OK, I've searched the Internet for the answer to this and haven't found anything... maybe I'm missing the obvious here or just asking the wrong question, but...
How do you call a WF WCF Workflow just by it's URL with parameters? I have a Workflow xmlx, we'll call it DeepThought.xamlx, an operation named TheQuestion and I need to pass the parameter Answer = 42 to it.
I've tried http://localhost:8042/DeepThought.xamlx/TheQuestion?Answer=42 and just about everything else I can think of. I've scoured the Internet and even the wsdl but am either just flat out missing the answer or simply not seeing it.
I assume it's possible, otherwise, what's the point? Clues appreciated.
At least out-of-the-box this is not possible. The standard Receive
activity uses SOAP. I'm sure it's possible to implement a custom Receive but I guess it would be a non-trivial amount of work.
You can also take a look a the following questions. They are REST-related but still may give you some options (a community RESTful endpoint is being mentioned, no idea of its current state though):
RESTful Workflow Service Endpoints in WF4 / WCF
WCF Workflow Service REST interface
I ended up implementing the workflow as a regular activity (non service) inside WCF. This gave me the ability to use their parameters and pass them to the workflow directly. In the end, not too difficult to implement.
Related
I spent few days search on this case. I checked out all wcf asynchronous implementaions.
I wasn't able to find what I was looking for.
Below is scenario.
WCF is running to accept xml
WCF needs to response to user for success receiving xml and release
the request immediately
WCF then needs to do processing to save xml to database and parsing xml to
convert something else.
I don't want to use separate service to process above. I want to use one service to handle all 3 cases above.
I checked out asynchronous way of coding in WCF, but this doesn't release the request right away. What is the best practice for this? Is there any sample code I can use?
Thank you in advance.
I think you would be better suited to using a different technology. Maybe look at Windows Workflow Foundation.
You can host WCF Workflow Services the same way as you host a standard WCF service, the main difference is that you can create specific workflows that can continue after acknowledging receipt of the original message.
You do this by persisting the message and returning to the user. WF allows you to create actions that continue after sending response back to the caller.
Visual studio provides you with a design surface that allows you to drag and drop components to create custom workflows. Additionally you can also make calls to other services if required.
With .net 4.5 you can now use C#, in previous versions of WF you had to use VB.net.
You can read about it on the MSDN site here:
http://msdn.microsoft.com/en-us/vstudio/jj684582.aspx
Hope this helps
I've been digging into the technical details and implementation of Windows Workflow 4.5 as a beginner and having decent results. My question is more of a "why and when" vs. a "how to" question so bear with me.
I've taken a familiar concept to us all and abstracted the business logic into WF, namely the universal log on process. What I wanted to accomplish is having reusable logic that I can call from an MVC website, a Windows Forms application, etc. and have everything run through the same workflow and I have achieved that.
Now I have 2 conceptual questions as to "when" to apply WF and when to use code.
1 - Take simple validation as an example. I'm trying to login but I've passed an empty user name or password string. Obviously, I want to send a message back to the end-user "UserName Required" and "Password Required", which I've done. Now, the way that I did that is I have a validation class (FluentValidation NuGet package if it matters) but the important thing is I'm doing this in code. So, in WF I call my validation code via an ExecuteMethod and everything works just fine. My question is: Is this the wrong approach with a WF mindset? Should I be doing inline WF "If" Actions/Decisions and building up the validation messages inside of WF directly versus calling out to some chunk of code? I'm asking not just for validation but as a concept we can all relate to but more generally should I be attempting to put anything and everything I can into WF itself or is it better to call custom code? I'm looking more for best practice with reasoning from seasoned Software Architects with WF experience versus someone's opinion if possible.
2 - Picking up a workflow on another machine. So, part of the same login workflow activity requires a service method call. I've written the code and workflow in such a way that the workflow receives an In parameter of ILogOnService which has an interface method "AuthenticateUser". The concrete implementation I'm passing in calls out to an MVC4 Web Api post method, in async, to do a standard Asp.Net membership ValidateUser. Again, should I be calling this Web Api PostAsync from inside the WF workflow? If so, doesn't that tightly-couple my workflow to Asp.Net Membership and my particular service choice. It seems there are ways to get the workflow to a certain point and then resume the process on another machine, e.g. where a service is running, and continue the process but I'm not able to find good examples of attempting that.
Just looking for some guidelines and ideas from the pros at this technology but I will pick the most informative answer.
There is nothing wrong with using C# code to implement details of a workflow. In fact I always tell people that if they are using WF4 with just the standard out of the box activities they are probably doing things wrong. You really need to be creating, or have someone else do it for your, custom activities that model business activities for your business. Now if that means creating an activity that validates a login using the FluentValidation that is perfectly fine. Another time you might build a higher level business activity out of lower level WF4 activities, just combine them as works best in your case.
Calling a service with something like PostAsync can work well if you know the action is short lived and is normally available. However when you get into SOA styles you really want to start using temporal decoupling so one service is not dependent on another service being available right away. And when you get into temporal decoupling you really want to be using queues, maybe MSMQ or maybe another similar technology. So in that cas you really want to send a one way message with a response queue and have to workflow go idle and wait for the response message to arrive. This would reload the workfloe, possibly on another machine. Now that might not always be appropriate, for example in your login it would not be much use to grant the login a day later because the membership service was unavailable, but can result in very scalable and fault tolerant systems. Of course there is no free lunch as these systems are very hard to design properly.
Was planning to use Service Routing (on WCF/REST) to do some common tasks before a request hits the actual service. Now that I read more about it, looks like REST is not supported yet on RoutingService and the suggested method is to use System.Web.Routing or ARR.
What needs to happen in the router is a key validation, a header value extraction and versioning.
ARR doesn't look right for this as it just routes and there is no "handler" we have access to. System.Web.Routing looks like a lot of custom implementation which might undermine the efficiency of WCF.
An old school alternative am thinking of is to have the common functionalities in one chain-of-responsibilities implementation and just compose it in every service. This has the disadvantage of being referenced in N number of places for N services. But this increasingly looks like the only alternative if I don't want to mess with the WCF handling of endpoints.
Am looking for advice on a right way to do this, and any samples.
Didn't try, but maybe writing a custom service behavior can solve your problem. Take a look here : Extending WCF with Custom Behaviors.
The idea is to extend the WCF engine with a custom behavior, then attaching your service with this behaviors. This is transparent for the services.
Take a look at HttpMessageHandlers in the new WCF Web Api project htttp://wcf.codeplex.com This mechanisms allows you to do something similar to Rack or WSGI. I have a couple of examples of what you can do with them on my blog http://www.bizcoder.com/index.php/2011/05/22/how-to-get-ahead-with-messagehandlers/
I'm trying to create a flexible security infrastructure for our WCF services on our intranet, but I'm not quite sure where I should be putting this code... there are so many different ways to extend WCF that I don't know for sure where to begin...
The basic idea: every time my service is called - for any operation - I want some code to run that does a custom access check using our existing security infrastructure to see if the user has access to perform the operation. If the user isn't authorized, I want it to throw an exception or something (not sure what it should do really) and prevent the call from ever making it to my service code.
Thoughts?
Thanks
I think that this will be a good starting point for implementing a custom authorization strategy.
I ended up having to use a MessageInspector in conjunction with a ParameterInspector to make it work how I needed.
I have a WCF service defined, it accepts JSON and maps that JSON to an object at which point I can then begin debugging code.
Sometimes, the object fails to create. Most recently my service had a BodyStyle of Wrapped but should have been Bare. In this case I would have liked to watch the request come in and see what happens to it as it gets mapped from JSON to POCO and then onto the service so I can watch for errors.
I'd also like to see what happends with the response where I have also had issues in the past.
What is the best way of seeing what is going on in WCF when it is (kind of) out of my control? What kind of logging/tracing can I use and can I see errors/exceptions being thrown by WCF?
Thanks
Scott
I don't know much but svctraceviewer might help in case you haven't heard about it already.
Arnis gives a good suggestion. I'd also suggest using Fiddler to trace WCF traffic assuming you are using a HTTP end point. I've used fiddler to troubleshoot WCF issues so it might be helpful to you as well.