REST Interfaces Explained

REST (REpresentational State Transfer) is an interface type that was created in 2000 by Roy Fielding in a doctoral dissertation. It is based on HTTP, so a REST interface is basically composed of GET, PUT, POST, HEAD, and DELETE operations.  I’ll explain REST Interfaces in this post, and follow-up with a Swift REST API example.

REST Interface HTTP Components

First, let’s look at each operation as defined by the HTTP components:

1. Method
   The operations typically are: COPY, DELETE, GET, HEAD, PUT, and POST.
   The server has complete freedom in defining these operations.
   Typically though, these operations are defined as follows:
   COPY – create a copy of an item.
   • DELETE – delete an item.
   • GET – read an item.
   • HEAD – read item meta-data.
   • PUT – create an item.
   • POST – write item meta-data.
2. URL
   The URL is commonly of the form:
   <http>://<ip><port>/<version>/<auth>/<parameters>
   Where:
   • <http> = “http” or “https”.
   • <ip> = ip address.
   • <port> = port number.
   • <version> = version string.
   • <auth> = authorization token.
   • <data> = operation specific data.
   • <parameters> = options.
     Parameters begins with a “?”.   Multiple parameters are seperated by a “&”.
3. Request Headers
   Operation input headers.
4. Response Headers
   Headers returned by the interface.
5. Response Data.
   Data returned by the interface in ASCII format.
6. Status Code
   HTTP status code. This code is in the range 1 – 600 and can be broken down as follows:
   • 1xx Informational.
   • 2xx Success.
   • 3xx Redirection.
   • 4xx Client Error.
   • 5xx Server Error.

Next time I’ll present a SWIFT REST Interface API example. In the meantime, what would you add to this explanation?