Techniques for Preventing Duplicate URLs in Your Website

Chances are, there are several different URLs that point to the same content on your website. For example, the URLs http://yoursite.com, http://yoursite.com/default.aspx, http://www.yoursite.com, or http://www.yoursite.com/default.aspx are all likely valid URLs that results in the same content, namely the homepage for yoursite.com. While having four different URLs reference the same content may not seem like a big deal, it can directly impact your website's search engine placement and, consequently, it's traffic. To a search engine, those four different URLs represent four different pages, even though the all produce the same content.

To understand how allowing duplicate URLs in your website can affect your search engine placement, first understand that search engines base a page's placement in the search results based, in part, on how many other websites link to the page. Now, imagine that there are 1,000 web pages from other websites that link to your homepage. You might conclude, then, that a search engine would rank the importance of your homepage based on those 1,000 links. But consider what would happen if 25% of those links linked to http://yoursite.com, 25% to http://yoursite.com/default.aspx, and so on. Rather than your homepage reflecting 1,000 inbound links, instead the search engine assumes there are only 250 links to http://yoursite.com, only 250 links to http://yoursite.com/default.aspx, and so on. In effect, redundant URLs can dilute your search engine ranking.

A key tenet of search engine optimization is URL normalization, or URL canonicalization. URL normalization is the process of eliminating duplicate URLs in your website. This article explores four different ways to implement URL normalization in your ASP.NET website. Read on to learn more!
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Maximize Your Website's Search Engine Placement Using Microsoft's Free SEO Toolkit

Search engine optimization, or SEO, is the practice of improving a website's position in search engines' results using unpaid techniques. The driver behind SEO is that a better (higher) position in the search results will, most likely, lead to more click throughs, increasing the website's visibility, audience, and profit. A previous article here on 4Guys, Search Engine Optimization Enhancements in ASP.NET 4, explored some of ASP.NET 4's new features designed to aid with SEO. Another helpful tool for SEO is Microsoft's SEO Toolkit, a free IIS add-on that you can run from your computer to inspect a local or remote website and identify potential issues that may impact its search engine rankings.

Using Microsoft's SEO Toolkit is simple. Once installed, run it and specify the website you want to analyze. The SEO Toolkit can analyze both local websites or remote ones. After you've specified the URL of the website to analyze, the SEO Toolkit will crawl the site, exploring its pages and identify potential issues that may affect the site's search engine rankings and offer suggestions on how to fix them. This article walks through getting started with the SEO Toolkit, showing how to use it and how to analyze its results and implement its suggestions to help improve your website's search engine placement. Read on to learn more!
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Managing View State in ASP.NET 4 Using the New ViewStateMode Property

The ASP.NET Web Forms model strives to encapsulate the lower level complexities involved in building a web application. Features like server-side event handlers, the page lifecycle, and view state effectively blur the line between the client and the server, simplify state management, and free the developer from worrying about HTTP, requests and responses, and similar matters. While these facets of the Web Forms model allow for rapid application development and make ASP.NET more accessible to developers with a web application background, their behavior can impact your website's behavior and performance.

View state is perhaps the most important - yet most misunderstood - feature of the Web Forms model. In a nutshell, view state is a technique that automatically persists programmatic changes to the Web controls on a page. By default, this state is serialized into a base-64 encoded string and included as a hidden <input> field in the Web Form. On postback, this state information is returned to the server as part of the POST request, at which point the server can deserialize it and reapply the persisted state to the controls in the control hierarchy. (If this last paragraph made crystal clear sense, great! If not, consider reading my article, Understanding ASP.NET View State, and Dave Reed's article, ViewStateMode in ASP.NET 4, before continuing.)

One potential issue with view state is that it can greatly bloat the size of your web pages. Each new version of ASP.NET seems to include new techniques for managing view state's footprint. ASP.NET 4 adds a new property to all Web controls, ViewStateMode, which allows developers to disable view state for a page by default and then selectively enable it for specific controls. This article reviews existing view state-related properties and then delves into the new ViewStateMode property. Read on to learn more!
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An Extensive Examination of LINQ: Extending LINQ - Adding Query Operators

As discussed in earlier installments of this article series - most notably in An Introduction to LINQ and The Standard Query Operators - one of LINQ's primary components is its set of standard query operators. A query operator is a method that operates on a sequence of data and performs some task based on that data, are implemented as extension methods on types that implement the IEnumerable<T> interface. Some of the standard query operators that we've explored throughout the articles in this series include: Count, Average, First, Skip, Take, Where, and OrderBy, among others.

While these standard query operators provide a great detail of functionality, there may be situations where they fall short. The good news is that it's quite easy to create your own query operators. Underneath the covers query operators are just methods that extend types that implement IEnumerable<T> and iterate over the sequence performing some task, such as computing the total number of items in the sequence, computing the average, filtering the results, or ordering them. This article examines how to extend LINQ's functionality by creating your own extension methods. Read on to learn more!
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Search Engine Optimization Enhancements in ASP.NET 4

Search engine optimization, or SEO, is the practice of improving a website's position in search engines' results using unpaid techniques. A better (higher) position in the search results will, in theory, lead to more click throughs, increasing the website's visibility and audience. There are a number of simple steps you can take on your website to improve your search engine ranking. A good first step is to download and run Microsoft's free Search Engine Optimization Toolkit. Point it at a remote website and the SEO Toolkit will crawl the links on the site and identify potential problems and offer suggestions on how to fix them.

ASP.NET 4 includes a handful of new methods, properties, and libraries to assist with search engine optimization, including ASP.NET Routing, permanent redirects, and the ability to programmatically specify values for certain <meta> tags. This article examines these enhancements and shows how they can be used for SEO purposes. Read on to learn more!
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An Extensive Examination of LINQ: Querying and Searching XML Documents Using LINQ to XML

XML is an increasingly popular way to encode documents, data, and electronic messages. Over the years Microsoft has offered a variety of libraries to facilitate creating, modifying, querying, and searching XML documents. LINQ to XML is a relatively new set of XML-related classes in the .NET Framework (found in the System.Xml.Linq namespace), which enable developers to work with XML documents using LINQ's features, syntax, and semantics. As discussed in an earlier article, Introducing LINQ to XML, LINQ to XML is a simpler and easier to use API than previous libraries. Because LINQ to XML can utilize LINQ's query syntax and assortment of standard query operators, LINQ to XML code is usually very terse and readable.

This article continues our look at LINQ to XML. Specifically, we explore how to query XML documents using axis methods as well as how to search and filter XML documents using both LINQ's Where method and XPath expressions. Read on to learn more!

Note: If you have not yet read Introducing LINQ to XML please do so before reading this article...
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Extending ASP.NET Output Caching

One of the most sure-fire ways to improve a web application's performance is to employ caching. Caching takes some expensive operation and stores its results in a quickly accessible location. Since it's inception, ASP.NET has offered two flavors of caching:

• Output Caching - caches the entire rendered markup of an ASP.NET page or User Control for a specified duration.
• Data Caching - a API for caching objects. Using the data cache you can write code to add, remove, and retrieve items from the cache.

Until recently, the underlying functionality of these two caching mechanisms was fixed - both cached data in the web server's memory. This has its drawbacks. In some cases, developers may want to save output cache content to disk. When using the data cache you may want to cache items to the cloud or to a distributed caching architecture like memcached. The good news is that with ASP.NET 4 and the .NET Framework 4, the output caching and data caching options are now much more extensible. Both caching features are now based upon the provider model, meaning that you can create your own output cache and data cache providers (or download and use a third-party or open source provider) and plug them into a new or existing ASP.NET 4 application.

This article focuses on extending the output caching feature. We'll walk through how to create a custom output cache provider that caches a page or User Control's rendered output to disk (as opposed to memory) and then see how to plug the provider into an ASP.NET application. A complete working example, available in both VB and C#, is available for download at the end of this article. Read on to learn more!
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