Proxy setup

In some locations Telegram Bots API urls will be unavailable. In this case all examples will just throw exception like:

Exception in thread "main" java.net.ConnectException: Connection refused
    at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
    at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
    at io.ktor.network.sockets.SocketImpl.connect$ktor_network(SocketImpl.kt:36)
    at io.ktor.network.sockets.SocketImpl$connect$1.invokeSuspend(SocketImpl.kt)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
    at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:56)
    at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:571)
    at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:738)
    at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:678)
    at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:665)

Process finished with exit code 1

There are several ways to solve this problem:

• Built-in proxy config (will require some socks or http proxy server)
• System-configured VPN or proxy
• Your own Bot API Server

Using Ktor Client built-in proxy

First of all, you will need to use one more library:

build.gradle:

implementation "io.ktor:ktor-client-okhttp:2.3.5"

Dependency note

In the snippet above was used version 2.3.5 which is actual for TelegramBotAPI at the moment of filling this documentation (october 11 2023, TelegramBotAPI version 9.2.2) and you can update version of this dependency in case if it is outdated.

For configuring proxy for your bot inside your program, you can use next snippet:

val botToken = "HERE MUST BE YOUR TOKEN" // (1)
val bot = telegramBot(botToken) { // (2)
    client = HttpClient(OkHttp) { // (3)
        engine { // (4)
            config { // (5)
                proxy( // (6)
                    Proxy( // (7)
                        Proxy.Type.SOCKS, // (8)
                        InetSocketAddress("127.0.0.1", 1080) // (9)
                    )
                )
            }
        }
    }
}

1. Here we are just creating variable botToken
2. Start creating bot
3. Setting HttpClient of our bot. On the time of documentation filling, OkHttp is one of the engines in Ktor system which supports socks proxy. More you can read on Ktor site in subparts about engines and proxy
4. Start setting up of HttpClient engine
5. Start setting up of HttpClient engine configuration
6. Start setting up of proxy
7. Creating proxy info object
8. Saying that it is Socks proxy
9. Creating address. Note that "127.0.0.1" and 1080 are configurable parameters

More complex and flexible variant

You may try to use custom engine for ktor. For example:

// JVM
// OkHttp engine
// Socks5 proxy

val bot = telegramBot(botToken) { // (1)
    val proxyHost = "your proxy host" // (2)
    val proxyPort = 1080 //your proxy port // (3)
    val username = "proxy username" // (4)
    val password = "proxy password" // (5)

    val proxyAddr = InetSocketAddress(proxyHost, proxyPort) // (6)
    val proxy = Proxy(Proxy.Type.SOCKS, proxyAddr) // (7)

    val passwordAuthentication = PasswordAuthentication(
        username,
        password.toCharArray()
    ) // (8)
    Authenticator.setDefault(object : Authenticator() { // (9)
        override fun getPasswordAuthentication(): PasswordAuthentication? { // (10)
            return if (requestingHost.lowercase() == proxyHost.lowercase()) { // (11)
                passwordAuthentication
            } else {
                null
            }
        }
    })
    this.client = HttpClient(OkHttp) { // (12)
        engine { // (13)
            config { // (14)
                proxy(proxy) // (15)
            }
        }
    }
}

1. Start creating telegram bot
2. Proxy host
3. Proxy port
4. Username for authentication. It is optional in case your proxy do not need auth
5. Password for authentication. It is optional in case your proxy do not need auth
6. Creating of proxy address for Proxy
7. Proxy address and type information
8. Proxy authentication info. It is optional in case your proxy do not need auth
9. Setting up of authenticator. It is optional in case your proxy do not need auth
10. Overriding of method that will return authentication info
11. In case when request has been sent to the proxy (common request) - using authentication
12. Creating of HttpClient and start configure it
13. Start setup engine
14. Start setup engine config
15. Setting up of proxy information

Next steps

• First bot