Add a file downloader to acid so modules can download files

diff --git a/acid/src/main/java/net/rizon/acid/util/FileDownloader.java b/acid/src/main/java/net/rizon/acid/util/FileDownloader.java
new file mode 100644 (file)
index 0000000..a20a839
--- /dev/null
+++ b/acid/src/main/java/net/rizon/acid/util/FileDownloader.java
@@ -0,0 +1,116 @@
+/*
+ * Copyright (c) 2017, Orillion <orillion@rizon.net>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+package net.rizon.acid.util;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.nio.channels.Channels;
+import java.nio.channels.ReadableByteChannel;
+import java.util.zip.GZIPInputStream;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ *
+ * @author Orillion <orillion@rizon.net>
+ */
+public class FileDownloader
+{
+       private static final Logger LOGGER = LoggerFactory.getLogger(FileDownloader.class);
+
+       public enum CompressionMethod
+       {
+               GZIP,
+               NONE,
+       }
+
+       /**
+        * Downloads a file from the specified url and decompresses it to the
+        * destination.
+        *
+        * @param url         URL to download from
+        * @param compression Compression method of the file
+        * @param destination Destination to write to
+        *
+        * @return true if successful, false otherwise
+        */
+       public static boolean download(String url, CompressionMethod compression, File destination)
+       {
+               try
+               {
+                       URL site = new URL(url);
+                       switch (compression)
+                       {
+                               case GZIP:
+                                       gzipDownload(site, destination);
+                                       break;
+                               case NONE:
+                                       noneDownload(site, destination);
+                                       break;
+                               default:
+                                       LOGGER.warn("Unknown compression method");
+                                       break;
+                       }
+               }
+               catch (IOException ex)
+               {
+                       LOGGER.error("Error while downloading file from url ["
+                                       + url.toString()
+                                       + "] to destination ["
+                                       + destination.toString()
+                                       + "] with compression ["
+                                       + compression.toString()
+                                       + "]", ex);
+                       return false;
+               }
+
+               return true;
+       }
+
+       private static void noneDownload(URL url, File destination) throws IOException
+       {
+               try (InputStream stream = url.openStream();
+                               FileOutputStream fos = new FileOutputStream(destination);
+                               ReadableByteChannel channel = Channels.newChannel(stream))
+               {
+                       fos.getChannel().transferFrom(channel, 0, Long.MAX_VALUE);
+               }
+       }
+
+       private static void gzipDownload(URL url, File destination) throws IOException
+       {
+               try (InputStream stream = url.openStream();
+                               GZIPInputStream gis = new GZIPInputStream(stream);
+                               FileOutputStream fos = new FileOutputStream(destination);
+                               ReadableByteChannel channel = Channels.newChannel(gis))
+               {
+                       fos.getChannel().transferFrom(channel, 0, Long.MAX_VALUE);
+               }
+       }
+}