Add RequestPreprocessor

Author: anfanik

library/src/main/java/com/pengrad/telegrambot/RequestPreprocessor.kt

@@ -0,0 +1,17 @@
+package com.pengrad.telegrambot
+
+import com.pengrad.telegrambot.request.BaseRequest
+import com.pengrad.telegrambot.response.BaseResponse
+
+@get:JvmName("getEmptyRequestPreprocessor")
+val EMPTY_REQUEST_PREPROCESSOR: RequestPreprocessor = object : RequestPreprocessor {
+    override fun <REQ : BaseRequest<REQ, RES>, RES : BaseResponse> process(request: BaseRequest<REQ, RES>) {
+        // do nothing
+    }
+}
+
+interface RequestPreprocessor {
+
+    fun <REQ : BaseRequest<REQ, RES>, RES : BaseResponse> process(request: BaseRequest<REQ, RES>)
+
+}

library/src/main/java/com/pengrad/telegrambot/TelegramBot.java

@@ -20,6 +20,8 @@
 import java.net.URLConnection;
 import java.util.concurrent.TimeUnit;
 
+import static com.pengrad.telegrambot.RequestPreprocessorKt.getEmptyRequestPreprocessor;
+
 /**
  * Stas Parshin
  * 16 October 2015
@@ -30,6 +32,7 @@ public class TelegramBot implements TelegramAware {
     private final TelegramBotClient api;
     private final FileApi fileApi;
     private final UpdatesHandler updatesHandler;
+    private final RequestPreprocessor requestPreprocessor;
 
     public TelegramBot(String botToken) {
         this(new Builder(botToken));
@@ -40,14 +43,17 @@ public TelegramBot(String botToken) {
         this.api = builder.api;
         this.fileApi = builder.fileApi;
         this.updatesHandler = builder.updatesHandler;
+        this.requestPreprocessor = builder.requestPreprocessor;
     }
 
     @NotNull
     public <T extends BaseRequest<T, R>, R extends BaseResponse> R execute(@NotNull BaseRequest<T, R> request) {
+        requestPreprocessor.process(request);
         return api.send(request);
     }
 
     public <T extends BaseRequest<T, R>, R extends BaseResponse> Cancellable execute(T request, Callback<T, R> callback) {
+        requestPreprocessor.process(request);
         return api.send(request, callback);
     }
 
@@ -100,6 +106,7 @@ public static final class Builder {
         private FileApi fileApi;
         private TelegramBotClient api;
         private UpdatesHandler updatesHandler;
+        private RequestPreprocessor requestPreprocessor;
 
         private OkHttpClient okHttpClient;
         private String apiUrl;
@@ -111,6 +118,7 @@ public Builder(String botToken) {
             api = new TelegramBotClient(client(null), gson(), apiUrl(API_URL, botToken, useTestServer));
             fileApi = new FileApi(botToken);
             updatesHandler = new UpdatesHandler(100);
+            requestPreprocessor = getEmptyRequestPreprocessor();
         }
 
         public Builder debug() {
@@ -143,6 +151,11 @@ public Builder useTestServer(boolean useTestServer) {
             return this;
         }
 
+        public Builder requestPreprocessor(RequestPreprocessor requestPreprocessor) {
+            this.requestPreprocessor = requestPreprocessor;
+            return this;
+        }
+
         public TelegramBot build() {
             if (okHttpClient != null || apiUrl != null) {
                 OkHttpClient client = okHttpClient != null ? okHttpClient : client(null);