Add gzip and deflate endpoints

Author: gaul

README.md

@@ -34,6 +34,8 @@ Java httpbin supports a subset of httpbin endpoints:
   an optional initial _delay_, then optionally returns with the given status _code_.
 - `/cache` Returns 200 unless an If-Modified-Since or If-None-Match header is provided, when it returns a 304.
 - `/cache/:n` Sets a Cache-Control header for _n_ seconds.
+- `/gzip` Returns gzip-encoded data.
+- `/deflate` Returns deflate-encoded data.
 - `/robots.txt` Returns some robots.txt rules.
 - `/deny` Denied by robots.txt file.
 - `/basic-auth/:user/:passwd` Challenges HTTP Basic Auth.

src/main/java/org/gaul/httpbin/HttpBinHandler.java

@@ -28,6 +28,9 @@
 import java.util.Map;
 import java.util.Random;
 import java.util.concurrent.TimeUnit;
+import java.util.zip.Deflater;
+import java.util.zip.DeflaterOutputStream;
+import java.util.zip.GZIPOutputStream;
 
 import javax.servlet.ServletException;
 import javax.servlet.http.Cookie;
@@ -125,6 +128,62 @@ private void handleHelper(Request baseRequest, HttpServletRequest request,
                 respondJSON(servletResponse, os, response);
                 baseRequest.setHandled(true);
                 return;
+            } else if (method.equals("GET") && uri.equals("/gzip")) {
+                Utils.copy(is, Utils.NULL_OUTPUT_STREAM);
+
+                JSONObject response = new JSONObject();
+                response.put("args", mapParametersToJSON(request));
+                response.put("headers", mapHeadersToJSON(request));
+                response.put("origin", request.getRemoteAddr());
+                response.put("url", getFullURL(request));
+                response.put("gzipped", true);
+
+                byte[] uncompressed = response.toString(/*indent=*/ 2).getBytes(
+                        StandardCharsets.UTF_8);
+                ByteArrayOutputStream baos = new ByteArrayOutputStream(
+                        uncompressed.length);
+                try (GZIPOutputStream gzipos = new GZIPOutputStream(baos)) {
+                    gzipos.write(uncompressed);
+                }
+                byte[] compressed = baos.toByteArray();
+
+                servletResponse.setContentLength(compressed.length);
+                servletResponse.setHeader("Content-Encoding", "gzip");
+                servletResponse.setContentType("application/json");
+                servletResponse.setStatus(HttpServletResponse.SC_OK);
+                os.write(compressed);
+                os.flush();
+                baseRequest.setHandled(true);
+                return;
+            } else if (method.equals("GET") && uri.equals("/deflate")) {
+                Utils.copy(is, Utils.NULL_OUTPUT_STREAM);
+
+                JSONObject response = new JSONObject();
+                response.put("args", mapParametersToJSON(request));
+                response.put("headers", mapHeadersToJSON(request));
+                response.put("origin", request.getRemoteAddr());
+                response.put("url", getFullURL(request));
+                response.put("deflated", true);
+
+                byte[] uncompressed = response.toString(/*indent=*/ 2).getBytes(
+                        StandardCharsets.UTF_8);
+                ByteArrayOutputStream baos = new ByteArrayOutputStream(
+                        uncompressed.length);
+                try (DeflaterOutputStream dos = new DeflaterOutputStream(
+                        baos, new Deflater(Deflater.DEFAULT_COMPRESSION,
+                                /*nowrap=*/ true))) {
+                    dos.write(uncompressed);
+                }
+                byte[] compressed = baos.toByteArray();
+
+                servletResponse.setContentLength(compressed.length);
+                servletResponse.setHeader("Content-Encoding", "deflate");
+                servletResponse.setContentType("application/json");
+                servletResponse.setStatus(HttpServletResponse.SC_OK);
+                os.write(compressed);
+                os.flush();
+                baseRequest.setHandled(true);
+                return;
             } else if (method.equals("GET") && uri.equals("/cache")) {
                 Utils.copy(is, Utils.NULL_OUTPUT_STREAM);