Reading a Local File using HTML5 and JavaScript

One area where the web has lacked for some time is the lack of a true file system.  HTML5 fills this void by providing a standard way of interacting with local files using the FIle API specification.

These APIs are used to read file locally, handling images etc. Some of the specifications are as listed below:

1. File: Provides read-only information about the file like name, filesize, mimetype etc.

2. FileList: Represents an array of individually selected files from the local system

3. Blob: Represents the raw binary data and allows access to range of bytes within the data which can be used for slicing file

4. FileReader: Provides methods to read data from file or Blob

ASP.NET Web API 2.0 and the new OData keywords

Web API gained OData Support with the Visual Studio 2012 Update 2 release. However it was missing support for some keywords like $select, $expand and $batch. Today we’ll see how to setup our ASP.NET project to use Web API 2.0 beta binaries in Visual Studio 2012 Update 2 and use the new Keywords.

Setting up a WebAPI 2.0 project using Visual Studio 2012

Step 1: We start our project with a Visual Studio 2012 ASP.NET Project. Note that we use .NET Framework 4.5. This is because Web API 2.0 takes dependency of .NET Framework 4.5.

webapi-project-empty-new

Web API 2.0 – Attribute Routing

Web API routing has been pretty flexible using the convention based routing and custom Route Templates. We could specify custom routes, but things got verbose and disconnected for situations where we had to define routes for sub-resources, like for example if you had a list of Books and each book had more than one author, to fetch the authors for a book, you might want a route like http://myapp/api/books/{id}/authors

To do this, we had to define a route in the Route Table as follows

config.Routes.MapHttpRoute(
    name: “AuthorsForBook”,
    routeTemplate: “api/books/{id}/authors”,
    defaults: new { controller = “books”, action=“GetBookAuthors” }
);


Now this works but if we wanted another one, say for a list of Authors, select an author and then the books they have authored, the URL would be http://myapp/api/authors/{id}/books

AngularJS – Post data using the $resource Service in an ASP.NET MVC app

Last time we looked at how we could use the $resource service to make our code more compact when making HTTP calls. Today we will see how to post data to a server using the $resource service.

We’ll continue using the code from the previous article. So you can download the zip from here or fork it from Github.

Posting Data

In our previous article we re-organized our application to use the $resource service. However we were only using the query function. As we know the resource function can also do GET, POST, PUT etc. Following is the map of actions to the HTTP verbs

{ 'get':    {method:'GET'},
  'save':   {method:'POST'},
  'query':  {method:'GET', isArray:true},
  'remove': {method:'DELETE'},
  'delete': {method:'DELETE'} };


(Source: Angular JS Documentation)

Using AngularJS Modules and Services Feature in an ASP.NET MVC application

In our previous post, Hello AngularJS – Building a Tweet Reader we saw how to create a simple ASP.NET MVC application using AngularJS. We saw how the $scope and $http objects were injected in our app by Angular. We also saw how to do Templating and DataBinding. Today we will learn a few more constructs like the Modules and Services.

As with our demos we’ll walk with a code sample to see how the AngularJS features are used.

The Sample AngularJS Application - Recap

We’ll continue where we left off with the previous ASP.NET MVC sample where we built a Twitter reader.

The ASP.NET MVC Controller

To quickly recap, we have an ASP.NET MVC application with an MVC Controller. The controller has the Index action method. Here the LinqToTwitter framework first checks if user is Authenticated, if not, it redirects to Twitter and gets user to Authenticate.

Action Filters in ASP.NET MVC

Continuing with our MVC 101 series today we look at an important MVC feature, Filters. Filters in ASP.NET MVC are a way to apply cross-cutting logic at the controller level. Some examples of cross-cutting logic is Security and Logging.

Security is a cross cutting concern because, once enabled, we need to apply it for all incoming requests in the web Application. Imagine a world where you don’t have filters, in such case for every request that comes in, you Action method in controller will have to check if the user was Authorized to perform the action and view its result.

This not only violates single responsibility principle of the Action Method (it’s doing two things, evaluating security and computing the Action’s output) but is also an extremely verbose and repetitive work that we’ve to do irrespective of what the Action is supposed to do. Moreover, writing Authentication Code in action method cannot be guaranteed. There is no certainty that a developer may or may not miss out on implementing the code!

ASP.NET MVC - Using Resource Files to Manage String Constants

This article is from our ASP.NET MVC 101 Tutorial Series

Continuing with the MVC 101 series, today we explore how to save strings in Resource files instead of constants spread out all over the application or worse, hard coded in the source itself.
Mind you, we are not looking at cultures and Internationalization today.

It is very easy to start working on a project and continue adding string in a random, unstructured and adhoc mixture of inline strings and string constants. However, as soon as the marketing team starts to demo the product, you get one change request after the other to update the text/message and error notifications. This is when things go south and you wish you had a central place to store all your string constants.

Hello Resource Files!

Getting Started with NUnit in ASP.NET MVC

Visual Studio 2012 comes with a perfectly capable Unit Testing system in MS Test. However if your team’s skills require you to use alternate Testing frameworks like NUnit, Visual Studio is game to play along. In this article, we’ll see the how we can setup NUnit to work with Visual Studio’s Test Explorer and run Unit tests in our project.

Setting up NUnit

There are two parts to NUnit setup for use in Visual Studio. First part is to install the framework, we can do this in two ways.

1. Download the 2.6.2 (latest at the time of writing) msi installer from http://www.nunit.org. Ensure Visual Studio is not running while the installer is running. This installs NUnit globally along with the NUnit test runner. However the test runner needs .NET 3.5 to run.

2. Another way to include NUnit in your project is to download it using the following Nuget Package Manager command

PM> install-package NUnit

Second part is to setup the NUnit Test Adapter so that Visual Studio recognizes the Test Cases in our project and allows us to Run them from the Test Explorer.