endpoint root path will redirect to /graphql (#283)

When users hit GraphQL url http://url:port/ they will be redirected to http://url:port/graphql.

Signed-off-by: Anthony Buckle <anthonybuckle@gmail.com>

ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/graphql/GraphQLHttpService.java

@@ -68,6 +68,7 @@ public class GraphQLHttpService {
 
   private static final InetSocketAddress EMPTY_SOCKET_ADDRESS = new InetSocketAddress("0.0.0.0", 0);
   private static final String APPLICATION_JSON = "application/json";
+  private static final String GRAPH_QL_ROUTE = "/graphql";
   private static final MediaType MEDIA_TYPE_JUST_JSON = MediaType.JSON_UTF_8.withoutParameters();
   private static final String EMPTY_RESPONSE = "";
 
@@ -140,9 +141,9 @@ public class GraphQLHttpService {
             BodyHandler.create()
                 .setUploadsDirectory(dataDir.resolve("uploads").toString())
                 .setDeleteUploadedFilesOnEnd(true));
-    router.route("/").method(GET).handler(this::handleEmptyRequest);
+    router.route("/").method(GET).method(POST).handler(this::handleEmptyRequestAndRedirect);
     router
-        .route("/graphql")
+        .route(GRAPH_QL_ROUTE)
         .method(GET)
         .method(POST)
         .produces(APPLICATION_JSON)
@@ -243,9 +244,12 @@ public class GraphQLHttpService {
     return NetworkUtility.urlForSocketAddress("http", socketAddress());
   }
 
-  // Facilitate remote health-checks in AWS, inter alia.
-  private void handleEmptyRequest(final RoutingContext routingContext) {
-    routingContext.response().setStatusCode(201).end();
+  // Empty Get/Post requests to / will be redirected to /graphql using 308 Permanent Redirect
+  private void handleEmptyRequestAndRedirect(final RoutingContext routingContext) {
+    HttpServerResponse response = routingContext.response();
+    response.setStatusCode(HttpResponseStatus.PERMANENT_REDIRECT.code());
+    response.putHeader("Location", "/graphql");
+    response.end();
   }
 
   private void handleGraphQLRequest(final RoutingContext routingContext) {
@@ -257,7 +261,12 @@ public class GraphQLHttpService {
 
       switch (request.method()) {
         case GET:
-          query = request.getParam("query");
+          final String queryString = request.getParam("query");
+          if (queryString == null) {
+            query = "";
+          } else {
+            query = queryString;
+          }
           operationName = request.getParam("operationName");
           final String variableString = request.getParam("variables");
           if (variableString != null) {
@@ -272,7 +281,12 @@ public class GraphQLHttpService {
             final String requestBody = routingContext.getBodyAsString().trim();
             final GraphQLJsonRequest jsonRequest =
                 Json.decodeValue(requestBody, GraphQLJsonRequest.class);
-            query = jsonRequest.getQuery();
+            final String jsonQuery = jsonRequest.getQuery();
+            if (jsonQuery == null) {
+              query = "";
+            } else {
+              query = jsonQuery;
+            }
             operationName = jsonRequest.getOperationName();
             Map<String, Object> jsonVariables = jsonRequest.getVariables();
             if (jsonVariables != null) {
@@ -282,7 +296,12 @@ public class GraphQLHttpService {
             }
           } else {
             // treat all else as application/graphql
-            query = routingContext.getBodyAsString().trim();
+            final String requestQuery = routingContext.getBodyAsString().trim();
+            if (requestQuery == null) {
+              query = "";
+            } else {
+              query = requestQuery;
+            }
             operationName = null;
             variables = Collections.emptyMap();
           }

ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/graphql/GraphQLHttpServiceCorsTest.java

@@ -140,7 +140,10 @@ public class GraphQLHttpServiceCorsTest {
   public void requestWithNoOriginShouldSucceedWhenCorsIsSet() throws Exception {
     graphQLHttpService = createGraphQLHttpServiceWithAllowedDomains("http://foo.io");
 
-    final Request request = new Request.Builder().url(graphQLHttpService.url()).build();
+    final Request request =
+        new Request.Builder()
+            .url(graphQLHttpService.url() + "/graphql?query={protocolVersion}")
+            .build();
 
     try (final Response response = client.newCall(request).execute()) {
       Assertions.assertThat(response.isSuccessful()).isTrue();

ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/graphql/GraphQLHttpServiceTest.java

@@ -36,8 +36,10 @@ import java.util.Optional;
 import java.util.Set;
 
 import graphql.GraphQL;
+import io.netty.handler.codec.http.HttpResponseStatus;
 import io.vertx.core.Vertx;
 import io.vertx.core.json.JsonObject;
+import okhttp3.HttpUrl;
 import okhttp3.MediaType;
 import okhttp3.OkHttpClient;
 import okhttp3.Request;
@@ -153,10 +155,26 @@ public class GraphQLHttpServiceTest {
   }
 
   @Test
-  public void handleEmptyRequest() throws Exception {
+  public void handleEmptyRequestAndRedirect() throws Exception {
     try (final Response resp =
         client.newCall(new Request.Builder().get().url(service.url()).build()).execute()) {
-      Assertions.assertThat(resp.code()).isEqualTo(201);
+      Assertions.assertThat(resp.code()).isEqualTo(HttpResponseStatus.BAD_REQUEST.code());
+    }
+    final RequestBody body = RequestBody.create(null, "");
+    try (final Response resp =
+        client.newCall(new Request.Builder().post(body).url(service.url()).build()).execute()) {
+      Assertions.assertThat(resp.code()).isEqualTo(HttpResponseStatus.PERMANENT_REDIRECT.code());
+      String location = resp.header("Location");
+      Assertions.assertThat(location).isNotEmpty().isNotNull();
+      HttpUrl redirectUrl = resp.request().url().resolve(location);
+      Assertions.assertThat(redirectUrl).isNotNull();
+      Request.Builder redirectBuilder = resp.request().newBuilder();
+      redirectBuilder.post(resp.request().body());
+      resp.body().close();
+      try (final Response redirectResp =
+          client.newCall(redirectBuilder.url(redirectUrl).build()).execute()) {
+        Assertions.assertThat(redirectResp.code()).isEqualTo(HttpResponseStatus.BAD_REQUEST.code());
+      }
     }
   }