Added basic Subsonic interface

app/src/main/java/com/cappielloantonio/play/subsonic/Subsonic.java

@@ -0,0 +1,51 @@
+package com.cappielloantonio.play.subsonic;
+
+import com.cappielloantonio.play.subsonic.base.Version;
+
+import java.util.List;
+import java.util.Map;
+
+public class Subsonic {
+    private final SubsonicPreferences preferences;
+
+    private static final Version API_MIN_VERSION = Version.of("1.13.0");
+    private static final Version API_MAX_VERSION = Version.of("1.15.0");
+
+    private Version apiVersion = API_MAX_VERSION;
+
+    public Subsonic(SubsonicPreferences preferences) {
+        this.preferences = preferences;
+    }
+
+    public SubsonicPreferences getPreferences() {
+        return preferences;
+    }
+
+    public static Version getApiMinVersion() {
+        return API_MIN_VERSION;
+    }
+
+    public static Version getApiMaxVersion() {
+        return API_MAX_VERSION;
+    }
+
+    public Version getApiVersion() {
+        return apiVersion;
+    }
+
+    public String createUrl(String path, Map<String, List<String>> params) {
+        final StringBuilder sb = new StringBuilder(preferences.getServerUrl());
+
+        sb.append("/rest/").append(path);
+        sb.append("?u=").append(preferences.getUsername());
+        sb.append("&s=").append(preferences.getAuthentication().getSalt());
+        sb.append("&t=").append(preferences.getAuthentication().getToken());
+        sb.append("&v=").append(getApiVersion().getVersionString());
+        sb.append("&c=").append(preferences.getClientName());
+        sb.append("&f=").append("xml");
+
+        params.keySet().forEach(k -> params.get(k).forEach(v -> sb.append("&").append(k).append("=").append(v)));
+
+        return sb.toString().replace("//rest", "/rest");
+    }
+}

app/src/main/java/com/cappielloantonio/play/subsonic/SubsonicPreferences.java

@@ -0,0 +1,73 @@
+package com.cappielloantonio.play.subsonic;
+
+import com.cappielloantonio.play.subsonic.utils.StringUtil;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.UUID;
+
+public class SubsonicPreferences {
+    private String serverUrl;
+    private String username;
+    private String clientName = "SubsonicJavaClient";
+    private int streamBitRate = 192;
+    private String streamFormat = "mp3";
+
+    private final SubsonicAuthentication authentication;
+
+    public SubsonicPreferences(String serverUrl, String username, String password) {
+        this.serverUrl = serverUrl;
+        this.username = username;
+        this.authentication = new SubsonicAuthentication(password);
+    }
+
+    public String getServerUrl() {
+        return serverUrl;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public String getClientName() {
+        return clientName;
+    }
+
+    public int getStreamBitRate() {
+        return streamBitRate;
+    }
+
+    public String getStreamFormat() {
+        return streamFormat;
+    }
+
+    public SubsonicAuthentication getAuthentication() {
+        return authentication;
+    }
+
+    public void setPassword(String password) {
+        authentication.update(password);
+    }
+
+    public static class SubsonicAuthentication {
+        private String salt;
+        private String token;
+
+        public SubsonicAuthentication(String password) {
+            update(password);
+        }
+
+        public String getSalt() {
+            return salt;
+        }
+
+        public String getToken() {
+            return token;
+        }
+
+        void update(String password) {
+            this.salt = UUID.randomUUID().toString();
+            this.token = StringUtil.tokenize(password + salt);
+        }
+    }
+}

app/src/main/java/com/cappielloantonio/play/subsonic/base/SubsonicIncompatibilityException.java

@@ -0,0 +1,13 @@
+package com.cappielloantonio.play.subsonic.base;
+
+public class SubsonicIncompatibilityException extends RuntimeException{
+    private final Version serverApiVersion;
+    private final Version minClientApiVersion;
+
+    public SubsonicIncompatibilityException(Version serverApiVersion, Version minClientApiVersion) {
+        super(String.format("Server API version %s is lower than minimal supported API version %s.", serverApiVersion, minClientApiVersion));
+
+        this.serverApiVersion = serverApiVersion;
+        this.minClientApiVersion = minClientApiVersion;
+    }
+}

app/src/main/java/com/cappielloantonio/play/subsonic/base/Version.java

@@ -0,0 +1,56 @@
+package com.cappielloantonio.play.subsonic.base;
+
+public class Version implements Comparable<Version> {
+
+    private static final String VERSION_PATTERN = "[0-9]+(\\.[0-9]+)*";
+    private final String versionString;
+
+    public static Version of(String versionString) {
+        return new Version(versionString);
+    }
+
+    private Version(String versionString) {
+        if (versionString == null || !versionString.matches(VERSION_PATTERN)) {
+            throw new IllegalArgumentException("Invalid version format");
+        }
+        this.versionString = versionString;
+    }
+
+    public String getVersionString() {
+        return versionString;
+    }
+
+    public boolean isLowerThan(Version version) {
+        return compareTo(version) < 0;
+    }
+
+    @Override
+    public int compareTo(Version that) {
+        if (that == null) {
+            return 1;
+        }
+
+        String[] thisParts = this.getVersionString().split("\\.");
+        String[] thatParts = that.getVersionString().split("\\.");
+
+        int length = Math.max(thisParts.length, thatParts.length);
+
+        for (int i = 0; i < length; i++) {
+            int thisPart = i < thisParts.length ? Integer.parseInt(thisParts[i]) : 0;
+            int thatPart = i < thatParts.length ? Integer.parseInt(thatParts[i]) : 0;
+
+            if (thisPart < thatPart) {
+                return -1;
+            }
+            if (thisPart > thatPart) {
+                return 1;
+            }
+        }
+        return 0;
+    }
+
+    @Override
+    public String toString() {
+        return versionString;
+    }
+}

app/src/main/java/com/cappielloantonio/play/subsonic/utils/StringUtil.java

@@ -0,0 +1,28 @@
+package com.cappielloantonio.play.subsonic.utils;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+public class StringUtil {
+    public static String tokenize(String s) {
+        final String MD5 = "MD5";
+        try {
+            MessageDigest digest = java.security.MessageDigest.getInstance(MD5);
+            digest.update(s.getBytes());
+            byte messageDigest[] = digest.digest();
+
+            StringBuilder hexString = new StringBuilder();
+            for (byte aMessageDigest : messageDigest) {
+                String h = Integer.toHexString(0xFF & aMessageDigest);
+                while (h.length() < 2) {
+                    h = "0" + h;
+                }
+                hexString.append(h);
+            }
+            return hexString.toString();
+        } catch (NoSuchAlgorithmException e) {
+            e.printStackTrace();
+        }
+        return "";
+    }
+}