(#79) Draft for sending responses back to clients from the mock UnixServer

src/test/java/com/amihaiemil/docker/mock/Response.java

@@ -25,6 +25,11 @@
  */
 package com.amihaiemil.docker.mock;
 
+import com.sun.grizzly.util.Charsets;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.WritableByteChannel;
+import java.time.Instant;
 import java.util.Locale;
 import org.apache.http.Header;
 import org.apache.http.HeaderIterator;
@@ -37,6 +42,7 @@
 import org.apache.http.entity.StringEntity;
 import org.apache.http.message.BasicStatusLine;
 import org.apache.http.params.HttpParams;
+import org.apache.http.util.EntityUtils;
 
 /**
  * An {@link HttpResponse} suitable for tests. Can be configured with 
@@ -45,6 +51,9 @@
  * @author George Aristy (george.aristy@gmail.com)
  * @version $Id$
  * @since 0.0.1
+ * @todo 79:30min The 'asString()' method needs a little more work (fix the
+ *  formatting on the date header value, etc) and then test the 'printTo()'
+ *  method in conjunction with the UnixServer.
  */
 public final class Response implements HttpResponse {
     /**
@@ -207,4 +216,47 @@ public HttpParams getParams() {
     public void setParams(final HttpParams params) {
         throw new UnsupportedOperationException("Not supported yet.");
     }
+
+    /**
+     * Prints itself to the channel.
+     * @param channel The channel.
+     * @throws IOException If an error occurs.
+     */
+    public void printTo(final WritableByteChannel channel) throws IOException {
+        channel.write(
+            ByteBuffer.wrap(
+                this.asString().getBytes(Charsets.UTF8_CHARSET)
+            )
+        );
+    }
+
+    /**
+     * This response as a string.
+     * @return String representation of this {@link Response}.
+     * @throws IOException If an error occurs.
+     */
+    private String asString() throws IOException {
+        final String CRLF = "" + (char) 0x0D + (char) 0x0A;
+        final StringBuilder builder = new StringBuilder("HTTP/")
+            .append(this.statusLine.getProtocolVersion())
+            .append(" ")
+            .append(this.statusLine.getStatusCode())
+            .append(" ")
+            .append(this.statusLine.getReasonPhrase())
+            .append(CRLF)
+            .append("Date: ")
+            .append(Instant.now())
+            .append(CRLF);
+        if (this.payload.getContentLength() > 0) {
+            builder.append("ContentType: ")
+                .append(this.payload.getContentType().getValue())
+                .append(CRLF)
+                .append("Content-Length: ")
+                .append(this.payload.getContentLength())
+                .append(CRLF)
+                .append(CRLF)
+                .append(EntityUtils.toString(this.payload));
+        }
+        return builder.toString();
+    }
 }

src/test/java/com/amihaiemil/docker/mock/UnixServer.java

@@ -27,7 +27,6 @@
 
 import java.io.Closeable;
 import java.io.IOException;
-import java.nio.ByteBuffer;
 import java.nio.channels.SelectionKey;
 import java.nio.channels.Selector;
 import java.nio.file.Files;
@@ -69,9 +68,10 @@ public final class UnixServer implements Closeable {
      * Ctor.
      * <p>
      * Eagerly opens a unix file socket created in a temp directory.
+     * @param response The mock response to send back to the caller.
      * @throws IOException If an I/O error occurs.
      */
-    public UnixServer() throws IOException {
+    public UnixServer(final Response response) throws IOException {
         this.socketFile = Files.createTempFile("", "");
         this.channel = UnixServerSocketChannel.open();
         this.channel.configureBlocking(false);
@@ -81,7 +81,7 @@ public UnixServer() throws IOException {
         this.selector = NativeSelectorProvider.getInstance().openSelector();
         this.channel.register(this.selector, SelectionKey.OP_READ);
         this.threadPool = Executors.newSingleThreadExecutor();
-        this.threadPool.submit(new Service(this.selector));
+        this.threadPool.submit(new Service(this.selector, response));
     }
 
     /**
@@ -108,13 +108,19 @@ private static final class Service implements Callable<Void> {
          * Selector.
          */
         private final Selector selector;
+        /**
+         * Response to send back to caller.
+         */
+        private final Response response;
 
         /**
          * Ctor.
          * @param selector The selector to listen on.
+         * @param response The response to send back to the client.
          */
-        private Service(final Selector selector) {
+        private Service(final Selector selector, final Response response) {
             this.selector = selector;
+            this.response = response;
         }
 
         @Override
@@ -129,10 +135,7 @@ public Void call() throws IOException {
                     final UnixSocketChannel channel =
                         (UnixSocketChannel) key.channel();
                     channel.configureBlocking(false);
-                    // @todo #41:30min Make the response from this buffer
-                    //  configurable and then implement some tests.
-                    final ByteBuffer buffer = ByteBuffer.wrap("".getBytes());
-                    channel.write(buffer);
+                    this.response.printTo(channel);
                 }
             }
             return null;