complete forwarder bot exmple

ForwarderBot/build.gradle

@@ -0,0 +1,38 @@
+buildscript {
+    repositories {
+        mavenLocal()
+        jcenter()
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+        classpath "org.jetbrains.kotlin:kotlin-serialization:$kotlin_version"
+    }
+}
+
+plugins {
+    id "org.jetbrains.kotlin.plugin.serialization" version "$kotlin_version"
+}
+
+apply plugin: 'kotlin'
+apply plugin: 'application'
+
+project.version = "0.1.0"
+project.group = "com.insanusmokrassar"
+
+mainClassName="com.insanusmokrassar.examples.ForwarderBotKt.main"
+
+repositories {
+    mavenLocal()
+    jcenter()
+    mavenCentral()
+}
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlin_coroutines_version"
+
+    implementation "com.github.insanusmokrassar:TelegramBotAPI:$telegram_bot_api_version"
+    implementation "com.github.insanusmokrassar:TelegramBotAPI-extensions-api:$telegram_bot_api_version"
+}

ForwarderBot/src/main/kotlin/com/insanusmokrassar/examples/ForwarderBot.kt

@@ -0,0 +1,50 @@
+package com.insanusmokrassar.examples
+
+import com.github.insanusmokrassar.TelegramBotAPI.bot.Ktor.KtorRequestsExecutor
+import com.github.insanusmokrassar.TelegramBotAPI.extensions.api.send.sendTextMessage
+import com.github.insanusmokrassar.TelegramBotAPI.types.ParseMode.MarkdownV2
+import com.github.insanusmokrassar.TelegramBotAPI.types.message.*
+import com.github.insanusmokrassar.TelegramBotAPI.types.message.abstracts.PossiblyForwardedMessage
+import com.github.insanusmokrassar.TelegramBotAPI.types.update.abstracts.BaseMessageUpdate
+import com.github.insanusmokrassar.TelegramBotAPI.utils.TelegramAPIUrlsKeeper
+import com.github.insanusmokrassar.TelegramBotAPI.utils.extensions.UpdateReceiver
+import com.github.insanusmokrassar.TelegramBotAPI.utils.extensions.startGettingOfUpdates
+import kotlinx.coroutines.*
+
+/**
+ * This bot will always return message about forwarder. In cases when sent message was not a forward message it will
+ * send suitable message
+ */
+suspend fun main(args: Array<String>) {
+    val botToken = args.first()
+
+    val bot = KtorRequestsExecutor(TelegramAPIUrlsKeeper(botToken))
+
+    val scope = CoroutineScope(Dispatchers.Default)
+
+    val callback: UpdateReceiver<BaseMessageUpdate> = { messageUpdate ->
+        val message = messageUpdate.data
+        val infoToSend = if (message is PossiblyForwardedMessage) {
+            val forwardInfo = message.forwardInfo
+            when (forwardInfo) {
+                null -> "There is no forward info"
+                is AnonymousForwardInfo -> "Anonymous user which signed as \"${forwardInfo.senderName}\""
+                is UserForwardInfo -> forwardInfo.from.let { user ->
+                    "User `${user.id.chatId}` (`${user.firstName} ${user.lastName}`: ${user.username ?.username ?: "Without username"})"
+                }
+                is ForwardFromChannelInfo -> "Channel (${forwardInfo.channelChat})"
+            }
+        } else {
+            "There is no forward info"
+        }
+        bot.sendTextMessage(message.chat, infoToSend, MarkdownV2)
+    }
+
+    bot.startGettingOfUpdates(
+        messageCallback = callback,
+        channelPostCallback = callback,
+        scope = scope
+    )
+
+    scope.coroutineContext[Job]!!.join()
+}