I recently came across a question on Stack Overflow asking about Boosting elasticsearch results with NEST when a secondary field is a specific value. I thought the question was interesting enough to warrant a blog post, the first I've written in a while!

I recently came across an issue within a pipeline of asynchronous method calls where an attempt to deserialize a response from json to a known type may throw an exception, usually when the response is not json. For example, this may be the case when using something like nginx as a proxy for authentication purposes and failed authentication returns a HTML page. A simple reproducible example would be

void Main()
{
    MainAsync().Wait();
}

async Task MainAsync()
{
    var result = await TryDeserializeAsync().ConfigureAwait(false);    
    Console.WriteLine(result);
}

Task<double?> TryDeserializeAsync()
{
    try { 
        return DeserializeAsync(); 
    }
    catch {
        // swallow any exceptions thrown.
    }
    return null;
}

async Task<double?> DeserializeAsync()
{
    await Task.Delay(100);
    throw new Exception("Serialization error");
}

Here we await TryDeserializeAsync() which in turn calls the actual DeserializeAsync() implementation, swallowing any exception that may occur in deserialization and simple returning null. That's the plan anyway.

In my last post I gave an example of how to use the bulk api to index many documents at a time into Elasticsearch. Once all of the documents have been indexed, it is very likely that we'll want to update individual documents within the index; In this post, we'll look at how to do this and some of the features available to manage multiple concurrent update requests to a given document.

In this blog post I’m going to show you how to get started with geospatial search with Elasticsearch, using the official and fantastic .NET client for Elasticsearch, NEST.  An example like this is best served with real data, so given this post was written from Australia, we’ll use the State Suburbs (SSC) from 2006 provided by the Australian Bureau of Statistics as the data of interest; it's provided in ESRI Shapefile format and contains a collection of all the Australian Suburbs, each with a name, code and geometry; We’ll need to extract each suburb from the Shapefile and serialize them to a format that can be persisted to Elasticsearch and so that we can query them.

TL;DR

I’ve put together a demo application to illustrate geospatial search using Elasticsearch and NEST..

I wanted to share a setup that has been working well for me for some time in keeping the layout of C# code consistent, easier to maintain and smoother when it comes to merging changes into git. It leverages ReSharper and SemanticMerge, two really awesome tools that allow you to remain focused on delivering features with minimum fuss.

With this setup, a simple keyboard shortcut restructures a C# code file according to defined settings, performing such actions as reordering members according to type, accessibility and name, removing regions, sorting Using directives and updating file headers. When it comes to merging these changes into source control, we can merge with confidence as SemanticMerge parses the C# file to determine changes at the class structural level, meaning we can happily reorder members ‘til our hearts content and let SemanticMerge deal with the fallout of determining the real changes. Enough of the hyperbole, let’s get set up!

Whenever I have a need to write a Windows Service, Topshelf is pretty much the first nuget package that I install to aid in the task. In a nutshell, Topshelf is a framework that makes writing Windows Services easier; you write a standard console application, add Topshelf to the mix and you now have an application that can be run as a console application whilst developing and debugging, and installed as a Windows Service when the need to deploy arises. It's a pretty frictionless experience, but there can be some a gotcha when using Topshelf in conjunction with MassTransit and Dependency Injection. I've experienced this a few times so thought I'd write it down here for next time!

As per the comments on my previous post about Managing Scripts for Razor Partial Views and Templates in ASP.NET MVC, I've created a Nuget package for the HtmlHelpers used. Go take a look and leave a comment if you find them useful; I plan to add additional helpers to the package over time for general functionality that is useful in any ASP.NET MVC application.

The model binding implementation in ASP.NET Web Api shares some similarities to the model binding you find in ASP.NET MVC and at the same time has some striking differences. For a more detailed discussion on web api parameter binding, check out Mike Stall’s excellent post on the topic. The topic of today’s post is how we define our own convention for parameter binding complex types when the request is a HTTP GET request.

TL;DR

I have written a ValueProvider for binding model collections from records in a CSV file. The source code is available on BitBucket.

Model binding in ASP.NET MVC is responsible for binding values to the models that form the parameter arguments to the controller action matched to the route. But where do model binders get these values from? That’s where Value Providers come in; A ValueProvider provides values for model binding and there are ValueProviders for providing values from

• a parent action (if the action is a child or nested action)
• a posted form value collection
• posted JSON
• route data
• the query string
• posted files

If you missed Anders Hejlsberg talk on the Future directions for C# and Visual Basic, go check it out now, I’ll wait.