add support for http proxy

src/main/java/org/web3j/spring/autoconfigure/Web3jAutoConfiguration.java

@@ -19,6 +19,11 @@
 import org.web3j.protocol.ipc.WindowsIpcService;
 import org.web3j.spring.actuate.Web3jHealthIndicator;
 
+import java.net.InetSocketAddress;
+import java.net.MalformedURLException;
+import java.net.Proxy;
+import java.net.URL;
+import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
 import okhttp3.OkHttpClient;
@@ -72,6 +77,7 @@ private Web3jService buildService(String clientAddress) {
 
     private OkHttpClient createOkHttpClient() {
         OkHttpClient.Builder builder = new OkHttpClient.Builder();
+        configureProxy(builder);
         configureLogging(builder);
         configureTimeouts(builder);
         return builder.build();
@@ -86,6 +92,17 @@ private void configureTimeouts(OkHttpClient.Builder builder) {
         }
     }
 
+    private void configureProxy(OkHttpClient.Builder builder) {
+        if (properties.getProxyUrl() != null) {
+            try {
+                URL proxyUrl = new URL(properties.getProxyUrl());
+                Proxy proxy = new Proxy(Objects.equals(proxyUrl.getProtocol(), "http") ? Proxy.Type.HTTP : Proxy.Type.SOCKS, new InetSocketAddress(proxyUrl.getHost(), proxyUrl.getPort()));
+                builder.proxy(proxy);
+            } catch (MalformedURLException ignored) {
+            }
+        }
+    }
+
     private static void configureLogging(OkHttpClient.Builder builder) {
         if (log.isDebugEnabled()) {
             HttpLoggingInterceptor logging = new HttpLoggingInterceptor(log::debug);

src/main/java/org/web3j/spring/autoconfigure/Web3jProperties.java

@@ -20,6 +20,9 @@ public class Web3jProperties {
 
     private Long httpTimeoutSeconds;
 
+
+    private String proxyUrl;
+
     public String getClientAddress() {
         return clientAddress;
     }
@@ -51,5 +54,12 @@ public Long getHttpTimeoutSeconds() {
     public void setHttpTimeoutSeconds(Long httpTimeoutSeconds) {
         this.httpTimeoutSeconds = httpTimeoutSeconds;
     }
+
+    public String getProxyUrl() { return proxyUrl; }
+
+    public void setProxyUrl(String proxyUrl) {
+        this.proxyUrl = proxyUrl;
+    }
+
 
 }

src/test/java/org/web3j/spring/autoconfigure/Web3jAutoConfigurationTest.java

@@ -50,6 +50,13 @@ public void testHttpClient() throws Exception {
                 "https://localhost:12345", HttpService.class);
     }
 
+    @Test
+    public void testHttpProxy() throws Exception {
+        verifyHttpProxyConnection(
+                "https://localhost:12345", "http://proxy.fakecompany.com:8080", HttpService.class);
+    }
+
+
     @Test
     public void testUnixIpcClient() throws IOException {
         Path path = Files.createTempFile("unix", "ipc");
@@ -129,6 +136,30 @@ private void verifyHttpConnection(
         assertThat(url, equalTo(expectedClientAddress));
     }
 
+    private void verifyHttpProxyConnection(
+            String clientAddress, String proxyUrl, Class<? extends Service> cls) throws Exception {
+        verifyHttpProxyConnection(clientAddress, clientAddress, proxyUrl, cls);
+    }
+
+    private void verifyHttpProxyConnection(
+            String clientAddress, String expectedClientAddress, String proxyUrl, Class<? extends Service> cls)
+            throws Exception {
+        load(EmptyConfiguration.class, "web3j.client-address=" + clientAddress, "web3j.proxy-url=http://proxy.fakecompany.com:8080");
+        Web3j web3j = this.context.getBean(Web3j.class);
+
+        Field web3jServiceField = JsonRpc2_0Web3j.class.getDeclaredField("web3jService");
+        web3jServiceField.setAccessible(true);
+        Web3jService web3jService = (Web3jService) web3jServiceField.get(web3j);
+
+        assertTrue(cls.isInstance(web3jService));
+
+        Field urlField = HttpService.class.getDeclaredField("url");
+        urlField.setAccessible(true);
+        String url = (String) urlField.get(web3jService);
+
+        assertThat(url, equalTo(expectedClientAddress));
+    }
+
     @Configuration
     static class EmptyConfiguration {
     }