Develop Reference

Structuring a Web API Stack for Versioning

So I've spent the past few hours trolling through all the genuinely fantastic advice for Web API Versioning. Some of my favourites, for those having as much fun as I am, in no particular order:
Best practices for API versioning?
Versioning REST API of an ASP.NET MVC application
http://www.troyhunt.com/2014/02/your-api-versioning-is-wrong-which-is.html
http://www.pluralsight.com/courses/web-api-design
http://www.pluralsight.com/courses/implementing-restful-aspdotnet-web-api
So all this advice has been very helpful in designing what is essentially the "front end" of the API. We can version the API calls... Now, I'm on to the hard part.
This is a heavily data driven application, for a company with several products (this is a new one) doing monthly releases. Some big customers who will want long-term support for API calls, some smaller customers who will want the latest releases. This we could manage with something similar to milestone/long-term-support releases of the API. Great.
But in practice this is going to get really messy, really fast. We've worked hard to separate out the layers of our own website, the beta Internal/External APIs, Repository Layers and even an SDK to boot. We separate out each release out into separate branches, but it's SAAS - we host the database. So we're not just going to be able to version the API calls - but everything underneath that. The Business Logic, Repository and the Database. Let's not even get started on Unit/Integration Testing.
So, trying and probably failing only ask one question here.
Is there a decent pattern for structuring a layered, data-driven, .NET application to cope with multiple versions?
Specifically how the database will change and how you can structure a generic stack to version it all. Some ideas I have include:
Updating old source control branches of the stack and deploying these
Keeping everything in the same project, but use folders/namespacing all the way down
Splitting the projects further - so the API solution has a number of "Controller" projects, with similar concepts for the logic/repo layers
We have a fair number of developers and no matter how much ace documentation I write, realistically it will only be read when something isn't working. So ideally it needs to be as glaringly obvious as possible for developers to get this right.

There is no perfect solution that fits every situation, whether data-driven or not.
This is really difficult to answer. Your best bet is to use multiple versioning strategies.
For example, if the database change is simply adding a new column, older versions of the APIs can ignore the new columns.
If the database change means you have to completely re-write the repository layer, then you may want to create a new repository and new controller, instead of just versioning an API method. Then on the endpoint, you could either version the route or consumers could call the replacement endpoint.
If there are dramatic changes at all levels of the API, then versioning at IIS with a separate virtual directory may be your solution (and this may have corresponding branches or labels in source control with the intent of supporting bug/fix only).
The folders / namespacing idea can get very confusing for developers, so I would steer away from it. Routing (i.e. [Route("/v4/Orders")]) may be the better way to handle it. Again, that depends on how much code and the nature of the changes.

Application project structure question

I would like to ask you what experience you have with developing and deploying one application that in general has some standard features, but the application can also have customer specific features.
For example:
Customer 1 have the standard features but also want a search function.
Customer 2 have the standard features only.
Customer 3 have the standard features and also want an employee calendar.
How would you solve this?
Would you have one project where you deploy all the application from and then have some kind of config file to determind which features are avaliable in the specific application?
Would you have one project for each customer? This is how I'm doing it now, but the problem here is that if there are bugs that need to be fixed in the standard features I have to fix them in every project.
Any other suggestions are very welcome.
The application is developed in Delphi and C#.

My company solves that problem by giving all customers all features. This keeps development simpler and allows us to spend more time working on improving the product and not have to spend time dealing with the complexities of optional features.
We sometimes meet mild resistance from clients who want a cheaper version with less functionality but that's never been a sales problem.
On the other hand if you sell clients cheaper less functional versions, they are liable to try to get away with these cheaper versions. This can then lead to them not liking the software as much they should because they bought the cheap crippled version. I strongly believe in getting the best product possible to the user.
This advice may not be appropriate to your personal situation, but you did say that any opinions would be welcome.

One version per customer is not a good idea, IMHO. It will stuck your sales one day or later.
Better let all features be released to all customers, i.e. just maintain one software, but locked by a password, for instance. You can give a unique licence number at the software installation in order to identify the customer (put its name in the licence), then compute some passwords according to this licence number, to unlock some features, on request - when paid. This password can be easily automated via a web site, with minimal cost for you.
Or you can also let all functions available for testing, but lock the printing or the saving - just to let the customer think about spending some money to have this "nice added feature".
Sometimes, having all features tend to create a "Gasworks" application. You'll probably need a separate setup application, to customize the application to your customer's needs. Worth thinking about this architecture.
Even with a revision control, multiple versions are a nightmare to maintain: for instance, just back-port all hotfixes to a previous version takes a lot of time. If you don't have to (because of regulatory purpose / certified versions e.g.), don't "branch" your software.

No definitely do not have one project per customer, you could have one solution per customer where you agregate all projects given setup need.
Just to give you in an alternative to plugin architecture, which is right way to go, but also usualy fairly complex.
Option1.
Put common functionality in main project (Core)
Additional stuff like calendar put in separated DLL projects ( one per functionality)
Create VS SOLUTIONS, where you agregate all projects for specific setup + Core. So customer1 will have Customer1Silution with Core and all additional projects he need, customer2 its solution with Core and its additional stuff.
Option2.
Have one big setup for every one and based on its configuration/license enable/ disable access to user to a additional functionality.
Depends on your resources like time, experience, people you work with, clients , you can chose an option more appropriate to you.
1 plugin based: may be the best one but it, complex and it will take a time you become familiar with it, if you never did before something similiar.
Option 1 easy and fast, but if the clients quantity and configyration become defer you will jump into scale problems.
Option 2 is an average between those two, but keep an eye on your setup dimension.
Considering tha fact that you refer projects and nit DLLs in your solutions, if you fix a problem in Core in one solution it will affect also all other solutions.

you have several options:
put the "standard features" into separate module(s) which can be used/linked by the other versions
use a "plugin-architecture" to load the optional features dynamically

In addition to what others have said there is another option: Conditional defines.
With conditional compiling you can wrap feature specific code with IFDEFS (IFDEF EmployeeCalendar, IFDEF SearchFunction...). Then for each client you copy the project file only and set the conditional defines according to features you want to include.
If a client wants/pays for additional feature you just add it to Conditional defines in that client's project file.
This is similar to the modules approach (BPL/DLL) but avoids the added cost of having to deploy/manage extra files. The drawback is that the feature set is fixed at compile time.
With BPL/DLL you could dynamically load additional modules at run time, but if that is not important in your case, then Conditional defines might be a good choice.
Of course if your features are not easily separable then you can end up with a lot of IFDEFs in the code, but then your problem is clear separation of features, and it would be the problem with modules too.

What are some useful strategies for converting a Classic ASP application to ASP.NET

We have a ten-year-old ASP application that we are considering planning an update for. We want to take advantage of the new technologies that ASP.NET has to offer, as well as the opportunity to fix some issues with the existing framework (the existing code-base is highly fragmented, nearly impossible to test, let alone debug, and the entire application appears to have been constructed according to the "Farmhouse Pattern".)
To that end, it seems that the time has come to rebuild this application. But, we are a small business, and we simply don't have the resources to either hire out the rebuild, nor to dedicate our small team of developers solely to the task of rebuilding (we've got other tasks on our plate, and can't concentrate on this one particular task for the length of time it would take to fully reconstruct the application).
What, then, are some useful strategies we can employ to help us convert this app, without having it consume all of our limited resources for the duration of the re-write?

Sounds like an interesting challenge. It's definitely not going to be easy, especially if you can't dedicate any resources to the project full time.
If you have a 10 year old application that is working, I would suggest not going for a complete re-write at all. I would start by sitting down and figuring out what you want your end product to be.
Is it going to be an ASP.NET MVC Web Application, an ASP.NET WebForms App, or something else? Once that decision is made, come up with a loose design for an architecture. If you do things correctly, you can build out bits and pieces of the business logic in .NET and utilize it from your Classic ASP code until you're ready to re-write the UI in .NET as well.

I agree with what Justin said; if you have a working application in place, you'll need a compelling reason (i.e., money) to justify the expense in rewriting the application for a new platform.
Although ASP classic and ASP.NET share a similar-looking syntax and some common coding conventions, they are very very different from each other. If you tried to simply copy-paste classic ASP code into an ASP.NET application, you might be able to get it to work, but you'd be missing out of a lot of the advantages of ASP.NET Web Forms or ASP.NET MVC (and their respective frameworks, of course).
You can, however, extend the functionality of the existing site with .NET code through web services or COM interop. We have a 10+ year old classic ASP web site and I've used both .NET web services (.asmx) and COM-callable .NET DLLs to enhance our existing application. In both cases, I wrote all of my new business logic in the .NET component and provided a chunky interface to work with the existing ASP page. That allowed my .NET code to be very easily testable and still use our existing (huge) investment in our classic ASP site.

The only approach that has worked for me is to carve of areas of functionality in small slices, and rewrite. "Converting" first, then refactoring seemed like a good idea a few times, but in the end just became horrible messes of code written in ASP.NET instead of ASP - and that added no value.
If you have a site that has distinct areas of functionality, carve one off and start with that (I chose "contact us"). Write it the way you think it should be written - that is, assume your new part is fitting into the end design of your well-written app. If you have to add "hacks" to interface with the old system, make sure they are isolated and commented.
When working on an update, think "can I carve of some of the functionality here into it's own bit?" - if so, convert it then update it. I found that if you insist on keeping the NEW app clean and allow yourself to add small hacks to the OLD app for communication, you get the best results.
This does mean you'll have two separate apps (two IIS web apps) for a while, and can make cookie/url and session management a bit hairy, as well as adding one more deployment concern. To combat this, make sure that you minimize state in your web app (always a good idea anyway), and share state through something other than Session.
If you do this a piece at a time, make the pieces small enough, and have a good design up-front, this works well - at least in my experience, it's the way that works best. Note that my experience may not match reality.

Choosing CMS vs Portal vs MVC+Components?

I need some help figuring out whether it'd be a good idea to use a CMS or portal solution for my latest project, which is (currently) an ASP.NET MVC application that must serve multiple customers (being a company or some other entity with a list of users) from a single installation (that is, a SaaS solution).
In addition to the core functionality, which includes document management/publishing, I also need to provide basic social features (such as blog, forum, gallery, polls, etc.). However, it is imperative that content is only visible for the customer to which it belongs, and my evaluation of a bunch of CMS and portal solutions has shed little light on whether they support this. They're pretty focused on single-user installations, and documentation on how to integrate with an existing MVC solution is pretty thin.
Essentially I'm looking for some guidance to help me discard dead-end options (the product does not meet requirements, imposes too many restrictions, is not mature, etc.) and find unexplored options before getting too far ahead with the project.
My requirements for the architecture include:
Multi-site support (using a single domain for hosting)
Watertight separation of content between customers
Full integration across components/features
SSO (single-sign-on)
Single-site experience (shared header/footer, unified navigation, unified tags, etc.)
Ease of development and deployment
Custom logic will be written using C# and ASP.NET MVC and any products should support this
I want to stay in control
Solution should offer features but otherwise stay out of the way (for example, not force stupid idioms on me, like insisting on GUIDs for primary keys)
Active development community
No single-man efforts
Recent source control activity
Reasonable levels of documentation and maturity
Does not have to be open source
I have spent a fair amount of time evaluating products and components, which I'll briefly share here:
Umbraco
Does not support ASP.NET MVC (yet, as someone is bound to otherwise comment)
Great community support, active development
Seems to be lots of work to get started
Kooboo
No source activity (no updates for almost two months)
GPL licensed? (need something that allows for closed source applications)
N2CMS
Partial ASP.NET MVC support
Every customer must have a separate domain
Limited source activity (not dead but not vibrant either)
Orchard
Microsoft-sponsored (which means it's likely to be over-architected, code-bloated and slow, although it does have some well known and respected contributors/leads)
Built using ASP.NET MVC
Looks promising feature-wise (but is unlikely to be stable at this stage)
AtomSite
Feels reasonably mature and has decent documentation, albeit with holes
Built using ASP.NET MVC
Limited source activity, single developer
MojoPortal
Looks good for a portal, but probably requires custom logic to be built as modules around the product (I was hoping to avoid that kind of lock-in if possible)
DotNetNuke (DNN), CommunityServer and Microsoft Office SharePoint Server (MOSS)
Definitely not my cup of tea ;)
BlogEngine.NET
Mature and feature-complete
No ASP.NET MVC support
Integration possible but not without lots of Web.config voodoo
Not sure if it supports customer separation
Given the list above I'm leaning towards AtomSite, N2CMS, Orchard or BlogEngine.NET. If I go with the latter I'll be using jitbit AspNetForum, which is a great match for my needs.
I'd probably prefer to use a custom ASP.NET MVC solution and individual components as this is likely to give me the greatest amount of control, but on the other hand, it'll make site theming and integration harder. What combinations have you tried, what worked well and what didn't? Anything important I'm leaving out of my evaluation? Any other relevant advice?
I'd appreciate it if the answers were not simply endorsements of your favorite product or way of doing things, but something that would help me choose or eliminate solution candidates given the requirements outlined above.

With the level of requirements you've specified, I'm personally going to have to lean towards the custom approach. You can hire someone to do the design (view) portion of the site for you, or you can buy a theme off the internet from site designers and customize it to your liking. (Sometimes just having somewhere to start is enough for intermediate level customization).
Multi-site support (using a single domain for hosting)
You're probably going to want to have control of your hosting environment, either a VPS (Virtual Private Server) or a dedicated box. This is still possible on shared hosting but not reccomended.
Watertight separation of content between customers
You'd probably have to spawn a unique app-pool for each customer with thier own services user for 100% seperation.
Full integration across components/features / SSO (single-sign-on) /Single-site experience (shared header/footer, unified navigation, unified tags, etc.)
This is going to be the tricky part. This Example may have some useful insight for you in the development process, but you're going to want a unified login service and have all sites use it or link to it.
Ease of development and deployment
This is where it gets tricky. Development ease comes from your background I think. MVC is definately the right choice in this respect then, knowing a lot about the right ways of going about building a site in MVC will aid in this process. Keep up to date by reading community blogs and listening to podcasts like Hanselminutes or DotNetRocks will help keep you in touch with the newest and greatest tools/technologies for making your site get off the ground quickly and effectively.
Deployment is the tricky spot. MSDeploy still isn't quite there. But if you can you probably will want to come up with a Dev -> Staging -> Release publish structure so you can test your code in a staging (mimiced production) environment.
Custom logic will be written using C# and MVC and any products should support this
I want to stay in control
If you develop the site in ASP.NET-MVC, you'll be able to build common libraries that you can use not just in your site, but also in your custom tooling. This will greatly reduce your code duplication and helps make sure operational unity is achieved. (Everything works the same way).
Solution should offer features but otherwise stay out of the way (e.g. not force stupid idioms on me, like insisting on GUIDs for primary keys)
While you'll have control in this situation, I'd strongly reccomend GUID Primary Keys. This allows Merge Replication, which can help you easily restore backups or use failover DB servers when things go awry.
Active development community
.NET has a great community out there, (including this one) and you should get lots of support if you ask for it politely.
No single-man efforts
Not sure what you mean here, You'd be the Single-Man unless you hire help, but even 2 people can do great things given a little time. Even one-man can do great things, but the framework you're running on here is backed by a commercially funded huge team.
Recent source control activity
Doesn't really apply to .NET, but a lot of the libraries that you may use (NHibernate, MVC Contrib, AutoFac, Etc...) will have lots of activity and constantly being improved.
Reasonable levels of documentation and maturity
.NET and most of the production level libraries developed for .NET (Mentioned above) actually have a pretty good degree of documentation. There's multiple paid & non-paid sources of information for .NET alone, and most libraries (are well supported by the community and known on StackOverflow)
Does not have to be open source
Look for support libraries that are LGPL (i.e. you can use it in commercial software, but if you modify the library you have to release the new library code if you release the binary.) You're pretty safe here, your site dosen't have to be open source if you use these libraries to support your development.
Well, that's my 2cents. The project you've described is no small job, you're looking at a considerable amount of work even if you go with a pre-built solution (mainly hacking it to work the way you want). I imagine your biggest hangups would be SSO & Security for the pre-done solutions. Not to say it's impossible, just tricky and the end result may not be exactly what you're looking for.
Also, look into OpenID, it may be the best solution for linking all your sites together and most pre-built systems can easily be ported to use it.

Take another look at MojoPortal. The CMS is awesome and the main developer , Joe Audette, is very responsive. I'm have several installations of the CMS running single and multiple sites.

I would lean towards a CMS based solution. Having a tested and production ready software not only reduces the development time but also helps in continuous upgrade and reduced bug count.
If you go down this route, you may want to also consider Sitefinity. Not only does it support all the features required by you, but also is built on .NET and supports MVC development. The product is built by Telerik, the makers of UX tools.
Disclaimer: I am employed by Telerik.

I've recently come across phpFox which is a social networking/forums/community site CMS. This may be of use to you and is fairly inexpensive.

The solution for the site of our company has become EBIZ CMS: full-featured site that includes social networking, online store, features a presentation, a forum, create HTML pages and much more, including the maintenance of professional technical support, so we do not even need help for installing by a programmer, and it is only US$ 9/month!

Expanding an existing ASP.NET 1.1 application using ASP.NET MVC

Currently I'm working with a big, old and extremely poorly written ASP.NET 1.1 application and the continuous maintenance is becoming quite a problem. Basically it's reaching breaking point and I'm reluctant to expand it any more than I have to as demanded by the business. Based on my experience creating other projects from scratch it would really suit an ASP.NET MVC based solution. Oh how I wish the world were that simple...
The fact is that I just cannot justify re-writing it from scratch and the business cannot afford it. The ideal solution would be to start writing an MVC-based application alongside it and begin a slow migration as new requirements arise.
I've read posts which state that this is entirely possible, but in my experiments I've not found it so easy. The current application contains several large data access and business logic layers shared by other applications that the company produces. These are also written in 1.1 and will not compile in 2.0 (and would destroy the other projects if I tried!) so I cannot upgrade them. Since I can't do that I'm stuck with an application that cannot even be opened in a .NET 3.5 capable visual studio. The new MVC app would also have to make use of these layers.
I am entirely open to suggestions. I'm desperate to find a solution that I can quickly demonstrate would allow me to improve the product immensely without taking too much time or affecting the rest of the business.

You could write a WCF service on top of the existing business layer and have your new app talk to that service instead of referencing the business layer directly.

You need to divide to conquer. Analyse the current app and its layers and see if you find a way to divide each significant piece of functionality into a discrete area with as few changes as possible.
Then make each area a unique service using the old technology.
Then you can rewrite each service slowly as you can fit it in and not affect the whole.
Otherwise you are going to have to come up with a convincing business case for your managers so that they allocate you the time to do the job properly. Sometimes our job is political as well as technical.