Adds basic wallet funder

src/main/java/org/web3j/console/WalletFunder.java

@@ -0,0 +1,132 @@
+/*
+ * Copyright 2019 Web3 Labs LTD.
+ *
+ * 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 org.web3j.console;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import okhttp3.MultipartBody;
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.RequestBody;
+import org.web3j.utils.Numeric;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.stream.IntStream;
+
+import static org.web3j.codegen.Console.exitError;
+import static org.web3j.crypto.Hash.sha256;
+
+/**
+ * Simple class for creating a wallet file.
+ */
+public class WalletFunder {
+
+    private static final String BASE_URL = "http://localhost:8000";
+    private static final String USAGE = "fund <destination-address>";
+
+    public static void main(String[] args) {
+        if (args.length != 1 && args.length != 3) {
+            exitError(USAGE);
+        }
+
+        try {
+            String transactionHash = fundWallet(args[0]);
+            System.out.println(
+                    String.format(
+                            "Your Rinkeby wallet was successfully funded. You can view the associated transaction here: https://rinkeby.explorer.epirus.web3labs.com/transactions/%s",
+                            transactionHash));
+        } catch (Exception e) {
+            System.err.println("The fund operation failed with the following exception:");
+            e.printStackTrace();
+            System.exit(-1);
+        }
+    }
+
+    private static boolean loading = true;
+
+    private static synchronized void loading(String msg) {
+        Thread th = new Thread(() -> {
+            String anim= "|/―\\";
+            try {
+                System.out.write("\r|".getBytes());
+                int current = 0;
+                while(loading) {
+                    current++;
+                    String data = "\r" + "[ " + anim.charAt(current % anim.length()) + " ] " + msg;
+                    System.out.write(data.getBytes());
+                    Thread.sleep(500);
+                }
+                System.out.write("\n".getBytes());
+            } catch (IOException | InterruptedException e) {
+                e.printStackTrace();
+            }
+        });
+        th.start();
+    }
+
+    private static String fundWallet(String walletAddress) throws Exception {
+        OkHttpClient client = new OkHttpClient();
+        ObjectMapper mapper = new ObjectMapper();
+
+        System.out.println("Sending funding request...");
+        Request getSeedRequest =
+                new okhttp3.Request.Builder().url(BASE_URL + "/seed/0.2").get().build();
+
+        String configResponse = client.newCall(getSeedRequest).execute().body().string();
+
+        WalletFunderConfig config = mapper.readValue(configResponse, WalletFunderConfig.class);
+
+        AtomicBoolean found = new AtomicBoolean(false);
+        AtomicInteger intResult = new AtomicInteger(0);
+        loading("Performing proof of work to validate your request");
+
+        IntStream.range(0, Integer.MAX_VALUE).parallel().forEach(i -> {
+            if (found.get()) return;
+            String potentialHash = Numeric.toHexString(sha256((i + config.seed).getBytes(StandardCharsets.UTF_8))).substring(2);
+            if (potentialHash.startsWith("0".repeat(config.difficulty))) {
+                found.set(true);
+                intResult.set(i);
+            }
+        });
+
+        loading = false;
+        RequestBody fundingBody = new MultipartBody.Builder()
+                .setType(MultipartBody.FORM)
+                .addFormDataPart("address", walletAddress)
+                .addFormDataPart("seed", config.seed)
+                .addFormDataPart("nonce", String.valueOf(intResult.get()))
+                .build();
+
+        Request sendEtherRequest = new okhttp3.Request.Builder().url(BASE_URL + "/send").post(fundingBody).build();
+
+        String sendResponse = client.newCall(sendEtherRequest).execute().body().string();
+
+        WalletFunderResult result = mapper.readValue(sendResponse, WalletFunderResult.class);
+
+        return result.result;
+    }
+
+}
+
+
+class WalletFunderConfig {
+    public int difficulty;
+    public String seed;
+}
+
+class WalletFunderResult {
+    public String result;
+}

src/main/java/org/web3j/console/WalletFunderConfig.java

@@ -0,0 +1,2 @@
+package org.web3j.console;
+

src/main/java/org/web3j/console/WalletRunner.java

@@ -18,13 +18,14 @@
 
 /** Class for managing our wallet command line utilities. */
 public class WalletRunner {
-    private static final String USAGE = "wallet create|update|send|fromkey";
+    private static final String USAGE = "wallet create|update|send|fromkey|fund";
 
     public static void run(String[] args) {
         main(args);
     }
 
     public static void main(String[] args) {
+
         if (args.length < 1) {
             Console.exitError(USAGE);
         } else {
@@ -41,6 +42,9 @@ public static void main(String[] args) {
                 case "fromkey":
                     KeyImporter.main(tail(args));
                     break;
+                case "fund":
+                    WalletFunder.main(tail(args));
+                    break;
                 default:
                     Console.exitError(USAGE);
             }