adds gzip support for press module

app/controllers/press/Press.java

@@ -1,6 +1,7 @@
 package controllers.press;
 
 import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
@@ -9,8 +10,10 @@
 import org.joda.time.format.DateTimeFormat;
 import org.joda.time.format.DateTimeFormatter;
 
+import play.Logger;
 import play.exceptions.UnexpectedException;
 import play.mvc.Controller;
+import play.mvc.Http.Header;
 import press.CachingStrategy;
 import press.PluginConfig;
 import press.ScriptCompressedFileManager;
@@ -21,6 +24,7 @@
 import press.StyleRequestHandler;
 import press.io.CompressedFile;
 import press.io.FileIO;
+import press.io.Gzip;
 
 public class Press extends Controller {
     public static final DateTimeFormatter httpDateTimeFormatter = DateTimeFormat
@@ -80,6 +84,31 @@ private static void renderCompressedFile(CompressedFile compressedFile, String t
             }
         }
 
+        /*
+         * google wants this: "Instructs proxy servers to cache two versions
+         * of the resource: one compressed, and one uncompressed. This helps
+         * avoid issues with public proxies that do not detect the presence
+         * of a Content-Encoding header properly."
+         */
+        response.headers.put("Vary", new Header("Vary", "Accept-Encoding"));
+
+        // attempt gzip if the client requests it.
+        //
+        Header encodings = request.headers.get("accept-encoding");
+
+        if (PluginConfig.gzipEnabled &&
+                (encodings != null) &&
+                (encodings.value().indexOf("gzip") != -1)) {
+            try {
+                ByteArrayOutputStream gzip = Gzip.gzip(inputStream);
+                response.setHeader("Content-Encoding", "gzip");
+                response.setHeader("Content-Length", gzip.size() + "");
+                renderBinary(new ByteArrayInputStream(gzip.toByteArray()), compressedFile.name());
+            } catch (IOException e) {
+                Logger.error(e, "Unable to compress output: %s", e.getMessage());
+            }
+        }
+
         renderBinary(inputStream, compressedFile.name());
     }
 

app/press/PluginConfig.java

@@ -48,6 +48,9 @@ public static class DefaultConfig {
         // compiled, they will be output raw.
         public static final boolean outputRawLess = false;
 
+        // If enabled, turns on gzip when the client supports it
+        public static final boolean gzipEnabled = false;
+
         public static class js {
             // The directory where source javascript files are read from
             public static final String srcDir = "/public/javascripts/";
@@ -85,6 +88,7 @@ public static class css {
     public static String contentHostingDomain;
     public static String p3pHeader;
     public static boolean outputRawLess;
+    public static boolean gzipEnabled;
 
     public static class js {
         public static String srcDir = DefaultConfig.js.srcDir;
@@ -134,6 +138,7 @@ public static void readConfig() {
                 DefaultConfig.contentHostingDomain);
         p3pHeader = ConfigHelper.getString("press.p3pHeader", DefaultConfig.p3pHeader);
         outputRawLess = ConfigHelper.getBoolean("press.outputRawLess", DefaultConfig.outputRawLess);
+        gzipEnabled = ConfigHelper.getBoolean("press.gzipEnabled", DefaultConfig.gzipEnabled);
 
         css.srcDir = ConfigHelper.getString("press.css.sourceDir", DefaultConfig.css.srcDir);
         css.compressedDir = ConfigHelper.getString("press.css.outputDir",

app/press/io/Gzip.java

@@ -0,0 +1,36 @@
+package press.io;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import java.util.zip.GZIPOutputStream;
+
+public class Gzip {
+
+    public static ByteArrayOutputStream gzip(final InputStream inputStream)
+        throws IOException
+    {
+        final ByteArrayOutputStream stringOutputStream = new ByteArrayOutputStream();
+        final OutputStream gzipOutputStream = new GZIPOutputStream(stringOutputStream);
+
+        final byte[] buf = new byte[5000];
+        int len;
+        while ((len = inputStream.read(buf)) > 0) {
+            gzipOutputStream.write(buf, 0, len);
+        }
+
+        inputStream.close();
+        gzipOutputStream.close();
+
+        return stringOutputStream;
+
+    }
+
+    public static ByteArrayOutputStream gzip(final String input)
+            throws IOException {
+        return gzip(new ByteArrayInputStream(input.getBytes()));
+    }
+}