From Device Description Working Group Wiki
The process of device recognition is an important stage in the use of the DDR API. Given some evidence from the delivery context (e.g. the HTTP headers of a request from a device), it is necessary to determine the identity of the device so that one may query a repository for information about that device.
This model assumes that recognition is separate from the repository lookup, which is a sensible assumption given the diversity of evidence that may be used. For example, some of the ways of recognizing a device are:
- The HTTP User Agent header
- The HTTP Accepts header
- Two or more of the HTTP headers in combination
- The IMEI of the mobile device
- Asking the user