[ECR-2906] LC: Implemented System API endpoints support

exonum-light-client/pom.xml

@@ -76,7 +76,7 @@
     <junit.jupiter.version>5.4.0</junit.jupiter.version>
     <mockito.version>2.24.0</mockito.version>
     <hamcrest.version>2.0.0.0</hamcrest.version>
-
+    <jsonpath.version>2.4.0</jsonpath.version>
     <!--Plugins-->
     <!-- Checkstyle -->
     <checkstyle.severity>warning</checkstyle.severity>
@@ -121,6 +121,12 @@
       <scope>test</scope>
     </dependency>
 
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-params</artifactId>
+      <scope>test</scope>
+    </dependency>
+
     <dependency>
       <groupId>org.mockito</groupId>
       <artifactId>mockito-junit-jupiter</artifactId>
@@ -142,6 +148,13 @@
       <scope>test</scope>
     </dependency>
 
+    <dependency>
+      <groupId>com.jayway.jsonpath</groupId>
+      <artifactId>json-path-assert</artifactId>
+      <version>${jsonpath.version}</version>
+      <scope>test</scope>
+    </dependency>
+
   </dependencies>
 
   <dependencyManagement>

exonum-light-client/src/main/java/com/exonum/client/ExonumClient.java

@@ -21,13 +21,17 @@
 
 import com.exonum.binding.common.hash.HashCode;
 import com.exonum.binding.common.message.TransactionMessage;
+import com.exonum.client.response.HealthCheckInfo;
 import java.net.MalformedURLException;
 import java.net.URL;
 import okhttp3.OkHttpClient;
 
 /**
  * Main interface for Exonum Light client.
  * Provides a convenient way for interaction with Exonum framework APIs.
+ * All the methods of the interface work in a blocking way
+ * i.e. invoke underlying request immediately, and block until the response can be processed
+ * or an error occurs.
  * <p/><i>Implementations of that interface are required to be thread-safe</i>.
  **/
 public interface ExonumClient {
@@ -40,6 +44,28 @@ public interface ExonumClient {
    */
   HashCode submitTransaction(TransactionMessage tx);
 
+  /**
+   * Returns a number of unconfirmed transactions which are currently located in
+   * the unconfirmed transactions pool and are waiting for acceptance to a block.
+   * @throws RuntimeException if the client is unable to complete a request
+   *        (e.g., in case of connectivity problems)
+   */
+  int getUnconfirmedTransactionsCount();
+
+  /**
+   * Returns the node health check information.
+   * @throws RuntimeException if the client is unable to complete a request
+   *        (e.g., in case of connectivity problems)
+   */
+  HealthCheckInfo healthCheck();
+
+  /**
+   * Returns string containing information about Exonum, Rust and OS version.
+   * @throws RuntimeException if the client is unable to complete a request
+   *        (e.g., in case of connectivity problems)
+   */
+  String getUserAgentInfo();
+
   /**
    * Returns Exonum client builder.
    */

exonum-light-client/src/main/java/com/exonum/client/ExonumHttpClient.java

@@ -17,16 +17,20 @@
 
 package com.exonum.client;
 
-import static com.exonum.binding.common.serialization.json.JsonSerializer.json;
+import static com.exonum.client.ExonumUrls.HEALTH_CHECK;
+import static com.exonum.client.ExonumUrls.MEMORY_POOL;
 import static com.exonum.client.ExonumUrls.SUBMIT_TRANSACTION;
+import static com.exonum.client.ExonumUrls.USER_AGENT;
 
 import com.exonum.binding.common.hash.HashCode;
 import com.exonum.binding.common.message.TransactionMessage;
+import com.exonum.client.response.HealthCheckInfo;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.io.BaseEncoding;
 import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.util.function.Function;
 import okhttp3.MediaType;
 import okhttp3.OkHttpClient;
 import okhttp3.Request;
@@ -53,20 +57,45 @@ class ExonumHttpClient implements ExonumClient {
   @Override
   public HashCode submitTransaction(TransactionMessage transactionMessage) {
     String msg = toHex(transactionMessage.toBytes());
+    Request request = postRequest(toFullUrl(SUBMIT_TRANSACTION),
+        ExplorerApiHelper.createSubmitTxBody(msg));
 
-    Request request = createRequest(toFullUrl(SUBMIT_TRANSACTION), new SubmitTxRequest(msg));
-    SubmitTxResponse result = blockingExecuteWithResponse(request, SubmitTxResponse.class);
+    return blockingExecuteAndParse(request, ExplorerApiHelper::parseSubmitTxResponse);
+  }
+
+  @Override
+  public int getUnconfirmedTransactionsCount() {
+    Request request = getRequest(toFullUrl(MEMORY_POOL));
+
+    return blockingExecuteAndParse(request, SystemApiHelper::parseMemoryPoolJson);
+  }
+
+  @Override
+  public HealthCheckInfo healthCheck() {
+    Request request = getRequest(toFullUrl(HEALTH_CHECK));
+
+    return blockingExecuteAndParse(request, SystemApiHelper::parseHealthCheckJson);
+  }
 
-    return result.getHash();
+  @Override
+  public String getUserAgentInfo() {
+    Request request = getRequest(toFullUrl(USER_AGENT));
+
+    return blockingExecutePlainText(request);
   }
 
   private static String toHex(byte[] array) {
     return HEX_ENCODER.encode(array);
   }
 
-  private static Request createRequest(URL url, Object requestBody) {
-    String jsonBody = json().toJson(requestBody);
+  private static Request getRequest(URL url) {
+    return new Request.Builder()
+        .url(url)
+        .get()
+        .build();
+  }
 
+  private static Request postRequest(URL url, String jsonBody) {
     return new Request.Builder()
         .url(url)
         .post(RequestBody.create(MEDIA_TYPE_JSON, jsonBody))
@@ -81,17 +110,20 @@ private URL toFullUrl(String relativeUrl) {
     }
   }
 
-  private <T> T blockingExecuteWithResponse(Request request, Class<T> responseObject) {
+  private String blockingExecutePlainText(Request request) {
     try (Response response = httpClient.newCall(request).execute()) {
       if (!response.isSuccessful()) {
         throw new RuntimeException("Execution wasn't success: " + response.toString());
       }
-      String responseJson = response.body().string();
-
-      return json().fromJson(responseJson, responseObject);
+      return response.body().string();
     } catch (IOException e) {
       throw new RuntimeException(e);
     }
   }
 
+  private <T> T blockingExecuteAndParse(Request request, Function<String, T> parser) {
+    String response = blockingExecutePlainText(request);
+    return parser.apply(response);
+  }
+
 }

exonum-light-client/src/main/java/com/exonum/client/ExonumUrls.java

@@ -21,5 +21,11 @@
  * Contains Exonum API URLs.
  */
 final class ExonumUrls {
-  static final String SUBMIT_TRANSACTION = "/api/explorer/v1/transactions";
+  private static final String EXPLORER_PATHS_PREFIX = "/api/explorer/v1";
+  private static final String SYS_PATHS_PREFIX = "/api/system/v1";
+  static final String SUBMIT_TRANSACTION = EXPLORER_PATHS_PREFIX + "/transactions";
+  static final String MEMORY_POOL = SYS_PATHS_PREFIX + "/mempool";
+  static final String HEALTH_CHECK = SYS_PATHS_PREFIX + "/healthcheck";
+  static final String USER_AGENT = SYS_PATHS_PREFIX + "/user_agent";
+
 }

exonum-light-client/src/main/java/com/exonum/client/ExplorerApiHelper.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2019 The Exonum Team
+ *
+ * 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.exonum.client;
+
+import static com.exonum.binding.common.serialization.json.JsonSerializer.json;
+
+import com.exonum.binding.common.hash.HashCode;
+import com.google.common.annotations.VisibleForTesting;
+import com.google.gson.annotations.SerializedName;
+import lombok.Value;
+
+/**
+ * Utility class for Exonum Explorer API.
+ */
+final class ExplorerApiHelper {
+
+  static String createSubmitTxBody(String message) {
+    SubmitTxRequest request = new SubmitTxRequest(message);
+    return json().toJson(request);
+  }
+
+  static HashCode parseSubmitTxResponse(String json) {
+    SubmitTxResponse response = json().fromJson(json, SubmitTxResponse.class);
+    return response.getHash();
+  }
+
+  /**
+   * Json object wrapper for submit transaction request.
+   */
+  @Value
+  @VisibleForTesting
+  static class SubmitTxRequest {
+    @SerializedName("tx_body")
+    String body;
+  }
+
+  /**
+   * Json object wrapper for submit transaction response.
+   */
+  @Value
+  private static class SubmitTxResponse {
+    @SerializedName("tx_hash")
+    HashCode hash;
+  }
+
+  private ExplorerApiHelper() {
+    throw new UnsupportedOperationException("Not instantiable");
+  }
+}

exonum-light-client/src/main/java/com/exonum/client/SystemApiHelper.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2019 The Exonum Team
+ *
+ * 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.exonum.client;
+
+import static com.exonum.binding.common.serialization.json.JsonSerializer.json;
+
+import com.exonum.client.response.ConsensusStatus;
+import com.exonum.client.response.HealthCheckInfo;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.annotations.SerializedName;
+import lombok.Value;
+
+/**
+ * Utility class for Exonum System API.
+ */
+final class SystemApiHelper {
+
+  static HealthCheckInfo parseHealthCheckJson(String json) {
+    // TODO: ECR-2925 (core dependency) change after the response format update
+    HealthCheckResponse response = json().fromJson(json, HealthCheckResponse.class);
+    String consensusStatus = response.getConsensusStatus().toUpperCase();
+    JsonElement connectivity = response.getConnectivity();
+    if (connectivity.isJsonObject()) {
+      JsonObject connectivityObject = connectivity.getAsJsonObject();
+      int connectionsNumber = connectivityObject
+          .get("Connected").getAsJsonObject()
+          .get("amount").getAsInt();
+      return new HealthCheckInfo(ConsensusStatus.valueOf(consensusStatus), connectionsNumber);
+    } else {
+      return new HealthCheckInfo(ConsensusStatus.valueOf(consensusStatus), 0);
+    }
+  }
+
+  static int parseMemoryPoolJson(String json) {
+    MemoryPoolResponse response = json().fromJson(json, MemoryPoolResponse.class);
+    return response.getSize();
+  }
+
+  /**
+   * Json object wrapper for memory pool response.
+   */
+  @Value
+  private static class MemoryPoolResponse {
+    int size;
+  }
+
+  /**
+   * Json object wrapper for health check response.
+   */
+  @Value
+  private class HealthCheckResponse {
+    @SerializedName("consensus_status")
+    String consensusStatus;
+    JsonElement connectivity;
+  }
+
+  private SystemApiHelper() {
+    throw new UnsupportedOperationException("Not instantiable");
+  }
+}

exonum-light-client/src/main/java/com/exonum/client/SubmitTxRequest.java → exonum-light-client/src/main/java/com/exonum/client/response/ConsensusStatus.java

@@ -15,16 +15,23 @@
  *
  */
 
-package com.exonum.client;
-
-import com.google.gson.annotations.SerializedName;
-import lombok.Value;
+package com.exonum.client.response;
 
 /**
- * Json object wrapper for submit transaction request.
+ * Consensus status of a particular node.
  */
-@Value
-class SubmitTxRequest {
-  @SerializedName("tx_body")
-  String body;
+public enum ConsensusStatus {
+  /**
+   * Shows that consensus is active
+   * i.e. it is enabled and the node has enough connected peers.
+   */
+  ACTIVE,
+  /**
+   * Shows that consensus is enabled on the node.
+   */
+  ENABLED,
+  /**
+   * Shows that consensus is disabled on the node.
+   */
+  DISABLED
 }