Android: Allow to provide a different HttpClient implementation

lib/android_build/app/build.gradle

@@ -30,6 +30,10 @@ android {
             version "3.10.2"
         }
     }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
 }
 
 dependencies {

lib/android_build/maesdk/src/main/java/com/microsoft/applications/events/HttpClient.java

@@ -23,17 +23,20 @@
 import android.os.Build;
 import android.provider.Settings;
 import android.util.Log;
+
 import androidx.annotation.Keep;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
+
 import java.io.BufferedInputStream;
 import java.io.OutputStream;
 import java.net.HttpURLConnection;
 import java.net.URL;
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -86,16 +89,15 @@ public final void onCapabilitiesChanged(
   private boolean m_metered;
 }
 
-class Request implements Runnable {
+class Request implements HttpClientRequest {
 
   Request(
-      HttpClient parent,
-      String url,
-      String method,
-      byte[] body,
-      String request_id,
-      int[] header_length,
-      byte[] header_buffer)
+          @NonNull HttpClient parent,
+          String url,
+          String method,
+          byte[] body,
+          String request_id,
+          @NonNull Map<String, String> headers)
       throws java.io.IOException {
     m_parent = parent;
     m_connection = (HttpURLConnection) parent.newUrl(url).openConnection();
@@ -106,13 +108,8 @@ class Request implements Runnable {
       m_connection.setDoOutput(true);
     }
     m_request_id = request_id;
-    int offset = 0;
-    for (int i = 0; i + 1 < header_length.length; i += 2) {
-      String k = new String(header_buffer, offset, header_length[i], UTF_8);
-      offset += header_length[i];
-      String v = new String(header_buffer, offset, header_length[i + 1], UTF_8);
-      offset += header_length[i + 1];
-      m_connection.setRequestProperty(k, v);
+    for (Map.Entry<String, String> header : headers.entrySet()) {
+      m_connection.setRequestProperty(header.getKey(), header.getValue());
     }
   }
 
@@ -188,9 +185,25 @@ public class HttpClient {
   private static final String ANDROID_DEVICE_CLASS_PC = "Android.PC";
   private static final String ANDROID_DEVICE_CLASS_PHONE = "Android.Phone";
 
+  static Map<String, String> convertHeaders(
+          int[] header_length,
+          byte[] header_buffer
+  ) {
+    int offset = 0;
+    Map<String, String> result = new HashMap<>(header_length.length);
+    for (int i = 0; i + 1 < header_length.length; i += 2) {
+      String k = new String(header_buffer, offset, header_length[i], UTF_8);
+      offset += header_length[i];
+      String v = new String(header_buffer, offset, header_length[i + 1], UTF_8);
+      offset += header_length[i + 1];
+      result.put(k, v);
+    }
+    return result;
+  }
+
   /** Shim FutureTask: we would like to @Keep the cancel method for JNI */
   static class FutureShim extends FutureTask<Boolean> {
-    FutureShim(Request inner) {
+    FutureShim(HttpClientRequest inner) {
       super(inner, true);
     }
 
@@ -202,7 +215,12 @@ public boolean cancel(boolean mayInterruptIfRunning) {
   }
 
   public HttpClient(Context context) {
+    this(context, new HttpClientRequest.Factory.AndroidUrlConnection());
+  }
+
+  public HttpClient(Context context, HttpClientRequest.Factory requestFactory) {
     m_context = context;
+    m_requestFactory = requestFactory;
     String path = System.getProperty("java.io.tmpdir");
     setCacheFilePath(path);
     setDeviceInfo(calculateID(context), Build.MANUFACTURER, Build.MODEL);
@@ -376,7 +394,8 @@ public FutureTask<Boolean> createTask(
       int[] header_index,
       byte[] header_buffer) {
     try {
-      Request r = new Request(this, url, method, body, request_id, header_index, header_buffer);
+      Map<String, String> headers = HttpClient.convertHeaders(header_index, header_buffer);
+      HttpClientRequest r = m_requestFactory.create(this, url, method, body, request_id, headers);
       return new FutureShim(r);
     } catch (Exception e) {
       return null;
@@ -393,4 +412,5 @@ public void executeTask(FutureTask<Boolean> t) {
   private android.net.ConnectivityManager m_connectivityManager;
   private PowerInfoReceiver m_power_receiver;
   private final Context m_context;
-}
+  private final HttpClientRequest.Factory m_requestFactory;
+}

lib/android_build/maesdk/src/main/java/com/microsoft/applications/events/HttpClientRequest.java

@@ -0,0 +1,31 @@
+//
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+//
+package com.microsoft.applications.events;
+
+import androidx.annotation.NonNull;
+
+import java.io.IOException;
+import java.util.Map;
+
+public interface HttpClientRequest extends Runnable {
+
+    interface Factory {
+        HttpClientRequest create(
+                @NonNull HttpClient parent,
+                String url,
+                String method,
+                byte[] body,
+                String request_id,
+                @NonNull Map<String, String> headers
+        ) throws IOException;
+
+        class AndroidUrlConnection implements HttpClientRequest.Factory {
+            @Override
+            public HttpClientRequest create(@NonNull HttpClient parent, String url, String method, byte[] body, String request_id, @NonNull Map<String, String> headers) throws IOException {
+                return new Request(parent, url, method, body, request_id, headers);
+            }
+        }
+    }
+}