add functions and comments for making HTTP-Requests.

These are comments and functions to get me into the swing of writting
Common Lisp. The code here is the main part of the system but this
commit is mostly about how this file and its code fits into the bigger
picture which is the system/code base.

src/ritherdon-rest.lisp

@@ -1,6 +1,37 @@
 ;;;; ritherdon-rest.lisp
 
+;;; A collection of functions to aid in the make
+;;; http-requests to the Ritherdon REST API. This project is help me
+;;; learn Common Lisp. So, there is not much emphasis on being too
+;;; strict on best practices and defensive coding.
+
+;;; NOTE: The Ritherdon REST API is part of an art exhibition at time
+;;; of writing (29/06/2021). You will need to check if the server is
+;;; still running if you want to run this code.
+
 (in-package #:ritherdon-rest)
 
-(defun hello ()
-  (print "The system is up and running."))
+;; All the data provided by the Ritherdon REST API is in JSON. Becuase
+;; of this I can set the `TEXT-CONTENT-TYPE' to JSON and keep it like
+;; that until further notice.
+(setq drakma:*text-content-types* (cons '("application" . "json")
+                                        drakma:*text-content-types*))
+
+;; The Base URL which you build all your HTTP Requests on. You will
+;; need to refer back to http://ritherdon.abbether.net/api/ui/ for the
+;; full set of URL's.
+(defvar *base-url* "http://ritherdon.abbether.net/api")
+
+;; The http-request is actually 'drakma:http-request'. I've done it
+;; this way to highlight the feature. It is the same as what you've
+;; used in the past with C# and 'using static' statements. So, not
+;; much to go into here apart from highlighting it's a thing in Common
+;; Lisp, too.
+(defun make-request (query)
+  (http-request (concatenate 'string *base-url* query)))
+
+;;  Same as the drakma example above. It can read as
+;;  'cl-json:decode-json-from-string' but omitted the 'cl-json'
+;;  bit. You will find all package declarations in /src/package.lisp'.
+(defun parse-request (query)
+  (decode-json-from-string(make-request query)))