How to choose right design solution for application? - asynchronous

Currently i am creating a design for a new enterprise application. Right now we have a lot of different proprietary solution and we wanna create a new one to switch from them all.
Briefly it is a kind of data destribution system. We have a lot of clients who needs a lot of different data.
What do i want:
1) Common REST API service
2) Some synchronoyu(async?) enviroment to send task and get data back. On image below you could see i think to use spring kafka request/reply template. It helps to scale my application in future.
3) Different typec of calculators for every kind of data
I search a lot how to do the second point the best way but didn't find any ready solutions or advices. Is it good to use kafka here? Maybe some one could give me advice about best practice in such situations.
Plz, send me links for articles or something else, because it will be a big application and i wanna start to create it rightly from the beginning.

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Filtering Data in ASP.NET Web Services

I've been using this site for quite a while, usually being able to sort out my questions by browsing through the questions and following tags. However, I've recently come across a question that is rather hard to lookup amongst the great number of questions asked - a question I hope some of you might be able to share your opinion on.
As my problem is a bit hard to fit into a single line, going in the title, I'll try to give a bit more details on the problem I've encountered. So, as the title says I need to filter, or limit, some of the response data my standard ASP.NET Soap-based Web service returns on invoking various web methods. The web service is used to return data used by other systems (a data repository more or less), where the client today is able to specify a few parameters on how the data should be filtered and in return a full-set of data back.
Well, easy enough I thought, just put additional filtering options on the existing web methods which needs a bit more filtered applied, make adjustments on the server-side and we are all set to go - well, unfortunately it turned out to be a bit more tricky then this.
The problem I am facing is that I'm working on a web service running in a production environment, which needs to be extended in such that additional filters can be applied to existing web method being invoked w/o affecting the calls already being made by other systems used by the customer using their client stubs. This is where I am a bit troubled, since I can't seem to find a "right solution" on extending the current web service.
Today, the filter is send as a custom data structure which holds information on which data should filtered, but I am not sure if I can simply just add more information to this data structure w/o breaking code at the clients? One of my co-workers suggested that I could implement a solution where I would extend the web.config on the server-side to hold a section with details on which data should be excluded (filtered out), but I don't find this to be a viable solution long-sighted - and I don't trust customers with such an option since this is likely to go wrong at some point. So the solution I am looking for is a way that I can apply a "second filter" to the data I am requesting from the client so instead of getting a full-set of data back it should only give a fraction, it implemented in such that the filter can be easily modified and it must not affect the current client calls.
Any suggestions on how I should approach this problem?
Thanks!
Kind regards,
E.
A pretty common practice is to create another instance of the application OR use part of the url to signify the version of the endpoint they are connecting to, perhaps the virtual directory is the date. That way old calls will go to the old API and new calls will come in on the new API.
http://api.example.com/dostuff
vs
http://api.example.com/6-7-2011/dostuff

Web Application Organization/Structure?

I've used MVC before and really like the way it is organized but at times I have to go back to working on ASP.net Webform applications and really wonder what the best way to organize the code is.
Does anyone know of resources that deal with just that? I am pretty familiar with C# but would like to gain further insight.
An example would be a news article portion of a website.
You'd have a web form to display the data to users and then one for administrators to post the articles. Do you simply do everything in the code behind or do you farm it out to another controller-like class you've created?
Break the logical components into separate modules, which could mean separate namespaces; so you might end up with separate assemblies as well.
You cannot code everything into the code-behind; especially if you are doing a large project. All you need to do is to decide on the data exchange contract between modules, or layers. You should clearly specify the module1 guy that you will need a method Foo(param1, param2, param2):bool, and you expect it to translate news into another language.

To Develop LMS and Scorm Sequesncing Engine

We want a LMS(coded in ASP.NET/vb.net) which is able to import SCORM packages & display it to learner for viewing content. I am totally new to SCORM and have been shifted to this project. I want to know how can I access SCORM Assessment object's (Test) result, like Learner ID, passed/fail, time.
Can you please guide me what will I need to implement in ASP.NET code to accomplish my goal ?
Task that I have done so far is,
Reading a manifest zip file, unzipping the file and get all information from the file(content name,description,items and launching page) and when user clicks on a particular course a pop up window is launching the page.
I eagerly want to know what I can do next to communicate with the LMS with the APIs. Shall I need to develop my own LMS to get the result,If there is a quiz which is running, all I need to know is the no of questions attempted by the user, whether the user is pass or fail and I need to store all information in the database for individual user so that I can review the result afterwards.
So the task remaining.
Tracking mechanism to deliver the content.
SCORM/LMS sequencing engine that controls the navigation between parts of SCORM conformant course.
Please help.
SLK at codeplex provides a good starting point. However, if you are truly wanting to provide an in-house written SCORM play that is fully compliant, you have a major task ahead of you. In essence there are three party you need to fully develop:
CAM - the unzipping process, which it sounds like you have already achieved.
RTE - the javascript host for SCORM, providing the 8 specified methods. Behind this you also need to implement the SCORM object model, which SLC does help with. If you have implemented all of this, then there should be data entries on the data model that indicate completion etc.
SN - the sequencing and navigation processing. This is significantly the most complex part. I am still in the process of trying to implement this, using SLC, and it is hard. It is the completion of this that will potentially give you more information that will enable you to know what has been done.
it is also worth looking at scorm.com, who are a consultancy, but provide a lot of useful information about the scorm standard.
That is true. SCORM is one of these stadarts where you can implement as little as possible. But you will need some of Javascript with a Backend-Script (JSON to the rescue) so you can track the scorm data, and save it your database.
But let me tell you this: This is the easiest task! Making your own course-creator is a whole other beast.

ASP.NET Scaffolding/Templating CRUD Solutions

I've been looking into ASP.NET Dynamic Data and how it does scaffolding and routing. I've only scratched the surface, but it's looking like I'd have to create a template for each table that I didn't want to display all columns the same way.
My first impression after looking at dynamic data is that it would seem like less time on the programmer to have to edit one-time generated user controls rather than build a template for each table that doesn't have a uniform display behavior.
What proven solutions are people currently using that help ease the laborious tasks of creating ASP.NET CRUD type user controls?
Thanks
In ASP.NET webforms we use CodeSmith. From a single entity we generate admin pages, codebehinds, service layers, data layers and db stored procedures. All in a matter of seconds. I'd recommend you check it our for quickly building the crud in your apps.
We're actually working on our own code generation tool. It has already proven to work perfectly on the lower layers and now we're on the way to extend it for the presentation layer, that is for generating user controls.
I've not looked into dynamic data (although I'd like to when I have some time) but my biggest fear is always to lose flexibility. The problem is that these front-ends are then maybe generated dynamically each time based on some template and editing, especially bringing in special customer wishes becomes quite difficult. For small standard apps it may work perfectly though.
What we're therefore doing is to "generate" these usercontrols based on a set of standard custom server controls we've developed, but we'll generate just the first time from some static information about the entities in our application. Then you can continue customizing.
Such systems should help the developer, improving his development speed, doing the initial awkward work but then they should give him the flexibility to modify till the maximum. They should not add additional complexity...
I used .netTiers CodeSmith templates long time ago (years) and it was proven so strong, so, it must be more than great now.
I know a (big) company who have built a customization engine (allowing GUI for internal company options) around those templates to use them in most of their applications and were so successful.
I've used http://www.ironspeed.com/ in the past which has been great. Saved us MONTHS of time on our last project which has a big DB, so the cost is worth it. But it looks a bit ugly and can be tricky to update the DB schema once you've generated.
Obviously not much widespread use out there other than whats provided in Visual Studio.
Have a look at Blinq.

ASP.NET based Workflow Engine

I am working on a design spec for a new application that will be heavily workflow driven.
Before I re-invent the wheel, is there a decent lightweight workflow engine that plugs into ASP.NET already around?
Basically, I'm looking for something that handles moving through a defined set of workflow pages while handling state management automatically.
If this isn't around already, I'll definitely try to abstract the engine from my app and put it on codeplex, as it would be really handy.
Any suggestions?
Note: .NET 2.0, so no WWF, though I think WWF is overkill for my needs.
EDIT: Seems like there is a legitimate need for this, and there isn't a product out there...So I might build this.
Here is what I'm picturing:
Custom Page class called WebFlowPage
All WebFlowPage's are registered in a Workflow mapper.
Each WebFlowPage has some form of state object.
A HttpHandler handles picking the appropriate WebFlowPage based upon the workflow, and populating it from the state object.
Is the workflow dynamic, or static?
If the workflows are simple, you could roll your own workflow engine.
In certain situations, it can be fairly simple, and just a couple of data tables to handle the rules, processing and state.
Alot of workflow engines are built for large scale processing (credit card applications, for example). For small scale, you should at least consider your own, which would eliminate the overhead and dependency of/on an engine.
Not sure exactly what you wish to do here, but Ra-Ajax can easily keep state at least if you want your solution ajaxified...
For reference purposes you might want to check out the Ajax Calendar sample or even the (banalistically implemented) Ajax Wizard sample. It surely beats the hell out of doing it with JavaScript...
And every time you "do something" you're in "server-land" which means you can store temporaries all the time as you wish...
The project is LGPL
(PS!
Yes I do work with it)
Building a custom workflow engine is not trivial, although it may seem simple at first. We've tried that. It depends a lot on the complexity of the logic you need it to cover.
Given the current state of the Windows Workflow Foundation and the lack of another framework that abstracts the workflow concepts, I would choose WF if you need complex logic, asynchronous handling or branches in your workflows.
Tracking your state through the workflow can be accomplished by carrying some kind of xml payload or storing the state in a database,
If your workflow is actually a sequential set of forms that need to be filled in by the user, tracking the steps and guiding the user to the next step can be accomplished with some simple custom solution.
You could take a look at the InRule engine too.
Also, there is nxBRE.
These too are mostly used for business rules.
InRule is proprietary, whereas nxBRE supports RuleML (the defacto standard).
You might need to make your own implementation for the pages, and use the rule engine as the "structure".
At this moment, I know that Sharepoint 2007 supports page workflows (using WF), but this would imply using .NET Framework 3 and deployng sharepoint.
My suggestion would be to use whatever you find more light and easier to use.
I think the term "workflow" is very open to interpretation. I have been working lately with a type of workflow that is very different from what you seem to be describing. Mine is a state machine based workflow where the state of a particular record determines what actions a user can take to move the record to the next step in the business process. So "workflow" in this instance means how the record flows from one state to another until it is finally completed.
Your usage of workflow seems to have more to do with moving a user from one page to another in a linear multi-step process, which is a completely different use case (correct me if I'm wrong). So before coming up with a general purpose "workflow" engine that anyone could use, I would recommend defining a little bit better exactly what types of situations this system would handle.
I've been using this for a few months http://objectflow.codeplex.com. Not asp specific but it may fit your needs
While browsing the web for some workflow & BPM resources, I found the following project: NetBPM. Unfortunately, the project seems to be stopped.
I don't think there is a workflow engine that will automatically handle state for you, but if you are moving through a set of pages like a process such as checkout on an ecommerce site, perhaps the ASP.NET wizard control could help you?
There are few workflow options. "Aspose" and "Skelta" are the offers I´m evaluating.
Fábio
you can use WorkFlow Engine, just read the document and run the Demo.
all of the features you need for a dynamic workflow engine they added in there.

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