Compact the REST-API output JSON unconditionally

The output JSON was initially compacted only when
the Accept header was set to 'application/json', from
the very initial Change-Id: I2014a2209.

The ability to get a pretty-printed JSON is still
available using the 'pp=1' query string, therefore
it is best to always compress the JSON output by
default.

Bug: Issue 13781
Change-Id: I2f1cb91e95e10b27b328764834d58d0799e01ed4
(cherry picked from commit 9c09efbc48038c3b03d5f388f95c845ae8b409c1)

2 files changed, 82 insertions, 17 deletions

diff --git a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
index 88c5106e67..a7c0e300fd 100644
--- a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
+++ b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
@@ -1071,7 +1071,7 @@ public class RestApiServlet extends HttpServlet {
     TemporaryBuffer.Heap buf = heap(HEAP_EST_SIZE, Integer.MAX_VALUE);
     buf.write(JSON_MAGIC);
     Writer w = new BufferedWriter(new OutputStreamWriter(buf, UTF_8));
-    Gson gson = newGson(config, req);
+    Gson gson = newGson(config);
     if (result instanceof JsonElement) {
       gson.toJson((JsonElement) result, w);
     } else {
@@ -1098,25 +1098,18 @@ public class RestApiServlet extends HttpServlet {
         req, res, asBinaryResult(buf).setContentType(JSON_TYPE).setCharacterEncoding(UTF_8));
   }
 
-  private static Gson newGson(
-      ListMultimap<String, String> config, @Nullable HttpServletRequest req) {
+  private static Gson newGson(ListMultimap<String, String> config) {
     GsonBuilder gb = OutputFormat.JSON_COMPACT.newGsonBuilder();
 
-    enablePrettyPrint(gb, config, req);
+    enablePrettyPrint(gb, config);
     enablePartialGetFields(gb, config);
 
     return gb.create();
   }
 
-  private static void enablePrettyPrint(
-      GsonBuilder gb, ListMultimap<String, String> config, @Nullable HttpServletRequest req) {
-    String pp = Iterables.getFirst(config.get("pp"), null);
-    if (pp == null) {
-      pp = Iterables.getFirst(config.get("prettyPrint"), null);
-      if (pp == null && req != null) {
-        pp = acceptsJson(req) ? "0" : "1";
-      }
-    }
+  private static void enablePrettyPrint(GsonBuilder gb, ListMultimap<String, String> config) {
+    String pp =
+        Iterables.getFirst(config.get("pp"), Iterables.getFirst(config.get("prettyPrint"), "0"));
     if ("1".equals(pp) || "true".equals(pp)) {
       gb.setPrettyPrinting();
     }
@@ -1573,10 +1566,6 @@ public class RestApiServlet extends HttpServlet {
     return CharMatcher.anyOf("<&").matchesAnyOf(text);
   }
 
-  private static boolean acceptsJson(HttpServletRequest req) {
-    return req != null && isType(JSON_TYPE, req.getHeader(HttpHeaders.ACCEPT));
-  }
-
   private static boolean acceptsGzip(HttpServletRequest req) {
     if (req != null) {
       String accepts = req.getHeader(HttpHeaders.ACCEPT_ENCODING);
diff --git a/javatests/com/google/gerrit/acceptance/rest/RestApiServletIT.java b/javatests/com/google/gerrit/acceptance/rest/RestApiServletIT.java
new file mode 100644
index 0000000000..bc454605ab
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/rest/RestApiServletIT.java
@@ -0,0 +1,76 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.acceptance.rest;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.apache.http.HttpStatus.SC_OK;
+
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.RestResponse;
+import com.google.gerrit.httpd.restapi.RestApiServlet;
+import java.io.IOException;
+import java.util.regex.Pattern;
+import org.apache.http.message.BasicHeader;
+import org.junit.Test;
+
+public class RestApiServletIT extends AbstractDaemonTest {
+  private static String ANY_REST_API = "/accounts/self/capabilities";
+  private static BasicHeader ACCEPT_STAR_HEADER = new BasicHeader("Accept", "*/*");
+  private static Pattern ANY_SPACE = Pattern.compile("\\s");
+
+  @Test
+  public void restResponseBodyShouldBeCompactWithoutSpaces() throws Exception {
+    RestResponse response = adminRestSession.getWithHeader(ANY_REST_API, ACCEPT_STAR_HEADER);
+    assertThat(response.getStatusCode()).isEqualTo(SC_OK);
+
+    assertThat(contentWithoutMagicJson(response)).doesNotContainMatch(ANY_SPACE);
+  }
+
+  @Test
+  public void restResponseBodyShouldBeCompactWithoutSpacesWhenPPIsZero() throws Exception {
+    assertThat(contentWithoutMagicJson(prettyJsonRestResponse("prettyPrint", 0)))
+        .doesNotContainMatch(ANY_SPACE);
+  }
+
+  @Test
+  public void restResponseBodyShouldBeCompactWithoutSpacesWhenPrerryPrintIsZero() throws Exception {
+    assertThat(contentWithoutMagicJson(prettyJsonRestResponse("pp", 0)))
+        .doesNotContainMatch(ANY_SPACE);
+  }
+
+  @Test
+  public void restResponseBodyShouldBePrettyfiedWhenPPIsOne() throws Exception {
+    assertThat(contentWithoutMagicJson(prettyJsonRestResponse("pp", 1))).containsMatch(ANY_SPACE);
+  }
+
+  @Test
+  public void restResponseBodyShouldBePrettyfiedWhenPrettyPrintIsOne() throws Exception {
+    assertThat(contentWithoutMagicJson(prettyJsonRestResponse("prettyPrint", 1)))
+        .containsMatch(ANY_SPACE);
+  }
+
+  private RestResponse prettyJsonRestResponse(String ppArgument, int ppValue) throws Exception {
+    RestResponse response =
+        adminRestSession.getWithHeader(
+            ANY_REST_API + "?" + ppArgument + "=" + ppValue, ACCEPT_STAR_HEADER);
+    assertThat(response.getStatusCode()).isEqualTo(SC_OK);
+
+    return response;
+  }
+
+  private String contentWithoutMagicJson(RestResponse response) throws IOException {
+    return response.getEntityContent().substring(RestApiServlet.JSON_MAGIC.length);
+  }
+}