I am (as I'm sure many of you are) pretty familiar with Rails' MVC design pattern as well as Django (and others') MTV design patter. I was wondering what other patterns other frameworks use for web application development. What are their strengths/weaknesses?
thanks
My miniature (60-line) MVC engine for PHP, http://code.google.com/p/barebonesmvc-php/, used successfully on an embedded consumer device by Cisco, relies on the "template method" pattern, wherein the parent class specifies the steps to an algorithm but the child class is responsible for implementing some of those steps.
static function sendResponse(IBareBonesController $controller) {
$controller->setMto($controller->applyRequestToModel());
$controller->mto->applyModelToView();
}
In the case of my engine, the developer needs to implement applyRequestToModel. Not only Spring's Web/MVC module, but also my applyModelToView method, takes a map/hash/assoc-array and makes it available to the view, except Spring conflates the two facets of MVC in the name of their abstraction (ModelAndView), whereas my abstraction is more appropriately name ModelTransferObject (aka $mto).
Speaking of Spring, in the GoF reference regarding the template method pattern, the GoF refer to "inversion of control"
MTV is just a more accurate name for what's usually called MVC. So in fact, Rails and Django use the same pattern. Is has established over years and hardly any framework does things differently, except maybe the half-object pattern. However, halb-objects have not established in the web world.
The "real" MVC is a pattern found in classical GUIs as well as within JavaScript (if you only look at what's happening within the browser). It is simply not applicable in the WWW so it had to be adapted. The result is confusingly often also called MVC, while MTV is a more accurate description.
Related
I am working in an asp.net mvc application that uses Ninject for DI. I have been attempting to implement Ninject Interception for logging, following this 2-part article. http://codepyre.com/2010/03/using-ninject-extensions-interception-part-1-the-basics/. I have tried both the method registration and attribute approaches, but neither approach will let me intercept methods on classes that aren't registered in the kernel.
The problem is that mine is a multi-tenant system where I often have to do different concrete operations depending on the client who is logged in. I execute the correct functionality using the Factory Pattern to give me the right class for each client as needed. However, the classes served up by the Factory are not in the kernel and therefore cannot be intercepted.
I'm looking for any sort of solution to this problem including an architectural rework if necessary, so that I can make everything Interceptable.
What you probably are looking for is aspect oriented programming (AOP) libraries.
Look at this question: What Aspect-Oriented Programming (AOP) libraries for .NET are still actively developed?
I have experience on MEAN STACK (mongo, express, angular and node). I am using AFNetworking for rest API. I am not able to manage MVC structure of my app. Actually I don't have the exact idea of what should be in model, controller and view folder of an iOS app. Any project template using AFNetworking or other rest API or any link would be appreciated.
Model-View-Controller (a.k.a MVC) is one of the most-used design pattern of all in Cocoa world. Here, controller handles the burden of saving, loading model objects as well as interaction with external resources such as network calls and/or core data.
However, in reality, this design approach can result in massive controller objects that makes it messy and less flexible. So, to encourage clean separation of role, a better design approach is used to move out the logic of networking or storage into a separate object.
There are couple of such design patterns that are built by respecting the principles of MVC. It really depends on your design approach.
For example, One of such pattern is, Model-View-Controller-Store (a.k.a MVCS), where you implement network/storage logic in "Store" Class (this is usually a singleton class). This also helps you to share common functionalities between different controllers.
I'd recommend you to read about design patterns in iOS. And, for your AFNetworking tut, you can refer this great tutorial.
I'm sorry if this is a stupid or obvious question, but I've spent the better part of a week researching, and I really can't find any resources that explain what MVC 4 and Razor are, and what they are intended to do in web development. I'm not necessarily asking for a really detailed description, even a link to a website or the name of a book that doesn't explain MVC 4 by referencing other technologies that I have also never used. I've looked through articles, articles and tutorials on everything from MSDN to graduate papers and I just don't get it.
I know what MVC the design pattern is, but one of the main things I can't get a straight answer to is what the difference is between MVC the pattern and MVC 4 the framework. As a web developer, will I ever have to change or make use of the frameworks, or is it something that is supposed to "stay out of your way" (to quote another SO post.) Is it something that gets generated by VS and I will never have to touch?
Again, I'm sorry if this is obvious, maybe I'm trying to make this more complicated than it actually is. All I have been looking for is a straight forward answer with concrete examples that don't contradict or complicate it any further.
Please...I'm at my wits end here. My last question was apparently too vague and got voted down and closed, so I tried to be more specific, but part of my problem is what are the right questions to ask.If there is anything that can say to clarify,please tell me.
I certainly don't want to discourage you any more than you appear to be at the moment, but in my opinion, if you can't make head or tail of the huge amount of material that already exists on MVC, then perhaps you are just not ready for it yet. That's OK - in fact Microsoft recognise that MVC is complicated, which is why they introduced the ASP.NET Web Pages framework (which is what gave birth to Razor syntax).
My advice would be to follow the link and download WebMatrix. Then follow some of the Web Pages tutorials. That way you can get your head around Razor without worrying too much about MVC for the time being.
Incidentally, ASP.NET MVC is a web development framework that enables you to build web applications based on the MVC pattern. You need to understand how MVC works in order to make use of the framework. You need to understand what Models are, what Views are and the role that Controllers play in the whole thing.
The framework itself is not an example of MVC.
Razor is a templating syntax that allows you to intermix C# (or VB) with HTML to output dynamic content in a View in MVC or a page in the Web Pages framework.
I know it may seem confusing, but it seems to me that you are over complicating things.
The simple matter is that MVC is a design pattern. That is, it's an abstract thing.. a philosophy of sorts. It's not a concrete thing. A design pattern simply gives you a description of how the pattern is supposed to work, and while it may give you a sample implementation, in general it leaves that implementation up to you.
ASP.NET MVC (whichever version) is a specific application framework that uses the MVC pattern as its basis. In other words, it's a concrete implementation of the MVC design pattern.
In fact, the ASP.NET MVC implementation isn't even a "true" implementation of the MVC design pattern, as certain compromises are necessary to make it work in a web based model. So it's really more "MVC design pattern inspired".
You're overthinking things. Just accept that ASP.NET MVC is a framework library that implements and MVC design pattern.
As for Razor, it's merely a templating library. That is, it allows you to define a page layout as text, and insert values at specific places (place-holders). It also allows code to be executed during the process of rendering a template, although this is discouraged in MVC except for very simple cases.
Razor is also used in ASP.NET WebPages technology, in those cases it tends to be more like PHP or classic asp in that all code exists in code blocks within the template itself. Both ASP.NET and WebPages use the Razor templating engine (also called a View Engine) but they use them in different ways.
When I start work on a new web application I tend to reach for the same tried & tested architecture of ASP.NET MVC, BLL (consisting of a set of services that contain all business logic) and a DAL (consisting of a set of repositories that facilitate the unit of work pattern over something like EF/*Linq to SQL*).
The controllers talk only to services, the services only to repositories and other services. At the service layer are where models are defined and these are used as input/output to/from the controllers.
My question is: what are others doing? I'm interested in knowing if people are doing anything different in the context of an ASP.NET MVC web application. For instance, there are concepts like CQRS and Domain Events. Is anyone using these to solve a problem with the method I've described above?
This question is mainly a source of attempting to discover what I don't know I don't know. I hope it's not too vague, but I think it's important to see what others are doing to evaluate your own methods.
We're basically doing what you're doing, except that we consider our repository interfaces to be services (they are defined in the business layer), and therefore our controllers often access them directly. An IoC container takes care of injecting the correct repository implementation via constructor injection. So the data layer depends on the business layer, and is in charge of implementing the repositories, while the business layer just assumes that all the repositories it has defined will be available at runtime.
We've further divided our product up into different modules of functionality. Some of the modules depend on one another (for example, everything depends on our core functionality, and most of the other modules depend on the web portal module), but keeping them in separate dlls helps us to avoid making these modules be too tightly coupled. The system can therefore only load the DLLs for the modules that a given client has paid for. We plan to use an event bus with events defined in the core module to allow the modules to communicate via a publish/subscribe model.
I am using CQRS with MVC. Its nice. You still use the MVC pattern, but in the controller I use the command pattern for the write, and just pure NHibernate Linq for the read... also some SolrNet for the read. :-)
When I first heard about StackOverflow, and heard that it was being built in ASP.Net MVC, I was a little confused. I thought ASP.Net was always an example of an MVC architecture. You have the .aspx page that provides the view, the .aspx.vb page that provides the controller, and you can create another class to be the model. The process for using MVC in ASP.Net is described in this Microsoft article.
So my question is. What Does ASP.Net MVC provide that you wouldn't be able to do with regular ASP.Net (even as far back as ASP.Net 1.1)? It is just fancy URLs? Is it just for bragging rights for MS to be able to compare themselves with new technologies like Ruby On Rails, and say, "We can do that too"? Is there something more that ASP.Net MVC actually provides, rather than a couple extra templates in the File->New menu?
I'm probably sounding really skeptical and negative right now, so I'll just stop. But I really want to know what ASP.Net MVC actually provides. Also, if anybody can tell me why it's Model-View-Controller and not in order of the layers of View-Controller-Model or Model-Control-View depending on whether you are going top to bottom, or vice versa, I'd really appreciate that too.
EDIT
Also, it's probably worth pointing out that I've never really cared for the web forms (AKA server controls) model either. I've only used it minimally, and never on the job.
.aspx doesn't fulfill the MVC pattern because the aspx page (the 'view') is called before the code behind (the 'controller').
This means that the controller has a 'hard dependency' on the view, which is very much against MVC principles.
One of the core benefits of MVC is that it allows you to test your controller (which contains a lot of logic) without instantiating a real view. You simply can't do this in the .aspx world.
Testing the controller all by itself is much faster than having to instantiate an entire asp.net pipeline (application, request, response, view state, session state etc).
Scott Guthrie explained it in this post "ASP.NET MVC Framework"
It enables clean separation of concerns, testability, and TDD by
default. All core contracts within
the MVC framework are interface based
and easily mockable (it includes
interface based
IHttpRequest/IHttpResponse
intrinsics). You can unit test the
application without having to run the
Controllers within an ASP.NET process
(making unit testing fast). You can
use any unit testing framework you
want to-do this testing (including
NUnit, MBUnit, MS Test, etc).
It is highly extensible and pluggable. Everything in the MVC
framework is designed so that it can
be easily replaced/customized (for
example: you can optionally plug-in
your own view engine, routing policy,
parameter serialization, etc). It
also supports using existing
dependency injection and IOC container
models (Windsor, Spring.Net,
NHibernate, etc).
It includes a very powerful URL mapping component that enables you to
build applications with clean URLs.
URLs do not need to have extensions
within them, and are designed to
easily support SEO and REST-friendly
naming patterns. For example, I could
easily map the /products/edit/4 URL to
the "Edit" action of the
ProductsController class in my project
above, or map the
/Blogs/scottgu/10-10-2007/SomeTopic/
URL to a "DisplayPost" action of a
BlogEngineController class.
The MVC framework supports using the existing ASP.NET .ASPX, .ASCX, and
.Master markup files as "view
templates" (meaning you can easily use
existing ASP.NET features like nested
master pages, <%= %> snippets,
declarative server controls,
templates, data-binding, localization,
etc). It does not, however, use the
existing post-back model for
interactions back to the server.
Instead, you'll route all end-user
interactions to a Controller class
instead - which helps ensure clean
separation of concerns and testability
(it also means no viewstate or page
lifecycle with MVC based views).
The ASP.NET MVC framework fully supports existing ASP.NET features
like forms/windows authentication, URL
authorization, membership/roles,
output and data caching,
session/profile state management,
health monitoring, configuration
system, the provider architecture,
etc.
Primarily, it makes it very easy to create testable websites with well defined separations of responsibility. Its also much easier to create valid XHTML UIs using the new MVC framework.
I've used the 2nd CTP (I think they're on five now) to start work on a website and, having created a few web applications before, I have to say its hundreds of times better than using the server control model.
Server controls are fine when you don't know what you're doing. As you start to learn about how web applications should function, you start fighting them. Eventually, you have to write your own to get past the shortcomings of current controls. Its at this point where the MVC starts to shine. And that's not even considering the testability of your website...
No more auto-generated html IDs!!! Anyone doing any sort of javascript appreciates this fact.
ASP.Net with it's code behind is almost MVC - but not - the one big thing that makes it not is that the codebehinds are tied directly to the aspx's - which is a big component of MVC. If you are thinking of the codebehinds as the controller - the should be completely decoupled from the view. The new .NET MVC rounds this out - and brings a complete MVC framework. Though there are existing ones for .NET already (see Spring.NET).
I looked through a couple simple examples such as this one. I can kind of see the difference. However, I don't really see how MVC uncouples the view from the controller. The view still references stuff that's in the controller. I do see how it makes it much easier to test, and that at least in MVC the controller doesn't have any knowledge of the view. And you wouldn't have to process the view to call methods in the controller. I can see that's quite a leap, even though at first glance it may not seem like much.
I do agree with #Will about fighting server controls. I've never worked in a situation where they were actually used, but many people I know who have, have run into quite a few limitations with them.
Article about ASP.net MVC Vs ASP.net Web form
http://weblogs.asp.net/shijuvarghese/archive/2008/07/09/asp-net-mvc-vs-asp-net-web-form.aspx