Category Archives: REST

Twin Cities Code Camp 2012 – Day 1

This post will be a compilation of my notes from Twin Cities Code Camp 2012.

Understanding WebAPI in ASP.NET MVC 4 – Matt Milner – Rapson 56

What is web api?

  • API for HTTP Services – client and server components
  • WCF vs MVC – why do we need this api?
  • WCF – some people just want HTTP, REST services is complicated. Global error handling is almost impossible. Goal was to make WCF extremely flexible. Transport neutral just like SOAP. Because WCF was trying to cover ALL transports and protocols, HTTP became buried.

MVC was primarily built to pass back a View – typically HTML. JSON/JSONP were after thoughts. This is not a perfect model for RESTful services.

HTTP is a protocol in and of itself. Don’t need another protocol (e.g. SOAP). The protocol has been optimized over the years.

HTTP is widely accessible and MUCH easier to reach ALL devices.

Web API MVC Integration

  • MVC is for web applications
  • Web API is for web APIs
  • what they have in common is usually the model or domain

Cool new features: media type formatters for resource type handling. validation at the handler level which supports cancelation and pass-through instead of lowest level – the action. Better json support with the new System.Json library. Self-hosted testing built upon a partial wcf service stack. Support for OData URI queries. Simply return IQueryable. CONS: partial support for OData – only $page, $filter, and $sort – not $select. Doesn’t seem like the will be adding support for this. There is talk about adding built in support for Expression for DTO transformation on the server side.

There is also talk about combining the ServiceResolver configuration (configuration.ServiceResolver.SetResolver) to support both MVC and WebAPI in the same call. For example, right now you configure your MVC service resolving and a separate configuration for WebAPI service resolving. Simplification of this is on the table. Hopefully by the time the release comes around, we see a unified method.

TAKEAWAY MESSAGE: FORGET COMPLICATED SOAP PROTOCOL which is the standard for RIA Services and WCF. Simplify your api with REST. Forget about the mvc paradigm of method based access to your resources. You now access your resources via GET, POST, PUT, DELETE. You access a resource from a Controller. One controller per type of resource. Web API has content negotiation. It returns the data in the format that your request based on the Accept header. If I want JSON, I get JSON. You could expand upon this to return resources in whatever format you need; image, doc, resume, and more. The same for xml. Etc… Input validation is handled by the model binding mechanisms of MVC which builds a model state object.

Note: WebAPI is NOT a replacement for WCF. If you still need to support multiple endpoints in different protocols (for example pure TCP), then WCF is still the best option out there. If you want a simplified API that will be accessible for the widest audience, consider WebAPI.

NOTE TO SELF: check out $.validator.unobtrusive.revalidate(form, validationResult) – validationResult is the json object; { “Speaker”: “Speaker is required” } – where in this example Speaker is the name attribute of the form input element – this takes a json object and interprets it using jquery.validation unobtrusive. Is this a NEW method?

Async Today and Tomorrow – Joe Mayo – Rapson 54

Talk about the Async CTP. How we use async programming today and how we will use it in the future. The Async CTP hides the complexity of async programming. It leverages the TPL (Tasks Parallel Library).

Why do we need async for UI responsiveness? Ex. click on a button in a Windows Form. The program does some long running operation. The user doesn’t know what is happening until all of a sudden, the UI shows something. NOT A GOOD USER EXPERIENCE.

TPL at it’s core revolves around the Task class. It has a fluent api. Uses continuation methods (similar to callbacks).

  • Language Integration – Changes to C# and VB in .NET. Async – the await and async Context Keywords.
  • Every platform – Desktop, Web, and Device
  • leverage Opportunities – Clarity, lifetime, progress, UI, and exceptions

void functions – regular event handlers
functions that return typeof Task<T>– represents the ongoing operation – get exceptions off of that task. The Task wraps the <T> – it holds information about what happened when it returned the <T>.

Async CTP code looks like synchronous code except for the await and async keywords.

Previous convention was to write methods with the Async as the end of the method name. For example WriteAsync. The new paradigm is to write the method as WriteTaskAsync.

Everything after the await keyword is the continuation.

Multiple tasks in parallel… Task.WhenAll.  Or alternatively, Task.WhenAny.  NEAT!

Task based Async Patterns – continuation, cancellation, etc. Task.Wait(), AggregateException, ae.InnerExceptions, CancellationToken

Notes:  this is going to be a fun library to work with.  I can hardwly wait to get home and start coding!  That was not sarcasm but true enthusiasm.

Android Development for the .NET Developer

This is about native Android development, not developing using PhoneGap or MonoDevelop.

http://mike-marshall.net outlines the way to install the JDK, SDK, and everything you need to get an Android IDE up and running here.

  • android.app.Activity class
  • Combined with layouts (views), represents a single type of work that can be accomplished in your application
  • Reusable
    • Can be chained within your application to build a workflow
    • Can be published for use by other applications through :Intents” (more later)

Outlines how to create an Android Application Project within Eclipse.

The .net delegate event handler does not apply.

Working with resources can be annoying.

“Form” designer is very similar to XAML designer in visual studio.  Nothing is absolutely positioned unless you tell it to be as such.

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