Earlier this year I wrote an article about Twitterizer, an open-source .NET library that can be used to integrate your application with Twitter. Using Twitterizer you can allow your visitors to post tweets, view their timeline, and much more, all without leaving your website. The original article, Integrating Twitter Into An ASP.NET Website, showed how to post tweets and view a timeline to a particular Twitter account using Twitterizer 1.0. To post a tweet to a specific account, Twitterizer 1.0 uses basic authentication. Basic authentication is a very simple authentication scheme. For an application to post a tweet to JohnDoe's Twitter account, it would submit JohnDoe's username and password (along with the tweet text) to Twitter's servers. Basic authentication, while easy to implement, is not an ideal authentication scheme as it requires that the integrating application know the username(s) and password(s) of the accounts that it is connected to. Consequently, a user must share her password in order to connect her Twitter account with the application. Such password sharing is not only insecure, but it can also cause difficulties down the line if the user changes her password or decides that she no longer wants to connect her account to certain applications (but wants to remain connected to others).
To remedy these issues, Twitter introduced support for OAuth, which is a simple, secure protocol for granting API access. In a nutshell, OAuth allows a user to connect an application to their Twitter account without having to share their password. Instead, the user is sent to Twitter's website where they confirm whether they want to connect to the application. Upon confirmation, Twitter generates a token that is then sent back to the application. The application then submits this token when integrating with the user's account. The token serves as proof that the user has allowed this application access to their account. (Twitter users can view what application's they're connected to and may revoke these tokens on an application-by-application basis.)
In late 2009, Twitter announced that it was ending its support for basic authentication in June 2010. As a result, the code examined in Integrating Twitter Into An ASP.NET Website, which uses basic authentication, will no longer work once the cut off date is reached. The good news is that the Twitterizer version 2.0 supports OAuth. This article examines how to use Twitterizer 2.0 and OAuth from a website. Specifically, we'll see how to retrieve and display a user's latest tweets and how to post a tweet from an ASP.NET page. Read on to learn more!