development than ASP.NET and jQuery
Much easier to implement quick incremental background loading of data
Much easier to implement client-side caching of commonly used data (important for remote offices)
More efficient data transfer from server (can use advanced WCF features unavailable to web browser)
Keyboard navigation better, since you can easily define shortcuts, etc, and not be limited by browser
Maintenance overhead much better using MVVM pattern
Softphone integration easy
Reasons to choose ASP.NET and jQuery:
None that I can see
In your scenario I would definitely choose WPF.
First of all, I would sit down and write the business requirements and specifications. It really doesn't matter what tech you use - proper planning will affect your project timeline more than technology choice. This is especially true for an in-house custom built app.
As far as development, I would take the requirements and lay out the backend functionality. I would actually implement the backend in WCF, regardless of the client technology - that way you could use best of both worlds if needed (for example for phone integration you could write a stand-alone WPF app). ASP.NET with jQuery can easily use WCF services (JSON or XML version) together with desktop client.
As far as development of the client forms, this highly depends on developers experience and your future plans. I am not going to go into advantages/disadvantages of developing web software here - there are a ton of articles in the last 10 years about cloud/web based software (for example salesforce). I would rather concentrate on deliverables - what is your team most comfortable with today and in the future. There's a huge difference between WPF and web development, from development standpoint, and it requires completely different experience.
Why not consider a hybrid solution - Silverlight
With Silverlight you get most of the goodness and statefullness of WPF (with almost exactly the same XAML and code), plus you get the deployment characteristics of ASP.NET
Many people consider Silverlight the next step after ASP.NET/AJAX, and it would definitely deliver all of the benefits of WPF relevant to your scenario.
WPF is the way to go, without a doubt. I agree with all that #Ray Burns has said.
Because:
You will get a richer, slicker, faster application.
It will be easier to build1.
Softphone/Scanner (i.e. hardware) integration is going to require browser plugins etc. and this can be a nightmare with a browser based application.
Keyboard navigation is still better with native applications.
IME Maintenance is easier with WPF applications.
Definitely use WCF to provide the backend via The Entity Framework, see The Entity Framework In Layered Architectures. You can do have a better integration with the backend in a native application because it can be called inline - no need for callbacks or ajax. I've built components for WPF that are linked via EF to the business logic to provide aware controls for simple stuff like validation. It's stunningly good to drop a customer name field onto a form and it just works.
To add additional components you need to build it with a proper well thought out plugin architecture. This is the same in both environments. I've got some thoughts on this I jotted down in my journal entitled Designing a plugin architecture for an application
When building a WPF application you will be writing in one language (e.g. C#) + markup (XAML). When building asp.net you endup with two languages + markup, as you always have to code some Javascript.
So, based on your requirements it has be to WPF / WCF (EF). A web based application will be a lot more work, more complexity, and not be as nice.
About 12 months ago I was fortunate enough to be given a free hand to choose the technology for a new application. I spent almost a month evaluating all of the options and came to the conclusion that it had to be C#, WPF, Entity Framework. After writing the application I can confirm that it was the right choice...
1. It will still be easier even if your programmers have to learn WPF first. WPF is much better thought out, great and lovely. very lovely. It just works right.
Hi
I think The question at issue is Windows-application or Web application(WPF for win-app VS asp for web-app), Which one is better for you and your project?. In this case your platform is network and your program must work on the net. so for this usage Web-app is better but there are a lot points existing which can make decisions hard. Network platform has great challenge.(according to my personal experience)
Working with web-app by asp.net is nearly hard. you must try to handle many thing's for web-app(request time, session management, even poor UI in comparison to WPF, j-query, etc ). Remember this is not as easy as simple web site.
But win-app is good for network with this condition: "local network"(mpls is almost the same). Absolutely developing win-app is easier than web-app ("At least number of users expert in net-program developing"). for this case WPF has many good things(UI , command, etc) also has many challenging point(like multi-threading and lack of expert developer in this field ) . I'm rather with wpf than asp but decisions is yours
And chalk point to good thing Silverlight but if you want to use this you must look at prism framework : http://compositewpf.codeplex.com/
I have recently developed a project separately with asp and silverlight(prism framework). developing silver-light version is too hard and takes more time than asp.net version but at the end SL-ver have great look nothing else!
Burns pointed to good issues about wpf. also consider Artemiy's post. your environment conditions is same for both of them. WPF/ASP can work with scanner and soft-phone cuz the base of both is on C# and .net library
Finally what ever your decisions is you must hire advance developer at least develop one business-app for the network platform.
Is your app a desktop app or web app.
If Desktop wpf is best.
If web based asp.net is best.
Don't front load your development with your get it up quick scenario. That never works well and results in a sloppy deployment. Take your time, cover all the steps (Business Requirements, System Design, Program Design, Code, TEST and TEST some more, Deployment)
Some points to be made for ASP.NET:
The pool of ASP.NET developers is much larger then the pool of WPF developers.
Which means you can probably find qualified ASP.NET developers easier.
ASP.NET is probably more future proof, chances of WPF getting large changes and being hard to port to later versions is probably larger.
Also keep in mind that the focus of MS seems to be on Silverlight so there might be a consolidation down the road which makes WPF obsolete.
More mature eco system of ASP.NET makes for more out of the box solutions to use to solve problems.
With multiple locations you might be able to skip a few layers and go directly to a website?
There is the requirement, to write a portal like ASP.NET based web application.
There should be a lightweigted central application, which implements the primary navigation and the authentication. The design is achieved by masterpages.
Then there are several more or less independent applications(old and new ones!!), which should easily and independent be integrated into this central application (which should be the entry point of these applications).
Which ways, architectures, patterns, techniques and possibilities can help and support to achieve these aims? For example makes it sense to run the (sub)applications in an iframe?
Are there (lightweighted and easy to learn) portal frameworks, which can be used (not big things like "DOTNETNUKE")?
Many thanks in advance for you hints, tips and help!
DON'T REINVENT THE WHEEL! The thing about DotNetNuke is that it can be as big or as small as you make it. If you use it properly, you will find that you can limit it to what you need. Don't put yourself through the same pain that others have already put themselves through. Unless of course you are only interested in learning from your pain.
I'm not saying that DNN is the right one for you. It may not be, but do spend the time to investigate a number of open source portals before you decide to write your own one. The features that you describe will take 1000s of hours to develop and test if you write them all from scratch.
#Michael Shimmins makes some good suggests about what to use to implement a portal app with some of the newer technology and best practice patterns. I would say, yes these are very good recommendations, but I would encourage you to either find someone who has already done it this way or start a new open source project on codeplex and get other to help you.
Daniel Dyson makes a fine point, but if you really want to implement it your self (there may be a reason), I would consider the following components:
MVC 2.0
Inversion of Control/Dependency Injection (StructureMap for instance)
Managed Extensibility Framework
NHibernate (either directly or through a library such as Sh#rp or Spring.NET
A service bus (NServiceBus for instance).
This combination gives you flexible user interface through MVC, which can be easily be added to via plugins (exposed and consumed via MEF), a standard data access library (NHibernate) which can be easily configured by the individual plugins to connect to specific databases, an ability to publish events and 'pick them up' by components composed at runtime (NServiceBus).
Using IoC and DI you can pass around interfaces which are resolved at runtime based on your required configuration. MEF gives you the flexibility of defining 'what' each plugin can do, and then leave it up to the plugins to do so, whilst your central application controls cross cutting concerns such as authentication, logging etc.
You have a good software product, so why would you make it SOA compatible?
You may want to do this to provide a looser coupling between your data services and your application layer. This will give more flexibility to reuse the service components for other products and allow you to change the underlying service architecture if need be without the need for your application to even know about the change.
Having said all that, I would first want to have an actual business use case that warrants making the switch before making the change. Changing simply to keep up with the latest buzzwords is just a waste of money. If you're starting a new project, however, you may want to consider a service-based architecture if it makes sense for your application.
In my opinion, only one good reason: you need interoperability between different platforms or technologies. Otherwise, save yourself a lot of grief and "just" make a well-mudlarized architecture - tell your boss it is SOA if that's what he wants to hear. Don't do it because you might move to or use other platforms in the future - you don't have an interoperability problem yet.
If you want your product to be integratable with other applications and your customers have actually voiced this wish / requirement then I would consider it, but otherwise it might be a big waste of time and money, especially if doing it might cause some lengthly architectural refactoring to make it work. But with no clear reason, it probably doesn't make sense to follow a trend just because others maybe doing it. Your customers will let you know when this is necessary.
That's a very difficult question to answer without more detail about your "good software product", but speaking in sweeping generalities:
If you implement an SOA scheme on your product, more developers will be able to consume the API services provided by your product because web services work across almost any development platform.
If your product is already a web application that publishes certain data, you might discover that you have readers/consumers of your data that are interested in doing analysis or building additional applications that you never thought of or may not ever have the available time to build.
The fact is: you don't need to.
SOA structure is very complicated to achieve. It requires care and organization style that I believe most companies will not have. (I'm glad if yours has such organization).
Tomas Erls talks about Contemporary SOA and Web Service First Generation. WS-I is the traditional web service style such as asp.net web services. Actually this traditional web services doesn't mean any service oriented; And what happens is people build simple web services and call them SOA.
Contemporary SOA, I believe, is an entire system structured based on services. Inside this "ecosystem", services would call each other to perform some tasks.
SOA analysis is painful and you need care. To build an ecosystem like that, you need to be prepared from the first moment.
Engineering service interfaces (contracts) is also paradigm. If you put some Lean Thinking at your belt, you should cut some desire to make state-of-art design.
If your system already works, fine! If someone will need integration in possible future which you don't know yet about it, don't do it now. But if your system is born to be consumed, them you think about it.
Best
I've been using WWF for a while as part of an internal call center application (ASP.NET), and while learning it was a good practice in understanding how a state machine based workflow system should work, I am definitely not in love with WWF itself. In my opinion it is:
Overly complex, especially for use within web apps (all that threaded runtime stuff)
Immature (ever worked with that horrible designer?)
Anemic in its current feature set
Does anyone have a suggestion for a better .NET based workflow framework? Specifically, I am looking for the following features:
State machine based (mapping states to available actions)
A focus on user permissions (controlling who has access to what actions)
The ability to run workflows as timed background tasks (for example, to send out reminders for items that have been sitting in a certain state for x days)
That's really all I need. I don't need to be able to "drag and drop" any activities or visually design the flow. I am perfectly comfortable writing actual code once a particular action is triggered.
You could try Simple State Machine. You would have to implement access control and background timers yourself, but that shouldn't be a big deal. SSM was also built out of frustration with WF. There are some other state machine implementations on Codeplex as well. If one of them doesn't fit he bill out of the box, they are open source and should get you close enough.
I wholeheartedly agree with you about state machines in WF - they aren't testable, are too complicated, the threading model is peculiar and hard to follow, and I'm not sure a visual designer could have been more poorly conceived for designing state machines graphically. I think this may be because the state machine concept feels tacked onto the WF runtime, which was designed for sequential state machines, something WF does a much better job with, in my opinion. The problem is that state machines are really not the same animal as a sequential work flow, and should have been given a first class implementation of their own, because the warping of WF to make it seem to support them turned out to be more or less unsupportable, if not actually unusable.
I would stay away from Drools.Net since it's last SVN commit was in September 2007. Looks nice but it seems a bit too risky to make such a big library part of your project when you know it doesn't get any attention anymore.
Try Drools.NET
Have a look at Workflow Engine. It is a lightweight workflow framework for .NET and Java solutions. It has an HTML5 visual designer, version control, a decent UI and supports a wide range of databases.
Do you have the option to consider BizTalk Server?
I quite enjoyed working with Oracle BPEL Process Manager. It's part of JDeveloper.
http://www.oracle.com/technology/bpel/index.html
http://gemsres.com/story/dec06/313602/jellema-fig1.jpg
You may want to take a look at Jazz - http://jazz.codeplex.com/
Try WF4.5. It was completely redesigned since .NET4.0.
First of all you should look for a engine supporting BPMN. BPMN is a standard in Workflow and Process management and well supported from a lot of projects.
Second you should think about the requirements to thus an engine.
When you look for a BPMN Engine, there are two different approaches:
Task-Orientated
These engines (e.g. JBoss BPM - jbpm) are designed to process an input data by a well defined process model. Each task in the model gives the control to a piece of code - either a standard or an individual implementation. The process ends when the process-token reaches the end of the process model (End-Event). This kind of processing takes milliseconds. The engine can be used for batch jobs or processing data with a complex process orientated flow.
Event-Driven
Human-Centric workflow engines are event driven (e.g. Imixs-Workflow). This is a kind of state machine but offers typically much more functionality. You can start a new processinstance by assigning your business object with the initial task (defined by the start event). Than the workflow engine allows you to trigger events assigned to each task, defined in your model. Each event (Intermediate CatchEvent) triggers the workflow engine to transfer the running processinstance to the next task (state). Until no new event is triggered, the processinstance 'waits' in the current task (state). An approval process is an typical example for this kind of human-centric workflow.
You can find a list of engines here.