Refactoring: IPInfo

app/src/main/java/eu/faircode/email/IPInfo.java

@@ -0,0 +1,38 @@
+package eu.faircode.email;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.InetAddress;
+import java.net.URL;
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.net.ssl.HttpsURLConnection;
+
+public class IPInfo {
+    private static Map<String, String> hostOrganization = new HashMap<>();
+
+    static String getOrganization(String host) throws IOException {
+        synchronized (hostOrganization) {
+            if (hostOrganization.containsKey(host))
+                return hostOrganization.get(host);
+        }
+        InetAddress address = InetAddress.getByName(host);
+        URL url = new URL("https://ipinfo.io/" + address.getHostAddress() + "/org");
+        Log.i("GET " + url);
+        HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
+        connection.setRequestMethod("GET");
+        connection.setReadTimeout(15 * 1000);
+        connection.connect();
+        try (BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()))) {
+            String organization = reader.readLine();
+            if ("undefined".equals(organization))
+                organization = null;
+            synchronized (hostOrganization) {
+                hostOrganization.put(host, organization);
+            }
+            return organization;
+        }
+    }
+}