Get currency from web

gistfile1.clj

(ns cataska
  (:use clojure.contrib.str-utils)
  (:import (java.net URL)
           (java.io BufferedReader InputStreamReader)))

(def coin
  ["TWD" "CNY" "JPY" "KRW"
   "HKD" "THB" "SGD" "IDR"
   "VND" "MYR" "PHP" "INR"
   "AED" "KWD" "AUD" "NZD"
   "USD" "CAD" "BRL" "MXN"
   "ARS" "CLP" "VEB" "EUR"
   "GBP" "RUB" "CHF" "SEK"
   "ZAR"])

(def calias {"NTD" "TWD", "RMB" "CNY"})

(def coins (str (str-join "|" coin) "|" (str-join "|" (keys calias))))

(defn incase-pattern [s]
  (. java.util.regex.Pattern (compile s java.util.regex.Pattern/CASE_INSENSITIVE)))

(defn expand-alias [alias]
  (if (calias alias)
    (calias alias)
    alias))

(defn make-url [money from to]
  (str "http://tw.money.yahoo.com/currency_exc_result?amt=" money
       "&from=" from
       "&to=" to))

(defn fetch-url [address]
  (with-open [stream (.openStream (URL. address))]
    (let [buf (BufferedReader. (InputStreamReader. stream))]
      (apply str (line-seq buf)))))

(defn extract-input2 [input]
  (let [r (incase-pattern (format "^([\\d\\.\\+\\-\\*\\/]+)\\s*(%s)\\s+to\\s+(%s)$" coins coins))
        matcher (re-matcher r input)]
    (if (.matches matcher)
      {:money (. matcher group 1)
       :from (expand-alias (.. matcher (group 2) toUpperCase))
       :to (expand-alias (.. matcher (group 3) toUpperCase))})))

(defn extract-input [input]
  (let [r (incase-pattern (format "^([\\d\\.\\+\\-\\*\\/]+)\\s*(%s)$" coins))
        matcher (re-matcher r input)]
    (if (.matches matcher)
      {:money (. matcher group 1)
       :from (expand-alias (.. matcher (group 2) toUpperCase))
       :to "TWD"}
      (extract-input2 input))))

(defn get-currency [s]
  (let [res (fetch-url (make-url (:money s) (:from s) (:to s)))
        r (re-pattern "經過計算後， (.+?)<div")
        matcher (re-matcher r res)]
    (if (.find matcher)
      (re-gsub #"</?em>" "" (. matcher group 1))
      "抱歉")))

(defn currency
  "Get currency from web"
  [text]
  (let [m (extract-input text)]
    (if m
      (get-currency m)
      "抱歉")))