Web Application Development Tips, Tricks and Techniques
HTML 5 C# Web Sockets server and ASP.NET client implementation
Jun 22nd
In the previous post we saw that Web Sockets are the best invention since sliced bread: they bring to the web the bidirectional full-duplex communication traditional desktop applications have been enjoying for quite some time now. It solves many current problems, and enables much more powerful applications than current standards.
I’ve developed a very basic Web Socket server implementation in C# just as a proof of concept. It handles the most basic operations you would expect from a server: start a new connection, disconnect, and send and receive data. Besides, I’ve developed the client part as well using regular ASP.NET. Actually it’s just plain HTML and JavaScript being served from an ASP.NET server – this example doesn’t use any fancy runat=server controls or anything of the like. The functionality is achieved with very simple and easy to understand JavaScript.
HTML 5 Web Sockets
May 30th
Following the series of posts discussing AJAX calls, today we’ll see what is going to be its evolution: Web Sockets. It’s still a very new technology, and support is starting to be implemented in most major browsers and web servers. But don’t count on using it yet, since most of the clients of your web app will not be able to use them. I’ll discuss web sockets here just so you know what the future is going to bring to the web apps world.
The history: the beginning of AJAX
The world wide web and the Internet started as a stateless content delivery mechanism, taking a step backwards compared to traditional desktop applications. Early Internet applications needed to explicitly request every piece of information, and the server sent only the requested data.
Then came what we now call “Web 2.0 application development”: Dynamic HTML, heavy usage of JavaScript, AJAX, and various plugins (Adobe Flash and Microsoft Silverlight). These applications were dynamic and responsive, and they brought much of that rich interactive experience users enjoyed in desktop client/server applications to the Internet. However, due to the request and response architecture that these applications are based on, the latest Rich Internet Applications still cannot match the connectivity and the capability to get real-time data that client/server applications had more than a decade ago.
AJAX call using ASP.NET Web Services
Apr 27th
We’ve already seen quite a few ways of performing AJAX calls: web pages, HTTP Handlers and Page Methods. Today we’ll see how to request data from the server using ASP.NET Web Services.
Web Services are a very general model for building applications, and can be implemented for any operation system that supports communication over the Internet. A Web Service is some programmable application logic accessible via standard Web protocols. It is often referred to as Web APIs as well, since they are a set of methods that provide some functionality through remote method calls. It is a way of offering some of your functionality to all of the internet. But, of course, some kind of restrictions and security can be built into your web services, if that’s what you wish.
AJAX call using an ASP.NET Page Method
Apr 6th
We’ve already been through AJAX calls using simple web pages and HTTP Handlers. But there’s still more ways to request data from the server. Today we’ll take a look at how to do so using server methods.
ASP.NET allows you to define methods in the code-behind of an ASPX page. This is very helpful in situations where you want to expose some specific server side functionality such as data retrieval for a specific page. If you need to make the operation available to multiple different .aspx pages it’s a better idea to use a web service so your pages can share the functionality. We’ll see how to use web services in the next post.
Please note that page methods must be declared as static, meaning a page method is completely self-contained, and no page controls are accessible through the page method. For example, if you have a textbox on the web form, there is no way the page method can get or set its value. Consequently any changes with regards to the controls have no affect on the page method. It is stateless and it does not carry any of the view-state data typically carried around by an ASP.NET page.
AJAX call using an ASP.NET HTTP Handler
Mar 23rd
We’ve already seen how to perform an AJAX call using just a simple ASP.NET web page. Now we’ll see how to do it with an HTTP handler instead of a web page.
But, what is an HTTP handler? Well, as its names suggests, it is an element that handles HTTP requests. Well, but that’s what an .aspx web page does, right? Sure, but in a lengthier, slower and resource-hungrier way. Regular web pages inherit from the System.Web.UI.Page class, which contains a lot of overhead and pre and post-processing in order to make it easier for the programmer to return HTML code to the client performing a request. In other words, the web page class has stuff to make it easier to develop a web page. It’s got some logic, doesn’t it?
AJAX call using an ASP.NET web page
Mar 9th
We already saw what an AJAX call is and the different types there are. Today we’re going to see how to perform an AJAX call using a regular web page at the server. The page will be the connection between the client’s web browser and the server. It will take care of performing the operations at the server (let it be some kind of processes or calculations, or just a regular database access).
I’ll be using jQuery in this example. jQuery is a superb Javascript framework, and is the one I use the most. If you don’t know what it is yet, then the first thing you should do is getting acquainted with it. This JavaScript framework has many convenient functions to make an AJAX call. These functions hide much of the complexity of an AJAX call: you can forget about the XMLHttpRequest object if you wish, and only worry about what to do with the data once you get it back from the server.
Different ways to use AJAX in ASP.NET
Feb 23rd
Today’s web applications are unthinkable without AJAX techniques. These techniques provide an improved user experience, and tighten the gap between traditional desktop applications and web applications. This means that mastering AJAX technologies is a must for anyone who’s doing serious web application development. In this article I’ll explain the basics of AJAX, and I will show how to program some AJAX calls using ASP.NET technology.
jqGrid multiselect: a little improvement
Nov 10th
The jqGrid plugin is fantastic. It provides an improved user experience and makes your web application stand out from the rest. But sometimes the default behaviour it has is not what we like, and those are the times when we have to dive into the source code to tweak it. And today was one of those times for me.
We’ve implemented the jqGrid plugin in a couple of pages in our project at work. We needed some multiselect in one of them. This option seems very easy to implement: just add a couple of options at creation time and you’re done… well, not quite. JqGrid’s multiselect default behaviour is not really the standard one. I mean, it is a multiselect, just not what the regular user might be used to.
jQuery Grid plugin: jqGrid
Nov 3rd
JqGrid is a jQuery plugin which provides impressive AJAX-enabled dynamic data tables. And when I say impressive, I mean fantastic. Not only it’s packed full of features, but it’s got a very nice look and feel as well. It’s got nothing to envy from traditional desktop application grids. I would say it’s even better than many of them.
Themeable interface: you can set it up as you wish
Javascript frameworks overview
Oct 26th
A Javascript framework is set of pre-written Javascript functions aimed at simplifying development. They take care of the most common and time-consuming tasks, like AJAX-related techniques. But why should we use them? Well, keep in mind that a Javascript framework:
- Saves you time. Even if you really love programming in Javascript, you will save a bunch of time doing your work with one these frameworks.
- Has much of your work already done. Don’t reinvent the wheel. Don’t waste time in doing something it has already been done and tested and re-tested by thousands of users.
- Makes you use less code. With less code you get a smaller file size, better maintenance and less development time.
- Makes your code more readable. Which also aids in better maintenance and less development time.
- Makes your web application execute faster. These frameworks are really fast in performing their tasks and most of them have been optimized for really fast execution.
- Makes your web application run in most modern browsers. If you dealt with Javascript a bit, you’ll have realized how different browsers have different ways of the doing the same exact stuff. Handcrafted cross-browser development can get annoying and irritating. These frameworks have already taken care of that and will just work in most browsers.
My name is Oliver Mezquita Prieto, and I'm a Software Engineer focused on web application development, both serverside and clientside, using ASP.NET technology.
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