gistfile1.clj

(ns rets
  (:import (org.apache.http.client HttpClient)
           (org.apache.http.client.methods HttpGet HttpPost)
           (org.apache.http.impl.client DefaultHttpClient)
           (org.apache.http.util EntityUtils)))

(use '[clojure.contrib.str-utils])

(def base-url "http://rets.realtracs.net:6103")
(def login-path "/rets/login")
(def logout-path "/rets/logout")
(def login-url (str base-url login-path))
(def logout-url (str base-url logout-path))
(def default-auth-query { :username "parkrets", :password "*******" })
(def default-query { :querytype "DMQL", :standardnames "0", :count "0", :format "COMPACT" })

(defn to-string [response]
  (EntityUtils/toString (.getEntity response)))

(defn- authenticate
  "Perform authtication of web service"
  []
  (to-string (.execute (DefaultHttpClient.) (HttpPost. login-url)))))

(defn- build-request
  [request]
  (doto request
       (.addHeader "Content-type" "application/xml")))

(defn- do-request
  "Perform requests to get XML"
  [request]
  (to-string (.execute (DefaultHttpClient.) (build-request request))))

(defn- map->querystring
  "Builds a string in the form of querytype=DMQL&standardnames=0&count=0"
  [m]
  (let [join-pair (fn [[k v]]
                    (str-join "=" [(.toUpperCase (name k)) v]))]
    (str-join "&"
              (reduce (fn [acc pair]
                        (conj acc (join-pair pair))) [] m))))
 
(defn- build-url
  "Build url"
  [query]
  (let [url (str base-url "?" (map->querystring (conj default-query query)))]
    (HttpGet. url)))

;; Public API
(defn property 
  "Get the RETS information for a particular MSL entry"
  [mlsnum]
  (do-request (build-url { :searchtype "Property", :class "RES", :mlsnum mlsnum })))

(defn query
  "Query the RETS service"
  [query]
  (do-request (build-request (query))))

;; Usage
(authenticate)
(property "100298")