added artist.getinfo and artist.getsimilar APIs

.gitignore

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+pom.xml
+*jar
+lib
+classes

project.clj

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+(defproject clj-lastfm "1.0.0-SNAPSHOT"
+  :description "Clojure interface to last.fm API"
+  :dependencies [[org.clojure/clojure "1.1.0"]
+                 [org.clojure/clojure-contrib "1.1.0"]
+                 [log4j "1.2.15" :exclusions [javax.mail/mail
+                                              javax.jms/jms
+                                              com.sun.jdmk/jmxtools
+                                              com.sun.jmx/jmxri]]])

src/clj_lastfm/core.clj

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+(ns clj-lastfm.core
+  (:import (java.net URI)
+           (java.text SimpleDateFormat)
+           (java.util TimeZone))
+  (:use [clj-lastfm.filecache]
+        [clojure.contrib.json.read :only (read-json)]
+        [clojure.walk :only (keywordize-keys)]
+        [clojure.contrib.import-static]
+        [clojure.contrib.logging]))
+
+(import-static java.lang.Integer parseInt)
+
+;;;;;;;;;; Basic ;;;;;;;;;;
+
+(def #^{:private true}
+  api-root-url ["http" "ws.audioscrobbler.com" "/2.0/"])
+
+(defn- api-key []
+  (let [lastfm-api-key (resolve '*lastfm-api-key*)]
+    (if (nil? lastfm-api-key)
+      (throw (IllegalStateException. "lastfm API key is not set"))
+      lastfm-api-key)))
+
+(def guid-pattern
+  #"^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$")
+
+(def #^{:private true} sdf
+  (doto (SimpleDateFormat. "EEE, dd MMMM yyyy HH:mm:ss +0000")
+    (.setTimeZone (TimeZone/getTimeZone "GMT"))))
+
+(defn parse-date [date-str]
+  (.parse sdf date-str))
+
+(defn- remove-nil-values [m]
+  (apply hash-map (apply concat (filter #(not (nil? (fnext %))) m))))
+
+(defn- create-url-query [query-params]
+  (apply str
+    (interpose
+      "&"
+      (map
+        #(str (name (first %)) "=" (second %))
+        (remove-nil-values query-params)))))
+
+(defn- create-url [query-params]
+  (.toURL
+    (apply
+      #(URI. %1 %2 %3 %4 %5)
+      (conj
+        api-root-url
+        (create-url-query
+          (merge query-params {:api_key @(api-key) :format "json"}))
+        nil))))
+
+(def #^{:private true} default-cache (create-file-cache))
+
+(defn- get-url
+  ([url] (get-url url default-cache))
+  ([url cache]
+    (do
+      (debug (str "URL: " url))
+      (get-file-content cache url))))
+
+(defn- get-data [params]
+  (let [url (create-url params)]
+    (-> url get-url read-json keywordize-keys)))
+
+(defn create-get-obj-fn [fixed-params parse-fn]
+  (fn [more-params]
+    (parse-fn (get-data (merge fixed-params more-params)))))
+
+(defn create-get-obj-field-fn [create-obj-fn extract-obj-id-fields-fn]
+  (fn [obj field-kw]
+    (let [field-val (obj field-kw)]
+      (if (nil? field-val)
+        ((apply create-obj-fn (extract-obj-id-fields-fn obj)) field-kw)
+        field-val))))
+
+;;;;;;;;;; Bio/Wiki ;;;;;;;;;;
+
+(defstruct bio-struct :published :summary :content)
+
+(defn parse-bio [data]
+  (struct
+    bio-struct
+    (-> data :published parse-date)
+    (-> data :summary)
+    (-> data :content)))
+
+;;;;;;;;;; Artist ;;;;;;;;;;
+
+(defstruct artist-struct
+  :name :url :mbid :streamable :listeners :playcount :bio)
+
+(defn parse-artist [data]
+  (struct
+    artist-struct
+    (-> data :artist :name)
+    (-> data :artist :url)
+    (-> data :artist :mbid)
+    (= 1 (-> data :artist :streamable parseInt))
+    (-> data :artist :stats :listeners parseInt)
+    (-> data :artist :stats :playcount parseInt)
+    (-> data :artist :bio parse-bio)))
+
+(def #^{:private true}
+  get-artist (create-get-obj-fn {:method "artist.getinfo"} parse-artist))
+
+(defmulti artist
+  (fn [artist-or-mbid & _]
+    (if (re-matches guid-pattern artist-or-mbid) :mbid :artist)))
+
+(defmethod artist :artist
+  ([artist-name] (artist artist-name nil nil))
+  ([artist-name username] (artist artist-name username nil))
+  ([artist-name username lang]
+    (get-artist {:artist artist-name :username username :lang lang})))
+
+(defmethod artist :mbid
+  ([mbid] (artist mbid nil nil))
+  ([mbid username] (artist mbid username nil))
+  ([mbid username lang]
+    (get-artist {:mbid mbid :username username :lang lang})))
+
+(def artist-info
+  (create-get-obj-field-fn artist #(vector (% :name))))
+
+(defn parse-artist-similar [data]
+  (map
+    #(struct artist-struct
+      (% :name)
+      (% :url)
+      (% :mbid)
+      (= 1 (-> % :streamable parseInt))
+      nil nil nil)
+    (-> data :similarartists :artist)))
+
+(def #^{:private true} get-artist-similar
+  (create-get-obj-fn {:method "artist.getsimilar"} parse-artist-similar))
+
+(defmulti artist-similar 
+  (fn [artst-or-name & _] 
+    (instance? clojure.lang.PersistentStructMap artst-or-name)))
+
+(defmethod artist-similar true 
+  ([artst] (-> artst :name artist-similar))
+  ([artst limit] (artist-similar (artst :name) limit)))
+
+(defmethod artist-similar false 
+  ([artist-name] (get-artist-similar {:artist artist-name}))
+  ([artist-name limit] (get-artist-similar {:artist artist-name :limit limit})))  
+
+(comment
+
+(def *lastfm-api-key* "23caa86333d2cb2055fa82129802780a")
+(def u2 (artist "u2"))
+(println (artist-info u2 :url))
+
+)

src/clj_lastfm/filecache.clj

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+(ns clj-lastfm.filecache
+  (:import (java.io File))
+  (:use clojure.contrib.duck-streams))
+
+(def default-cache-dir (File. (System/getProperty "java.io.tmpdir")))
+(def default-expiry-time (* 24 60)) ;in minutes
+
+(defn- minutes-to-millis [mins] (* mins 1000 60))
+(defn- recently-modified? [#^File file expiry-time]
+  (> (.lastModified file)
+    (- (System/currentTimeMillis) (minutes-to-millis expiry-time))))
+
+(defn create-file-cache
+  "Creates a file cache"
+  ([] (create-file-cache default-cache-dir default-expiry-time))
+  ([cache-dir] (create-file-cache cache-dir default-expiry-time))
+  ([cache-dir expiry-time]
+    {:cache-dir cache-dir :expiry-time expiry-time}))
+
+(defn get-file-content
+  "Gets the content of the URL provided from cache if present, else fetches and
+  caches it and returns the content"
+  [{#^File cache-dir :cache-dir expiry-time :expiry-time} url]
+  (let [url-hash (hash url)
+        cache-file (File. (str (.getCanonicalPath cache-dir)
+                               File/separator "clj-lastfm-" url-hash))]
+    (do
+      (when-not (and (.exists cache-file) (recently-modified? cache-file expiry-time))
+        (copy (reader url) cache-file))
+      (slurp (.getCanonicalPath cache-file)))))
+
+(comment
+
+(def cache (create-file-cache))
+(def url "http://ws.audioscrobbler.com/2.0/?method=artist.gettoptracks&artist=bon%20jovi&api_key=23caa86333d2cb2055fa82129802780a&format=json")
+(println (get-file-content cache url))
+
+)

src/log4j.properties

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+# Based on the example properties given at http://logging.apache.org/log4j/1.2/manual.html
+# Set root logger level to DEBUG and its only appender to A1.
+log4j.rootLogger=DEBUG,A1
+
+# A1 is set to be a ConsoleAppender.
+log4j.appender.A1=org.apache.log4j.ConsoleAppender
+
+# A1 uses PatternLayout.
+log4j.appender.A1.layout=org.apache.log4j.PatternLayout
+log4j.appender.A1.layout.ConversionPattern= %-5p %c - %m%n