My company has a fairly old fat client application written in Delphi. We are very interested in replacing it with a shiny new web application. This will make maintenance a breeze and many clients want a web application.
The application is extremely rich in domain knowledge, some of which is out of our control. Our clients use the program to manage their own clients and report them to the government. So an inaccurate program is a pretty big thing. The old program has no tests. We are not sure yet if we will implement automated testing with the new one.
We first planned to basically start from scratch. But we are short handed and wanting to basically get everyone on the web as soon as possible. So instead of starting from scratch we've decided to try to make use of the legacy fat-client database.
The database is SQL Server and can be used in SQL Server 2008 easily. It is very rich in stored procedures, functions, a few triggers, and lots of tables with over 80 columns... But it is decently normalized. We want for both the web application and fat client to be capable of using the same database. This is so that if something breaks badly in the web application, our clients can still use the fat client and connect to our servers. After the web application is considered "stable", we'd deprecate the fat client.
Has anyone else done this? What tips can you give? We want to, after getting everyone on the website, to slowly change the database structure to take care of some design deficiencies. What is the best way to keep this in a data access layer so that later changes are easy?
And what about actually making the screens? Is there any way easier than just rewriting an 80 field form in ASP.Net? Are there any tools that can make this easier?
The current plan is to use ASP.Net WebForms (.Net 3.5). I'd really like to use MVC, but no one on the team knows it including me.
We are not sure yet if we will implement automated testing with the
new one.
Implement automated testing. What's the point in replacing one buggy program with another?
Good question, but "Slowly change" the db structure after getting everyone on the website, sounds like a joke...
I would rather take the opportunity to create a fresh db structure, write a bulletproof migration script for you db, that you can try out and rewrite a zillion times without any side effect fro your clients, and then write whaterver you want (fat/web) on the new db, have it tested and migrate everyone when it's ready.
I have a couple suggestions:
1) create a service layer to abstract away the dependance on the DAL. In a situation as you describe having a layer of indirection for the UI and BLL to rely on makes DB changes much safer.
2) Create automated tests (both unit and integration), especially if you plan on making fairly significant changes to the Domain or Persistance layers (BLL/DAL). To make this really easy you should always try to program to an interface. This makes your code more flexible as well as letting you use mocking frameworks (Moq is one I like) to ensure your tests truely are unit tests and not integration tests.
3) Take a look at DDD (http://domaindrivendesign.org/) as it seems to fit pretty well with the given scenario. At the very least there are some very useful patterns that can help make your application more flexible.
4) MVC isnt very hard to learn at all, it is however an easy way to get unit testing setup for the UI as a result of the MVC architecture (testing the controller and not the view). That said, there is no reason you couldn't unit test web forms, its just a bit more work. MVC really is just a UI framework/design pattern (more Model2 but we can ignore that for now). It gets you closer to the metal so to speak as you will be writting a lot more HTML and using a Model (the 'M') for passing data around.
For DDD take a look at Eric Evans book: http://www.amazon.com/Domain-Driven-Design-Tackling-Complexity-Software/dp/0321125215/ref=sr_1_1?s=books&ie=UTF8&qid=1317333430&sr=1-1
Hope that helps
ASP.NEt forms is a no starter, is completely inappropriate for something like this. I recommend to start with something like Creating an OData API for StackOverflow including XML and JSON in 30 minutes, then build your Web app on top of that (ie. push it to the client, use JQuery/Silverlight).
Related
I am currently a front end developer. I know HTML and CSS pretty well, I'm OK with jQuery and know some Vanilla JS. I have an idea for a website I want to create where I will be storing data for products (data that I will be grabbing from various websites around the web). It's basically a help me choose application where the user will go through some steps and be given some choices based on their selections. This site is nothing new, but it's more for learning purposes/portfolio work.
Most of my co-workers use ASP.NET and I've seen that you can setup a website like this using ASP.NET and the provided server controls along with C#, however, I want to take another route that allows me to do the same thing NOT using ASP.NET (C# is OK and preferred if that is possible) in that I can grab data, store data, and bind data to my page.
In addition to this, I would like to do this on the Mac.
Here's a list of things I have looked at:
MongoDB (I was really confused by the setup and didn't read anywhere that this would definitely be the solution).
AngularJS
EmberJS
BackboneJS
Several other JS frameworks
Ruby on Rails
Note about the above: Some of the above might be the solution, but I don't want to start spending time learning them only to realize a week in that this is not going to help me get to my goal.
If this post would be better suited for another stack site please let me know. Thank you.
To create a basic website with a persistence you'll need to deal with three parts the front-end (client), back-end (server) and the persistence (database). Of the things that you've listed Angular, Ember and Backbone are all front-end frameworks. They each have their own way of approaching the issue but they all work in the client facing part of the project so views, interaction and dispatching data to the backend. Rails is the only thing that you've listed that's a back-end framework, another option for the back-end if you're more familiar with JS might be Node and Express. Node allows you to build a server in JS and Express is one of the more popular Node frameworks. That section will be responsible for getting the calls for data and calls with data from the front-end and dispatching the appropriate response. Rails typically works with with a SQL database like MySQL or PostGres out of the box because Rails' active record is meant to work with SQL. Mongo is a NoSQL database and I think people are getting it working with Rails but I don't know that it's highly common. Mongo's shell is pretty much javascript and it stores data as JSON (not technically but close enough) so it's been a comfortable choice for JS developers learning back-end. Either Rails or Node can get a server up and running locally on your machine so you can work with the full architecture. So what it comes down to really is picking one of each from those sections and making them play nicely together. For your purposes I would think that the way to go would be either a basic Rails app (probably with MySQL) and using jQuery ajax calls to manage some calls from the front-end or building something with the so-called MEAN stack (Mongo, Express, Angular, Node) which is all JS and using Angulars built in http functionality to handle those calls. Hope this at least narrowed the field of research a bit. Really thats a pretty open question and there are a lot of options.
What is your webhosting site? I suggestPhpmyadmin Or Mysqldatabase You can create tables and strings where you can put the websites you wanna "grab" data from and put a little javascript in there to tell your website if blahblahnlah =blahblahblah then get id="website1"
Some clarifications:
At first, you need to distinguish between a server side language (used to program the functionality) and a database (used to store data).
C# is a language of the .net framework. Regarding websites, there's no C# without ASP.net.
There are two major groups for realizing back end solutions: PHP (market share ~ 40%) and ASP (~ 25%). PHP is a programming language, ASP.net incorporates several programming languages (mainly C# and VB.net).
Both worlds are able to connect to databases: For PHP, this is mainly MySQL, for ASP.net it is mostly Microsoft SQL server.
If you're in my position you have a big WebForms applications which have escalated to this unmaintainable thing. Things break when you add new features and you need an inexpensive maintainable way to do some kind of automated testing.
Now, from my understanding, the right thing to do would be to try building an abstraction layout of the page and user control model present in ASP.NET WebForms however, seeing as it would require a major investment in an existing application it is not an option.
I'm trying and pushing for a REST-like development as much as possible because it has some nice properties. And while doing this I've written a simple spider bot that crawls all URLs it can find and tries, simply getting them.
This allowed my to quickly find bad data that was causing problems and avoid having my end-users clicking on broken things, however, this is of course not enough.
I continued work on my crawler and it's developed into a simple REST client that tries different input combination, looking for a probable bug or crash. It's more intelligent that just an exhaustive search (because it knows about the ASP.NET WebForms application layer) and my goal here is to basically explore the state of the web application, hoping to hit all the corner cases before our users.
Does anyone have any experience doing something similar?
Also, for you test gurus out there. Is this a complete waste of time, or will I be able to actually say something about the quality here? From my perspective it seems to hit a sweet spot in that it will try things a potential end user would though a browser.
As I said before, we're stuck in a bad place. And we need a simple way out of it, right now.
We've tried things like Selenium, but it mandates a lot of extra work and we change things all the time, it's just no possible to maintain multiple selenium test suits for 50 different applications.
Of all the types of testing to implement, unit testing is both the easiest and the most likely to yield results, in terms of less bugs and more maintainable code. Get that worked out before you deal with automated integration testing
Pick an IOC Container - I like Ninject for this personally
Find a convenient place to inject "service" classes into your Page (the consturctor of a base Page class or override the module that loads pages, whatever works for you)
Pick a unit test framework and if you don't have an automated build then set one up; include running a full suite of unit tests in that build
Every time you go near a piece of logic in an aspx.cs file, see if you can't isolate it in a service and wrap unit tests around it
Take a look at whether the MVP Pattern would be good for you - we found it decreased productivity as much as it increased testability (it did both a lot), but it works for some people
See about slowly migrating your app over to MVC, a page at a time if necessary
And remember, you are not going to fix this problem overnight, you don't have time. Just keep improving test coverage and you'll see the benefits over time.
What part of your application is breaking? The UI, or the business logic?
Business logic should be completely separated from the user interface, and should be tested separately. In particular, it's much easier to use automated unit testing tools against separated business logic than it is against UI.
If i am rigth you have a large web form and want to run some standard end user tests each time you do a new release.
I can recomend the Selenium IDE adon for firefox.
it will allow you to record your user actions, e.g filling in a form, and allow you to replay those actions at any time. an easy way to run some test over a form with differnt data.
For internal code testing write some Unit tests using NUnit
Let me start off by stating that I am a novice developer, so please excuse the elementary nature of my question(s).
I am currently working on a Flex Application, and am getting more and more confused about when to use server side scripting, and when to develop web services. For most of the functionality I am working on, I am taking various files from the user (client), uploading to the server for processing/conversion, then sending back to client in new format.
I am accomplishing most of this using asp.net generic handlers (ashx) files, but not very confident this is best practice. But at the same time, does making web services make any more sense? What would be considered best practice for this? Any suggestions would be greatly appreciated.
The way I look at it is as follows:
Web Services mean Established Best Practice.
For most of our development, we don't need to create "Web Services", or what I'm thinking when I think REST, SOAP, and the Twitter API. You only need to start doing that once you've got something you're going to be using every day for years.
Clean and DRY code will Lead you to Creating a Web Service
If you spend the time to clearly define the parts of your upload-process-render Architecture, and you find that it can be applied to almost everything you are doing, then all you need to do to make it a Web Service is define a clear, 1-2-3 set of rules for using the system (GET/POST data, etc.). As long as you are consciously building an architecture the whole way, you'll end up creating a Web Service if it's worthy. Otherwise there's no need.
It sounds like you have a clear workflow going, I don't know anything about asp.net though.
As far as it being confusing sometimes, and best practices, I suggest the following:
Create a Flex Library Project for your "generic ashx file handling" Flex classes. Give it a cool, simple name.
Create a .NET Library Project that encapsulates all the logic for your server-side file processing. Host it online and make it open source. I recommend github. Test it as you go, and document it, its purpose and the theory behind it.
If you don't have to do anymore work at this point, and it's just plug and chug, then you've probably arrived at something that might become a Web Service, though that's probably a few years down the road.
I don't think you should try to create a Web Service right off the bat. Just make some clean and reusable code, make a few examples, get it online and open source, have others contribute and give feedback, and if it solves a specific problem, then make it a web service. You can just use REST for now probably, and build your system around that. RestfulX is a great library for that.
Best,
Lance
making web services without any sense make no sense ;)
Now in the world of FLEX as3 with flash version 10, you can easily read local files, modify them with whatever modifcation algorithm and save local files without pinging server.
You only have to use webservices if you want to get some server data or to send some data to server. that's all.
RSTanvir
Flash / Flex uses a simple HTTP POST approach for file uploads, so trying to do that using SOAP web services will be problematic. Your approach of using ASHX here sounds reasonable to me.
To send / receive data that isn't file based (e.g. a list of files the user has uploaded previously), I would recommend looking at the open source Fluorine FX library. Fluorine uses AMF which is a highly performant way of doing data transfer with Flash. It's also purely configuration-based, which means you don't need to code against any of its APIs, just configure Fluorine to expose your .NET service classes. You could easily add attributes to those same classes to expose them as SOAP web services via WCF if you need that in the future. I would not recommend using SOAP with Flex however, due to the performance losses and also because the Flex implementation of SOAP has a history of bugs and interoperability problems.
I'm thinking about going into the ASP.NET MVC scene.
I've seen the videos at http://asp.net/learn, but they havn't impressed me.
So can you answer me, what makes MVC "so impressive", and why does it make life better and easier?
ASP.NET MVC is much more in tune with the technology on which it is layered. ASP.NET Forms attempted to pretend that there was a nice fat stateful infrastucture as there is in a standard WinForms app. However HTTP and Web servers do not like fat stateful applications.
ASP.NET MVC allows for a separation of concerns. The request is processed by a controller not a "Web Page", it chooses how to respond and what UI is needed to present that response. The controller builds the set of structured data needed by its choice of view then hands over that data to the view.
This division allows much easier testing, the view is merely a means to present what should be a complete well munged chunk of data. Its way easier to build a test for something which takes structured data in and responds with structured data.
ASP.NET Forms is almost impossible to test in this way (especially without expensive tools claiming to achieve it). Hence an MVC application is easier to get right and much easier to ensure it stays right by consistently running existing tests.
Caveat: The major draw back of ASP.NET MVC right now is lack of solid documentation. I've been assured that docs are coming "soon".
Have you ever worked on a large project that had great intentions when it started but 3 years later was a complete mess?
MVC is a just pattern it can be misused the same as ASP.NET is misused. It is just harder to do.
Model–View–Controller (MVC) is an
architectural pattern used in software
engineering. Successful use of the
pattern isolates business logic from
user interface considerations,
resulting in an application where it
is easier to modify either the visual
appearance of the application or the
underlying business rules without
affecting the other.
It allows you to separate your logic in a way that makes sense to most people. While at the same time it lends itself well to testing.
I am in the early stages of planning a conversion of a large classic ASP database application to ASP.Net and I'm having trouble picking out which data access method to use. I have played around with Linq To SQL, Dynamic Data, strongly typed datasets, Enterprise Library (Data Access Application Blocks), and a tiny bit with Entity Framework, but none of them have jumped out to me as "the one". There are just too many choices - my head is swimming, help me choose!
Perhaps it would help to give some background on the application that I am converting along with the priorities...
The back end is Microsoft SQL Server (2005 or later) and we are committed to that, so I don't need to worry about ever supporting a different database platform.
The database is very mature and contains a great deal of the business logic. It is highly normalized and makes extensive use of stored procedures, triggers, and views. I would rather not reinvent two wheels at the same time, so I'd like to make as few changes to the database as possible. So, I need to choose a data access method that is flexible enough to let me work around any quirks in the database.
The application has many data entry forms and extensive searching and reporting capabilities (reports are another beast which I will tackle later).
The application needs to be flexible enough to deal with minor changes to the database structure. The application (and database) may be installed at different sites where minor custom modifications are made to the database. Ideally the application could identify the database extensions and react appropriately. In other words, if I need to store an O/R mapping in the application, I need to be able to swap that out (or refresh it easily) when installing the application and database at a new site.
Rapid application development is critical. Since the database is already done and the user interface is going to closely match the existing application, I'm hoping to find something where we can crank this out fairly quickly. I am willing to sacrifice not using the absolute latest and greatest technology if it will save time in development. In other words, if there is a steep learning curve to using something like Entity Framework, I'm fine with going something like strongly typed Datasets and a custom DAL if it will speed up the process.
I am a total newbie to ASP.Net but am intimately familiar with Classic ASP, T-SQL and the old ADO (e.g. disconnected recordsets). If any of the data access methods is better suited for someone coming from my background, I might lean in that direction.
Thanks for any advice that you can offer!
Look at all three articles in this series:
High Performance Data Access Layer Architecture Part 1
Great advice.
You may want to look at decoupling the database layer from the asp layer so that you can not only give more flexbility in making the decision, but when you have to make changes to a customer's database you can just swap in a new dll without changing anything else.
By using dependency injection you can use xml to tell the framework which concrete class to use for an interface.
The advantage to doing this is that you can then go with one database approach, and if you later decide to change to another, then you can just change the dll and go on without making any changes to other layers.
Since you are more familiar with it why not just go directly to the database at the moment by making your own connections? Then you can move the rest of your code and along the way you can decide which of the myriad of technologies to use.
For a new application I am working on I am starting with LINQ to SQL for it, mainly because development will be quicker, but, later, if I decide that won't meet my needs I will just swap it out.
nHibernate might be a good fit. You can store the mapping in external configuration files which would solve your needs. Another option might be using ActiveRecord, which is based upon nHibernate.
nHibernate has a neat feature which you might find helpful. It's called a Dynamic property which is basically a name value pair collection populated by pulling the column names from the mapping file. So when you add a column at your client site, you update the mapping file and you'd be able to access the data through a collection on the object.