Connecting to FourSquare using oAuth

Open authorization (known normally by its shortened name, oAuth) is an open standard developed for authorization that allows a user to share private data stored on one site or device (for example, a mobile phone) with another site. Instead of using credentials such as a username and password, oAuth relies on tokens. Each token has within it a series of details encoded for a specific site (for example, FourSquare or Twitter), using specific resources or permissions (that is, photos or your personal information) for a specific duration of time (for example, 2 hours).

FourSquare is a popular location-based social networking site specifically made for GPS-enabled mobile devices. It allows you to check in to various locations and, in doing so, earn points and rewards in the form of badges. In this recipe, we will use oAuth to connect to FourSquare and retrieve an access token that we can use later on to enable our application to check-in to various locations...